WorldWideScience

Sample records for dot nanoparticle cellular

  1. Dynamics and mechanisms of quantum dot nanoparticle cellular uptake

    Directory of Open Access Journals (Sweden)

    Telford William G

    2010-06-01

    Full Text Available Abstract Background The rapid growth of the nanotechnology industry and the wide application of various nanomaterials have raised concerns over their impact on the environment and human health. Yet little is known about the mechanism of cellular uptake and cytotoxicity of nanoparticles. An array of nanomaterials has recently been introduced into cancer research promising for remarkable improvements in diagnosis and treatment of the disease. Among them, quantum dots (QDs distinguish themselves in offering many intrinsic photophysical properties that are desirable for targeted imaging and drug delivery. Results We explored the kinetics and mechanism of cellular uptake of QDs with different surface coatings in two human mammary cells. Using fluorescence microscopy and laser scanning cytometry (LSC, we found that both MCF-7 and MCF-10A cells internalized large amount of QD655-COOH, but the percentage of endocytosing cells is slightly higher in MCF-7 cell line than in MCF-10A cell line. Live cell fluorescent imaging showed that QD cellular uptake increases with time over 40 h of incubation. Staining cells with dyes specific to various intracellular organelles indicated that QDs were localized in lysosomes. Transmission electron microscopy (TEM images suggested a potential pathway for QD cellular uptake mechanism involving three major stages: endocytosis, sequestration in early endosomes, and translocation to later endosomes or lysosomes. No cytotoxicity was observed in cells incubated with 0.8 nM of QDs for a period of 72 h. Conclusions The findings presented here provide information on the mechanism of QD endocytosis that could be exploited to reduce non-specific targeting, thereby improving specific targeting of QDs in cancer diagnosis and treatment applications. These findings are also important in understanding the cytotoxicity of nanomaterials and in emphasizing the importance of strict environmental control of nanoparticles.

  2. Nanogel-quantum dot hybrid nanoparticles for live cell imaging

    International Nuclear Information System (INIS)

    Hasegawa, Urara; Nomura, Shin-ichiro M.; Kaul, Sunil C.; Hirano, Takashi; Akiyoshi, Kazunari

    2005-01-01

    We report here a novel carrier of quantum dots (QDs) for intracellular labeling. Monodisperse hybrid nanoparticles (38 nm in diameter) of QDs were prepared by simple mixing with nanogels of cholesterol-bearing pullulan (CHP) modified with amino groups (CHPNH 2 ). The CHPNH 2 -QD nanoparticles were effectively internalized into the various human cells examined. The efficiency of cellular uptake was much higher than that of a conventional carrier, cationic liposome. These hybrid nanoparticles could be a promising fluorescent probe for bioimaging

  3. Liposome encapsulation of fluorescent nanoparticles: Quantum dots and silica nanoparticles

    International Nuclear Information System (INIS)

    Chen, C.-S.; Yao Jie; Durst, Richard A.

    2006-01-01

    Quantum dots (QDs) and silica nanoparticles (SNs) are relatively new classes of fluorescent probes that overcome the limitations encountered by organic fluorophores in bioassay and biological imaging applications. We encapsulated QDs and SNs in liposomes and separated nanoparticle-loaded liposomes from unencapsulated nanoparticles by size exclusion chromatography. Fluorescence correlation spectroscopy was used to measure the average number of nanoparticles inside each liposome. Results indicated that nanoparticle-loaded liposomes were formed and separated from unencapsulated nanoparticles by using a Sepharose gel. As expected, fluorescence self-quenching of nanoparticles inside liposomes was not observed. Each liposome encapsulated an average of three QDs. These studies demonstrated that nanoparticles could be successfully encapsulated into liposomes and provided a methodology to quantify the number of nanoparticles inside each liposome by fluorescence correlation spectroscopy

  4. Quadra-Quantum Dots and Related Patterns of Quantum Dot Molecules: Basic Nanostructures for Quantum Dot Cellular Automata Application

    Directory of Open Access Journals (Sweden)

    Somsak Panyakeow

    2010-10-01

    Full Text Available Laterally close-packed quantum dots (QDs called quantum dot molecules (QDMs are grown by modified molecular beam epitaxy (MBE. Quantum dots could be aligned and cross hatched. Quantum rings (QRs created from quantum dot transformation during thin or partial capping are used as templates for the formations of bi-quantum dot molecules (Bi-QDMs and quantum dot rings (QDRs. Preferable quantum dot nanostructure for quantum computation based on quantum dot cellular automata (QCA is laterally close-packed quantum dot molecules having four quantum dots at the corners of square configuration. These four quantum dot sets are called quadra-quantum dots (QQDs. Aligned quadra-quantum dots with two electron confinements work like a wire for digital information transmission by Coulomb repulsion force, which is fast and consumes little power. Combination of quadra-quantum dots in line and their cross-over works as logic gates and memory bits. Molecular Beam Epitaxial growth technique called 'Droplet Epitaxy' has been developed for several quantum nanostructures such as quantum rings and quantum dot rings. Quantum rings are prepared by using 20 ML In-Ga (15:85 droplets deposited on a GaAs substrate at 390'C with a droplet growth rate of 1ML/s. Arsenic flux (7'8'10-6Torr is then exposed for InGaAs crystallization at 200'C for 5 min. During droplet epitaxy at a high droplet thickness and high temperature, out-diffusion from the centre of droplets occurs under anisotropic strain. This leads to quantum ring structures having non-uniform ring stripes and deep square-shaped nanoholes. Using these peculiar quantum rings as templates, four quantum dots situated at the corners of a square shape are regrown. Two of these four quantum dots are aligned either or, which are preferable crystallographic directions of quantum dot alignment in general.

  5. Design of Efficient Mirror Adder in Quantum- Dot Cellular Automata

    Science.gov (United States)

    Mishra, Prashant Kumar; Chattopadhyay, Manju K.

    2018-03-01

    Lower power consumption is an essential demand for portable multimedia system using digital signal processing algorithms and architectures. Quantum dot cellular automata (QCA) is a rising nano technology for the development of high performance ultra-dense low power digital circuits. QCA based several efficient binary and decimal arithmetic circuits are implemented, however important improvements are still possible. This paper demonstrate Mirror Adder circuit design in QCA. We present comparative study of mirror adder cells designed using conventional CMOS technique and mirror adder cells designed using quantum-dot cellular automata. QCA based mirror adders are better in terms of area by order of three.

  6. Neurotransmitter Specific, Cellular-Resolution Functional Brain Mapping Using Receptor Coated Nanoparticles: Assessment of the Possibility

    Science.gov (United States)

    Forati, Ebrahim; Sabouni, Abas; Ray, Supriyo; Head, Brian; Schoen, Christian; Sievenpiper, Dan

    2015-01-01

    Receptor coated resonant nanoparticles and quantum dots are proposed to provide a cellular-level resolution image of neural activities inside the brain. The functionalized nanoparticles and quantum dots in this approach will selectively bind to different neurotransmitters in the extra-synaptic regions of neurons. This allows us to detect neural activities in real time by monitoring the nanoparticles and quantum dots optically. Gold nanoparticles (GNPs) with two different geometries (sphere and rod) and quantum dots (QDs) with different sizes were studied along with three different neurotransmitters: dopamine, gamma-Aminobutyric acid (GABA), and glycine. The absorption/emission spectra of GNPs and QDs before and after binding of neurotransmitters and their corresponding receptors are reported. The results using QDs and nanorods with diameter 25nm and aspect rations larger than three were promising for the development of the proposed functional brain mapping approach. PMID:26717196

  7. Cellular membrane trafficking of mesoporous silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Fang, I-Ju [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    This dissertation mainly focuses on the investigation of the cellular membrane trafficking of mesoporous silica nanoparticles. We are interested in the study of endocytosis and exocytosis behaviors of mesoporous silica nanoparticles with desired surface functionality. The relationship between mesoporous silica nanoparticles and membrane trafficking of cells, either cancerous cells or normal cells was examined. Since mesoporous silica nanoparticles were applied in many drug delivery cases, the endocytotic efficiency of mesoporous silica nanoparticles needs to be investigated in more details in order to design the cellular drug delivery system in the controlled way. It is well known that cells can engulf some molecules outside of the cells through a receptor-ligand associated endocytosis. We are interested to determine if those biomolecules binding to cell surface receptors can be utilized on mesoporous silica nanoparticle materials to improve the uptake efficiency or govern the mechanism of endocytosis of mesoporous silica nanoparticles. Arginine-glycine-aspartate (RGD) is a small peptide recognized by cell integrin receptors and it was reported that avidin internalization was highly promoted by tumor lectin. Both RGD and avidin were linked to the surface of mesoporous silica nanoparticle materials to investigate the effect of receptor-associated biomolecule on cellular endocytosis efficiency. The effect of ligand types, ligand conformation and ligand density were discussed in Chapter 2 and 3. Furthermore, the exocytosis of mesoporous silica nanoparticles is very attractive for biological applications. The cellular protein sequestration study of mesoporous silica nanoparticles was examined for further information of the intracellular pathway of endocytosed mesoporous silica nanoparticle materials. The surface functionality of mesoporous silica nanoparticle materials demonstrated selectivity among the materials and cancer and normal cell lines. We aimed to determine

  8. Two Novel Quantum-Dot Cellular Automata Full Adders

    Directory of Open Access Journals (Sweden)

    Mahdie Qanbari

    2013-01-01

    Full Text Available Quantum-dot cellular automata (QCA is an efficient technology to create computing devices. QCA is a suitable candidate for the next generation of digital systems. Full adders are the main member of computational systems because other operations can be implemented by adders. In this paper, two QCA full adders are introduced. The first one is implemented in one layer, and the second one is implemented in three layers. Five-input majority gate is used in both of them. These full adders are better than pervious designs in terms of area, delay, and complexity.

  9. Quantum dot nanoparticle conjugation, characterization, and applications in neuroscience

    Science.gov (United States)

    Pathak, Smita

    Quantum dot are semiconducting nanoparticles that have been used for decades in a variety of applications such as solar cells, LEDs and medical imaging. Their use in the last area, however, has been extremely limited despite their potential as revolutionary new biological labeling tools. Quantum dots are much brighter and more stable than conventional fluorophores, making them optimal for high resolution imaging and long term studies. Prior work in this area involves synthesizing and chemically conjugating quantum dots to molecules of interest in-house. However this method is both time consuming and prone to human error. Additionally, non-specific binding and nanoparticle aggregation currently prevent researchers from utilizing this system to its fullest capacity. Another critical issue that has not been addressed is determining the number of ligands bound to nanoparticles, which is crucial for proper interpretation of results. In this work, methods to label fixed cells using two types of chemically modified quantum dots are studied. Reproducible non-specific artifact labeling is consistently demonstrated if antibody-quantum dot conditions are less than optimal. In order to explain this, antibodies bound to quantum dots were characterized and quantified. While other groups have qualitatively characterized antibody functionalized quantum dots using TEM, AFM, UV spectroscopy and gel electrophoresis, and in some cases have reported calculated estimates of the putative number of total antibodies bound to quantum dots, no quantitative experimental results had been reported prior to this work. The chemical functionalization and characterization of quantum dot nanocrystals achieved in this work elucidates binding mechanisms of ligands to nanoparticles and allows researchers to not only translate our tools to studies in their own areas of interest but also derive quantitative results from these studies. This research brings ease of use and increased reliability to

  10. Enhanced intratumoral uptake of quantum dots concealed within hydrogel nanoparticles

    International Nuclear Information System (INIS)

    Nair, Ashwin; Shen Jinhui; Thevenot, Paul; Zou Ling; Tang Liping; Cai Tong; Hu Zhibing

    2008-01-01

    Effective nanomedical devices for tumor imaging and drug delivery are not yet available. In an attempt to construct a more functional device for tumor imaging, we have embedded quantum dots (which have poor circulatory behavior) within hydrogel nanoparticles made of poly-N-isopropylacrylamide. We found that the hydrogel encapsulated quantum dots are more readily taken up by cultured tumor cells. Furthermore, in a melanoma model, hydrogel encapsulated quantum dots also preferentially accumulate in the tumor tissue compared with normal tissue and have ∼16-fold greater intratumoral uptake compared to non-derivatized quantum dots. Our results suggest that these derivatized quantum dots, which have greatly improved tumor localization, may enhance cancer monitoring and chemotherapy.

  11. Reversible Flip-Flops in Quantum-Dot Cellular Automata

    Science.gov (United States)

    Rad, Samaneh Kazemi; Heikalabad, Saeed Rasouli

    2017-09-01

    Quantum-dot cellular automata is a new technology to design the efficient combinational and sequential circuits at the nano-scale. This technology has many desirable advantages compared to the CMOS technology such as low power consumption, less occupation area and low latency. These features make it suitable for use in flip-flop design. In this paper, with knowing the characteristics of reversible logic, we design new structures for flip-flops. The operations of these structures are evaluated with QCADesigner Version 2.0.3 simulator. In addition, we calculate the power dissipation of these structures by QCAPro tool. The results illustrated that proposed structures are efficient compared to the previous ones.

  12. Universal shift register implementation using quantum dot cellular automata

    Directory of Open Access Journals (Sweden)

    Tamoghna Purkayastha

    2018-06-01

    Full Text Available Quantum-dot Cellular Automata (QCA demands to be a promising alternative of CMOS in ultra large scale circuit integration. Arithmetic and logic unit designs using QCA are of high research interest. A layout of four and eight bit universal shift register (USR has been proposed. Initially QCA layouts of D flip-flop with clear and 4 to 1 multiplexer are designed, which are extended to design 4 and 8-bit parallel in parallel out (PIPO shift register. Finally the PIPO is utilized to design 4-bit and 8-bit USR. By the comparative analysis it is observed that the proposed D Flip-flop achieved 40% clock delay improvement, whereas the modified layout of 4 to 1 multiplexer achieved 30% cell count reduction and 17% clock delay reduction from the previous works. This results in 31% reduction in cell count, 45% reduction in area and 55% reduction in clock cycle delay in 8 bit USR layout.

  13. Quantum dot multiplexing for the profiling of cellular receptors

    Science.gov (United States)

    Lee-Montiel, Felipe T.; Li, Peter; Imoukhuede, P. I.

    2015-11-01

    The profiling of cellular heterogeneity has wide-reaching importance for our understanding of how cells function and react to their environments in healthy and diseased states. Our ability to interpret and model cell behavior has been limited by the difficulties of measuring cell differences, for example, comparing tumor and non-tumor cells, particularly at the individual cell level. This demonstrates a clear need for a generalizable approach to profile fluorophore sites on cells or molecular assemblies on beads. Here, a multiplex immunoassay for simultaneous detection of five different angiogenic markers was developed. We targeted angiogenic receptors in the vascular endothelial growth factor family (VEGFR1, VEGFR2 and VEGFR3) and Neuropilin (NRP) family (NRP1 and NRP2), using multicolor quantum dots (Qdots). Copper-free click based chemistry was used to conjugate the monoclonal antibodies with 525, 565, 605, 655 and 705 nm CdSe/ZnS Qdots. We tested and performed colocalization analysis of our nanoprobes using the Pearson correlation coefficient statistical analysis. Human umbilical vein endothelial cells (HUVEC) were tested. The ability to easily monitor the molecular indicators of angiogenesis that are a precursor to cancer in a fast and cost effective system is an important step towards personalized nanomedicine.The profiling of cellular heterogeneity has wide-reaching importance for our understanding of how cells function and react to their environments in healthy and diseased states. Our ability to interpret and model cell behavior has been limited by the difficulties of measuring cell differences, for example, comparing tumor and non-tumor cells, particularly at the individual cell level. This demonstrates a clear need for a generalizable approach to profile fluorophore sites on cells or molecular assemblies on beads. Here, a multiplex immunoassay for simultaneous detection of five different angiogenic markers was developed. We targeted angiogenic receptors

  14. Design of arithmetic circuits in quantum dot cellular automata nanotechnology

    CERN Document Server

    Sridharan, K

    2015-01-01

    This research monograph focuses on the design of arithmetic circuits in Quantum Dot Cellular Automata (QCA). Using the fact that the 3-input majority gate is a primitive in QCA, the book sets out to discover hitherto unknown properties of majority logic in the context of arithmetic circuit designs. The pursuit for efficient adders in QCA takes two forms. One involves application of the new results in majority logic to existing adders. The second involves development of a custom adder for QCA technology. A QCA adder named as hybrid adder is proposed and it is shown that it outperforms existing multi-bit adders with respect to area and delay. The work is extended to the design of a low-complexity multiplier for signed numbers in QCA. Furthermore the book explores two aspects unique to QCA technology, namely thermal robustness and the role of interconnects. In addition, the book introduces the reader to QCA layout design and simulation using QCADesigner. Features & Benefits: This research-based book: ·  �...

  15. Evaluation of cellular influences caused by calcium carbonate nanoparticles.

    Science.gov (United States)

    Horie, Masanori; Nishio, Keiko; Kato, Haruhisa; Endoh, Shigehisa; Fujita, Katsuhide; Nakamura, Ayako; Kinugasa, Shinichi; Hagihara, Yoshihisa; Yoshida, Yasukazu; Iwahashi, Hitoshi

    2014-03-05

    The cellular effects of calcium carbonate (CaCO₃) nanoparticles were evaluated. Three kinds of CaCO₃ nanoparticles were employed in our examinations. One of the types of CaCO₃ nanoparticles was highly soluble. And solubility of another type of CaCO₃ nanoparticle was lower. A stable CaCO₃ nanoparticle medium dispersion was prepared and applied to human lung carcinoma A549 cells and human keratinocyte HaCaT cells. Then, mitochondrial activity, cell membrane damage, colony formation ability, DNA injury, induction of oxidative stress, and apoptosis were evaluated. Although the influences of CaCO₃ nanoparticles on mitochondrial activity and cell membrane damage were small, "soluble" CaCO₃ nanoparticles exerted some cellular influences. Soluble CaCO₃ nanoparticles also induced a cell morphological change. Colony formation was inhibited by CaCO₃ nanoparticle exposure. In particular, soluble CaCO₃ nanoparticles completely inhibited colony formation. The influence on intracellular the reactive oxygen species (ROS) level was small. Soluble CaCO₃ nanoparticles caused an increase in C/EBP-homologous protein (CHOP) expression and the activation of caspase-3. Moreover, CaCO₃ exposure increased intracellular the Ca²⁺ level and activated calpain. These results suggest that cellular the influences of CaCO₃ nanoparticles are mainly caused by intracellular calcium release and subsequently disrupt the effect of calcium signaling. In conclusion, there is possibility that soluble CaCO₃ nanoparticles induce cellular influences such as a cell morphological change. Cellular influence of CaCO₃ nanoparticles is caused by intracellular calcium release. If inhaled CaCO₃ nanoparticles have the potential to influence cellular events. However, the effect might be not severe because calcium is omnipresent element in cell. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  16. Increased cellular uptake of peptide-modified PEGylated gold nanoparticles.

    Science.gov (United States)

    He, Bo; Yang, Dan; Qin, Mengmeng; Zhang, Yuan; He, Bing; Dai, Wenbing; Wang, Xueqing; Zhang, Qiang; Zhang, Hua; Yin, Changcheng

    2017-12-09

    Gold nanoparticles are promising drug delivery vehicles for nucleic acids, small molecules, and proteins, allowing various modifications on the particle surface. However, the instability and low bioavailability of gold nanoparticles compromise their clinical application. Here, we functionalized gold nanoparticles with CPP fragments (CALNNPFVYLI, CALRRRRRRRR) through sulfhydryl PEG to increase their stability and bioavailability. The resulting gold nanoparticles were characterized with transmission electron microscopy (TEM), dynamic light scattering (DLS), UV-visible spectrometry and X-ray photoelectron spectroscopy (XPS), and the stability in biological solutions was evaluated. Comparing to PEGylated gold nanoparticles, CPP (CALNNPFVYLI, CALRRRRRRRR)-modified gold nanoparticles showed 46 folds increase in cellular uptake in A549 and B16 cell lines, as evidenced by the inductively coupled plasma atomic emission spectroscopy (ICP-AES). The interactions between gold nanoparticles and liposomes indicated CPP-modified gold nanoparticles bind to cell membrane more effectively than PEGylated gold nanoparticles. Surface plasmon resonance (SPR) was used to measure interactions between nanoparticles and the membrane. TEM and uptake inhibitor experiments indicated that the cellular entry of gold nanoparticles was mediated by clathrin and macropinocytosis. Other energy independent endocytosis pathways were also identified. Our work revealed a new strategy to modify gold nanoparticles with CPP and illustrated the cellular uptake pathway of CPP-modified gold nanoparticles. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. A comparative analysis of electronic and molecular quantum dot cellular automata

    International Nuclear Information System (INIS)

    Umamahesvari, H.; Ajitha, D.

    2015-01-01

    This paper presents a comparative analysis of electronic quantum-dot cellular automata (EQCA) and Magnetic quantum dot Cellular Automata (MQCA). QCA is a computing paradigm that encodes and processes information by the position of individual electrons. To enhance the high dense and ultra-low power devices, various researches have been actively carried out to find an alternative way to continue and follow Moore’s law, so called “beyond CMOS technology”. There have been several proposals for physically implementing QCA, EQCA and MQCA are the two important QCAs reported so far. This paper provides a comparative study on these two QCAs

  18. Cellular Stress Response to Engineered Nanoparticles: Effect of Size, Surface Coating, and Cellular Uptake

    Science.gov (United States)

    CELLULAR STRESS RESPONSE TO ENGINEERED NANOPARTICLES: EFFECT OF SIZE, SURFACE COATING, AND CELLULAR UPTAKE RY Prasad 1, JK McGee2, MG Killius1 D Ackerman2, CF Blackman2 DM DeMarini2 , SO Simmons2 1 Student Services Contractor, US EPA, RTP, NC 2 US EPA, RTP, NC The num...

  19. Energy dissipation dataset for reversible logic gates in quantum dot-cellular automata.

    Science.gov (United States)

    Bahar, Ali Newaz; Rahman, Mohammad Maksudur; Nahid, Nur Mohammad; Hassan, Md Kamrul

    2017-02-01

    This paper presents an energy dissipation dataset of different reversible logic gates in quantum-dot cellular automata. The proposed circuits have been designed and verified using QCADesigner simulator. Besides, the energy dissipation has been calculated under three different tunneling energy level at temperature T =2 K. For estimating the energy dissipation of proposed gates; QCAPro tool has been employed.

  20. Biological cellular response to carbon nanoparticle toxicity

    International Nuclear Information System (INIS)

    Panessa-Warren, B J; Warren, J B; Wong, S S; Misewich, J A

    2006-01-01

    Recent advances in nanotechnology have increased the development and production of many new nanomaterials with unique characteristics for industrial and biomedical uses. The size of these new nanoparticles (<100 nm) with their high surface area and unusual surface chemistry and reactivity poses unique problems for biological cells and the environment. This paper reviews the current research on the reactivity and interactions of carbon nanoparticles with biological cells in vivo and in vitro, with ultrastructural images demonstrating evidence of human cell cytotoxicity to carbon nanoparticles characteristic of lipid membrane peroxidation, gene down regulation of adhesive proteins, and increased cell death (necrosis, apoptosis), as well as images of nontoxic carbon nanoparticle interactions with human cells. Although it is imperative that nanomaterials be systematically tested for their biocompatibility and safety for industrial and biomedical use, there are now ways to develop and redesign these materials to be less cytotoxic, and even benign to cell systems. With this new opportunity to utilize the unique properties of nanoparticles for research, industry and medicine, there is a responsibility to test and optimize these new nanomaterials early during the development process, to eliminate or ameliorate identified toxic characteristics

  1. Nanoparticle Surface Functionality Dictates Cellular and Systemic Toxicity

    DEFF Research Database (Denmark)

    Saei, Amir Ata; Yazdani, Mahdieh; Lohse, Samuel E.

    2017-01-01

    can greatly enhance subsequent therapeutic effects of NPs while diminishing their adverse side effects. In this review, we will focus on the effect of surface functionality on the cellular uptake and the transport of NPs by various subcellular processes.......Engineered nanoparticles (NPs) have opened new frontiers in therapeutics and diagnostics in recent years. The surface functionality of these nanoparticles often predominates their interactions with various biological components of human body, and proper selection or control of surface functionality...

  2. Cellular interactions of lauric acid and dextran-coated magnetite nanoparticles

    International Nuclear Information System (INIS)

    Pradhan, Pallab; Giri, Jyotsnendu; Banerjee, Rinti; Bellare, Jayesh; Bahadur, Dhirendra

    2007-01-01

    In vitro cytocompatibility and cellular interactions of lauric acid and dextran-coated magnetite nanoparticles were evaluated with two different cell lines (mouse fibroblast and human cervical carcinoma). Lauric acid-coated magnetite nanoparticles were less cytocompatible than dextran-coated magnetite nanoparticles and cellular uptake of lauric acid-coated magnetic nanoparticles was more than that of dextran-coated magnetite nanoparticles. Lesser cytocompatibility and higher uptake of lauric acid-coated magnetite nanoparticles as compared to dextran-coated magnetic nanoparticles may be due to different cellular interactions by coating material. Thus, coating plays an important role in modulation of biocompatibility and cellular interaction of magnetic nanoparticles

  3. Semiconductor quantum dots as fluorescent probes for in vitro and in vivo bio-molecular and cellular imaging

    Directory of Open Access Journals (Sweden)

    Sarwat B. Rizvi

    2010-08-01

    Full Text Available Over the years, biological imaging has seen many advances, allowing scientists to unfold many of the mysteries surrounding biological processes. The ideal imaging resolution would be in nanometres, as most biological processes occur at this scale. Nanotechnology has made this possible with functionalised nanoparticles that can bind to specific targets and trace processes at the cellular and molecular level. Quantum dots (QDs or semiconductor nanocrystals are luminescent particles that have the potential to be the next generation fluorophores. This paper is an overview of the basics of QDs and their role as fluorescent probes for various biological imaging applications. Their potential clinical applications and the limitations that need to be overcome have also been discussed.

  4. Cellular uptake and radiosensitization of SR-2508 loaded PLGA nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jin Cheng [Fourth Military Medical University, Department of Radiation Medicine (China); Bai Ling [Xi' an Gaoxin Hospital, Department of Clinical Laboratories (China); Wu Hong [Fourth Military Medical University, Department of Pharmacy (China); Teng Zenghui [Fourth Military Medical University, Department of Pharmacology (China); Guo Guozhen, E-mail: guozhengg@tom.co [Fourth Military Medical University, Department of Radiation Medicine (China); Chen Jingyuan, E-mail: jy_chen@fmmu.edu.c [Fourth Military Medical University, Department of Occupational and Environmental Health (China)

    2008-08-15

    SR-2508 (etanidazole), a hypoxic radiosensitizer, has potential applications in radiotherapy. The poly(d,l-lactide-co-glycolide)(PLGA) nanoparticles containing SR-2508 were prepared by w/o/w emulsification-solvent evaporation method. The physicochemical characteristics of the nanoparticles (i.e. encapsulation efficiency, particle size distribution, morphology, in vitro release) were studied. The cellular uptake of the nanoparticles for the two human tumor cell lines: human breast carcinoma cells (MCF-7) and human carcinoma cervices cells (HeLa), was evaluated by fluorescence microscopy and transmission electronic microscopy. Cell viability was measured by the ability of single cell to form colonies in vitro. The prepared nanoparticles were spherical in shape with size between 90 nm and 190 nm. The encapsulation efficiency was 20.06%. The drug release pattern exhibited an initial burst followed by a plateau for over 24 h. The cellular uptake of nanoparticles was observed. Co-culture of MCF-7 and HeLa cells with SR-2508 loaded nanoparticles showed that released SR-2508 retained its bioactivity and effectively sensitized two hypoxic tumor cell lines to radiation. The radiosensitization of SR-2508 loaded nanoparticles was more significant than that of free drug.

  5. Cellular uptake and radiosensitization of SR-2508 loaded PLGA nanoparticles

    International Nuclear Information System (INIS)

    Jin Cheng; Bai Ling; Wu Hong; Teng Zenghui; Guo Guozhen; Chen Jingyuan

    2008-01-01

    SR-2508 (etanidazole), a hypoxic radiosensitizer, has potential applications in radiotherapy. The poly(d,l-lactide-co-glycolide)(PLGA) nanoparticles containing SR-2508 were prepared by w/o/w emulsification-solvent evaporation method. The physicochemical characteristics of the nanoparticles (i.e. encapsulation efficiency, particle size distribution, morphology, in vitro release) were studied. The cellular uptake of the nanoparticles for the two human tumor cell lines: human breast carcinoma cells (MCF-7) and human carcinoma cervices cells (HeLa), was evaluated by fluorescence microscopy and transmission electronic microscopy. Cell viability was measured by the ability of single cell to form colonies in vitro. The prepared nanoparticles were spherical in shape with size between 90 nm and 190 nm. The encapsulation efficiency was 20.06%. The drug release pattern exhibited an initial burst followed by a plateau for over 24 h. The cellular uptake of nanoparticles was observed. Co-culture of MCF-7 and HeLa cells with SR-2508 loaded nanoparticles showed that released SR-2508 retained its bioactivity and effectively sensitized two hypoxic tumor cell lines to radiation. The radiosensitization of SR-2508 loaded nanoparticles was more significant than that of free drug.

  6. Nanotoxicity assessment of quantum dots: from cellular to primate studies.

    Science.gov (United States)

    Yong, Ken-Tye; Law, Wing-Cheung; Hu, Rui; Ye, Ling; Liu, Liwei; Swihart, Mark T; Prasad, Paras N

    2013-02-07

    Tremendous research efforts have been devoted to fabricating high quality quantum dots (QDs) for applications in biology and medicine. Much of this research was pursued with an ultimate goal of using QDs in clinical applications. However, a great deal of concern has been voiced about the potential hazards of QDs due to their heavy-metal content. Many studies have demonstrated toxicity of various QDs in cell culture studies. However, in a smaller number of studies using small animal models (mice and rats), no abnormal behaviour or tissue damage was noticed over periods of months after the systemic administration of QDs. Nevertheless, the correlation of these results with the potential for negative effects of QD on humans remains unclear. Many urgent questions must be answered before the QDs community moves into the clinical research phase. This review provides an overview of the toxicity assessment of QDs, ranging from cell culture studies to animal models and discusses their findings. Guidelines for using various nonhuman primate models for QD toxicity studies are highlighted. This review article is intended to promote the awareness of current developments of QD applications in biology, the potential toxicity of QDs, and approaches to minimizing toxicity.

  7. Correlative Light- and Electron Microscopy Using Quantum Dot Nanoparticles.

    Science.gov (United States)

    Killingsworth, Murray C; Bobryshev, Yuri V

    2016-08-07

    A method is described whereby quantum dot (QD) nanoparticles can be used for correlative immunocytochemical studies of human pathology tissue using widefield fluorescence light microscopy and transmission electron microscopy (TEM). To demonstrate the protocol we have immunolabeled ultrathin epoxy sections of human somatostatinoma tumor using a primary antibody to somatostatin, followed by a biotinylated secondary antibody and visualization with streptavidin conjugated 585 nm cadmium-selenium (CdSe) quantum dots (QDs). The sections are mounted on a TEM specimen grid then placed on a glass slide for observation by widefield fluorescence light microscopy. Light microscopy reveals 585 nm QD labeling as bright orange fluorescence forming a granular pattern within the tumor cell cytoplasm. At low to mid-range magnification by light microscopy the labeling pattern can be easily recognized and the level of non-specific or background labeling assessed. This is a critical step for subsequent interpretation of the immunolabeling pattern by TEM and evaluation of the morphological context. The same section is then blotted dry and viewed by TEM. QD probes are seen to be attached to amorphous material contained in individual secretory granules. Images are acquired from the same region of interest (ROI) seen by light microscopy for correlative analysis. Corresponding images from each modality may then be blended to overlay fluorescence data on TEM ultrastructure of the corresponding region.

  8. A dynamically reconfigurable logic cell: from artificial neural networks to quantum-dot cellular automata

    Science.gov (United States)

    Naqvi, Syed Rameez; Akram, Tallha; Iqbal, Saba; Haider, Sajjad Ali; Kamran, Muhammad; Muhammad, Nazeer

    2018-02-01

    Considering the lack of optimization support for Quantum-dot Cellular Automata, we propose a dynamically reconfigurable logic cell capable of implementing various logic operations by means of artificial neural networks. The cell can be reconfigured to any 2-input combinational logic gate by altering the strength of connections, called weights and biases. We demonstrate how these cells may appositely be organized to perform multi-bit arithmetic and logic operations. The proposed work is important in that it gives a standard implementation of an 8-bit arithmetic and logic unit for quantum-dot cellular automata with minimal area and latency overhead. We also compare the proposed design with a few existing arithmetic and logic units, and show that it is more area efficient than any equivalent available in literature. Furthermore, the design is adaptable to 16, 32, and 64 bit architectures.

  9. Solving the Ternary Quantum-Dot Cellular Automata Logic Gate Problem by Means of Adiabatic Switching

    Science.gov (United States)

    Pecar, Primoz; Mraz, Miha; Zimic, Nikolaj; Janez, Miha; Lebar Bajec, Iztok

    2008-06-01

    Quantum-dot cellular automata (QCA) are one of the most promising alternative platforms of the future. Recent years have witnessed the development of basic logic structures as well as more complex processing structures, however most in the realm of binary logic. On the grounds that future platforms should not disregard the advantages of multi-valued logic, Lebar Bajec et al. were the first to show that quantum-dot cellular automata can be used for the implementation of ternary logic as well. In their study the ternary AND and OR logic functions proved to be the most troublesome primitive to implement. This research presents a revised solution that is based on adiabatic switching.

  10. Coulomb coupling and the role of symmetries in quantum-dot arrays for cellular automata

    International Nuclear Information System (INIS)

    Ramirez, F.; Cota, E.; Ulloa, S. E.

    2000-01-01

    Using a group-theoretical analysis of the symmetries of a quantum dot array, we investigate the role of defects on the energetics of the system and the resulting charge configurations (or polarization of the cell). We find that for the typical four- or five-element geometries proposed, even small asymmetries introduced by defects in the system, or variations in the local electrostatic environment, can give rise to large effects on the polarization of the ground state and the corresponding low-energy excitations. These shifts are likely to produce important effects in the operation of the cellular automata proposed using these quantum dots. In particular, we find that the sensitivity to polarization changes induced by a driver cell decreases dramatically, and the polarization values are no longer fully defined. These effects would both force the use of stronger driving fields, and may also complicate the dynamical behavior of the cellular automata. (c) 2000 The American Physical Society

  11. Design of Improved Arithmetic Logic Unit in Quantum-Dot Cellular Automata

    Science.gov (United States)

    Heikalabad, Saeed Rasouli; Gadim, Mahya Rahimpour

    2018-06-01

    The quantum-dot cellular automata (QCA) can be replaced to overcome the limitation of CMOS technology. An arithmetic logic unit (ALU) is a basic structure of any computer devices. In this paper, design of improved single-bit arithmetic logic unit in quantum dot cellular automata is presented. The proposed structure for ALU has AND, OR, XOR and ADD operations. A unique 2:1 multiplexer, an ultra-efficient two-input XOR and a low complexity full adder are used in the proposed structure. Also, an extended design of this structure is provided for two-bit ALU in this paper. The proposed structure of ALU is simulated by QCADesigner and simulation result is evaluated. Evaluation results show that the proposed design has best performance in terms of area, complexity and delay compared to the previous designs.

  12. New efficient five-input majority gate for quantum-dot cellular automata

    International Nuclear Information System (INIS)

    Farazkish, Razieh; Navi, Keivan

    2012-01-01

    A novel fault-tolerant five-input majority gate for quantum-dot cellular automata is presented. Quantum-dot cellular automata (QCA) is an emerging technology which is considered to be presented in future computers. Two principle logic elements in QCA are “majority gate” and “inverter.” In this paper, we propose a new approach to the design of fault-tolerant five-input majority gate by considering two-dimensional arrays of QCA cells. We analyze fault tolerance properties of such block five-input majority gate in terms of misalignment, missing, and dislocation cells. Some physical proofs are used for verifying five-input majority gate circuit layout and functionality. Our results clearly demonstrate that the redundant version of the block five-input majority gate is more robust than the standard style for this gate.

  13. Cytotoxicity of metal and semiconductor nanoparticles indicated by cellular micromotility.

    Science.gov (United States)

    Tarantola, Marco; Schneider, David; Sunnick, Eva; Adam, Holger; Pierrat, Sebastien; Rosman, Christina; Breus, Vladimir; Sönnichsen, Carsten; Basché, Thomas; Wegener, Joachim; Janshoff, Andreas

    2009-01-27

    In the growing field of nanotechnology, there is an urgent need to sensitively determine the toxicity of nanoparticles since many technical and medical applications are based on controlled exposure to particles, that is, as contrast agents or for drug delivery. Before the in vivo implementation, in vitro cell experiments are required to achieve a detailed knowledge of toxicity and biodegradation as a function of the nanoparticles' physical and chemical properties. In this study, we show that the micromotility of animal cells as monitored by electrical cell-substrate impedance analysis (ECIS) is highly suitable to quantify in vitro cytotoxicity of semiconductor quantum dots and gold nanorods. The method is validated by conventional cytotoxicity testing and accompanied by fluorescence and dark-field microscopy to visualize changes in the cytoskeleton integrity and to determine the location of the particles within the cell.

  14. Energy dissipation dataset for reversible logic gates in quantum dot-cellular automata

    Directory of Open Access Journals (Sweden)

    Ali Newaz Bahar

    2017-02-01

    Full Text Available This paper presents an energy dissipation dataset of different reversible logic gates in quantum-dot cellular automata. The proposed circuits have been designed and verified using QCADesigner simulator. Besides, the energy dissipation has been calculated under three different tunneling energy level at temperature T=2 K. For estimating the energy dissipation of proposed gates; QCAPro tool has been employed.

  15. Quasi-adiabatic Switching for Metal-Island Quantum-dot Cellular Automata

    OpenAIRE

    Toth, Geza; Lent, Craig S.

    2000-01-01

    Recent experiments have demonstrated a working cell suitable for implementing the Quantum-dot Cellular Automata (QCA) paradigm. These experiments have been performed using metal island clusters. The most promising approach to QCA operation involves quasi-adiabatically switching the cells. This has been analyzed extensively in gated semiconductor cells. Here we present a metal island cell structure that makes quasi-adiabatic switching possible. We show how this permits quasi-adiabatic clocking...

  16. Ultrafast spontaneous emission modulation of graphene quantum dots interacting with Ag nanoparticles in solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jianwei [Department of Physics, Shanghai University, Shanghai 200444 (China); Research Center of Quantum Macro-Phenomenon and Application, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210 (China); Lu, Jian, E-mail: luj@sari.ac.cn; Wang, Zhongyang, E-mail: wangzy@sari.ac.cn [Research Center of Quantum Macro-Phenomenon and Application, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210 (China); Wang, Liang [School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444 (China); Tian, Linfan [Research Center of Quantum Macro-Phenomenon and Application, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210 (China); School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210 (China); Deng, Xingxia [Research Center of Quantum Macro-Phenomenon and Application, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210 (China); School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Tian, Lijun [Department of Physics, Shanghai University, Shanghai 200444 (China); Pan, Dengyu [School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China)

    2016-07-11

    We investigated the strong interaction between graphene quantum dots and silver nanoparticles in solution using time-resolved photoluminescence techniques. In solution, the silver nanoparticles are surrounded by graphene quantum dots and interacted with graphene quantum dots through exciton-plasmon coupling. An ultrafast spontaneous emission process (lifetime 27 ps) was observed in such a mixed solution. This ultrafast lifetime corresponds to the emission rate exceeding 35 GHz, with the purcell enhancement by a factor of ∼12. These experiment results pave the way for the realization of future high speed light sources applications.

  17. An energy and cost efficient majority-based RAM cell in quantum-dot cellular automata

    Directory of Open Access Journals (Sweden)

    Milad Bagherian Khosroshahy

    Full Text Available Nanotechnologies, notably quantum-dot cellular automata, have achieved major attentions for their prominent features as compared to the conventional CMOS circuitry. Quantum-dot cellular automata, particularly owning to its considerable reduction in size, high switching speed and ultra-low energy consumption, is considered as a potential alternative for the CMOS technology. As the memory unit is one of the most essential components in a digital system, designing a well-optimized QCA random access memory (RAM cell is an important area of research. In this paper, a new five-input majority gate is presented which is suitable for implementing efficient single-layer QCA circuits. In addition, a new RAM cell with set and reset capabilities is designed based on the proposed majority gate, which has an efficient and low-energy structure. The functionality, performance and energy consumption of the proposed designs are evaluated based on the QCADesigner and QCAPro tools. According to the simulation results, the proposed RAM design leads to on average 38% lower total energy dissipation, 25% smaller area, 20% lower cell count, 28% lower delay and 60% lower QCA cost as compared to its previous counterparts. Keywords: Quantum-dot cellular automata (QCA, Majority gate, Random access memory (RAM, Energy efficiency

  18. Physical Property Control on the Cellular Uptake Pathway and Spatial Distribution of Nanoparticles in Cells.

    Science.gov (United States)

    Ahn, Sungsook; Seo, Eunseok; Kim, Ki Hean; Lee, Sang Joon

    2015-06-01

    Nanoparticles have been developed in broad biomedical research in terms of effective cellular interactions to treat and visualize diseased cells. Considering the charge and polar functional groups of proteins that are embedded in cellular membranes, charged nanoparticles have been strategically developed to enhance electrostatic cellular interactions. In this study, we show that cellular uptake efficiency, pathway, and spatial distribution of gold nanoparticles in a cell are significantly modulated based on the surface condition of gold nanoparticles and human cancer cells that were tuned by controlling the pH of the medium and by introducing an electron beam. Cellular uptake efficiency is increased when electrostatic attraction is induced between the cells and the gold nanoparticles. Cell surface modification changes the cellular uptake pathways of the gold nanoparticles and concentrates the gold nanoparticles at the membrane region. Surface modification of the gold nanoparticles also contributes to deep penetration and homogeneous spatial distributions in a cell.

  19. Carboxymethyl chitosan based nanocomposites containing chemically bonded quantum dots and magnetic nanoparticles

    Science.gov (United States)

    Ding, Yongling; Yin, Hong; Chen, Rui; Bai, Ru; Chen, Chunying; Hao, Xiaojuan; Shen, Shirley; Sun, Kangning; Liu, Futian

    2018-03-01

    A biocompatible nanocomposite consisting of fluorescent quantum dots (QDs) and magnetic nanoparticles (MNPs) has been constructed via carboxymethyl chitosan (CMCS), resulting in magnetic-fluorescent nanoparticles (MFNPs). In these MFNPs, QDs and MNPs are successfully conjugated via covalent bonds onto the surface of CMCS. The composite retains favorable magnetic and fluorescent properties and shows a good colloidal stability in physiological environments. Folate (FA) as a specific targeting ligand was further incorporated into the nanocomposites to form a delivery vehicle with a targeting function. The therapeutic activity was achieved by loading chemotherapeutic drug doxorubicin (DOX) through electrostatic and hydrophobic interactions. The cumulative DOX release profile shows pH-sensitive. Both flow cytometry analysis and confocal laser scanning microscopic observation suggested that these nanocomposites were uptaken by cancer cells via FA receptor-mediated endocytosis pathway. In summary, the CMCS based nanocomposites developed in this work have a great potential for effective cancer-targeting and drug delivery, as well as in situ cellular imaging.

  20. Dynamic cellular uptake of mixed-monolayer protected nanoparticles.

    Science.gov (United States)

    Carney, Randy P; Carney, Tamara M; Mueller, Marie; Stellacci, Francesco

    2012-12-01

    Nanoparticles (NPs) are gaining increasing attention for potential application in medicine; consequently, studying their interaction with cells is of central importance. We found that both ligand arrangement and composition on gold nanoparticles play a crucial role in their cellular internalization. In our previous investigation, we showed that 66-34OT nanoparticles coated with stripe-like domains of hydrophobic (octanethiol, OT, 34%) and hydrophilic (11-mercaptoundecane sulfonate, MUS, 66%) ligands permeated through the cellular lipid bilayer via passive diffusion, in addition to endo-/pino-cytosis. Here, we show an analysis of NP internalization by DC2.4, 3T3, and HeLa cells at two temperatures and multiple time points. We study four NPs that differ in their surface structures and ligand compositions and report on their cellular internalization by intracellular fluorescence quantification. Using confocal laser scanning microscopy we have found that all three cell types internalize the 66-34OT NPs more than particles coated only with MUS, or particles coated with a very similar coating but lacking any detectable ligand shell structure, or 'striped' particles but with a different composition (34-66OT) at multiple data points.

  1. Optical response of a quantum dot-metal nanoparticle hybrid interacting with a weak probe field.

    Science.gov (United States)

    Kosionis, Spyridon G; Terzis, Andreas F; Sadeghi, Seyed M; Paspalakis, Emmanuel

    2013-01-30

    We study optical effects in a hybrid system composed of a semiconductor quantum dot and a spherical metal nanoparticle that interacts with a weak probe electromagnetic field. We use modified nonlinear density matrix equations for the description of the optical properties of the system and obtain a closed-form expression for the linear susceptibilities of the quantum dot, the metal nanoparticle, and the total system. We then investigate the dependence of the susceptibility on the interparticle distance as well as on the material parameters of the hybrid system. We find that the susceptibility of the quantum dot exhibits optical transparency for specific frequencies. In addition, we show that there is a range of frequencies of the applied field for which the susceptibility of the semiconductor quantum dot leads to gain. This suggests that in such a hybrid system quantum coherence can reverse the course of energy transfer, allowing flow of energy from the metallic nanoparticle to the quantum dot. We also explore the susceptibility of the metal nanoparticle and show that it is strongly influenced by the presence of the quantum dot.

  2. An Optimized Three-Level Design of Decoder Based on Nanoscale Quantum-Dot Cellular Automata

    Science.gov (United States)

    Seyedi, Saeid; Navimipour, Nima Jafari

    2018-03-01

    Quantum-dot Cellular Automata (QCA) has been potentially considered as a supersede to Complementary Metal-Oxide-Semiconductor (CMOS) because of its inherent advantages. Many QCA-based logic circuits with smaller feature size, improved operating frequency, and lower power consumption than CMOS have been offered. This technology works based on electron relations inside quantum-dots. Due to the importance of designing an optimized decoder in any digital circuit, in this paper, we design, implement and simulate a new 2-to-4 decoder based on QCA with low delay, area, and complexity. The logic functionality of the 2-to-4 decoder is verified using the QCADesigner tool. The results have shown that the proposed QCA-based decoder has high performance in terms of a number of cells, covered area, and time delay. Due to the lower clock pulse frequency, the proposed 2-to-4 decoder is helpful for building QCA-based sequential digital circuits with high performance.

  3. The Development of Design Tools for Fault Tolerant Quantum Dot Cellular Automata Based Logic

    Science.gov (United States)

    Armstrong, Curtis D.; Humphreys, William M.

    2003-01-01

    We are developing software to explore the fault tolerance of quantum dot cellular automata gate architectures in the presence of manufacturing variations and device defects. The Topology Optimization Methodology using Applied Statistics (TOMAS) framework extends the capabilities of the A Quantum Interconnected Network Array Simulator (AQUINAS) by adding front-end and back-end software and creating an environment that integrates all of these components. The front-end tools establish all simulation parameters, configure the simulation system, automate the Monte Carlo generation of simulation files, and execute the simulation of these files. The back-end tools perform automated data parsing, statistical analysis and report generation.

  4. The Design of Fault Tolerant Quantum Dot Cellular Automata Based Logic

    Science.gov (United States)

    Armstrong, C. Duane; Humphreys, William M.; Fijany, Amir

    2002-01-01

    As transistor geometries are reduced, quantum effects begin to dominate device performance. At some point, transistors cease to have the properties that make them useful computational components. New computing elements must be developed in order to keep pace with Moore s Law. Quantum dot cellular automata (QCA) represent an alternative paradigm to transistor-based logic. QCA architectures that are robust to manufacturing tolerances and defects must be developed. We are developing software that allows the exploration of fault tolerant QCA gate architectures by automating the specification, simulation, analysis and documentation processes.

  5. Six-Correction Logic (SCL Gates in Quantum-dot Cellular Automata (QCA

    Directory of Open Access Journals (Sweden)

    Md. Anisur Rahman

    2015-11-01

    Full Text Available Quantum Dot Cellular Automata (QCA is a promising nanotechnology in Quantum electronics for its ultra low power consumption, faster speed and small size features. It has significant advantages over the Complementary Metal–Oxide–Semiconductor (CMOS technology. This paper present, a novel QCA representation of Six-Correction Logic (SCL gate based on QCA logic gates: the Maj3, Maj AND gate and Maj OR. In order to design and verify the functionality of the proposed layout, QCADesigner a familiar QCA simulator has been employed. The simulation results confirm correctness of the claims and its usefulness in designing a digital circuits.

  6. The role of surface charge in cellular uptake and cytotoxicity of medical nanoparticles

    Directory of Open Access Journals (Sweden)

    Fröhlich E

    2012-11-01

    Full Text Available Eleonore FröhlichCenter for Medical Research, Medical University of Graz, Graz, AustriaAbstract: Many types of nanoparticles (NPs are tested for use in medical products, particularly in imaging and gene and drug delivery. For these applications, cellular uptake is usually a prerequisite and is governed in addition to size by surface characteristics such as hydrophobicity and charge. Although positive charge appears to improve the efficacy of imaging, gene transfer, and drug delivery, a higher cytotoxicity of such constructs has been reported. This review summarizes findings on the role of surface charge on cytotoxicity in general, action on specific cellular targets, modes of toxic action, cellular uptake, and intracellular localization of NPs. Effects of serum and intercell type differences are addressed. Cationic NPs cause more pronounced disruption of plasma-membrane integrity, stronger mitochondrial and lysosomal damage, and a higher number of autophagosomes than anionic NPs. In general, nonphagocytic cells ingest cationic NPs to a higher extent, but charge density and hydrophobicity are equally important; phagocytic cells preferentially take up anionic NPs. Cells do not use different uptake routes for cationic and anionic NPs, but high uptake rates are usually linked to greater biological effects. The different uptake preferences of phagocytic and nonphagocytic cells for cationic and anionic NPs may influence the efficacy and selectivity of NPs for drug delivery and imaging.Keywords: endocytosis, plasma membrane, lysosomes, polystyrene particles, quantum dots, dendrimers

  7. Iterative Cellular Screening System for Nanoparticle Safety Testing

    Directory of Open Access Journals (Sweden)

    Franziska Sambale

    2015-01-01

    Full Text Available Nanoparticles have the potential to exhibit risks to human beings and to the environment; due to the wide applications of nanoproducts, extensive risk management must not be neglected. Therefore, we have constructed a cell-based, iterative screening system to examine a variety of nanoproducts concerning their toxicity during development. The sensitivity and application of various cell-based methods were discussed and proven by applying the screening to two different nanoparticles: zinc oxide and titanium dioxide nanoparticles. They were used as benchmarks to set up our methods and to examine their effects on mammalian cell lines. Different biological processes such as cell viability, gene expression of interleukin-8 and heat shock protein 70, as well as morphology changes were investigated. Within our screening system, both nanoparticle suspensions and coatings can be tested. Electric cell impedance measurements revealed to be a good method for online monitoring of cellular behavior. The implementation of three-dimensional cell culture is essential to better mimic in vivo conditions. In conclusion, our screening system is highly efficient, cost minimizing, and reduces the need for animal studies.

  8. Cellular internalization, transcellular transport, and cellular effects of silver nanoparticles in polarized Caco-2 cells following apical or basolateral exposure

    International Nuclear Information System (INIS)

    Imai, Shunji; Morishita, Yuki; Hata, Tomoyuki; Kondoh, Masuo; Yagi, Kiyohito; Gao, Jian-Qing; Nagano, Kazuya; Higashisaka, Kazuma; Yoshioka, Yasuo; Tsutsumi, Yasuo

    2017-01-01

    When considering the safety of ingested nanomaterials, it is important to quantitate their transfer across intestinal cells; however, little information exists about the effects of nanomaterial size or exposure side (apical versus basolateral epithelial surface) on nanomaterial transfer. Here, we examined cellular internalization and transcellular transport, and the effects of nanomaterials on Caco-2 monolayers after apical or basolateral exposure to Ag or Au nanoparticles with various sizes. After apical treatment, both internalization and transfer to the basolateral side of the monolayers were greater for smaller Ag nanoparticles than for larger Ag nanoparticles. In contrast, after basolateral treatment, larger Ag nanoparticles were more internalized than smaller Ag nanoparticles, but the transfer to the apical side was greater for smaller Ag nanoparticles. Au nanoparticles showed different rules of internalization and transcellular transport compared with Ag nanoparticles. Furthermore, the paracellular permeability of the Caco-2 monolayers was temporarily increased by Ag nanoparticles (5 μg/mL; diameters, ≤10 nm) following basolateral but not apical exposure. We conclude that the internalization, transfer, and effects of nanomaterials in epithelial cell monolayers depend on the size and composition of nanomaterials, and the exposure side. - Highlights: • Ag and Au nanoparticles can transfer across Caco-2 monolayers. • Cellular uptake of nanoparticles change between apical and basolateral exposure. • Basolateral Ag nanoparticle exposure increases the permeability of Caco-2 monolayers.

  9. A Customizable Quantum-Dot Cellular Automata Building Block for the Synthesis of Classical and Reversible Circuits.

    Science.gov (United States)

    Moustafa, Ahmed; Younes, Ahmed; Hassan, Yasser F

    2015-01-01

    Quantum-dot cellular automata (QCA) are nanoscale digital logic constructs that use electrons in arrays of quantum dots to carry out binary operations. In this paper, a basic building block for QCA will be proposed. The proposed basic building block can be customized to implement classical gates, such as XOR and XNOR gates, and reversible gates, such as CNOT and Toffoli gates, with less cell count and/or better latency than other proposed designs.

  10. Quantum dot tailored to single wall carbon nanotubes: a multifunctional hybrid nanoconstruct for cellular imaging and targeted photothermal therapy.

    Science.gov (United States)

    Nair, Lakshmi V; Nagaoka, Yutaka; Maekawa, Toru; Sakthikumar, D; Jayasree, Ramapurath S

    2014-07-23

    Hybrid nanomaterial based on quantum dots and SWCNTs is used for cellular imaging and photothermal therapy. Furthermore, the ligand conjugated hybrid system (FaQd@CNT) enables selective targeting in cancer cells. The imaging capability of quantum dots and the therapeutic potential of SWCNT are available in a single system with cancer targeting property. Heat generated by the system is found to be high enough to destroy cancer cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. An energy and cost efficient majority-based RAM cell in quantum-dot cellular automata

    Science.gov (United States)

    Khosroshahy, Milad Bagherian; Moaiyeri, Mohammad Hossein; Navi, Keivan; Bagherzadeh, Nader

    Nanotechnologies, notably quantum-dot cellular automata, have achieved major attentions for their prominent features as compared to the conventional CMOS circuitry. Quantum-dot cellular automata, particularly owning to its considerable reduction in size, high switching speed and ultra-low energy consumption, is considered as a potential alternative for the CMOS technology. As the memory unit is one of the most essential components in a digital system, designing a well-optimized QCA random access memory (RAM) cell is an important area of research. In this paper, a new five-input majority gate is presented which is suitable for implementing efficient single-layer QCA circuits. In addition, a new RAM cell with set and reset capabilities is designed based on the proposed majority gate, which has an efficient and low-energy structure. The functionality, performance and energy consumption of the proposed designs are evaluated based on the QCADesigner and QCAPro tools. According to the simulation results, the proposed RAM design leads to on average 38% lower total energy dissipation, 25% smaller area, 20% lower cell count, 28% lower delay and 60% lower QCA cost as compared to its previous counterparts.

  12. Single quantum dot tracking reveals the impact of nanoparticle surface on intracellular state.

    Science.gov (United States)

    Zahid, Mohammad U; Ma, Liang; Lim, Sung Jun; Smith, Andrew M

    2018-05-08

    Inefficient delivery of macromolecules and nanoparticles to intracellular targets is a major bottleneck in drug delivery, genetic engineering, and molecular imaging. Here we apply live-cell single-quantum-dot imaging and tracking to analyze and classify nanoparticle states after intracellular delivery. By merging trajectory diffusion parameters with brightness measurements, multidimensional analysis reveals distinct and heterogeneous populations that are indistinguishable using single parameters alone. We derive new quantitative metrics of particle loading, cluster distribution, and vesicular release in single cells, and evaluate intracellular nanoparticles with diverse surfaces following osmotic delivery. Surface properties have a major impact on cell uptake, but little impact on the absolute cytoplasmic numbers. A key outcome is that stable zwitterionic surfaces yield uniform cytosolic behavior, ideal for imaging agents. We anticipate that this combination of quantum dots and single-particle tracking can be widely applied to design and optimize next-generation imaging probes, nanoparticle therapeutics, and biologics.

  13. Dual-excitation upconverting nanoparticle and quantum dot aptasensor for multiplexed food pathogen detection

    OpenAIRE

    Kurt, Hasan; Yüce, Meral; Yuce, Meral; Hussain, Babar; Budak, Hikmet

    2016-01-01

    In this report, a dual-excitation sensing method was developed using aptamer-functionalized quantum dots and upconverting nanoparticles, exhibiting Stokes and anti-Stokes type excitation profiles, respectively. Conjugation of the aptamer-functionalized luminescent nanoparticles with the magnetic beads, comprising short DNA sequences that were partially complementary to the aptamer sequences, enabled facile separation of the analyte-free conjugates for fluorescent measurement. UV–Visible spect...

  14. Active cellular sensing with quantum dots: Transitioning from research tool to reality; a review

    Energy Technology Data Exchange (ETDEWEB)

    Delehanty, James B., E-mail: james.delehanty@nrl.navy.mil [Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Susumu, Kimihiro, E-mail: susumu@ccs.nrl.navy.mil [Optical Sciences Division, Code 5611, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Manthe, Rachel L., E-mail: rmanthe@umd.edu [Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Fischell Department of Bioengineering, School of Engineering, University of Maryland College Park, College Park, MD 20742 (United States); Algar, W. Russ, E-mail: russ.algar.ctr.ca@nrl.navy.mil [Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); College of Science, George Mason University, Fairfax, VA 22030 (United States); Medintz, Igor L., E-mail: igor.medintz@nrl.navy.mil [Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, DC 20375 (United States)

    2012-10-31

    Highlights: Black-Right-Pointing-Pointer Quantum dots (QDs) have evolved beyond mere cellular labeling reagents. Black-Right-Pointing-Pointer Significant advances have been made in QD materials, surface coatings and bioconjugation. Black-Right-Pointing-Pointer Cellular targeting/delivery has been achieved using polymers, peptides, proteins. Black-Right-Pointing-Pointer Numerous QD-based sensing applications: extracellular, membrane, intracellular. - Abstract: The application of luminescent semiconductor quantum dots (QDs) within a wide range of biological imaging and sensing formats is now approaching its 15th year. The unique photophysical properties of these nanomaterials have long been envisioned as having the potential to revolutionize biosensing within cellular studies that rely on fluorescence. However, it is only now that these materials are making the transition towards accomplishing this goal. With the idea of understanding how to actively incorporate QDs into different types of cellular biosensing, we review the progress in many of the areas relevant to achieving this goal. This includes the synthesis of the QDs themselves, with an emphasis on minimizing potential toxicity, along with the general methods for making these nanocrystalline structures stable in aqueous media. We next survey some methods for conjugating QDs to biomolecules to allow them to participate in active biosensing. Lastly, we extensively review many of the applications where QDs have been demonstrated in an active role in cellular biosensing. These formats cover a wide range of possibilities including where the QDs have contributed to: monitoring the cell's interaction with its extracellular environment; elucidating the complex molecular interplay that characterizes the plasma membrane; understanding how cells continuously endocytose and exocytose materials across the cellular membrane; visualizing organelle trafficking; and, perhaps most importantly, monitoring the intracellular

  15. Active cellular sensing with quantum dots: Transitioning from research tool to reality; a review

    International Nuclear Information System (INIS)

    Delehanty, James B.; Susumu, Kimihiro; Manthe, Rachel L.; Algar, W. Russ; Medintz, Igor L.

    2012-01-01

    Highlights: ► Quantum dots (QDs) have evolved beyond mere cellular labeling reagents. ► Significant advances have been made in QD materials, surface coatings and bioconjugation. ► Cellular targeting/delivery has been achieved using polymers, peptides, proteins. ► Numerous QD-based sensing applications: extracellular, membrane, intracellular. - Abstract: The application of luminescent semiconductor quantum dots (QDs) within a wide range of biological imaging and sensing formats is now approaching its 15th year. The unique photophysical properties of these nanomaterials have long been envisioned as having the potential to revolutionize biosensing within cellular studies that rely on fluorescence. However, it is only now that these materials are making the transition towards accomplishing this goal. With the idea of understanding how to actively incorporate QDs into different types of cellular biosensing, we review the progress in many of the areas relevant to achieving this goal. This includes the synthesis of the QDs themselves, with an emphasis on minimizing potential toxicity, along with the general methods for making these nanocrystalline structures stable in aqueous media. We next survey some methods for conjugating QDs to biomolecules to allow them to participate in active biosensing. Lastly, we extensively review many of the applications where QDs have been demonstrated in an active role in cellular biosensing. These formats cover a wide range of possibilities including where the QDs have contributed to: monitoring the cell's interaction with its extracellular environment; elucidating the complex molecular interplay that characterizes the plasma membrane; understanding how cells continuously endocytose and exocytose materials across the cellular membrane; visualizing organelle trafficking; and, perhaps most importantly, monitoring the intracellular presence of target molecules such as nucleic acids, nutrients, cofactors, and ions or, alternatively

  16. Cadmium-containing nanoparticles: Perspectives on pharmacology and toxicology of quantum dots

    International Nuclear Information System (INIS)

    Rzigalinski, Beverly A.; Strobl, Jeannine S.

    2009-01-01

    The field of nanotechnology is rapidly expanding with the development of novel nanopharmaceuticals that have potential for revolutionizing medical treatment. The rapid pace of expansion in this field has exceeded the pace of pharmacological and toxicological research on the effects of nanoparticles in the biological environment. The development of cadmium-containing nanoparticles, known as quantum dots, show great promise for treatment and diagnosis of cancer and targeted drug delivery, due to their size-tunable fluorescence and ease of functionalization for tissue targeting. However, information on pharmacology and toxicology of quantum dots needs much further development, making it difficult to assess the risks associated with this new nanotechnology. Further, nanotechnology poses yet another risk for toxic cadmium, which will now enter the biological realm in nano-form. In this review, we discuss cadmium-containing quantum dots and their physicochemical properties at the nano-scale. We summarize the existing work on pharmacology and toxicology of cadmium-containing quantum dots and discuss perspectives in their utility in disease treatment. Finally, we identify critical gaps in our knowledge of cadmium quantum dot toxicity, and how these gaps need to be assessed to enable quantum dot nanotechnology to transit safely from bench to bedside.

  17. Biological interactions of quantum dot nanoparticles in skin and in human epidermal keratinocytes

    International Nuclear Information System (INIS)

    Zhang, Leshuai W.; Yu, William W.; Colvin, Vicki L.; Monteiro-Riviere, Nancy A.

    2008-01-01

    Quantum dots nanoparticles have novel optical properties for biomedical applications and electronics, but little is known about their skin permeability and interaction with cells. QD621 are nail-shaped nanoparticles that contain a cadmium/selenide core with a cadmium sulfide shell coated with polyethylene glycol (PEG) and are soluble in water. QD were topically applied to porcine skin flow-through diffusion cells to assess penetration at 1 μM, 2 μM and 10 μM for 24 h. QD were also studied in human epidermal keratinocytes (HEK) to determine cellular uptake, cytotoxicity and inflammatory potential. Confocal microscopy depicted the penetration of QD621 through the uppermost stratum corneum (SC) layers of the epidermis and fluorescence was found primarily in the SC and near hair follicles. QD were found in the intercellular lipid bilayers of the SC by transmission electron microscopy (TEM). Inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis for cadmium (Cd) and fluorescence for QD both did not detect Cd nor fluorescence signal in the perfusate at any time point or concentration. In HEK, viability decreased significantly (p < 0.05) from 1.25 nM to 10nM after 24 h and 48 h. There was a significant increase in IL-6 at 1.25 nM to 10 nM, while IL-8 increased from 2.5nM to 10nM after 24 h and 48 h. TEM of HEK treated with 10 nM of QD621 at 24 h depicted QD in cytoplasmic vacuoles and at the periphery of the cell membranes. These results indicate that porcine skin penetration of QD621 is minimal and limited primarily to the outer SC layers, yet if the skin were damaged allowing direct QD exposure to skin or keratinocytes, an inflammatory response could be initiated

  18. Iron Oxide Nanoparticles Stimulates Extra-Cellular Matrix Production in Cellular Spheroids

    Directory of Open Access Journals (Sweden)

    Megan Casco

    2017-01-01

    Full Text Available Nanotechnologies have been integrated into drug delivery, and non-invasive imaging applications, into nanostructured scaffolds for the manipulation of cells. The objective of this work was to determine how the physico-chemical properties of magnetic nanoparticles (MNPs and their spatial distribution into cellular spheroids stimulated cells to produce an extracellular matrix (ECM. The MNP concentration (0.03 mg/mL, 0.1 mg/mL and 0.3 mg/mL, type (magnetoferritin, shape (nanorod—85 nm × 425 nm and incorporation method were studied to determine each of their effects on the specific stimulation of four ECM proteins (collagen I, collagen IV, elastin and fibronectin in primary rat aortic smooth muscle cell. Results demonstrated that as MNP concentration increased there was up to a 6.32-fold increase in collagen production over no MNP samples. Semi-quantitative Immunohistochemistry (IHC results demonstrated that MNP type had the greatest influence on elastin production with a 56.28% positive area stain compared to controls and MNP shape favored elastin stimulation with a 50.19% positive area stain. Finally, there are no adverse effects of MNPs on cellular contractile ability. This study provides insight on the stimulation of ECM production in cells and tissues, which is important because it plays a critical role in regulating cellular functions.

  19. Defect-tolerance analysis of fundamental quantum-dot cellular automata devices

    Directory of Open Access Journals (Sweden)

    Yongqiang Zhang

    2015-04-01

    Full Text Available Quantum-dot cellular automata (QCA is a burgeoning technology at the nano-scale range, with the potential for lower power consumption, smaller size and faster speed than conventional complementary metal–oxide semiconductor-based technology. Because of its ultra-density integration and its inherent physical properties, fault-tolerance is an important property to consider in the research and manufacture of QCA. In this paper, one type of defect, in which displacement and misalignment occur coinstantaneously, is investigated in detail on rudimentary QCA devices (majority voter (MV, inverter, wire with QCADesigner. Another MV with rotated cells is also proposed, and it is more robust than the original one. Simulation results present the defect-tolerance of these devices, that is, the maximum precise region the defective cell can be moved moreover, with correct logical function. These conclusions have a meaningful guiding significance for QCA physical implementation and fault-tolerance research.

  20. High-performance full adder architecture in quantum-dot cellular automata

    Directory of Open Access Journals (Sweden)

    Hamid Rashidi

    2017-06-01

    Full Text Available Quantum-dot cellular automata (QCA is a new and promising computation paradigm, which can be a viable replacement for the complementary metal–oxide–semiconductor technology at nano-scale level. This technology provides a possible solution for improving the computation in various computational applications. Two QCA full adder architectures are presented and evaluated: a new and efficient 1-bit QCA full adder architecture and a 4-bit QCA ripple carry adder (RCA architecture. The proposed architectures are simulated using QCADesigner tool version 2.0.1. These architectures are implemented with the coplanar crossover approach. The simulation results show that the proposed 1-bit QCA full adder and 4-bit QCA RCA architectures utilise 33 and 175 QCA cells, respectively. Our simulation results show that the proposed architectures outperform most results so far in the literature.

  1. Design of Efficient Full Adder in Quantum-Dot Cellular Automata

    Directory of Open Access Journals (Sweden)

    Bibhash Sen

    2013-01-01

    Full Text Available Further downscaling of CMOS technology becomes challenging as it faces limitation of feature size reduction. Quantum-dot cellular automata (QCA, a potential alternative to CMOS, promises efficient digital design at nanoscale. Investigations on the reduction of QCA primitives (majority gates and inverters for various adders are limited, and very few designs exist for reference. As a result, design of adders under QCA framework is gaining its importance in recent research. This work targets developing multi-layered full adder architecture in QCA framework based on five-input majority gate proposed here. A minimum clock zone (2 clock with high compaction (0.01 μm2 for a full adder around QCA is achieved. Further, the usefulness of such design is established with the synthesis of high-level logic. Experimental results illustrate the significant improvements in design level in terms of circuit area, cell count, and clock compared to that of conventional design approaches.

  2. Novel Design for Quantum Dots Cellular Automata to Obtain Fault-Tolerant Majority Gate

    International Nuclear Information System (INIS)

    Razieh Farazkish, R.; Sayedsalehi, S.; Navi, K.

    2012-01-01

    Quantum-dot Cellular Automata (QCA) is one of the most attractive technologies for computing at nano scale. The principle element in QCA is majority gate. In this paper, fault-tolerance properties of the majority gate is analyzed. This component is suitable for designing fault-tolerant QCA circuits. We analyze fault-tolerance properties of three-input majority gate in terms of misalignment, missing, and dislocation cells. In order to verify the functionality of the proposed component some physical proofs using kink energy (the difference in electrostatic energy between the two polarization states) and computer simulations using QCA Designer tool are provided. Our results clearly demonstrate that the redundant version of the majority gate is more robust than the standard style for this gate.

  3. Design of a fault-tolerant reversible control unit in molecular quantum-dot cellular automata

    Science.gov (United States)

    Bahadori, Golnaz; Houshmand, Monireh; Zomorodi-Moghadam, Mariam

    Quantum-dot cellular automata (QCA) is a promising emerging nanotechnology that has been attracting considerable attention due to its small feature size, ultra-low power consuming, and high clock frequency. Therefore, there have been many efforts to design computational units based on this technology. Despite these advantages of the QCA-based nanotechnologies, their implementation is susceptible to a high error rate. On the other hand, using the reversible computing leads to zero bit erasures and no energy dissipation. As the reversible computation does not lose information, the fault detection happens with a high probability. In this paper, first we propose a fault-tolerant control unit using reversible gates which improves on the previous design. The proposed design is then synthesized to the QCA technology and is simulated by the QCADesigner tool. Evaluation results indicate the performance of the proposed approach.

  4. Novel Design for Quantum Dots Cellular Automata to Obtain Fault-Tolerant Majority Gate

    Directory of Open Access Journals (Sweden)

    Razieh Farazkish

    2012-01-01

    Full Text Available Quantum-dot Cellular Automata (QCA is one of the most attractive technologies for computing at nanoscale. The principle element in QCA is majority gate. In this paper, fault-tolerance properties of the majority gate is analyzed. This component is suitable for designing fault-tolerant QCA circuits. We analyze fault-tolerance properties of three-input majority gate in terms of misalignment, missing, and dislocation cells. In order to verify the functionality of the proposed component some physical proofs using kink energy (the difference in electrostatic energy between the two polarization states and computer simulations using QCA Designer tool are provided. Our results clearly demonstrate that the redundant version of the majority gate is more robust than the standard style for this gate.

  5. Gold nanoparticle cellular uptake, toxicity and radiosensitisation in hypoxic conditions

    International Nuclear Information System (INIS)

    Jain, Suneil; Coulter, Jonathan A.; Butterworth, Karl T.; Hounsell, Alan R.; McMahon, Stephen J.; Hyland, Wendy B.; Muir, Mark F.; Dickson, Glenn R.; Prise, Kevin M.; Currell, Fred J.; Hirst, David G.; O’Sullivan, Joe M.

    2014-01-01

    Background and purpose: Gold nanoparticles (GNPs) are novel agents that have been shown to cause radiosensitisation in vitro and in vivo. Tumour hypoxia is associated with radiation resistance and reduced survival in cancer patients. The interaction of GNPs with cells in hypoxia is explored. Materials and methods: GNP uptake, localization, toxicity and radiosensitisation were assessed in vitro under oxic and hypoxic conditions. Results: GNP cellular uptake was significantly lower under hypoxic than oxic conditions. A significant reduction in cell proliferation in hypoxic MDA-MB-231 breast cancer cells exposed to GNPs was observed. In these cells significant radiosensitisation occurred in normoxia and moderate hypoxia. However, in near anoxia no significant sensitisation occurred. Conclusions: GNP uptake occurred in hypoxic conditions, causing radiosensitisation in moderate, but not extreme hypoxia in a breast cancer cell line. These findings may be important for the development of GNPs for cancer therapy

  6. Tuneable nanoparticle-nanofiber composite substrate for improved cellular adhesion.

    Science.gov (United States)

    Nicolini, Ariana M; Toth, Tyler D; Yoon, Jeong-Yeol

    2016-09-01

    This work presents a novel technique using a reverse potential electrospinning mode for fabricating nanoparticle-embedded composites that can be tailored to represent various fiber diameters, surface morphologies, and functional groups necessary for improved cellular adhesion. Polycaprolactone (PCL) nanofibers were electrospun in both traditional positive (PP) and reverse potential (RP) electrical fields. The fibers were incorporated with 300nm polystyrene (PS) fluorescent particles, which contained carboxyl, amine groups, and surfactants. In the unconventional RP, the charged colloidal particles and surfactants were shown to have an exaggerated effect on Taylor cone morphology and fiber diameter caused by the changes in charge density and surface tension of the bulk solution. The RP mode was shown to lead to a decrease in fiber diameter from 1200±100nm (diameter±SE) for the nanofibers made with PCL alone to 440±80nm with the incorporation of colloidal particles, compared to the PP mode ranging from 530±90nm to 350±50nm, respectively. The nanoparticle-nanofiber composite substrates were cultured with human umbilical vein endothelial cells (HUVECs) and evaluated for cellular viability and adhesion for up to 5 days. Adhesion to the nanofibrous substrates was improved by 180±10% with the addition of carboxylated particles and by 480±60% with the functionalization of an RGD ligand compared to the PCL nanofibers. The novel approach of electrospinning in the RP mode with the addition of colloids in order to alter charge density and surface tension could be utilized towards many applications, one being implantable biomaterials and tissue engineered scaffolds as demonstrated in this work. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. The cellular uptake and transport of zein nanoparticles: Effect of sodium caseinate

    Science.gov (United States)

    Cellular evaluation of zein nanoparticles has not been studied systematically due to their poor redispersibility. Caseinate (CAS) stabilized zein nanoparticles have been recently developed with better redispersibility in salt solutions. In this study, zein-CAS nanoparticles were prepared with differ...

  8. Dual-excitation upconverting nanoparticle and quantum dot aptasensor for multiplexed food pathogen detection.

    Science.gov (United States)

    Kurt, Hasan; Yüce, Meral; Hussain, Babar; Budak, Hikmet

    2016-07-15

    In this report, a dual-excitation sensing method was developed using aptamer-functionalized quantum dots and upconverting nanoparticles, exhibiting Stokes and anti-Stokes type excitation profiles, respectively. Conjugation of the aptamer-functionalized luminescent nanoparticles with the magnetic beads, comprising short DNA sequences that were partially complementary to the aptamer sequences, enabled facile separation of the analyte-free conjugates for fluorescent measurement. UV-Visible spectroscopy, Circular Dichroism spectroscopy, Dynamic Light Scattering and Polyacrylamide Gel Electrophoresis techniques were used to characterize the aptamer probes developed. The target-specific luminescent conjugates were applied for multiplex detection of model food pathogens, Salmonella typhimurium, and Staphylococcus aureus, in which the fluorescent emission spectra were obtained under UV excitation at 325nm for quantum dots and NIR excitation at 980nm for upconverting nanoparticles, respectively. The dual-excitation strategy was aimed to minimize cross-talk between the luminescent signals for multiplexed detection, and yielded limit of detection values of 16 and 28cfumL(-1) for Staphylococcus aureus, and Salmonella typhimurium, respectively. By employing a greater number of quantum dots and upconverting nanoparticles with non-overlapping fluorescent emissions, the proposed methodology might be exploited further to detect several analytes, simultaneously. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Use of titanium dioxide nanoparticles biosynthesized by Bacillus mycoides in quantum dot sensitized solar cells.

    Science.gov (United States)

    Ordenes-Aenishanslins, Nicolás Alexis; Saona, Luis Alberto; Durán-Toro, Vicente María; Monrás, Juan Pablo; Bravo, Denisse Margarita; Pérez-Donoso, José Manuel

    2014-07-16

    One of the major challenges of nanotechnology during the last decade has been the development of new procedures to synthesize nanoparticles. In this context, biosynthetic methods have taken hold since they are simple, safe and eco-friendly. In this study, we report the biosynthesis of TiO2 nanoparticles by an environmental isolate of Bacillus mycoides, a poorly described Gram-positive bacterium able to form colonies with novel morphologies. This isolate was able to produce TiO2 nanoparticles at 37 ° C in the presence of titanyl hydroxide. Biosynthesized nanoparticles have anatase polymorphic structure, spherical morphology, polydisperse size (40-60 nm) and an organic shell as determined by UV-vis spectroscopy, TEM, DLS and FTIR, respectively. Also, conversely to chemically produced nanoparticles, biosynthesized TiO2 do not display phototoxicity. In order to design less expensive and greener solar cells, biosynthesized nanoparticles were evaluated in Quantum Dot Sensitized Solar Cells (QDSSCs) and compared with chemically produced TiO2 nanoparticles. Solar cell parameters such as short circuit current density (ISC) and open circuit voltage (VOC) revealed that biosynthesized TiO2 nanoparticles can mobilize electrons in QDSSCs similarly than chemically produced TiO2. Our results indicate that bacterial extracellular production of TiO2 nanoparticles at low temperatures represents a novel alternative for the construction of green solar cells.

  10. Nanoparticle bioconjugate for controlled cellular delivery of doxorubicin

    Science.gov (United States)

    Sangtani, Ajmeeta; Petryayeva, Eleonora; Wu, Miao; Susumu, Kimihiro; Oh, Eunkeu; Huston, Alan L.; Lasarte-Aragones, Guillermo; Medintz, Igor L.; Algar, W. Russ; Delehanty, James B.

    2018-02-01

    Nanoparticle (NP)-mediated drug delivery offers the potential to overcome limitations of systemic delivery, including the ability to specifically target cargo and control release of NP-associated drug cargo. Doxorubicin (DOX) is a widely used FDA-approved cancer therapeutic; however, multiple side effects limit its utility. Thus, there is wide interest in modulating toxicity after cell delivery. Our goal here was to realize a NP-based DOX-delivery system that can modulate drug toxicity by controlling the release kinetics of DOX from the surface of a hard NP carrier. To achieve this, we employed a quantum dot (QD) as a central scaffold which DOX was appended via three different peptidyl linkages (ester, disulfide, hydrazone) that are cleavable in response to various intracellular conditions. Attachment of a cell penetrating peptide (CPP) containing a positively charged polyarginine sequence facilitates endocytosis of the ensemble. Polyhistidine-driven metal affinity coordination was used to self-assemble both peptides to the QD surface, allowing for fine control over both the ratio of peptides attached to the QD as well as DOX dose delivered to cells. Microplate-based Förster resonance energy transfer assays confirmed the successful ratiometric assembly of the conjugates and functionality of the linkages. Cell delivery experiments and cytotoxicity assays were performed to compare the various cleavable linkages to a control peptide where DOX is attached through an amide bond. The role played by various attachment chemistries used in QD-peptide-drug assemblies and their implications for the rationale in design of NPbased constructs for drug delivery is described here.

  11. Array of nanoparticles coupling with quantum-dot: Lattice plasmon quantum features

    Science.gov (United States)

    Salmanogli, Ahmad; Gecim, H. Selcuk

    2018-06-01

    In this study, we analyze the interaction of lattice plasmon with quantum-dot in order to mainly examine the quantum features of the lattice plasmon containing the photonic/plasmonic properties. Despite optical properties of the localized plasmon, the lattice plasmon severely depends on the array geometry, which may influence its quantum features such as uncertainty and the second-order correlation function. To investigate this interaction, we consider a closed system containing an array of the plasmonic nanoparticles and quantum-dot. We analyze this system with full quantum theory by which the array electric far field is quantized and the strength coupling of the quantum-dot array is analytically calculated. Moreover, the system's dynamics are evaluated and studied via the Heisenberg-Langevin equations to attain the system optical modes. We also analytically examine the Purcell factor, which shows the effect of the lattice plasmon on the quantum-dot spontaneous emission. Finally, the lattice plasmon uncertainty and its time evolution of the second-order correlation function at different spatial points are examined. These parameters are dramatically affected by the retarded field effect of the array nanoparticles. We found a severe quantum fluctuation at points where the lattice plasmon occurs, suggesting that the lattice plasmon photons are correlated.

  12. Gold nanoparticles cellular toxicity and recovery: adipose Derived Stromal cells.

    Science.gov (United States)

    Mironava, Tatsiana; Hadjiargyrou, Michael; Simon, Marcia; Rafailovich, Miriam H

    2014-03-01

    Gold nanoparticles (AuNPs) are currently used in numerous medical applications. Herein, we describe their in vitro impact on human adipose-derived stromal cells (ADSCs) using 13 nm and 45 nm citrate-coated AuNPs. In their non-differentiated state, ADSCs were penetrated by the AuNPs and stored in vacuoles. The presence of the AuNPs in ADSCs resulted in increased population doubling times, decreased cell motility and cell-mediated collagen contraction. The degree to which the cells were impacted was a function of particle concentration, where the smaller particles required a sevenfold higher concentration to have the same effect as the larger ones. Furthermore, AuNPs reduced adipogenesis as measured by lipid droplet accumulation and adiponectin secretion. These effects correlated with transient increases in DLK1 and with relative reductions in fibronectin. Upon removal of exogenous AuNPs, cellular NP levels decreased and normal ADSC functions were restored. As adiponectin helps regulate energy metabolism, local fluctuations triggered by AuNPs can lead to systemic changes. Hence, careful choice of size, concentration and clinical application duration of AuNPs is warranted.

  13. Quantum Dots Encapsulated with Canine Parvovirus-Like Particles Improving the Cellular Targeted Labeling.

    Directory of Open Access Journals (Sweden)

    Dan Yan

    Full Text Available Quantum dots (QDs have a promising prospect in live-cell imaging and sensing because of unique fluorescence features. QDs aroused significant interest in the bio-imaging field through integrating the fluorescence properties of QDs and the delivery function of biomaterial. The natural tropism of Canine Parvovirus (CPV to the transferrin receptor can target specific cells to increase the targeting ability of QDs in cell imaging. CPV virus-like particles (VLPs from the expression of the CPV-VP2 capsid protein in a prokaryotic expression system were examined to encapsulate the QDs and deliver to cells with an expressed transferrin receptor. CPV-VLPs were used to encapsulate QDs that were modified using 3-mercaptopropionic acid. Gel electrophoresis, fluorescence spectrum, particle size, and transmission electron microscopy verified the conformation of a complex, in which QDs were encapsulated in CPV-VLPs (CPV-VLPs-QDs. When incubated with different cell lines, CPV-VLPs-QDs significantly reduced the cytotoxicity of QDs and selectively labeled the cells with high-level transferrin receptors. Cell-targeted labeling was achieved by utilizing the specific binding between the CPV capsid protein VP2 of VLPs and cellular receptors. CPV-VLPs-QDs, which can mimic the native CPV infection, can recognize and attach to the transferrin receptors on cellular membrane. Therefore, CPV-VLPs can be used as carriers to facilitate the targeted delivery of encapsulated nanomaterials into cells via receptor-mediated pathways. This study confirmed that CPV-VLPs can significantly promote the biocompatibility of nanomaterials and could expand the application of CPV-VLPs in biological medicine.

  14. Designing Nanoscale Counter Using Reversible Gate Based on Quantum-Dot Cellular Automata

    Science.gov (United States)

    Moharrami, Elham; Navimipour, Nima Jafari

    2018-04-01

    Some new technologies such as Quantum-dot Cellular Automata (QCA) is suggested to solve the physical limits of the Complementary Metal-Oxide Semiconductor (CMOS) technology. The QCA as one of the novel technologies at nanoscale has potential applications in future computers. This technology has some advantages such as minimal size, high speed, low latency, and low power consumption. As a result, it is used for creating all varieties of memory. Counter circuits as one of the important circuits in the digital systems are composed of some latches, which are connected to each other in series and actually they count input pulses in the circuit. On the other hand, the reversible computations are very important because of their ability in reducing energy in nanometer circuits. Improving the energy efficiency, increasing the speed of nanometer circuits, increasing the portability of system, making smaller components of the circuit in a nuclear size and reducing the power consumption are considered as the usage of reversible logic. Therefore, this paper aims to design a two-bit reversible counter that is optimized on the basis of QCA using an improved reversible gate. The proposed reversible structure of 2-bit counter can be increased to 3-bit, 4-bit and more. The advantages of the proposed design have been shown using QCADesigner in terms of the delay in comparison with previous circuits.

  15. Bennett clocking of quantum-dot cellular automata and the limits to binary logic scaling

    International Nuclear Information System (INIS)

    Lent, Craig S; Liu Mo; Lu Yuhui

    2006-01-01

    We examine power dissipation in different clocking schemes for molecular quantum-dot cellular automata (QCA) circuits. 'Landauer clocking' involves the adiabatic transition of a molecular cell from the null state to an active state carrying data. Cell layout creates devices which allow data in cells to interact and thereby perform useful computation. We perform direct solutions of the equation of motion for the system in contact with the thermal environment and see that Landauer's Principle applies: one must dissipate an energy of at least k B T per bit only when the information is erased. The ideas of Bennett can be applied to keep copies of the bit information by echoing inputs to outputs, thus embedding any logically irreversible circuit in a logically reversible circuit, at the cost of added circuit complexity. A promising alternative which we term 'Bennett clocking' requires only altering the timing of the clocking signals so that bit information is simply held in place by the clock until a computational block is complete, then erased in the reverse order of computation. This approach results in ultralow power dissipation without additional circuit complexity. These results offer a concrete example in which to consider recent claims regarding the fundamental limits of binary logic scaling

  16. Role of correlation in the operation of quantum-dot cellular automata

    International Nuclear Information System (INIS)

    Toth, Geza; Lent, Craig S.

    2001-01-01

    Quantum-dot cellular automata (QCA) may offer a viable alternative of traditional transistor-based technology at the nanoscale. When modeling a QCA circuit, the number of degrees of freedom necessary to describe the quantum mechanical state increases exponentially making modeling even modest size cell arrays difficult. The intercellular Hartree approximation largely reduces the number of state variables and still gives good results especially when the system remains near ground state. This suggests that a large part of the correlation degrees of freedom are not essential from the point of view of the dynamics. In certain cases, however, such as, for example, the majority gate with unequal input legs, the Hartree approximation gives qualitatively wrong results. An intermediate model is constructed between the Hartree approximation and the exact model, based on the coherence vector formalism. By including correlation effects to a desired degree, it improves the results of the Hartree method and gives the approximate dynamics of the correlation terms. It also models the majority gate correctly. Beside QCA cell arrays, our findings are valid for Ising spin chains in transverse magnetic field, and can be straightforwardly generalized for coupled two-level systems with a more complicated Hamiltonian. [copyright] 2001 American Institute of Physics

  17. Resonance fluorescence spectrum of a p-doped quantum dot coupled to a metallic nanoparticle

    Science.gov (United States)

    Carreño, F.; Antón, M. A.; Arrieta-Yáñez, Francisco

    2013-11-01

    The resonance fluorescence spectrum (RFS) of a hybrid system consisting of a p-doped semiconductor quantum dot (QD) coupled to a metallic nanoparticle (MNP) is analyzed. The quantum dot is described as a four-level atomlike system using the density matrix formalism. The lower levels are Zeeman-split hole spin states and the upper levels correspond to positively charged excitons containing a spin-up, spin-down hole pair and a spin electron. A linearly polarized laser field drives two of the optical transitions of the QD and produces localized surface plasmons in the nanoparticle, which act back upon the QD. The frequencies of these localized plasmons are very different along the two principal axes of the nanoparticle, thus producing an anisotropic modification of the spontaneous emission rates of the allowed optical transitions, which is accompanied by very minor local field corrections. This manifests into dramatic modifications in the RFS of the hybrid system in contrast to the one obtained for the isolated QD. The RFS is analyzed as a function of the nanoparticle's aspect ratio, the external magnetic field applied in the Voigt geometry, and the Rabi frequency of the driving field. It is shown that the spin of the QD is imprinted onto certain sidebands of the RFS, and that the signal at these sidebands can be optimized by engineering the shape of the MNP.

  18. Epidermal Growth Factor Enhances Cellular Uptake of Polystyrene Nanoparticles by Clathrin-Mediated Endocytosis.

    Science.gov (United States)

    Phuc, Le Thi Minh; Taniguchi, Akiyoshi

    2017-06-19

    The interaction between nanoparticles and cells has been studied extensively, but most research has focused on the effect of various nanoparticle characteristics, such as size, morphology, and surface charge, on the cellular uptake of nanoparticles. In contrast, there have been very few studies to assess the influence of cellular factors, such as growth factor responses, on the cellular uptake efficiency of nanoparticles. The aim of this study was to clarify the effects of epidermal growth factor (EGF) on the uptake efficiency of polystyrene nanoparticles (PS NPs) by A431 cells, a human carcinoma epithelial cell line. The results showed that EGF enhanced the uptake efficiency of A431 cells for PS NPs. In addition, inhibition and localization studies of PS NPs and EGF receptors (EGFRs) indicated that cellular uptake of PS NPs is related to the binding of EGF-EGFR complex and PS NPs. Different pathways are used to enter the cells depending on the presence or absence of EGF. In the presence of EGF, cellular uptake of PS NPs is via clathrin-mediated endocytosis, whereas, in the absence of EGF, uptake of PS NPs does not involve clathrin-mediated endocytosis. Our findings indicate that EGF enhances cellular uptake of PS NPs by clathrin-mediated endocytosis. This result could be important for developing safe nanoparticles and their safe use in medical applications.

  19. Epidermal Growth Factor Enhances Cellular Uptake of Polystyrene Nanoparticles by Clathrin-Mediated Endocytosis

    Directory of Open Access Journals (Sweden)

    Le Thi Minh Phuc

    2017-06-01

    Full Text Available The interaction between nanoparticles and cells has been studied extensively, but most research has focused on the effect of various nanoparticle characteristics, such as size, morphology, and surface charge, on the cellular uptake of nanoparticles. In contrast, there have been very few studies to assess the influence of cellular factors, such as growth factor responses, on the cellular uptake efficiency of nanoparticles. The aim of this study was to clarify the effects of epidermal growth factor (EGF on the uptake efficiency of polystyrene nanoparticles (PS NPs by A431 cells, a human carcinoma epithelial cell line. The results showed that EGF enhanced the uptake efficiency of A431 cells for PS NPs. In addition, inhibition and localization studies of PS NPs and EGF receptors (EGFRs indicated that cellular uptake of PS NPs is related to the binding of EGF–EGFR complex and PS NPs. Different pathways are used to enter the cells depending on the presence or absence of EGF. In the presence of EGF, cellular uptake of PS NPs is via clathrin-mediated endocytosis, whereas, in the absence of EGF, uptake of PS NPs does not involve clathrin-mediated endocytosis. Our findings indicate that EGF enhances cellular uptake of PS NPs by clathrin-mediated endocytosis. This result could be important for developing safe nanoparticles and their safe use in medical applications.

  20. Synthesis of SnS nanoparticles by SILAR method for quantum dot-sensitized solar cells.

    Science.gov (United States)

    Tsukigase, Hiroki; Suzuki, Yoshikazu; Berger, Marie-Hélène; Sagawa, Takashi; Yoshikawa, Susumu

    2011-03-01

    SnS-sensitized TiO2 electrodes were applied in quantum dot-sensitized solar cells (QDSSCs) which are environmentally more favorable than conventional Cd or Pb-chalcogenide-sensitized electrodes. SnS nanoparticles were well-distributed over the surface of TiO2 nanoparticles by the successive ionic layer adsorption and reaction (SILAR) method. Deposited SnS nanoparticles had diameter about 3 nm. Under AM1.5 irradiation with 100 mW/cm2 light intensity (at 1 sun), the energy conversion efficiency of obtained cells reached a value of 0.21% (0.25 cm2) at SILAR coating cycles of 5. In addition, the photovoltaic performance was improved by additional ZnS coating on the surface of SnS-sensitized TiO2 electrodes.

  1. Coherently-enabled environmental control of optics and energy transfer pathways of hybrid quantum dot-metallic nanoparticle systems.

    Science.gov (United States)

    Hatef, Ali; Sadeghi, Seyed M; Fortin-Deschênes, Simon; Boulais, Etienne; Meunier, Michel

    2013-03-11

    It is well-known that optical properties of semiconductor quantum dots can be controlled using optical cavities or near fields of localized surface plasmon resonances (LSPRs) of metallic nanoparticles. In this paper we study the optics, energy transfer pathways, and exciton states of quantum dots when they are influenced by the near fields associated with plasmonic meta-resonances. Such resonances are formed via coherent coupling of excitons and LSPRs when the quantum dots are close to metallic nanorods and driven by a laser beam. Our results suggest an unprecedented sensitivity to the refractive index of the environment, causing significant spectral changes in the Förster resonance energy transfer from the quantum dots to the nanorods and in exciton transition energies. We demonstrate that when a quantum dot-metallic nanorod system is close to its plasmonic meta-resonance, we can adjust the refractive index to: (i) control the frequency range where the energy transfer from the quantum dot to the metallic nanorod is inhibited, (ii) manipulate the exciton transition energy shift of the quantum dot, and (iii) disengage the quantum dot from the metallic nanoparticle and laser field. Our results show that near meta-resonances the spectral forms of energy transfer and exciton energy shifts are strongly correlated to each other.

  2. Synthesis, characterization and applications of carboxylated and polyethylene-glycolated bifunctionalized InP/ZnS quantum dots in cellular internalization mediated by cell-penetrating peptides.

    Science.gov (United States)

    Liu, Betty R; Winiarz, Jeffrey G; Moon, Jong-Sik; Lo, Shih-Yen; Huang, Yue-Wern; Aronstam, Robert S; Lee, Han-Jung

    2013-11-01

    Semiconductor nanoparticles, also known as quantum dots (QDs), are widely used in biomedical imaging studies and pharmaceutical research. Cell-penetrating peptides (CPPs) are a group of small peptides that are able to traverse cell membrane and deliver a variety of cargoes into living cells. CPPs deliver QDs into cells with minimal nonspecific absorption and toxic effect. In this study, water-soluble, monodisperse, carboxyl-functionalized indium phosphide (InP)/zinc sulfide (ZnS) QDs coated with polyethylene glycol lipids (designated QInP) were synthesized for the first time. The physicochemical properties (optical absorption, fluorescence and charging state) and cellular internalization of QInP and CPP/QInP complexes were characterized. CPPs noncovalently interact with QInP in vitro to form stable CPP/QInP complexes, which can then efficiently deliver QInP into human A549 cells. The introduction of 500nM of CPP/QInP complexes and QInP at concentrations of less than 1μM did not reduce cell viability. These results indicate that carboxylated and polyethylene-glycolylated (PEGylated) bifunctionalized QInP are biocompatible nanoparticles with potential for use in biomedical imaging studies and drug delivery applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. The role of the tunneling matrix element and nuclear reorganization in the design of quantum-dot cellular automata molecules

    Science.gov (United States)

    Henry, Jackson; Blair, Enrique P.

    2018-02-01

    Mixed-valence molecules provide an implementation for a high-speed, energy-efficient paradigm for classical computing known as quantum-dot cellular automata (QCA). The primitive device in QCA is a cell, a structure with multiple quantum dots and a few mobile charges. A single mixed-valence molecule can function as a cell, with redox centers providing quantum dots. The charge configuration of a molecule encodes binary information, and device switching occurs via intramolecular electron transfer between dots. Arrays of molecular cells adsorbed onto a substrate form QCA logic. Individual cells in the array are coupled locally via the electrostatic electric field. This device networking enables general-purpose computing. Here, a quantum model of a two-dot molecule is built in which the two-state electronic system is coupled to the dominant nuclear vibrational mode via a reorganization energy. This model is used to explore the effects of the electronic inter-dot tunneling (coupling) matrix element and the reorganization energy on device switching. A semi-classical reduction of the model also is made to investigate the competition between field-driven device switching and the electron-vibrational self-trapping. A strong electron-vibrational coupling (high reorganization energy) gives rise to self-trapping, which inhibits the molecule's ability to switch. Nonetheless, there remains an expansive area in the tunneling-reorganization phase space where molecules can support adequate tunneling. Thus, the relationship between the tunneling matrix element and the reorganization energy affords significant leeway in the design of molecules viable for QCA applications.

  4. A metric for characterizing the bistability of molecular quantum-dot cellular automata

    International Nuclear Information System (INIS)

    Lu Yuhui; Lent, Craig S

    2008-01-01

    Much of molecular electronics involves trying to use molecules as (a) wires, (b) diodes or (c) field-effect transistors. In each case the criterion for determining good performance is well known: for wires it is conductance, for diodes it is conductance asymmetry, while for transistors it is high transconductance. Candidate molecules can be screened in terms of these criteria by calculating molecular conductivity in forward and reverse directions, and in the presence of a gating field. Hence so much theoretical work has focused on understanding molecular conductance. In contrast a molecule used as a quantum-dot cellular automata (QCA) cell conducts no current at all. The keys to QCA functionality are (a) charge localization, (b) bistable charge switching within the cell and (c) electric field coupling between one molecular cell and its neighbor. The combination of these effects can be examined using the cell-cell response function which relates the polarization of one cell to the induced polarization of a neighboring cell. The response function can be obtained by calculating the molecular electronic structure with ab initio quantum chemistry techniques. We present an analysis of molecular QCA performance that can be applied to any candidate molecule. From the full quantum chemistry, all-electron ab initio calculations we extract parameters for a reduced-state model which reproduces the cell-cell response function very well. Techniques from electron transfer theory are used to derive analytical models of the response function and can be employed on molecules too large for full ab initio treatment. A metric is derived which characterizes molecular QCA performance the way transconductance characterizes transistor performance. This metric can be assessed from absorption measurements of the electron transfer band or quantum chemistry calculations of appropriate sophistication

  5. Additive interaction of carbon dots extracted from soluble coffee and biogenic silver nanoparticles against bacteria

    International Nuclear Information System (INIS)

    Andrade, Patricia F.; Durán, Nelson; Nakazato, Gerson

    2017-01-01

    It is known the presence of carbon dots (CDs) in carbohydrate based foods. CDs extracted from coffee grounds and instant coffee was also published. CDs from soluble coffee revealed an average size of 4.4 nm. CDs were well-dispersed in water, fluorescent and we have characterized by XPS, XRD analysis, fluorescence and by FTIR spectra. The MIC value by serial micro-dilution assays for CDs on S. aureus ATCC 25923 was 250 μg/mL and E. coli ATCC 25922 >1000 ug/mL. For silver nanoparticles biogenically synthesized was 6.7 μg/mL. Following the checkerboard assay with combining ½ MIC values of the MICs of 125 μg/mL of carbon dots and 3.4 μg/mL of silver nanoparticles, following the fractionated inhibitory concentration (FIC) index methodology, on S. aureus gave a fractionated inhibitory concentration (FIC) value of 1.0, meaning additive interaction. In general, the unfunctionalized CDs showed to be inefficient as antibacterial compounds, however the CDs extracted from Coffee powder and together silver nanoparticles appeared interesting as antibacterial association. (paper)

  6. Protein Corona Analysis of Silver Nanoparticles Links to Their Cellular Effects.

    Science.gov (United States)

    Juling, Sabine; Niedzwiecka, Alicia; Böhmert, Linda; Lichtenstein, Dajana; Selve, Sören; Braeuning, Albert; Thünemann, Andreas F; Krause, Eberhard; Lampen, Alfonso

    2017-11-03

    The breadth of applications of nanoparticles and the access to food-associated consumer products containing nanosized materials lead to oral human exposure to such particles. In biological fluids nanoparticles dynamically interact with biomolecules and form a protein corona. Knowledge about the protein corona is of great interest for understanding the molecular effects of particles as well as their fate inside the human body. We used a mass spectrometry-based toxicoproteomics approach to elucidate mechanisms of toxicity of silver nanoparticles and to comprehensively characterize the protein corona formed around silver nanoparticles in Caco-2 human intestinal epithelial cells. Results were compared with respect to the cellular function of proteins either affected by exposure to nanoparticles or present in the protein corona. A transcriptomic data set was included in the analyses in order to obtain a combined multiomics view of nanoparticle-affected cellular processes. A relationship between corona proteins and the proteomic or transcriptomic responses was revealed, showing that differentially regulated proteins or transcripts were engaged in the same cellular signaling pathways. Protein corona analyses of nanoparticles in cells might therefore help in obtaining information about the molecular consequences of nanoparticle treatment.

  7. Unambiguous observation of shape effects on cellular fate of nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Chu, Z.; Zhang, S.; Zhang, B.; Zhang, C.; Fang, C. Y.; Řehoř, Ivan; Cígler, Petr; Chang, H. C.; Lin, G.; Liu, R.; Li, Q.

    2014-01-01

    Roč. 4, Mar 28 (2014), 4495/1-4495/9 ISSN 2045-2322 R&D Projects: GA ČR GAP108/12/0640; GA MŠk(CZ) LH11027 Institutional support: RVO:61388963 Keywords : mesoporous silica nanoparticles * gene delivery * gold nanoparticles Subject RIV: CC - Organic Chemistry Impact factor: 5.578, year: 2014

  8. Functionalization and cellular uptake of boron carbide nanoparticles

    DEFF Research Database (Denmark)

    Mortensen, M. W.; Björkdahl, O.; Sørensen, P. G.

    2006-01-01

    In this paper we present surface modification strategies of boron carbide nanoparticles, which allow for bioconjugation of the transacting transcriptional activator (TAT) peptide and fluorescent dyes. Coated nanoparticles can be translocated into murine EL4 thymoma cells and B16 F10 malignant...

  9. "Cloud" assemblies: quantum dots form electrostatically bound dynamic nebulae around large gold nanoparticles.

    Science.gov (United States)

    Lilly, G Daniel; Lee, Jaebeom; Kotov, Nicholas A

    2010-10-14

    Dynamic self-assembled structures of nanoparticles can be produced using predominantly electrostatic interactions. Such assemblies were made from large, positively charged Au metal nanoparticles surrounded by an electrostatically bound cloud of smaller, negatively charged CdSe/ZnS or CdTe quantum dots. At low concentrations they are topologically similar to double electric layers of ions and corona-like assemblies linked by polymer chains. They can also be compared to the topological arrangement of some planetary systems in space. The great advantages of the cloud assemblies are (1) their highly dynamic nature compared to more rigid covalently bound assemblies, (2) simplicity of preparation, and (3) exceptional versatility in components and resulting optical properties. Photoluminescence intensity enhancement originating from quantum resonance between excitons and plasmons was observed for CdSe/ZnS quantum dots, although CdTe dots displayed emission quenching. To evaluate more attentively their dynamic behavior, emission data were collected for the cloud-assemblies with different ratios of the components and ionic strengths of the media. The emission of the system passes through a maximum for 80 QDs ∶ 1 Au NP as determined by the structure of the assemblies and light absorption conditions. Ionic strength dependence of luminescence intensity contradicts the predictions based on the Gouy-Chapman theory and osmotic pressure at high ionic strengths due to formation of larger chaotic colloidally stable assemblies. "Cloud" assemblies made from different nanoscale components can be used both for elucidation of most fundamental aspects of nanoparticle interactions, as well as for practical purposes in sensing and biology.

  10. Cellular uptake and transport of zein nanoparticles: effects of sodium caseinate.

    Science.gov (United States)

    Luo, Yangchao; Teng, Zi; Wang, Thomas T Y; Wang, Qin

    2013-08-07

    Cellular evaluation of zein nanoparticles has not been studied systematically due to their poor redispersibility. Caseinate (CAS)-stabilized zein nanoparticles have been recently developed with better redispersibility in salt solutions. In this study, zein-CAS nanoparticles were prepared with different zein/CAS mass ratios. The prepared nanoparticles demonstrated good stabilities to maintain particle size (120-140 nm) in cell culture medium and HBSS buffer at 37 °C. The nanoparticles showed no cytotoxicity for Caco-2 cells for 72 h. CAS not only significantly enhanced cell uptake of zein nanoparticles in a concentration- and time-dependent manner but also remarkably improved epithelial transport through Caco-2 cell monolayer. The cell uptake of zein-CAS nanoparticles indicated an energy-dependent endocytosis process as evidenced by cell uptake under blocking conditions, that is, 4 °C, sodium azide, and colchicine. Fluorescent microscopy clearly showed the internalization of zein-CAS nanoparticles. This study may shed some light on the cellular evaluations of hydrophobic protein nanoparticles.

  11. In one harness: the interplay of cellular responses and subsequent cell fate after quantum dot uptake

    KAUST Repository

    Gladkovskaya, Olga; Gun'Ko, Yuri K.; O'Connor, Gerard M.; Gogvadze, Vladimir; Rochev, Yury

    2016-01-01

    is to organize existing knowledge into lucid biological and mathematical models. In our review we aim to describe the interplay of various cell death mechanisms triggered by quantum dots as a consequence of particle parameters and experimental conditions.

  12. Plasmon-enhanced second harmonic generation in semiconductor quantum dots close to metal nanoparticles

    Directory of Open Access Journals (Sweden)

    Andrea V. Bragas

    2011-03-01

    Full Text Available We report the enhancement of the optical second harmonic signal in non-centrosymmetric semiconductor CdS quantum dots, when they are placed in close contact with isolated silver nanoparticles. The intensity enhancement is about 1000. We also show that the enhancement increases when the incoming laser frequency $omega$ is tuned toward the spectral position of the silver plasmon at $2omega$, proving that the silver nanoparticle modifies the nonlinear emission.Received: 8 March 2011, Accepted: 30 May 2011; Edited by: L. Viña; Reviewed by: R. Gordon, Department of Electrical and Computer Engineering, University of Victoria, British Columbia, Canada; DOI: 10.4279/PIP.030002Cite as: P. M. Jais, C. von Bilderling, A. V. Bragas, Papers in Physics 3, 030002 (2011

  13. Examining changes in cellular communication in neuroendocrine cells after noble metal nanoparticle exposure.

    Science.gov (United States)

    Love, Sara A; Liu, Zhen; Haynes, Christy L

    2012-07-07

    As nanoparticles enjoy increasingly widespread use in commercial applications, the potential for unintentional exposure has become much more likely during any given day. Researchers in the field of nanotoxicity are working to determine the physicochemical nanoparticle properties that lead to toxicity in an effort to establish safe design rules. This work explores the effects of noble metal nanoparticle exposure in murine chromaffin cells, focusing on examining the effects of size and surface functionality (coating) in silver and gold, respectively. Carbon-fibre microelectrode amperometry was utilized to examine the effect of exposure on exocytosis function, at the single cell level, and provided new insights into the compromised functions of cells. Silver nanoparticles of varied size, between 15 and 60 nm diameter, were exposed to cells and found to alter the release kinetics of exocytosis for those cells exposed to the smallest examined size. Effects of gold were examined after modification with two commonly used 'bio-friendly' polymers, either heparin or poly (ethylene glycol), and gold nanoparticles were found to induce altered cellular adhesion or the number of chemical messenger molecules released, respectively. These results support the body of work suggesting that noble metal nanoparticles perturb exocytosis, typically altering the number of molecules and kinetics of release, and supports a direct disruption of the vesicle matrix by the nanoparticle. Overall, it is clear that various nanoparticle physicochemical properties, including size and surface coating, do modulate changes in cellular communication via exocytosis.

  14. Controllable synthesis, growth mechanism and optical properties of the ZnSe quantum dots and nanoparticles with different crystalline phases

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Bo [Key Laboratory of Excited State Physics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern Nan-Hu Road, Changchun 130033 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Institute of Condensed State Physics, Jilin Normal University, Siping 136000 (China); Yang, Jinghai, E-mail: jhyang1@jlnu.edu.cn [Institute of Condensed State Physics, Jilin Normal University, Siping 136000 (China); Cao, Jian; Yang, Lili; Gao, Ming; Wei, Maobin; Liu, Yang [Institute of Condensed State Physics, Jilin Normal University, Siping 136000 (China); Song, Hang [Key Laboratory of Excited State Physics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern Nan-Hu Road, Changchun 130033 (China)

    2013-03-15

    Graphical abstract: The ZnSe quantum dots (3.5 nm) with the wurtzite structure exhibited a strong near band-edge emission (NBE) peak centered at 422 nm. The zinc blende ZnSe nanoparticles (21 nm) exhibited near-band-edge luminescence peak centered at 472 nm. Highlights: ► The results of TEM showed that the ZnSe quantum dots were about 3.5 nm. ► The ZnSe quantum dots exhibited a near band-edge emission peak centered at 422 nm. ► The ZnSe nanoparticles exhibited near-band-edge luminescence peak centered at 472 nm. - Abstract: ZnSe precursors were prepared by a solvothermal method at 180 °C without any surface-active agents. ZnSe quantum dots and nanoparticles were obtained by annealing the precursors at 300 °C for 2 h in argon atmosphere. The ZnSe quantum dots were about 3.5 nm, while the ZnSe nanoparticles were about 21 nm, as observed using TEM. The growth mechanisms for the two samples were discussed; this proved that the high coordination ability of ethylenediamine to zinc played an important role in the final phase of the products. The ZnSe quantum dots with the wurtzite structure exhibited a strong near band-edge emission (NBE) peak centered at 422 nm, which was blue-shifted in comparison to that of the bulk ZnSe, which was mainly caused by the quantum confinement effect. However, the zinc blende ZnSe nanoparticles exhibited a near-band-edge luminescence peak centered at 472 nm.

  15. Optical response of hybrid semiconductor quantum dot-metal nanoparticle system: Beyond the dipole approximation

    Science.gov (United States)

    Mohammadzadeh, Atefeh; Miri, MirFaez

    2018-01-01

    We study the response of a semiconductor quantum dot-metal nanoparticle system to an external field E 0 cos ( ω t ) . The borders between Fano, double peaks, weak transition, strong transition, and bistability regions of the phase diagram move considerably as one regards the multipole effects. The exciton-induced transparency is an artifact of the dipole approximation. The absorption of the nanoparticle, the population inversion of the quantum dot, the upper and lower limits of intensity where bistability occurs, the characteristic time to reach the steady state, and other features of the hybrid system change due to the multipole effects. The phase diagrams corresponding to the fields parallel and perpendicular to the axis of system are quite distinguishable. Thus, both the intensity and the polarization of the incident field can be used to control the system. In particular, the incident polarization can be used to switch on and switch off the bistable behavior. For applications such as miniaturized bistable devices and nanosensors sensitive to variations of the dielectric constant of the surrounding medium, multipole effects must be considered.

  16. Synthesis and application of luminescent single CdS quantum dot encapsulated silica nanoparticles directed for precision optical bioimaging

    Directory of Open Access Journals (Sweden)

    Veeranarayanan S

    2012-07-01

    Full Text Available Srivani Veeranarayanan, Aby Cheruvathoor Poulose, M Sheikh Mohamed, Yutaka Nagaoka, Seiki Iwai, Yuya Nakagame, Shosaku Kashiwada, Yasuhiko Yoshida, Toru Maekawa, D Sakthi KumarBio Nano Electronics Research Centre, Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe, JapanAbstract: This paper presents the synthesis of aqueous cadmium sulfide (CdS quantum dots (QDs and silica-encapsulated CdS QDs by reverse microemulsion method and utilized as targeted bio-optical probes. We report the role of CdS as an efficient cell tag with fluorescence on par with previously documented cadmium telluride and cadmium selenide QDs, which have been considered to impart high levels of toxicity. In this study, the toxicity of bare QDs was efficiently quenched by encapsulating them in a biocompatible coat of silica. The toxicity profile and uptake of bare CdS QDs and silica-coated QDs, along with the CD31-labeled, silica-coated CdS QDs on human umbilical vein endothelial cells and glioma cells, were investigated. The effect of size, along with the time-dependent cellular uptake of the nanomaterials, has also been emphasized. Enhanced, high-specificity imaging toward endothelial cell lines in comparison with glioma cells was achieved with CD31 antibody-conjugated nanoparticles. The silica-coated nanomaterials exhibited excellent biocompatibility and greater photostability inside live cells, in addition to possessing an extended shelf life. In vivo biocompatibility and localization study of silica-coated CdS QDs in medaka fish embryos, following direct nanoparticle exposure for 24 hours, authenticated the nanomaterials' high potential for in vivo imaging, augmented with superior biocompatibility. As expected, CdS QD-treated embryos showed 100% mortality, whereas the silica-coated QD-treated embryos stayed viable and healthy throughout and after the experiments, devoid of any deformities. We provide highly cogent and convincing evidence for such

  17. Stability and toxicity of ZnO quantum dots: Interplay between nanoparticles and bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Bellanger, Xavier, E-mail: xavier.bellanger@univ-lorraine.fr [Université de Lorraine and CNRS, Laboratoire de Chimie Physique et Microbiologie pour l’Environnement (LCPME), UMR 7564, 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy (France); Billard, Patrick, E-mail: patrick.billard@univ-lorraine.fr [Université de Lorraine and CNRS, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), UMR 7360, Boulevard des Aiguillettes, Faculté des Sciences et Techniques, BP 70239, 54506 Vandoeuvre-lès-Nancy (France); Schneider, Raphaël, E-mail: raphael.schneider@univ-lorraine.fr [Université de Lorraine and CNRS, Laboratoire Réactions et Génie des Procédés (LRGP), UMR 7274, 1 rue Grandville, BP 20451, 54001 Nancy Cedex (France); Balan, Lavinia, E-mail: lavinia.balan@uha.fr [Institut de Science des Matériaux de Mulhouse (IS2M), UMR 7361, CNRS, 15 rue Jean Starcky, 68093 Mulhouse (France); Merlin, Christophe, E-mail: christophe.merlin@univ-lorraine.fr [Université de Lorraine and CNRS, Laboratoire de Chimie Physique et Microbiologie pour l’Environnement (LCPME), UMR 7564, 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy (France)

    2015-02-11

    Graphical abstract: - Highlights: • Dilution of aminosilane-capped ZnO QDs dramatically increases their dissolution. • Bacteria limit Zn{sup 2+} leakage from ZnO QDs in a physiological-dependent process. • Implementation of biosensors for assessing free metal promotes QDs instability. • Dialysis combined to ICP allows studying QDs stability without prior dilution. - Abstract: The toxicity of quantum dots (QDs) has been commonly attributed to the release of metal ions from the core as well as to the production of reactive oxygen species. However, the information related to the stability of the nanoparticles are relatively scarce although this parameter may strongly influence their toxicity. The stability of aminosilane-capped ZnO QDs, here used as model nanoparticles, was investigated by inductively coupled plasma-optical emission spectrometer (ICP-OES) and whole cell biosensors using a dialysis setup to separate the QDs from the leaked Zn{sup 2+} ions. The integrity of the ZnO QDs appeared strongly affected by their dilution in aqueous medium, whereas the nanoparticles were slightly stabilized by bacteria. Our results demonstrate some inadequacy between the implementation and use of whole cell biosensors, and the monitoring of metal release from QDs.

  18. Silver and gold nanoparticle coated membranes applied to protein dot blots

    International Nuclear Information System (INIS)

    Xie, F.; Drozdowicz-Tomsia, K.; Shtoyko, T.; Goldys, E. M.

    2011-01-01

    Detection and identification of low abundance biomarker proteins is frequently based on various types of membrane-based devices. Lowering of the protein detection limits is vital in commercial applications such as lateral flow assays and in Western blots widely used in proteomics. These currently suffer from insufficient detection sensitivity and low retention for small 2–5 kDa proteins. In this study, we report the deposition of two types of metal nanoparticles: gold colloids (50–95 nm diameter) and silver fractals onto a range of commonly used types of membranes including polyvinylidene fluoride (PVDF). Due to strong affinity of proteins to noble metals, such modified membranes have the potential to effectively capture trace proteins preventing their loss. The membranes modified by metal particles were characterized optically and by SEM. The membrane performance in protein dot blots was evaluated using the protein—fluorophore conjugates Deep Purple-bovine serum albumin and fluorescein—human serum albumin. We found that the metal nanoparticles increase light extinction by metals, which is balanced by increased fluorescence, so that the effective fluorescence signal is unchanged. This feature combined with the capture of proteins by the nanoparticles embedded in the membrane increases the detection limit of membrane assays.

  19. In one harness: the interplay of cellular responses and subsequent cell fate after quantum dot uptake

    KAUST Repository

    Gladkovskaya, Olga

    2016-09-13

    Rapid growth and expansion of engineered nanomaterials will occur when the technology can be used safely. Quantum dots have excellent prospects in clinical applications, but the issue of toxicity has not yet been resolved. To enable their medical implementation, the effect on, and mechanisms in, live cells should be clearly known and predicted. A massive amount of experimental data dedicated to nanotoxicity has been accumulated to-date, but it lacks a logical structure. The current challenge is to organize existing knowledge into lucid biological and mathematical models. In our review we aim to describe the interplay of various cell death mechanisms triggered by quantum dots as a consequence of particle parameters and experimental conditions.

  20. PEG-phospholipid-encapsulated bismuth sulfide and CdSe/ZnS quantum dot core–shell nanoparticle and its computed tomography/fluorescence performance

    International Nuclear Information System (INIS)

    Chen, Jun; Yang, Xiao-Quan; Qin, Meng-Yao; Zhang, Xiao-Shuai; Xuan, Yang; Zhao, Yuan-Di

    2015-01-01

    In this paper, polyethylene glycol-phospholipid structure is used to synthesize hybrid cluster of 40–50 nm diameter that contains hydrophobic bismuth sulfide nanoparticles and CdSe/ZnS quantum dots. The composite probe’s toxicity, CT imaging, and fluorescence imaging performance are also studied. Experimental results show that the nanocomposite hybrid cluster has obvious CT contrast enhancement and fluorescence imaging capability in vitro even after cellular uptake. It gives a CT number of 700 (Hounsfield units) at 15 mg/mL, higher than that of the current iobitridol CT contrast agent. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide experiment reveals that it has low cytotoxicity at concentration up to of 3.14 mg/mL of Bi, indicating the composite probe has potential ability for CT and fluorescence bimodal imaging

  1. Cellular oxido-reductive proteins of Chlamydomonas reinhardtii control the biosynthesis of silver nanoparticles

    Directory of Open Access Journals (Sweden)

    Barwal Indu

    2011-12-01

    Full Text Available Abstract Background Elucidation of molecular mechanism of silver nanoparticles (SNPs biosynthesis is important to control its size, shape and monodispersity. The evaluation of molecular mechanism of biosynthesis of SNPs is of prime importance for the commercialization and methodology development for controlling the shape and size (uniform distribution of SNPs. The unicellular algae Chlamydomonas reinhardtii was exploited as a model system to elucidate the role of cellular proteins in SNPs biosynthesis. Results The C. reinhardtii cell free extract (in vitro and in vivo cells mediated synthesis of silver nanoparticles reveals SNPs of size range 5 ± 1 to 15 ± 2 nm and 5 ± 1 to 35 ± 5 nm respectively. In vivo biosynthesized SNPs were localized in the peripheral cytoplasm and at one side of flagella root, the site of pathway of ATP transport and its synthesis related enzymes. This provides an evidence for the involvement of oxidoreductive proteins in biosynthesis and stabilization of SNPs. Alteration in size distribution and decrease of synthesis rate of SNPs in protein-depleted fractions confirmed the involvement of cellular proteins in SNPs biosynthesis. Spectroscopic and SDS-PAGE analysis indicate the association of various proteins on C. reinhardtii mediated in vivo and in vitro biosynthesized SNPs. We have identified various cellular proteins associated with biosynthesized (in vivo and in vitro SNPs by using MALDI-MS-MS, like ATP synthase, superoxide dismutase, carbonic anhydrase, ferredoxin-NADP+ reductase, histone etc. However, these proteins were not associated on the incubation of pre-synthesized silver nanoparticles in vitro. Conclusion Present study provides the indication of involvement of molecular machinery and various cellular proteins in the biosynthesis of silver nanoparticles. In this report, the study is mainly focused towards understanding the role of diverse cellular protein in the synthesis and capping of silver

  2. Coherent confinement of plasmonic field in quantum dot-metallic nanoparticle molecules.

    Science.gov (United States)

    Sadeghi, S M; Hatef, A; Fortin-Deschenes, Simon; Meunier, Michel

    2013-05-24

    Interaction of a hybrid system consisting of a semiconductor quantum dot and a metallic nanoparticle (MNP) with a laser beam can replace the intrinsic plasmonic field of the MNP with a coherently normalized field (coherent-plasmonic or CP field). In this paper we show how quantum coherence effects in such a hybrid system can form a coherent barrier (quantum cage) that spatially confines the CP field. This allows us to coherently control the modal volume of this field, making it significantly smaller or larger than that of the intrinsic plasmonic field of the MNP. We investigate the spatial profiles of the CP field and discuss how the field barrier depends on the collective states of the hybrid system.

  3. Au Nanoparticles as Interfacial Layer for CdS Quantum Dot-sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Zhu Guang

    2010-01-01

    Full Text Available Abstract Quantum dot-sensitized solar cells based on fluorine-doped tin oxide (FTO/Au/TiO2/CdS photoanode and polysulfide electrolyte are fabricated. Au nanoparticles (NPs as interfacial layer between FTO and TiO2 layer are dip-coated on FTO surface. The structure, morphology and impedance of the photoanodes and the photovoltaic performance of the cells are investigated. A power conversion efficiency of 1.62% has been obtained for FTO/Au/TiO2/CdS cell, which is about 88% higher than that for FTO/TiO2/CdS cell (0.86%. The easier transport of excited electron and the suppression of charge recombination in the photoanode due to the introduction of Au NP layer should be responsible for the performance enhancement of the cell.

  4. Modeling Quantum Dot Nanoparticle Fate and Transport in Saturated Porous Media under Varying Flow Conditions

    Science.gov (United States)

    Becker, M. D.; Wang, Y.; Englehart, J.; Pennell, K. D.; Abriola, L. M.

    2010-12-01

    As manufactured nanomaterials become more prevalent in commercial and industrial applications, the development of mathematical models capable of predicting nanomaterial transport and retention in subsurface systems is crucial to assessing their fate and distribution in the environment. A systematic modeling approach based on a modification of clean-bed filtration theory was undertaken to elucidate mechanisms governing the transport and deposition behavior of quantum dots in saturated quartz sand as a function of grain size and flow velocity. The traditional deposition governing equation, which assumes irreversible attachment by a first-order rate (katt), was modified to include a maximum or limiting retention capacity (Smax) and first-order detachment of particles from the solid phase (kdet). Quantum dot mobility experiments were performed in columns packed with three size fractions of Ottawa sand (d50 = 125, 165, and 335 μm) at two different pore-water velocities (0.8 m/d and 7.6 m/d). The CdSe quantum dots in a CdZnS shell and polyacrylic acid coating were negatively charged (zeta potential measured ca. -35 mV) with a hydrodynamic diameter of approximately 30 nm. Fitted values of katt, Smax, and kdet were obtained for each transport and deposition experiment through the implementation of a nonlinear least-squares routine developed to fit the model to experimental breakthrough and retention data via multivariate optimization. Fitted attachment rates and retention capacities increased exponentially with decreasing grain size at both flow rates, while no discernable trend was apparent for the fitted detachment rates. Maximum retention capacity values were plotted against a normalized mass flux expression, which accounts for flow conditions and grain size. A power function fit to the data yielded a dependence that was consistent with a previous study undertaken with fullerene nanoparticles.

  5. Paclitaxel molecularly imprinted polymer-PEG-folate nanoparticles for targeting anticancer delivery: Characterization and cellular cytotoxicity

    International Nuclear Information System (INIS)

    Esfandyari-Manesh, Mehdi; Darvishi, Behrad; Ishkuh, Fatemeh Azizi; Shahmoradi, Elnaz; Mohammadi, Ali; Javanbakht, Mehran; Dinarvand, Rassoul; Atyabi, Fatemeh

    2016-01-01

    showed high drug loading and encapsulation efficiency, 15.57 ± 0.84 and 100%, respectively. • Nanoparticles demonstrated a superior cellular uptake over non-targeted nanoparticles. • IC_5_0 of nanoparticles and IC_5_0 of free paclitaxel were 4.86 ± 0.91 and 32.80 ± 3.80 nM, respectively. • The imprinted nanoparticles showed high affinity to paclitaxel in biological samples.

  6. Paclitaxel molecularly imprinted polymer-PEG-folate nanoparticles for targeting anticancer delivery: Characterization and cellular cytotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Esfandyari-Manesh, Mehdi [Nanotechnology Research Center,Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Department of Chemistry, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Darvishi, Behrad [Nanotechnology Research Center,Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Ishkuh, Fatemeh Azizi [Department of Chemistry, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Shahmoradi, Elnaz [Department of Chemical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Mohammadi, Ali [Nanotechnology Research Center,Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Javanbakht, Mehran [Department of Chemistry, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Dinarvand, Rassoul [Nanotechnology Research Center,Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Atyabi, Fatemeh, E-mail: atyabifa@tums.ac.ir [Nanotechnology Research Center,Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2016-05-01

    showed high drug loading and encapsulation efficiency, 15.57 ± 0.84 and 100%, respectively. • Nanoparticles demonstrated a superior cellular uptake over non-targeted nanoparticles. • IC{sub 50} of nanoparticles and IC{sub 50} of free paclitaxel were 4.86 ± 0.91 and 32.80 ± 3.80 nM, respectively. • The imprinted nanoparticles showed high affinity to paclitaxel in biological samples.

  7. A dual-mode nanosensor based on carbon quantum dots and gold nanoparticles for discriminative detection of glutathione in human plasma.

    Science.gov (United States)

    Shi, Yupeng; Pan, Yi; Zhang, Heng; Zhang, Zhaomin; Li, Mei-Jin; Yi, Changqing; Yang, Mengsu

    2014-06-15

    Glutathione (GSH) plays key roles in biological systems and serves many cellular functions. Since biothiols all incorporate thiol, carboxylic and amino groups, discriminative detection of GSH over cysteine (Cys) and homocysteine (Hcy) is still challenging. We herein report a dual-mode nanosensor with both colorimetric and fluorometric readout based on carbon quantum dots and gold nanoparticles for discriminative detection of GSH over Cys/Hcy. The proposed sensing system consists of AuNPs and fluorescent carbon quantum dots (CQDs), where CQDs function as fluorometric reporter, and AuNPs serve a dual function as colorimetric reporter and fluorescence quencher. The mechanism of the nanosensor is based on two distance-dependent phenomenons, color change of AuNPs and FRET. Through controlling the surface properties of as-prepared nanoparticles, the addition of CQDs into AuNPs colloid solution might induce the aggregation of AuNPs and CQDs, leading to AuNPs color changing from red to blue and CQDs fluorescence quench. However, the presence of GSH can protect AuNPs from being aggregated and enlarge the inter-particle distance, which subsequently produces color change and fluorescent signal recovery. The nanosensor described in this report reflects on its simplicity and flexibility, where no further surface functionalization is required for the as-prepared nanoparticles, leading to less laborious and more cost-effective synthesis. The proposed dual-mode nanosensor demonstrated highly selectivity toward GSH, and allows the detection of GSH as low as 50 nM. More importantly, the nanosensor could not only function in aqueous solution for GSH detection with high sensitivity but also exhibit sensitive responses toward GSH in complicated biological environments, demonstrating its potential in bioanalysis and biodection, which might be significant in disease diagnosis in the future. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Electric Field Modulation of Semiconductor Quantum Dot Photoluminescence: Insights Into the Design of Robust Voltage-Sensitive Cellular Imaging Probes.

    Science.gov (United States)

    Rowland, Clare E; Susumu, Kimihiro; Stewart, Michael H; Oh, Eunkeu; Mäkinen, Antti J; O'Shaughnessy, Thomas J; Kushto, Gary; Wolak, Mason A; Erickson, Jeffrey S; Efros, Alexander L; Huston, Alan L; Delehanty, James B

    2015-10-14

    The intrinsic properties of quantum dots (QDs) and the growing ability to interface them controllably with living cells has far-reaching potential applications in probing cellular processes such as membrane action potential. We demonstrate that an electric field typical of those found in neuronal membranes results in suppression of the QD photoluminescence (PL) and, for the first time, that QD PL is able to track the action potential profile of a firing neuron with millisecond time resolution. This effect is shown to be connected with electric-field-driven QD ionization and consequent QD PL quenching, in contradiction with conventional wisdom that suppression of the QD PL is attributable to the quantum confined Stark effect.

  9. A unique structure for the multiplexer in quantum-dot cellular automata to create a revolution in design of nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Naji Asfestani, Mazaher; Rasouli Heikalabad, Saeed, E-mail: s.rasouli@iaut.ac.ir

    2017-05-01

    Quantum-dot cellular automata (QCA) is the advent of technology and suitable replacement for semiconductor transistor technology. In this paper, a unique structure for the 2:1 multiplexer is presented in QCA. The structure of this component is simple, ultra-efficient and very useful to implement the various logical functions. The proposed structure does not follow any Boolean function. It takes advantage of the inherent characteristics of quantum technology to produce the desired output. Based on these principles, we design the new and efficient structures for the 4:1 multiplexer and 8:1 multiplexer in the QCA technology. These structures are designed with QCADesigner simulator and simulation results are examined. Investigation results indicate the amazing performance of proposed structure compared to existing structures in terms of area, complexity, power consumption and latency.

  10. A novel multiplexer-based structure for random access memory cell in quantum-dot cellular automata

    Science.gov (United States)

    Naji Asfestani, Mazaher; Rasouli Heikalabad, Saeed

    2017-09-01

    Quantum-dot cellular automata (QCA) is a new technology in scale of nano and perfect replacement for CMOS circuits in the future. Memory is one of the basic components in any digital system, so designing the random access memory (RAM) with high speed and optimal in QCA is important. In this paper, by employing the structure of multiplexer, a novel RAM cell architecture is proposed. The proposed architecture is implemented without the coplanar crossover approach. The proposed architecture is simulated using the QCADesigner version 2.0.3 and QCAPro. The simulation results demonstrate that the proposed QCA RAM architecture has the best performance in terms of delay, circuit complexity, area, cell count and energy consumption in comparison with other QCA RAM architectures.

  11. Design and implementation of an efficient single layer five input majority voter gate in quantum-dot cellular automata.

    Science.gov (United States)

    Bahar, Ali Newaz; Waheed, Sajjad

    2016-01-01

    The fundamental logical element of a quantum-dot cellular automata (QCA) circuit is majority voter gate (MV). The efficiency of a QCA circuit is depends on the efficiency of the MV. This paper presents an efficient single layer five-input majority voter gate (MV5). The structure of proposed MV5 is very simple and easy to implement in any logical circuit. This proposed MV5 reduce number of cells and use conventional QCA cells. However, using MV5 a multilayer 1-bit full-adder (FA) is designed. The functional accuracy of the proposed MV5 and FA are confirmed by QCADesigner a well-known QCA layout design and verification tools. Furthermore, the power dissipation of proposed circuits are estimated, which shows that those circuits dissipate extremely small amount of energy and suitable for reversible computing. The simulation outcomes demonstrate the superiority of the proposed circuit.

  12. The cellular magnetic response and biocompatibility of biogenic zinc- and cobalt-doped magnetite nanoparticles

    Science.gov (United States)

    Moise, Sandhya; Céspedes, Eva; Soukup, Dalibor; Byrne, James M.; El Haj, Alicia J.; Telling, Neil D.

    2017-01-01

    The magnetic moment and anisotropy of magnetite nanoparticles can be optimised by doping with transition metal cations, enabling their properties to be tuned for different biomedical applications. In this study, we assessed the suitability of bacterially synthesized zinc- and cobalt-doped magnetite nanoparticles for biomedical applications. To do this we measured cellular viability and activity in primary human bone marrow-derived mesenchymal stem cells and human osteosarcoma-derived cells. Using AC susceptibility we studied doping induced changes in the magnetic response of the nanoparticles both as stable aqueous suspensions and when associated with cells. Our findings show that the magnetic response of the particles was altered after cellular interaction with a reduction in their mobility. In particular, the strongest AC susceptibility signal measured in vitro was from cells containing high-moment zinc-doped particles, whilst no signal was observed in cells containing the high-anisotropy cobalt-doped particles. For both particle types we found that the moderate dopant levels required for optimum magnetic properties did not alter their cytotoxicity or affect osteogenic differentiation of the stem cells. Thus, despite the known cytotoxicity of cobalt and zinc ions, these results suggest that iron oxide nanoparticles can be doped to sufficiently tailor their magnetic properties without compromising cellular biocompatibility.

  13. Impact of cell adhesion and migration on nanoparticle uptake and cellular toxicity.

    Science.gov (United States)

    Pitchaimani, Arunkumar; Nguyen, Tuyen Duong Thanh; Koirala, Mukund; Zhang, Yuntao; Aryal, Santosh

    2017-09-01

    In vitro cell-nanoparticle (NP) studies involve exposure of NPs onto the monolayer cells growing at the bottom of a culture plate, and assumed that the NPs evenly distributed for a dose-responsive effect. However, only a few proportion of the administered dose reaches the cells depending on their size, shape, surface, and density. Often the amount incubated (administered dose) is misled as a responsive dose. Herein, we proposed a cell adhesion-migration (CAM) strategy, where cells incubated with the NP coated cell culture substrate to maximize the cell-NP interaction and investigated the physiological properties of the cells. In the present study, cell adhesion and migration pattern of human breast cancer cell (MCF-7) and mouse melanoma cell (B16-F10) on cell culture substrate decorated with toxic (cetyltrimethylammonium bromide, CTAB) and biocompatible (poly (sodium 4-styrenesulphonate), PSS) gold nanoparticles (AuNPs) of different sizes (5 and 40nm) were investigated and evaluated for cellular uptake efficiency, proliferation, and toxicity. Results showed enhanced cell adhesion, migration, and nanoparticle uptake only on biocompatible PSS coated AuNP, irrespective of its size. Whereas, cytotoxic NP shows retard proliferation with reduced cellular uptake efficiency. Considering the importance of cell adhesion and migration on cellular uptake and cytotoxicity assessment of nanoparticle, CAM strategy would hold great promises in cell-NP interaction studies. Copyright © 2017. Published by Elsevier Ltd.

  14. Cellular transfer of magnetic nanoparticles via cell microvesicles: impact on cell tracking by magnetic resonance imaging.

    Science.gov (United States)

    Silva, Amanda K Andriola; Wilhelm, Claire; Kolosnjaj-Tabi, Jelena; Luciani, Nathalie; Gazeau, Florence

    2012-05-01

    Cell labeling with magnetic nanoparticles can be used to monitor the fate of transplanted cells in vivo by magnetic resonance imaging. However, nanoparticles initially internalized in administered cells might end up in other cells of the host organism. We investigated a mechanism of intercellular cross-transfer of magnetic nanoparticles to different types of recipient cells via cell microvesicles released under cellular stress. Three cell types (mesenchymal stem cells, endothelial cells and macrophages) were labeled with 8-nm iron oxide nanoparticles. Then cells underwent starvation stress, during which they produced microvesicles that were subsequently transferred to unlabeled recipient cells. The analysis of the magnetophoretic mobility of donor cells indicated that magnetic load was partially lost under cell stress. Microvesicles shed by stressed cells participated in the release of magnetic label. Moreover, such microvesicles were uptaken by naïve cells, resulting in cellular redistribution of nanoparticles. Iron load of recipient cells allowed their detection by MRI. Cell microvesicles released under stress may be disseminated throughout the organism, where they can be uptaken by host cells. The transferred cargo may be sufficient to allow MRI detection of these secondarily labeled cells, leading to misinterpretations of the effectiveness of transplanted cells.

  15. Cellular imaging and folate receptor targeting delivery of gum kondagogu capped gold nanoparticles in cancer cells.

    Science.gov (United States)

    Kumar, Sathish Sundar Dhilip; Mahesh, Ayyavu; Antoniraj, M Gover; Rathore, Hanumant Singh; Houreld, N N; Kandasamy, Ruckmani

    2018-04-01

    In this study, the green synthesis of gum kondagogu capped gold nanoparticles (GK-GNPs) was prepared using a naturally available polysaccharide. The anionic gum capped GK-GNPs enabled the successful coupling of folic acid (FA) and fluorescein isothiocyanate (FITC) to produce a fluorescently labelled GNP (F2-GNP). F2-GNPs were further characterized using different physicochemical methods Cellular viability, cellular imaging, and targeted delivery of F2-GNPs were further evaluated in both folate receptor positive (MCF-7) and folate receptor negative (A549) cancer cells. Physicochemical characterization revealed a nanoparticle with a small size (37 nm), smooth surface (surface charge of -23.7 mV), crystallinity of gold nanoparticles and existence of gum kondagogu in the F2-GNPs. Cellular uptake of F2-GNPs indicated a greater affinity towards folate receptor positive cells. This study shows that the F2-GNPs is as an effective nanocarrier for targeted drug delivery and cellular imaging via folate receptors. Copyright © 2017. Published by Elsevier B.V.

  16. Highly Parallel Computing Architectures by using Arrays of Quantum-dot Cellular Automata (QCA): Opportunities, Challenges, and Recent Results

    Science.gov (United States)

    Fijany, Amir; Toomarian, Benny N.

    2000-01-01

    There has been significant improvement in the performance of VLSI devices, in terms of size, power consumption, and speed, in recent years and this trend may also continue for some near future. However, it is a well known fact that there are major obstacles, i.e., physical limitation of feature size reduction and ever increasing cost of foundry, that would prevent the long term continuation of this trend. This has motivated the exploration of some fundamentally new technologies that are not dependent on the conventional feature size approach. Such technologies are expected to enable scaling to continue to the ultimate level, i.e., molecular and atomistic size. Quantum computing, quantum dot-based computing, DNA based computing, biologically inspired computing, etc., are examples of such new technologies. In particular, quantum-dots based computing by using Quantum-dot Cellular Automata (QCA) has recently been intensely investigated as a promising new technology capable of offering significant improvement over conventional VLSI in terms of reduction of feature size (and hence increase in integration level), reduction of power consumption, and increase of switching speed. Quantum dot-based computing and memory in general and QCA specifically, are intriguing to NASA due to their high packing density (10(exp 11) - 10(exp 12) per square cm ) and low power consumption (no transfer of current) and potentially higher radiation tolerant. Under Revolutionary Computing Technology (RTC) Program at the NASA/JPL Center for Integrated Space Microelectronics (CISM), we have been investigating the potential applications of QCA for the space program. To this end, exploiting the intrinsic features of QCA, we have designed novel QCA-based circuits for co-planner (i.e., single layer) and compact implementation of a class of data permutation matrices, a class of interconnection networks, and a bit-serial processor. Building upon these circuits, we have developed novel algorithms and QCA

  17. The inhibition of optical excitations and enhancement of Rabi flopping in hybrid quantum dot-metallic nanoparticle systems

    International Nuclear Information System (INIS)

    Sadeghi, S M

    2009-01-01

    We study the inhibition of optical excitation and enhancement of Rabi flopping and frequency in semiconductor quantum dots via plasmonic effects. This is done by demonstrating that the interaction of a quantum dot with a laser field in the vicinity of a metallic nanoparticle can be described in terms of optical Bloch equations with a plasmically normalized Rabi frequency. We show that in the weak-field regime plasmonic effects can suppress the interband transitions, inhibiting exciton generation. In the strong-field regime these effects delay the response of the quantum dot to the laser field and enhance Rabi flopping. We relate these to the conversion of Rabi frequency from a real quantity into a complex and strongly frequency-dependent quantity as plasmonic effects become significant. We show that, within the strong-field regime, in the wavelength range where real and imaginary parts of this frequency reach their maxima, a strongly frequency-dependent enhancement of carrier excitation can happen.

  18. The distribution and degradation of radiolabeled superparamagnetic iron oxide nanoparticles and quantum dots in mice

    Directory of Open Access Journals (Sweden)

    Denise Bargheer

    2015-01-01

    Full Text Available 51Cr-labeled, superparamagnetic, iron oxide nanoparticles (51Cr-SPIOs and 65Zn-labeled CdSe/CdS/ZnS-quantum dots (65Zn-Qdots were prepared using an easy, on demand, exchange-labeling technique and their particokinetic parameters were studied in mice after intravenous injection. The results indicate that the application of these heterologous isotopes can be used to successfully mark the nanoparticles during initial distribution and organ uptake, although the 65Zn-label appeared not to be fully stable. As the degradation of the nanoparticles takes place, the individual transport mechanisms for the different isotopes must be carefully taken into account. Although this variation in transport paths can bring new insights with regard to the respective trace element homeostasis, it can also limit the relevance of such trace material-based approaches in nanobioscience. By monitoring 51Cr-SPIOs after oral gavage, the gastrointestinal non-absorption of intact SPIOs in a hydrophilic or lipophilic surrounding was measured in mice with such high sensitivity for the first time. After intravenous injection, polymer-coated, 65Zn-Qdots were mainly taken up by the liver and spleen, which was different from that of ionic 65ZnCl2. Following the label for 4 weeks, an indication of substantial degradation of the nanoparticles and the release of the label into the Zn pool was observed. Confocal microscopy of rat liver cryosections (prepared 2 h after intravenous injection of polymer-coated Qdots revealed a colocalization with markers for Kupffer cells and liver sinusoidal endothelial cells (LSEC, but not with hepatocytes. In J774 macrophages, fluorescent Qdots were found colocalized with lysosomal markers. After 24 h, no signs of degradation could be detected. However, after 12 weeks, no fluorescent nanoparticles could be detected in the liver cryosections, which would confirm our 65Zn data showing a substantial degradation of the polymer-coated CdSe/CdS/ZnS-Qdots in

  19. DNA-encapsulated magnesium phosphate nanoparticles elicit both humoral and cellular immune responses in mice

    Directory of Open Access Journals (Sweden)

    Gajadhar Bhakta

    2014-01-01

    Full Text Available The efficacy of pEGFP (plasmid expressing enhanced green fluorescent protein-encapsulated PEGylated (meaning polyethylene glycol coated magnesium phosphate nanoparticles (referred to as MgPi-pEGFP nanoparticles for the induction of immune responses was investigated in a mouse model. MgPi-pEGFP nanoparticles induced enhanced serum antibody and antigen-specific T-lymphocyte responses, as well as increased IFN-γ and IL-12 levels compared to naked pEGFP when administered via intravenous, intraperitoneal or intramuscular routes. A significant macrophage response, both in size and activity, was also observed when mice were immunized with the nanoparticle formulation. The response was highly specific for the antigen, as the increase in interaction between macrophages and lymphocytes as well as lymphocyte proliferation took place only when they were re-stimulated with recombinant green fluorescence protein (rGFP. Thus the nanoparticle formulation elicited both humoral as well as cellular responses. Cytokine profiling revealed the induction of Th-1 type responses. The results suggest DNA-encapsulated magnesium phosphate (MgPi nanoparticles may constitute a safer, more stable and cost-efficient DNA vaccine formulation.

  20. Biocompatible transferrin-conjugated sodium hexametaphosphate-stabilized gold nanoparticles: synthesis, characterization, cytotoxicity and cellular uptake

    International Nuclear Information System (INIS)

    Parab, Harshala J; Huang, Jing-Hong; Liu, Ru-Shi; Lai, Tsung-Ching; Jan, Yi-Hua; Wang, Jui-Ling; Hsiao, Michael; Chen, Chung-Hsuan; Hwu, Yeu-Kuang; Tsai, Din Ping; Chuang, Shih-Yi; Pang, Jong-Hwei S

    2011-01-01

    The feasibility of using gold nanoparticles (AuNPs) for biomedical applications has led to considerable interest in the development of novel synthetic protocols and surface modification strategies for AuNPs to produce biocompatible molecular probes. This investigation is, to our knowledge, the first to elucidate the synthesis and characterization of sodium hexametaphosphate (HMP)-stabilized gold nanoparticles (Au-HMP) in an aqueous medium. The role of HMP, a food additive, as a polymeric stabilizing and protecting agent for AuNPs is elucidated. The surface modification of Au-HMP nanoparticles was carried out using polyethylene glycol and transferrin to produce molecular probes for possible clinical applications. In vitro cell viability studies performed using as-synthesized Au-HMP nanoparticles and their surface-modified counterparts reveal the biocompatibility of the nanoparticles. The transferrin-conjugated nanoparticles have significantly higher cellular uptake in J5 cells (liver cancer cells) than control cells (oral mucosa fibroblast cells), as determined by inductively coupled plasma mass spectrometry. This study demonstrates the possibility of using an inexpensive and non-toxic food additive, HMP, as a stabilizer in the large-scale generation of biocompatible and monodispersed AuNPs, which may have future diagnostic and therapeutic applications.

  1. Biocompatible transferrin-conjugated sodium hexametaphosphate-stabilized gold nanoparticles: synthesis, characterization, cytotoxicity and cellular uptake

    Energy Technology Data Exchange (ETDEWEB)

    Parab, Harshala J; Huang, Jing-Hong; Liu, Ru-Shi [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Lai, Tsung-Ching; Jan, Yi-Hua; Wang, Jui-Ling; Hsiao, Michael; Chen, Chung-Hsuan [Genomics Research Center, Academia Sinica, Taipei 115, Taiwan (China); Hwu, Yeu-Kuang [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Tsai, Din Ping [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Chuang, Shih-Yi; Pang, Jong-Hwei S, E-mail: rsliu@ntu.edu.tw, E-mail: mhsiao@gate.sinica.edu.tw [Graduate Institute of Clinical Medical Sciences, Chang Gung University, Tao-Yuan, Taiwan (China)

    2011-09-30

    The feasibility of using gold nanoparticles (AuNPs) for biomedical applications has led to considerable interest in the development of novel synthetic protocols and surface modification strategies for AuNPs to produce biocompatible molecular probes. This investigation is, to our knowledge, the first to elucidate the synthesis and characterization of sodium hexametaphosphate (HMP)-stabilized gold nanoparticles (Au-HMP) in an aqueous medium. The role of HMP, a food additive, as a polymeric stabilizing and protecting agent for AuNPs is elucidated. The surface modification of Au-HMP nanoparticles was carried out using polyethylene glycol and transferrin to produce molecular probes for possible clinical applications. In vitro cell viability studies performed using as-synthesized Au-HMP nanoparticles and their surface-modified counterparts reveal the biocompatibility of the nanoparticles. The transferrin-conjugated nanoparticles have significantly higher cellular uptake in J5 cells (liver cancer cells) than control cells (oral mucosa fibroblast cells), as determined by inductively coupled plasma mass spectrometry. This study demonstrates the possibility of using an inexpensive and non-toxic food additive, HMP, as a stabilizer in the large-scale generation of biocompatible and monodispersed AuNPs, which may have future diagnostic and therapeutic applications.

  2. Quantum dot-decorated semiconductor micro- and nanoparticles: A review of their synthesis, characterization and application in photocatalysis.

    Science.gov (United States)

    Bajorowicz, Beata; Kobylański, Marek P; Gołąbiewska, Anna; Nadolna, Joanna; Zaleska-Medynska, Adriana; Malankowska, Anna

    2018-06-01

    Quantum dot (QD)-decorated semiconductor micro- and nanoparticles are a new class of functional nanomaterials that have attracted considerable interest for their unique structural, optical and electronic properties that result from the large surface-to-volume ratio and the quantum confinement effect. In addition, because of QDs' excellent light-harvesting capacity, unique photoinduced electron transfer, and up-conversion behaviour, semiconductor nanoparticles decorated with quantum dots have been used widely in photocatalytic applications for the degradation of organic pollutants in both the gas and aqueous phases. This review is a comprehensive overview of the recent progress in synthesis methods for quantum dots and quantum dot-decorated semiconductor composites with an emphasis on their composition, morphology and optical behaviour. Furthermore, various approaches used for the preparation of QD-based composites are discussed in detail with respect to visible and UV light-induced photoactivity. Finally, an outlook on future development is proposed with the goal of overcoming challenges and stimulating further research into this promising field. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Cellular uptake of folate-conjugated lipophilic superparamagnetic iron oxide nanoparticles

    International Nuclear Information System (INIS)

    Woo, Kyoungja; Moon, Jihyung; Choi, Kyu-Sil; Seong, Tae-Yeon; Yoon, Kwon-Ha

    2009-01-01

    We prepared five folate-conjugated lipophilic superparamagnetic iron oxide nanoparticles (F 5 -Liposuperparamagnetic iron oxide nanoparticles(SPIONs), 5.5 and 11 nm) and investigated their cellular uptake with KB cells, which is one of the representative folate-receptor over-expressing human epidermoid carcinoma cells, using MRI. The cellular uptake tests with the respective 5.5 and 11 nm F 5 -LipoSPIONs at a fixed particle concentration showed appreciable amount of receptor-mediated uptakes and the specificity was higher in 5.5 nm SPIONs, due to its higher folic acid (FA) density, without inhibition. However, the numbers of the particles taken up under FA inhibition were similar, irrespective of their sizes.

  4. Cellular uptake of folate-conjugated lipophilic superparamagnetic iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Kyoungja [Nano-Materials Research Center, Korea Institute of Science and Technology, P. O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of)], E-mail: kjwoo@kist.re.kr; Moon, Jihyung [Nano-Materials Research Center, Korea Institute of Science and Technology, P. O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of); Department of Materials Science and Engineering, Korea University, 5-1, Anam-Dong, Sungbook-Ku, Seoul, 136-713 (Korea, Republic of); Choi, Kyu-Sil [Division of Molecular Imaging, Samsung Biomedical Research Institute, Samsung Medical Center, 50 Ilwon-Dong, Kangnam-Ku, Seoul 135-710 (Korea, Republic of); Seong, Tae-Yeon [Department of Materials Science and Engineering, Korea University, 5-1, Anam-Dong, Sungbook-Ku, Seoul, 136-713 (Korea, Republic of); Yoon, Kwon-Ha [Institute for Radiological Imaging Science, Wonkwang University School of Medicine, 344-2, Shinyong, Iksan, Jeonbuk 570-749 (Korea, Republic of)

    2009-05-15

    We prepared five folate-conjugated lipophilic superparamagnetic iron oxide nanoparticles (F{sub 5}-Liposuperparamagnetic iron oxide nanoparticles(SPIONs), 5.5 and 11 nm) and investigated their cellular uptake with KB cells, which is one of the representative folate-receptor over-expressing human epidermoid carcinoma cells, using MRI. The cellular uptake tests with the respective 5.5 and 11 nm F{sub 5}-LipoSPIONs at a fixed particle concentration showed appreciable amount of receptor-mediated uptakes and the specificity was higher in 5.5 nm SPIONs, due to its higher folic acid (FA) density, without inhibition. However, the numbers of the particles taken up under FA inhibition were similar, irrespective of their sizes.

  5. Release Properties and Cellular Uptake in Caco-2 Cells of Size-Controlled Chitosan Nanoparticles.

    Science.gov (United States)

    Je, Hyun Jeong; Kim, Eun Suh; Lee, Ji-Soo; Lee, Hyeon Gyu

    2017-12-20

    The influences of particle size on the physicochemical, release, and cellular uptake properties of chitosan nanoparticles (CSNPs) were investigated. Ionotropic CSNPs of different sizes (200-1000 nm) loaded with two model core materials (resveratrol or coumarin-6) were prepared using tripolyphosphate and carrageenan as cross-linkers. With an increase of particle size, zeta potential (34.6 ± 0.5 to 51.1 ± 0.9) and entrapment efficiency (14.9 ± 1.4 to 40.9 ± 1.9) of the CSNPs were significantly (p cellular uptake of CSNPs were significantly increased from 3.70 ± 0.03 to 5.24 ± 0.20 with an increase of particle size from 200 to 600 nm, whereas those significantly decreased from 5.24 ± 0.20 to 4.55 ± 0.2 for particles larger than 600 nm in transwell assay. Moreover, much the same uptake patterns were also observed in confocal microscopy and flow cytometry. Investigation of cellular uptake of CSNPs revealed positive correlations between ZP and EE and indicated the effects of complex factors of nanoparticles other than size. These results provide a better understanding of CSNPs absorption and raises the possibility of controlling alternative nanoparticle properties to enhance bioavailability.

  6. The effect of particle shape on cellular interaction and drug delivery applications of micro- and nanoparticles.

    Science.gov (United States)

    Jindal, Anil B

    2017-10-30

    Encapsulation of therapeutic agents in nanoparticles offers several benefits including improved bioavailability, site specific delivery, reduced toxicity and in vivo stability of proteins and nucleotides over conventional delivery options. These benefits are consequence of distinct in vivo pharmacokinetic and biodistribution profile of nanoparticles, which is dictated by the complex interplay of size, surface charge and surface hydrophobicity. Recently, particle shape has been identified as a new physical parameter which has exerted tremendous impact on cellular uptake and biodistribution, thereby in vivo performance of nanoparticles. Improved therapeutic efficacy of anticancer agents using non-spherical particles is the recent development in the field. Additionally, immunological response of nanoparticles was also altered when antigens were loaded in non-spherical nanovehicles. The apparent impact of particle shape inspired the new research in the field of drug delivery. The present review therefore details the research in this field. The review focuses on methods of fabrication of particles of non-spherical geometries and impact of particle shape on cellular uptake, biodistribution, tumor targeting and production of immunological responses. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Silver Nanoparticle-Mediated Cellular Responses in Various Cell Lines: An in Vitro Model

    Directory of Open Access Journals (Sweden)

    Xi-Feng Zhang

    2016-09-01

    Full Text Available Silver nanoparticles (AgNPs have attracted increased interest and are currently used in various industries including medicine, cosmetics, textiles, electronics, and pharmaceuticals, owing to their unique physical and chemical properties, particularly as antimicrobial and anticancer agents. Recently, several studies have reported both beneficial and toxic effects of AgNPs on various prokaryotic and eukaryotic systems. To develop nanoparticles for mediated therapy, several laboratories have used a variety of cell lines under in vitro conditions to evaluate the properties, mode of action, differential responses, and mechanisms of action of AgNPs. In vitro models are simple, cost-effective, rapid, and can be used to easily assess efficacy and performance. The cytotoxicity, genotoxicity, and biocompatibility of AgNPs depend on many factors such as size, shape, surface charge, surface coating, solubility, concentration, surface functionalization, distribution of particles, mode of entry, mode of action, growth media, exposure time, and cell type. Cellular responses to AgNPs are different in each cell type and depend on the physical and chemical nature of AgNPs. This review evaluates significant contributions to the literature on biological applications of AgNPs. It begins with an introduction to AgNPs, with particular attention to their overall impact on cellular effects. The main objective of this review is to elucidate the reasons for different cell types exhibiting differential responses to nanoparticles even when they possess similar size, shape, and other parameters. Firstly, we discuss the cellular effects of AgNPs on a variety of cell lines; Secondly, we discuss the mechanisms of action of AgNPs in various cellular systems, and try to elucidate how AgNPs interact with different mammalian cell lines and produce significant effects; Finally, we discuss the cellular activation of various signaling molecules in response to AgNPs, and conclude with

  8. Facile, Large-Quantity Synthesis of Stable, Tunable-Color Silicon Nanoparticles and Their Application for Long-Term Cellular Imaging.

    Science.gov (United States)

    Zhong, Yiling; Sun, Xiaotian; Wang, Siyi; Peng, Fei; Bao, Feng; Su, Yuanyuan; Li, Youyong; Lee, Shuit-Tong; He, Yao

    2015-06-23

    We herein introduce a facile, low-cost photochemical method capable of rapid (nanoparticles (SiNPs) of tunable optical properties (peak emission wavelength in the range of 470-560 nm) under ambient air conditions, by introducing 1,8-naphthalimide as a reducing agent and surface ligands. The as-prepared SiNPs feature robust storage stability and photostability preserving strong and stable fluorescent during long-term (>3 h) high-power UV irradiation, in contrast to the rapid fluorescence quenching within 2 h of conventional organic dyes and II-VI quantum dots under the same conditions. The as-prepared SiNPs serving as photostable nanoprobes are workable for cellular imaging in long-term manners. Our findings provide a powerful method for mild-condition and low-cost, large-quantity production of highly fluorescent and photostable SiNPs for various promising applications.

  9. Optical pumping of a single hole spin in a p-doped quantum dot coupled to a metallic nanoparticle

    Science.gov (United States)

    Antón, M. A.; Carreño, F.; Melle, Sonia; Calderón, Oscar G.; Cabrera-Granado, E.; Singh, Mahi R.

    2013-05-01

    The preparation of quantum states with a defined spin is analyzed in a hybrid system consisting of a p-doped semiconductor quantum dot (QD) coupled to a metallic nanoparticle. The quantum dot is described as a four-level atom-like system using the density matrix formalism. The lower levels are Zeeman-split hole spin states and the upper levels correspond to positively charged excitons containing a spin-up, spin-down hole pair and a spin electron. A metallic nanoparticle with spheroidal geometry is placed in close proximity to the quantum dot, and its effects are considered in the quasistatic approximation. A linearly polarized laser field drives two of the optical transitions of the QD and produces localized surface plasmons in the nanoparticle which act back upon the QD. The frequencies of these localized plasmons are very different along the two principal axes of the nanoparticle, thus producing an anisotropic modification of the spontaneous emission rates of the allowed optical transitions which is accompanied by local-field corrections. This effect translates into a preferential acceleration of some of the optical pathways and therefore into a fast initialization of the QD by excitation with a short optical pulse. The population transfer between the lower levels of the QD and the fidelity is analyzed as a function of the nanoparticle's aspect ratio, the external magnetic field, and the Rabi frequency of the driving field. It is also shown that the main effect of the local-field corrections is a lengthening of the time elapsed to reach the steady-state. The hole spin is predicted to be successfully cooled from 5 to 0.04 K at a magnetic field of 4.6 T applied in the Voigt geometry.

  10. Preparation of strongly fluorescent silica nanoparticles of polyelectrolyte-protected cadmium telluride quantum dots and their application to cell toxicity and imaging

    International Nuclear Information System (INIS)

    Tang Jianhua; Xie Lian; Zhang Bin; Qiu Ting; Qi Bin; Xie Hongping

    2012-01-01

    Graphical abstract: The staining effect of the control group (a), QDs-SiO 2 (b) and QDs-PDADMAC-SiO 2 (c). Highlights: ► The fluorescence intensity of QDs-PDADMAC-SiO 2 is stronger than that of QDs-SiO 2 . ► The fluorescence stability of QDs-PDADMAC-SiO 2 is better than that of QDs-SiO 2 . ► The cytotoxicity of QDs-PDADMAC-SiO 2 was lower than that of QDs-SiO 2 ► The staining effect of QDs-PDADMAC-SiO 2 was much better than that of QDs-SiO 2 . - Abstract: Based on the polyelectrolyte-protected CdTe quantum dots (QDs), which were prepared by self-assembling of QDs and poly-diallyldimethylammonium chloride (PDADMAC) in the help of electrostatic attraction, the strong fluorescence silica nanoparticles (QDs-PDADMAC-SiO 2 ) have been prepared via a water-in-oil reverse microemulsion method. Transmission electron microscopy and Zeta potential analysis were used to characterize the as-prepared nanoparticles. All of the particles were almost spherical and there is a uniform distribution of the particle size with the average diameter about 25 nm. There is a large Zeta potential of −35.07 mV which is necessary for good monodispersity of nanoparticles solution. As compared with the QDs coated by SiO 2 (QDs-SiO 2 ), the QDs-PDADMAC-SiO 2 nanoparticles have much stronger fluorescence, and their fluorescence stability could be obviously improved. Moreover, QDs-PDADMAC-SiO 2 exhibits good biological compatibility which promotes their application in cellular imaging.

  11. Cytotoxicity and cellular uptake of different sized gold nanoparticles in ovarian cancer cells

    Science.gov (United States)

    Kumar, Dhiraj; Mutreja, Isha; Chitcholtan, Kenny; Sykes, Peter

    2017-11-01

    Nanomedicine has advanced the biomedical field with the availability of multifunctional nanoparticles (NPs) systems that can target a disease site enabling drug delivery and helping to monitor the disease. In this paper, we synthesised the gold nanoparticles (AuNPs) with an average size 18, 40, 60 and 80 nm, and studied the effect of nanoparticles size, concentration and incubation time on ovarian cancer cells namely, OVCAR5, OVCAR8, and SKOV3. The size measured by transmission electron microscopy images was slightly smaller than the hydrodynamic diameter; measured size by ImageJ as 14.55, 38.13, 56.88 and 78.56 nm. The cellular uptake was significantly controlled by the AuNPs size, concentration, and the cell type. The nanoparticles uptake increased with increasing concentration, and 18 and 80 nm AuNPs showed higher uptake ranging from 1.3 to 5.4 μg depending upon the concentration and cell type. The AuNPs were associated with a temporary reduction in metabolic activity, but metabolic activity remained more than 60% for all sample types; NPs significantly affected the cell proliferation activity in first 12 h. The increase in nanoparticle size and concentration induced the production of reactive oxygen species in 24 h.

  12. Assessing potential peptide targeting ligands by quantification of cellular adhesion of model nanoparticles under flow conditions.

    Science.gov (United States)

    Broda, Ellen; Mickler, Frauke Martina; Lächelt, Ulrich; Morys, Stephan; Wagner, Ernst; Bräuchle, Christoph

    2015-09-10

    Sophisticated drug delivery systems are coated with targeting ligands to improve the specific adhesion to surface receptors on diseased cells. In our study, we developed a method with which we assessed the potential of peptide ligands to specifically bind to receptor overexpressing target cells. Therefore, a microfluidic setup was used where the cellular adhesion of nanoparticles with ligand and of control nanoparticles was observed in parallel under the same experimental conditions. The effect of the ligand on cellular binding was quantified by counting the number of adhered nanoparticles with ligand and differently labeled control nanoparticles on single cells after incubation under flow conditions. To provide easy-to-synthesize, stable and reproducible nanoparticles which mimic the surface characteristics of drug delivery systems and meet the requirements for quantitative analysis, latex beads based on amine-modified polystyrene were used as model nanoparticles. Two short peptides were tested to serve as targeting ligand on the beads by increasing the specific binding to HuH7 cells. The c-Met binding peptide cMBP2 was used for hepatocyte growth factor receptor (c-Met) targeting and the peptide B6 for transferrin receptor (TfR) targeting. The impact of the targeting peptide on binding was investigated by comparing the beads with ligand to different internal control beads: 1) without ligand and tailored surface charge (electrostatic control) and 2) with scrambled peptide and similar surface charge, but a different amino acid sequence (specificity control). Our results demonstrate that the method is very useful to select suitable targeting ligands for specific nanoparticle binding to receptor overexpressing tumor cells. We show that the cMBP2 ligand specifically enhances nanoparticle adhesion to target cells, whereas the B6 peptide mediates binding to tumor cells mainly by nonspecific interactions. All together, we suggest that cMBP2 is a suitable choice for

  13. Fano Effect and Quantum Entanglement in Hybrid Semiconductor Quantum Dot-Metal Nanoparticle System.

    Science.gov (United States)

    He, Yong; Zhu, Ka-Di

    2017-06-20

    In this paper, we review the investigation for the light-matter interaction between surface plasmon field in metal nanoparticle (MNP) and the excitons in semiconductor quantum dots (SQDs) in hybrid SQD-MNP system under the full quantum description. The exciton-plasmon interaction gives rise to the modified decay rate and the exciton energy shift which are related to the exciton energy by using a quantum transformation method. We illustrate the responses of the hybrid SQD-MNP system to external field, and reveal Fano effect shown in the absorption spectrum. We demonstrate quantum entanglement between two SQD mediated by surface plasmon field. In the absence of a laser field, concurrence of quantum entanglement will disappear after a few ns. If the laser field is present, the steady states appear, so that quantum entanglement produced will reach a steady-state entanglement. Because one of all optical pathways to induce Fano effect refers to the generation of quantum entangled states, It is shown that the concurrence of quantum entanglement can be obtained by observation for Fano effect. In a hybrid system including two MNP and a SQD, because the two Fano quantum interference processes share a segment of all optical pathways, there is correlation between the Fano effects of the two MNP. The investigations for the light-matter interaction in hybrid SQD-MNP system can pave the way for the development of the optical processing devices and quantum information based on the exciton-plasmon interaction.

  14. Methionine-mediated synthesis of magnetic nanoparticles and functionalization with gold quantum dots for theranostic applications

    Directory of Open Access Journals (Sweden)

    Arūnas Jagminas

    2017-08-01

    Full Text Available Biocompatible superparamagnetic iron oxide nanoparticles (NPs through smart chemical functionalization of their surface with fluorescent species, therapeutic proteins, antibiotics, and aptamers offer remarkable potential for diagnosis and therapy of disease sites at their initial stage of growth. Such NPs can be obtained by the creation of proper linkers between magnetic NP and fluorescent or drug probes. One of these linkers is gold, because it is chemically stable, nontoxic and capable to link various biomolecules. In this study, we present a way for a simple and reliable decoration the surface of magnetic NPs with gold quantum dots (QDs containing more than 13.5% of Au+. Emphasis is put on the synthesis of magnetic NPs by co-precipitation using the amino acid methionine as NP growth-stabilizing agent capable to later reduce and attach gold species. The surface of these NPs can be further conjugated with targeting and chemotherapy agents, such as cancer stem cell-related antibodies and the anticancer drug doxorubicin, for early detection and improved treatment. In order to verify our findings, high-resolution transmission electron microscopy (HRTEM, atomic force microscopy (AFM, FTIR spectroscopy, inductively coupled plasma mass spectroscopy (ICP-MS, and X-ray photoelectron spectroscopy (XPS of as-formed CoFe2O4 NPs before and after decoration with gold QDs were applied.

  15. Fano Effect and Quantum Entanglement in Hybrid Semiconductor Quantum Dot-Metal Nanoparticle System

    Directory of Open Access Journals (Sweden)

    Yong He

    2017-06-01

    Full Text Available In this paper, we review the investigation for the light-matter interaction between surface plasmon field in metal nanoparticle (MNP and the excitons in semiconductor quantum dots (SQDs in hybrid SQD-MNP system under the full quantum description. The exciton-plasmon interaction gives rise to the modified decay rate and the exciton energy shift which are related to the exciton energy by using a quantum transformation method. We illustrate the responses of the hybrid SQD-MNP system to external field, and reveal Fano effect shown in the absorption spectrum. We demonstrate quantum entanglement between two SQD mediated by surface plasmon field. In the absence of a laser field, concurrence of quantum entanglement will disappear after a few ns. If the laser field is present, the steady states appear, so that quantum entanglement produced will reach a steady-state entanglement. Because one of all optical pathways to induce Fano effect refers to the generation of quantum entangled states, It is shown that the concurrence of quantum entanglement can be obtained by observation for Fano effect. In a hybrid system including two MNP and a SQD, because the two Fano quantum interference processes share a segment of all optical pathways, there is correlation between the Fano effects of the two MNP. The investigations for the light-matter interaction in hybrid SQD-MNP system can pave the way for the development of the optical processing devices and quantum information based on the exciton-plasmon interaction.

  16. Epitope imprinted polymer nanoparticles containing fluorescent quantum dots for specific recognition of human serum albumin

    International Nuclear Information System (INIS)

    Wang, Yi-Zhi; Li, Dong-Yan; He, Xi-Wen; Li, Wen-You; Zhang, Yu-Kui

    2015-01-01

    Epitope imprinted polymer nanoparticles (EI-NPs) were prepared by one-pot polymerization of N-isopropylacrylamide in the presence of CdTe quantum dots and an epitope (consisting of amino acids 598 to 609) of human serum albumin (HSA). The resulting EI-NPs exhibit specific recognition ability and enable direct fluorescence quantification of HSA based on a fluorescence turn-on mode. The polymer was characterized by FT-IR, X-ray photoelectron spectroscopy, transmission electron microscopy and dynamic light scattering. The linear calibration graph was obtained in the range of 0.25–5 μmol · mL −1 with the detection limit of 44.3 nmol · mL −1 . The EI-NPs were successfully applied to the direct fluorometric quantification of HSA in samples of human serum. Overall, this approach provides a promising tool to design functional fluorescent materials with protein recognition capability and specific applications in proteomics. (author)

  17. Fluorometric immunoassay for human serum albumin based on its inhibitory effect on the immunoaggregation of quantum dots with silver nanoparticles

    Science.gov (United States)

    Marukhyan, Seda S.; Gasparyan, Vardan K.

    2017-02-01

    Quantitative determination of HSA was conducted by competitive immunoassay. Inhibition of aggregation of antibody conjugated quantum dots (QD) with albumin conjugated silver nanoparticles (AgNPs) in the presence of HSA was conducted. If antibody-loaded CdSe QDs aggregate with HSA-coated silver nanoparticles the distance between the two kinds of nanoparticles will be reduced enough to cause fluorescence resonance energy transfer (FRET). In this case the yellow fluorescence of the Ab-QDs is quenched. However if HSA (antigen) is added to the Ab-QDs their surface will be blocked and they cannot aggregate any longer with the HSA-AgNPs. Hence, fluorescence will not be quenched. The drop of the intensity of fluorescence (peaking at 570 nm) is inversely correlated with the concentration of HSA in the sample. The method allows to determine HSA in the 30-600 ng·mL-1 concentration range.

  18. Carbon dots based dual-emission silica nanoparticles as ratiometric fluorescent probe for nitrite determination in food samples.

    Science.gov (United States)

    Xiang, Guoqiang; Wang, Yule; Zhang, Heng; Fan, Huanhuan; Fan, Lu; He, Lijun; Jiang, Xiuming; Zhao, Wenjie

    2018-09-15

    In this work, a simple and effective strategy for designing a ratiometric fluorescent nanosensor was described. A carbon dots (CDs) based dual-emission nanosensor for nitrite was prepared by coating the CDs on to dye-doped silica nanoparticles. Dual-emission silica nanoparticles fluorescence was quenched in sulfuric acid using potassium bromate (KBrO 3 ). The nitrite present catalyzed the KBrO 3 oxidation, resulting in ratiometric fluorescence response of the dual-emission silica nanoparticles. Several important parameters affecting the performance of the nanosensor were investigated. Under optimized conditions, the limit of detection was 1.0 ng mL -1 and the linear range 10-160 ng mL -1 . Furthermore, the sensor was suitable for nitrite determination in different food samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Silica coating of luminescent quantum dots prepared in aqueous media for cellular labeling

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Yunfei; Li, Yan, E-mail: yli@ecust.edu.cn; Zhong, Xinhua, E-mail: zhongxh@ecust.edu.cn

    2014-12-15

    Graphical abstract: A facile route based on modified Stöber method was used for the synthesis of silica coated QDs (QD@SiO{sub 2}) starting from aqueously prepared CdTe/CdS QDs. The resultant QD@SiO{sub 2} exhibited a significant increase in emission efficiency compared with that of the initial QDs, along with a small size (∼5 nm in diameter), great stability and low cytotoxicity, which makes it a good candidate as robust biomarker. - Highlights: • We present a facile modified Stöber method to prepare highly luminescent QD@SiO{sub 2}. • The PL efficiency of QDs increases significantly after silica coating. • QD@SiO{sub 2} exhibits small size (∼5 nm) and great dispersibility in aqueous solution. • QD@SiO{sub 2} presents extraordinary photo and colloidal stability. • The silica shell eliminates QD cytotoxicity, providing the access of bioconjugation. - Abstract: Silica coating is an effective approach for rendering luminescent quantum dots (QDs) with water dispersibility and biocompatibility. However, it is still challenging to prepare silica-coated QDs (QD@SiO{sub 2}) with high emission efficiency, small size and great stability in favor for bioapplication. Herein, we reported a modified Stöber method for silica coating of aqueously-prepared CdTe/CdS QDs. With the coexistence of Cd{sup 2+} and thioglycolic acid (TGA), a thin silica shell was formed around QDs by the hydrolysis of tetraethyl orthosilicate (TEOS). The resultant QD@SiO{sub 2} with a small size (∼5 nm in diameter) exhibits significantly higher emission efficiencies than that of the initial QDs. Also, QD@SiO{sub 2} has extraordinary photo and colloidal stability (pH range of 5–13, 4.0 M NaCl solution). Protected by the silica shell, the cytotoxicity of QDs could be reduced. Moreover, the QD@SiO{sub 2} conjugated with folic acid (FA) presents high specific binding toward receptor-positive HeLa cells over receptor-negative A549 cells.

  20. Antimicrobial activity and cellular toxicity of nanoparticle-polymyxin B conjugates

    Science.gov (United States)

    Park, Soonhyang; Chibli, Hicham; Wong, Jody; Nadeau, Jay L.

    2011-05-01

    We investigate the antimicrobial activity and cytotoxicity to mammalian cells of conjugates of the peptide antibiotic polymyxin B (PMB) to Au nanoparticles and CdTe quantum dots. Au nanoparticles fully covered with PMB are identical in antimicrobial activity to the free drug alone, whereas partially-conjugated Au particles show decreased effectiveness in proportion to the concentration of Au. CdTe-PMB conjugates are more toxic to Escherichia coli than PMB alone, resulting in a flattening of the steep PMB dose-response curve. The effect is most pronounced at low concentrations of PMB, with a greater effect on the concentration required to reduce growth by half (IC50) than on the concentration needed to inhibit all growth (minimum inhibitory concentration, MIC). The Gram positive organism Staphylococcus aureus is resistant to both PMB and CdTe, showing minimal increased sensitivity when the two are conjugated. Measurement of reactive oxygen species (ROS) generation shows a significant reduction in photo-generated hydroxyl and superoxide radicals with CdTe-PMB as compared with bare CdTe. There is a corresponding reduction in toxicity of QD-PMB versus bare CdTe to mammalian cells, with nearly 100% survival in fibroblasts exposed to bactericidal concentrations of QD-PMB. The situation in bacteria is more complex: photoexcitation of the CdTe particles plays a small role in IC50 but has a significant effect on the MIC, suggesting that at least two different mechanisms are responsible for the antimicrobial action seen. These results show that it is possible to create antimicrobial agents using concentrations of CdTe quantum dots that do not harm mammalian cells.

  1. Antimicrobial activity and cellular toxicity of nanoparticle-polymyxin B conjugates

    International Nuclear Information System (INIS)

    Park, Soonhyang; Chibli, Hicham; Wong, Jody; Nadeau, Jay L

    2011-01-01

    We investigate the antimicrobial activity and cytotoxicity to mammalian cells of conjugates of the peptide antibiotic polymyxin B (PMB) to Au nanoparticles and CdTe quantum dots. Au nanoparticles fully covered with PMB are identical in antimicrobial activity to the free drug alone, whereas partially-conjugated Au particles show decreased effectiveness in proportion to the concentration of Au. CdTe-PMB conjugates are more toxic to Escherichia coli than PMB alone, resulting in a flattening of the steep PMB dose-response curve. The effect is most pronounced at low concentrations of PMB, with a greater effect on the concentration required to reduce growth by half (IC50) than on the concentration needed to inhibit all growth (minimum inhibitory concentration, MIC). The Gram positive organism Staphylococcus aureus is resistant to both PMB and CdTe, showing minimal increased sensitivity when the two are conjugated. Measurement of reactive oxygen species (ROS) generation shows a significant reduction in photo-generated hydroxyl and superoxide radicals with CdTe-PMB as compared with bare CdTe. There is a corresponding reduction in toxicity of QD-PMB versus bare CdTe to mammalian cells, with nearly 100% survival in fibroblasts exposed to bactericidal concentrations of QD-PMB. The situation in bacteria is more complex: photoexcitation of the CdTe particles plays a small role in IC50 but has a significant effect on the MIC, suggesting that at least two different mechanisms are responsible for the antimicrobial action seen. These results show that it is possible to create antimicrobial agents using concentrations of CdTe quantum dots that do not harm mammalian cells.

  2. Antimicrobial activity and cellular toxicity of nanoparticle-polymyxin B conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soonhyang; Chibli, Hicham; Wong, Jody; Nadeau, Jay L, E-mail: jay.nadeau@mcgill.ca [Department of Biomedical Engineering, McGill University, 3775 University Street, Montreal QC, H3A 2B4 (Canada)

    2011-05-06

    We investigate the antimicrobial activity and cytotoxicity to mammalian cells of conjugates of the peptide antibiotic polymyxin B (PMB) to Au nanoparticles and CdTe quantum dots. Au nanoparticles fully covered with PMB are identical in antimicrobial activity to the free drug alone, whereas partially-conjugated Au particles show decreased effectiveness in proportion to the concentration of Au. CdTe-PMB conjugates are more toxic to Escherichia coli than PMB alone, resulting in a flattening of the steep PMB dose-response curve. The effect is most pronounced at low concentrations of PMB, with a greater effect on the concentration required to reduce growth by half (IC50) than on the concentration needed to inhibit all growth (minimum inhibitory concentration, MIC). The Gram positive organism Staphylococcus aureus is resistant to both PMB and CdTe, showing minimal increased sensitivity when the two are conjugated. Measurement of reactive oxygen species (ROS) generation shows a significant reduction in photo-generated hydroxyl and superoxide radicals with CdTe-PMB as compared with bare CdTe. There is a corresponding reduction in toxicity of QD-PMB versus bare CdTe to mammalian cells, with nearly 100% survival in fibroblasts exposed to bactericidal concentrations of QD-PMB. The situation in bacteria is more complex: photoexcitation of the CdTe particles plays a small role in IC50 but has a significant effect on the MIC, suggesting that at least two different mechanisms are responsible for the antimicrobial action seen. These results show that it is possible to create antimicrobial agents using concentrations of CdTe quantum dots that do not harm mammalian cells.

  3. Toward Efficient Design of Reversible Logic Gates in Quantum-Dot Cellular Automata with Power Dissipation Analysis

    Science.gov (United States)

    Sasamal, Trailokya Nath; Singh, Ashutosh Kumar; Ghanekar, Umesh

    2018-04-01

    Nanotechnologies, remarkably Quantum-dot Cellular Automata (QCA), offer an attractive perspective for future computing technologies. In this paper, QCA is investigated as an implementation method for designing area and power efficient reversible logic gates. The proposed designs achieve superior performance by incorporating a compact 2-input XOR gate. The proposed design for Feynman, Toffoli, and Fredkin gates demonstrates 28.12, 24.4, and 7% reduction in cell count and utilizes 46, 24.4, and 7.6% less area, respectively over previous best designs. Regarding the cell count (area cover) that of the proposed Peres gate and Double Feynman gate are 44.32% (21.5%) and 12% (25%), respectively less than the most compact previous designs. Further, the delay of Fredkin and Toffoli gates is 0.75 clock cycles, which is equal to the delay of the previous best designs. While the Feynman and Double Feynman gates achieve a delay of 0.5 clock cycles, equal to the least delay previous one. Energy analysis confirms that the average energy dissipation of the developed Feynman, Toffoli, and Fredkin gates is 30.80, 18.08, and 4.3% (for 1.0 E k energy level), respectively less compared to best reported designs. This emphasizes the beneficial role of using proposed reversible gates to design complex and power efficient QCA circuits. The QCADesigner tool is used to validate the layout of the proposed designs, and the QCAPro tool is used to evaluate the energy dissipation.

  4. A novel power-efficient high-speed clock management unit using quantum-dot cellular automata

    International Nuclear Information System (INIS)

    Abutaleb, M. M.

    2017-01-01

    Quantum-dot cellular automata (QCA) is one of the most attractive alternatives for complementary metal-oxide semiconductor technology. The QCA widely supports a new paradigm in the field of nanotechnology that has the potential for high density, low power, and high speed. The clock manager is an essential building block in the new microwave and radio frequency integrated circuits. This paper describes a novel QCA-based clock management unit (CMU) that provides innovative clocking capabilities. The proposed CMU is achieved by utilizing edge-triggered D-type flip-flops (D-FFs) in the design of frequency synthesizer and phase splitter. Edge-triggered D-FF structures proposed in this paper have the successful QCA implementation and simulation with the least complexity and power dissipation as compared to earlier structures. The frequency synthesizer is used to generate new clock frequencies from the reference clock frequency based on a combination of power-of-two frequency dividers. The phase splitter is integrated with the frequency synthesizer to generate four clock signals that are 90"o out of phase with each other. This paper demonstrates that the proposed QCA CMU structure has a superior performance. Furthermore, the proposed CMU is straightforwardly scalable due to the use of modular component architecture.

  5. Synthesis of a Neutral Mixed-Valence Diferrocenyl Carborane for Molecular Quantum-Dot Cellular Automata Applications.

    Science.gov (United States)

    Christie, John A; Forrest, Ryan P; Corcelli, Steven A; Wasio, Natalie A; Quardokus, Rebecca C; Brown, Ryan; Kandel, S Alex; Lu, Yuhui; Lent, Craig S; Henderson, Kenneth W

    2015-12-14

    The preparation of 7-Fc(+) -8-Fc-7,8-nido-[C2 B9 H10 ](-) (Fc(+) FcC2 B9 (-) ) demonstrates the successful incorporation of a carborane cage as an internal counteranion bridging between ferrocene and ferrocenium units. This neutral mixed-valence Fe(II) /Fe(III) complex overcomes the proximal electronic bias imposed by external counterions, a practical limitation in the use of molecular switches. A combination of UV/Vis-NIR spectroscopic and TD-DFT computational studies indicate that electron transfer within Fc(+) FcC2 B9 (-) is achieved through a bridge-mediated mechanism. This electronic framework therefore provides the possibility of an all-neutral null state, a key requirement for the implementation of quantum-dot cellular automata (QCA) molecular computing. The adhesion, ordering, and characterization of Fc(+) FcC2 B9 (-) on Au(111) has been observed by scanning tunneling microscopy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. A novel power-efficient high-speed clock management unit using quantum-dot cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    Abutaleb, M. M., E-mail: mustafa-abotaleb@h-eng.helwan.edu.eg [Helwan University, Department of Electronics, Communications and Computer Engineering (Egypt)

    2017-04-15

    Quantum-dot cellular automata (QCA) is one of the most attractive alternatives for complementary metal-oxide semiconductor technology. The QCA widely supports a new paradigm in the field of nanotechnology that has the potential for high density, low power, and high speed. The clock manager is an essential building block in the new microwave and radio frequency integrated circuits. This paper describes a novel QCA-based clock management unit (CMU) that provides innovative clocking capabilities. The proposed CMU is achieved by utilizing edge-triggered D-type flip-flops (D-FFs) in the design of frequency synthesizer and phase splitter. Edge-triggered D-FF structures proposed in this paper have the successful QCA implementation and simulation with the least complexity and power dissipation as compared to earlier structures. The frequency synthesizer is used to generate new clock frequencies from the reference clock frequency based on a combination of power-of-two frequency dividers. The phase splitter is integrated with the frequency synthesizer to generate four clock signals that are 90{sup o} out of phase with each other. This paper demonstrates that the proposed QCA CMU structure has a superior performance. Furthermore, the proposed CMU is straightforwardly scalable due to the use of modular component architecture.

  7. Cytotoxicity and cellular uptake of tri-block copolymer nanoparticles with different size and surface characteristics

    Directory of Open Access Journals (Sweden)

    Bhattacharjee Sourav

    2012-04-01

    Full Text Available Abstract Background Polymer nanoparticles (PNP are becoming increasingly important in nanomedicine and food-based applications. Size and surface characteristics are often considered to be important factors in the cellular interactions of these PNP, although systematic investigations on the role of surface properties on cellular interactions and toxicity of PNP are scarce. Results Fluorescent, monodisperse tri-block copolymer nanoparticles with different sizes (45 and 90 nm and surface charges (positive and negative were synthesized, characterized and studied for uptake and cytotoxicity in NR8383 and Caco-2 cells. All types of PNP were taken up by the cells. The positive smaller PNP45 (45 nm showed a higher cytotoxicity compared to the positive bigger PNP90 (90 nm particles including reduction in mitochondrial membrane potential (ΔΨm, induction of reactive oxygen species (ROS production, ATP depletion and TNF-α release. The negative PNP did not show any cytotoxic effect. Reduction in mitochondrial membrane potential (ΔΨm, uncoupling of the electron transfer chain in mitochondria and the resulting ATP depletion, induction of ROS and oxidative stress may all play a role in the possible mode of action for the cytotoxicity of these PNP. The role of receptor-mediated endocytosis in the intracellular uptake of different PNP was studied by confocal laser scanning microscopy (CLSM. Involvement of size and charge in the cellular uptake of PNP by clathrin (for positive PNP, caveolin (for negative PNP and mannose receptors (for hydroxylated PNP were found with smaller PNP45 showing stronger interactions with the receptors than bigger PNP90. Conclusions The size and surface characteristics of polymer nanoparticles (PNP; 45 and 90 nm with different surface charges play a crucial role in cellular uptake. Specific interactions with cell membrane-bound receptors (clathrin, caveolin and mannose leading to cellular internalization were observed to depend on

  8. Dispersion Behaviour of Silica Nanoparticles in Biological Media and Its Influence on Cellular Uptake.

    Science.gov (United States)

    Halamoda-Kenzaoui, Blanka; Ceridono, Mara; Colpo, Pascal; Valsesia, Andrea; Urbán, Patricia; Ojea-Jiménez, Isaac; Gioria, Sabrina; Gilliland, Douglas; Rossi, François; Kinsner-Ovaskainen, Agnieszka

    2015-01-01

    Given the increasing variety of manufactured nanomaterials, suitable, robust, standardized in vitro screening methods are needed to study the mechanisms by which they can interact with biological systems. The in vitro evaluation of interactions of nanoparticles (NPs) with living cells is challenging due to the complex behaviour of NPs, which may involve dissolution, aggregation, sedimentation and formation of a protein corona. These variable parameters have an influence on the surface properties and the stability of NPs in the biological environment and therefore also on the interaction of NPs with cells. We present here a study using 30 nm and 80 nm fluorescently-labelled silicon dioxide NPs (Rubipy-SiO2 NPs) to evaluate the NPs dispersion behaviour up to 48 hours in two different cellular media either supplemented with 10% of serum or in serum-free conditions. Size-dependent differences in dispersion behaviour were observed and the influence of the living cells on NPs stability and deposition was determined. Using flow cytometry and fluorescence microscopy techniques we studied the kinetics of the cellular uptake of Rubipy-SiO2 NPs by A549 and CaCo-2 cells and we found a correlation between the NPs characteristics in cell media and the amount of cellular uptake. Our results emphasize how relevant and important it is to evaluate and to monitor the size and agglomeration state of nanoparticles in the biological medium, in order to interpret correctly the results of the in vitro toxicological assays.

  9. Smart Nanoparticles Undergo Phase Transition for Enhanced Cellular Uptake and Subsequent Intracellular Drug Release in a Tumor Microenvironment.

    Science.gov (United States)

    Ye, Guihua; Jiang, Yajun; Yang, Xiaoying; Hu, Hongxiang; Wang, Beibei; Sun, Lu; Yang, Victor C; Sun, Duxin; Gao, Wei

    2018-01-10

    Inefficient cellular uptake and intracellular drug release at the tumor site are two major obstacles limiting the antitumor efficacy of nanoparticle delivery systems. To overcome both problems, we designed a smart nanoparticle that undergoes phase transition in a tumor microenvironment (TME). The smart nanoparticle is generated using a lipid-polypetide hybrid nanoparticle, which comprises a PEGylated lipid monolayer shell and a pH-sensitive hydrophobic poly-l-histidine core and is loaded with the antitumor drug doxorubicin (DOX). The smart nanoparticle undergoes a two-step phase transition at two different pH values in the TME: (i) At the TME (pH e : 7.0-6.5), the smart nanoparticle swells, and its surface potential turns from negative to neutral, facilitating the cellular uptake; (ii) After internalization, at the acid endolysosome (pH endo : 6.5-4.5), the smart nanoparticle dissociates and induces endolysosome escape to release DOX into the cytoplasm. In addition, a tumor-penetrating peptide iNRG was modified on the surface of the smart nanoparticle as a tumor target moiety. The in vitro studies demonstrated that the iNGR-modified smart nanoparticles promoted cellular uptake in the acidic environment (pH 6.8). The in vivo studies showed that the iNGR-modified smart nanoparticles exerted more potent antitumor efficacy against late-stage aggressive breast carcinoma than free DOX. These data suggest that the smart nanoparticles may serve as a promising delivery system for sequential uptake and intracellular drug release of antitumor agents. The easy preparation of these smart nanoparticles may also have advantages in the future manufacture for clinical trials and clinical use.

  10. One-pot fabrication of high-quality InP/ZnS (core/shell) quantum dots and their application to cellular imaging.

    Science.gov (United States)

    Hussain, Sahid; Won, Nayoun; Nam, Jutaek; Bang, Jiwon; Chung, Hyokyun; Kim, Sungjee

    2009-07-13

    True colors: High-quality InP and InP/ZnS quantum dots (QDs) are obtained by means of a simple one-pot method in the presence of polyethylene glycol (PEG). Rapid and size-controlled reactions lead to highly crystalline and nearly monodisperse QDs at relatively low temperatures. The particles emit from cyan blue to far-red, and are successfully used in cellular imaging (see figure).

  11. Cellular and molecular responses of E. fetida coelomocytes exposed to TiO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bigorgne, Emilie, E-mail: emilie.bigorgne@univ-lorraine.fr; Foucaud, Laurent [Universite de Lorraine-Laboratoire des Interactions Ecotoxicologique Biodiversite Ecosystemes (LIEBE) (France); Caillet, Celine [Universite de Lorraine-Laboratoire Environnement et Mineralurgie (LEM) CNRS UMR7569 (France); Giamberini, Laure; Nahmani, Johanne [Universite de Lorraine-Laboratoire des Interactions Ecotoxicologique Biodiversite Ecosystemes (LIEBE) (France); Thomas, Fabien [Universite de Lorraine-Laboratoire Environnement et Mineralurgie (LEM) CNRS UMR7569 (France); Rodius, Francois [Universite de Lorraine-Laboratoire des Interactions Ecotoxicologique Biodiversite Ecosystemes (LIEBE) (France)

    2012-07-15

    An in vitro approach using coelomocytes of Eisenia fetida was investigated to evaluate toxicity of TiO{sub 2} nanoparticles. Coelomocytes were exposed to well-dispersed suspension of small aggregates (130 nm) of TiO{sub 2} nanoparticles (1-25 {mu}g/ml) during 4, 12 and 24 h. Intracellular localisation suggested that the main route of uptake was endocytosis. Cellular responses showed that TiO{sub 2} nanoparticles were not cytotoxic and had no effect on phagocytosis at any of the four concentrations for each time tested. Concerning molecular responses, an increase of fetidin and metallothionein mRNA expression was observed starting from 4 h of exposure. In contrast, expression of coelomic cytolytic factor mRNA decreased for 10 and 25 {mu}g/ml after 4 h. Superoxide dismutase, catalase and glutathione-S-transferase expression were not modified suggesting that oxidative stress was not induced by TiO{sub 2} in our experimental conditions. This in vitro approach showed that TiO{sub 2} nanoparticles were taken up by coelomocytes and they could modify the molecular response of immune and detoxification system.

  12. Hybrid structures based on gold nanoparticles and semiconductor quantum dots for biosensor applications

    Directory of Open Access Journals (Sweden)

    Kurochkina M

    2018-04-01

    Full Text Available Margarita Kurochkina,1 Elena Konshina,1 Aleksandr Oseev,2 Soeren Hirsch3 1Centre of Information Optical Technologies, ITMO University, Saint Petersburg, Russia; 2Institute of Micro and Sensor Systems, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; 3Department of Engineering, University of Applied Sciences Brandenburg, Brandenburg an der Havel, Germany Background: The luminescence amplification of semiconductor quantum dots (QD in the presence of self-assembled gold nanoparticles (Au NPs is one of way for creating biosensors with highly efficient transduction. Aims: The objective of this study was to fabricate the hybrid structures based on semiconductor CdSe/ZnS QDs and Au NP arrays and to use them as biosensors of protein. Methods: In this paper, the hybrid structures based on CdSe/ZnS QDs and Au NP arrays were fabricated using spin coating processes. Au NP arrays deposited on a glass wafer were investigated by optical microscopy and absorption spectroscopy depending on numbers of spin coating layers and their baking temperature. Bovine serum albumin (BSA was used as the target protein analyte in a phosphate buffer. A confocal laser scanning microscope was used to study the luminescent properties of Au NP/QD hybrid structures and to test BSA. Results: The dimensions of Au NP aggregates increased and the space between them decreased with increasing processing temperature. At the same time, a blue shift of the plasmon resonance peak in the absorption spectra of Au NP arrays was observed. The deposition of CdSe/ZnS QDs with a core diameter of 5 nm on the surface of the Au NP arrays caused an increase in absorption and a red shift of the plasmon peak in the spectra. The exciton–plasmon enhancement of the QDs’ photoluminescence intensity has been obtained at room temperature for hybrid structures with Au NPs array pretreated at temperatures of 100°C and 150°C. It has been found that an increase in the weight content of BSA

  13. Cellular Internalization and Biocompatibility of Periodic Mesoporous Organosilica Nanoparticles with Tunable Morphologies: From Nanospheres to Nanowires

    KAUST Repository

    Fatieiev, Yevhen

    2017-01-10

    This work describes the sol-gel syntheses of para-substituted phenylene-bridged periodic mesoporous organosilica (PMO) nanoparticles (NPs) with tunable morphologies ranging from nanowires to nanospheres. The findings show the key role of the addition of organic co-solvents in the aqueous templates on the final morphologies of PMO NPs. Other factors such as the temperature, the stirring speed, and the amount of organic solvents also influence the shape of PMO NPs. The tuning of the shape of the PMO nanomaterials made it possible to study the influence of the particle morphology on the cellular internalization and biocompatibility.

  14. Cellular uptake and cytotoxicity of positively charged chitosan gold nanoparticles in human lung adenocarcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seon Young; Jang, Soo Hwa [Seoul National University, Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Institute for Veterinary Science (Korea, Republic of); Park, Jin; Jeong, Saeromi; Park, Jin Ho; Ock, Kwang Su [Soongsil University, Department of Chemistry (Korea, Republic of); Lee, Kangtaek [Yonsei University, Department of Chemical and Biomolecular Engineering (Korea, Republic of); Yang, Sung Ik [Kyung Hee University, College of Environment and Applied Chemistry (Korea, Republic of); Joo, Sang-Woo, E-mail: sjoo@ssu.ac.kr [Soongsil University, Department of Chemistry (Korea, Republic of); Ryu, Pan Dong; Lee, So Yeong, E-mail: leeso@snu.ac.kr [Seoul National University, Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Institute for Veterinary Science (Korea, Republic of)

    2012-12-15

    Cellular uptake, cytotoxicity, and mechanisms of cytotoxicity of the positively charged Au nanoparticles (NPs) were examined in A549 cells, which are one of the most characterized pulmonary cellular systems. Positively charged Au NPs were prepared by chemical reduction using chitosan. The dimension and surface charge of Au NPs were examined by transmission electron microscopy (TEM), dynamic light scattering, and zeta potential measurements. The uptake of Au NPs into A549 cells was also monitored using TEM and dark-field microscopy (DFM) and z-stack confocal microRaman spectroscopy. DFM live cell imaging was also performed to monitor the entry of chitosan Au NPs in real time. The cytotoxic assay, using both methylthiazol tetrazolium and lactate dehydrogenase assays revealed that positively charged Au NPs decreased cell viability. Flow cytometry, DNA fragmentation, real-time PCR, and western blot analysis suggest that positively charged chitosan Au NPs provoke cell damage through both apoptotic and necrotic pathways.

  15. Cellular uptake and cytotoxicity of positively charged chitosan gold nanoparticles in human lung adenocarcinoma cells

    International Nuclear Information System (INIS)

    Choi, Seon Young; Jang, Soo Hwa; Park, Jin; Jeong, Saeromi; Park, Jin Ho; Ock, Kwang Su; Lee, Kangtaek; Yang, Sung Ik; Joo, Sang-Woo; Ryu, Pan Dong; Lee, So Yeong

    2012-01-01

    Cellular uptake, cytotoxicity, and mechanisms of cytotoxicity of the positively charged Au nanoparticles (NPs) were examined in A549 cells, which are one of the most characterized pulmonary cellular systems. Positively charged Au NPs were prepared by chemical reduction using chitosan. The dimension and surface charge of Au NPs were examined by transmission electron microscopy (TEM), dynamic light scattering, and zeta potential measurements. The uptake of Au NPs into A549 cells was also monitored using TEM and dark-field microscopy (DFM) and z-stack confocal microRaman spectroscopy. DFM live cell imaging was also performed to monitor the entry of chitosan Au NPs in real time. The cytotoxic assay, using both methylthiazol tetrazolium and lactate dehydrogenase assays revealed that positively charged Au NPs decreased cell viability. Flow cytometry, DNA fragmentation, real-time PCR, and western blot analysis suggest that positively charged chitosan Au NPs provoke cell damage through both apoptotic and necrotic pathways.

  16. Electrochemiluminescent detection of Pb{sup 2+} by graphene/gold nanoparticles and CdSe quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Liping, E-mail: lipinglu@bjut.edu.cn; Guo, Linqing; Li, Jiao; Kang, Tianfang; Cheng, Shuiyuan

    2016-12-01

    Highlights: • An ECL sensor was fabricated based on the distance dependent between CdSe QDs and gold nanoparticles. • The ssDNA strands rich in G bases adopt the G4 conformation when Pb{sup 2+} is present in detection system. • AuNPs/RGO composite improved the performance of electron transfer of sensor. • The ECL sensor was used to detect Pb{sup 2+} concentration in an actual water sample with high sensitivity and selectivity. - Abstract: A highly sensitive electrochemiluminescent detection method for lead ions (Pb(II)) was fabricated based on the distance-dependent quenching of the electrochemiluminescence from CdSe quantum dots by nanocomposites of graphene and gold nanoparticles. Graphene/gold nanoparticles were electrochemically deposited onto a glassy carbon electrode through the constant potential method. Thiol-labeled DNA was then assembled on the surface of the electrode via gold−sulfur bonding, following which the amino-labeled terminal of the DNA was linked to carboxylated CdSe quantum dots by the formation of amide bonds. The 27-base aptamer was designed with two different domains: the immobilization and detection sequences. The immobilization sequence was paired with 12 complementary bases and immobilized on the gold electrode; the single-stranded detection sequence, rich in G bases, formed a G-quadruplex (G4) structure in the presence of Pb{sup 2+}. The formation of G4 shortens the distance between the CdSe quantum dots and the Au electrode, which decreases the electrochemiluminescent intensity in a linear fashion, proportional to the concentration of Pb(II). The linear range of the sensor was 10{sup −10} to 10{sup −8} mol/L (R = 0.9819) with a detection limit of 10{sup −10} mol/L. This sensor detected Pb(II) in real water samples with satisfactory results.

  17. The agglomeration state of nanoparticles can influence the mechanism of their cellular internalisation.

    Science.gov (United States)

    Halamoda-Kenzaoui, Blanka; Ceridono, Mara; Urbán, Patricia; Bogni, Alessia; Ponti, Jessica; Gioria, Sabrina; Kinsner-Ovaskainen, Agnieszka

    2017-06-26

    Significant progress of nanotechnology, including in particular biomedical and pharmaceutical applications, has resulted in a high number of studies describing the biological effects of nanomaterials. Moreover, a determination of so-called "critical quality attributes", that is specific physicochemical properties of nanomaterials triggering the observed biological response, has been recognised as crucial for the evaluation and design of novel safe and efficacious therapeutics. In the context of in vitro studies, a thorough physicochemical characterisation of nanoparticles (NPs), also in the biological medium, is necessary to allow a correlation with a cellular response. Following this concept, we examined whether the main and frequently reported characteristics of NPs such as size and the agglomeration state can influence the level and the mechanism of NP cellular internalization. We employed fluorescently-labelled 30 and 80 nm silicon dioxide NPs, both in agglomerated and non-agglomerated form. Using flow cytometry, transmission electron microscopy, the inhibitors of endocytosis and gene silencing we determined the most probable routes of cellular uptake for each form of tested silica NPs. We observed differences in cellular uptake depending on the size and the agglomeration state of NPs. Caveolae-mediated endocytosis was implicated particularly in the internalisation of well dispersed silica NPs but with an increase of the agglomeration state of NPs a combination of endocytic pathways with a predominant role of macropinocytosis was noted. We demonstrated that the agglomeration state of NPs is an important factor influencing the level of cell uptake and the mechanism of endocytosis of silica NPs.

  18. Managing magnetic nanoparticle aggregation and cellular uptake: a precondition for efficient stem-cell differentiation and MRI tracking.

    Science.gov (United States)

    Fayol, Delphine; Luciani, Nathalie; Lartigue, Lenaic; Gazeau, Florence; Wilhelm, Claire

    2013-02-01

    The labeling of stem cells with iron oxide nanoparticles is increasingly used to enable MRI cell tracking and magnetic cell manipulation, stimulating the fields of tissue engineering and cell therapy. However, the impact of magnetic labeling on stem-cell differentiation is still controversial. One compromising factor for successful differentiation may arise from early interactions of nanoparticles with cells during the labeling procedure. It is hypothesized that the lack of control over nanoparticle colloidal stability in biological media may lead to undesirable nanoparticle localization, overestimation of cellular uptake, misleading MRI cell tracking, and further impairment of differentiation. Herein a method is described for labeling mesenchymal stem cells (MSC), in which the physical state of citrate-coated nanoparticles (dispersed versus aggregated) can be kinetically tuned through electrostatic and magnetic triggers, as monitored by diffusion light scattering in the extracellular medium and by optical and electronic microscopy in cells. A set of statistical cell-by-cell measurements (flow cytometry, single-cell magnetophoresis, and high-resolution MRI cellular detection) is used to independently quantify the nanoparticle cell uptake and the effects of nanoparticle aggregation. Such aggregation confounds MRI cell detection as well as global iron quantification and has adverse effects on chondrogenetic differentiation. Magnetic labeling conditions with perfectly stable nanoparticles-suitable for obtaining differentiation-capable magnetic stem cells for use in cell therapy-are subsequently identified. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Elucidating the Function of Penetratin and a Static Magnetic Field in Cellular Uptake of Magnetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    David Stirling

    2013-02-01

    Full Text Available Nanotechnology plays an increasingly important role in the biomedical arena. In particular, magnetic nanoparticles (mNPs have become important tools in molecular diagnostics, in vivo imaging and improved treatment of disease, with the ultimate aim of producing a more theranostic approach. Due to their small sizes, the nanoparticles can cross most of the biological barriers such as the blood vessels and the blood brain barrier, thus providing ubiquitous access to most tissues. In all biomedical applications maximum nanoparticle uptake into cells is required. Two promising methods employed to this end include functionalization of mNPs with cell-penetrating peptides to promote efficient translocation of cargo into the cell and the use of external magnetic fields for enhanced delivery. This study aimed to compare the effect of both penetratin and a static magnetic field with regards to the cellular uptake of 200 nm magnetic NPs and determine the route of uptake by both methods. Results demonstrated that both techniques increased particle uptake, with penetratin proving more cell specific. Clathrin- medicated endocytosis appeared to be responsible for uptake as shown via PCR and western blot, with Pitstop 2 (known to selectively block clathrin formation blocking particle uptake. Interestingly, it was further shown that a magnetic field was able to reverse or overcome the blocking, suggesting an alternative route of uptake.

  20. Toxicity of silver nanoparticles in human macrophages: uptake, intracellular distribution and cellular responses

    Science.gov (United States)

    Haase, A.; Tentschert, J.; Jungnickel, H.; Graf, P.; Mantion, A.; Draude, F.; Plendl, J.; Goetz, M. E.; Galla, S.; Mašić, A.; Thuenemann, A. F.; Taubert, A.; Arlinghaus, H. F.; Luch, A.

    2011-07-01

    Silver nanoparticles (SNP) are among the most commercialized nanoparticles worldwide. They can be found in many diverse products, mostly because of their antibacterial properties. Despite its widespread use only little data on possible adverse health effects exist. It is difficult to compare biological data from different studies due to the great variety in sizes, coatings or shapes of the particles. Here, we applied a novel synthesis approach to obtain SNP, which are covalently stabilized by a small peptide. This enables a tight control of both size and shape. We applied these SNP in two different sizes of 20 or 40 nm (Ag20Pep and Ag40Pep) and analyzed responses of THP-1-derived human macrophages. Similar gold nanoparticles with the same coating (Au20Pep) were used for comparison and found to be non-toxic. We assessed the cytotoxicity of particles and confirmed their cellular uptake via transmission electron microscopy and confocal Raman microscopy. Importantly a majority of the SNP could be detected as individual particles spread throughout the cells. Furthermore we studied several types of oxidative stress related responses such as induction of heme oxygenase I or formation of protein carbonyls. In summary, our data demonstrate that even low doses of SNP exerted adverse effects in human macrophages.

  1. Toxicity of silver nanoparticles in human macrophages: uptake, intracellular distribution and cellular responses

    International Nuclear Information System (INIS)

    Haase, A; Tentschert, J; Jungnickel, H; Goetz, M E; Luch, A; Graf, P; Mantion, A; Thuenemann, A F; Draude, F; Galla, S; Arlinghaus, H F; Plendl, J; Masic, A; Taubert, A

    2011-01-01

    Silver nanoparticles (SNP) are among the most commercialized nanoparticles worldwide. They can be found in many diverse products, mostly because of their antibacterial properties. Despite its widespread use only little data on possible adverse health effects exist. It is difficult to compare biological data from different studies due to the great variety in sizes, coatings or shapes of the particles. Here, we applied a novel synthesis approach to obtain SNP, which are covalently stabilized by a small peptide. This enables a tight control of both size and shape. We applied these SNP in two different sizes of 20 or 40 nm (Ag20Pep and Ag40Pep) and analyzed responses of THP-1-derived human macrophages. Similar gold nanoparticles with the same coating (Au20Pep) were used for comparison and found to be non-toxic. We assessed the cytotoxicity of particles and confirmed their cellular uptake via transmission electron microscopy and confocal Raman microscopy. Importantly a majority of the SNP could be detected as individual particles spread throughout the cells. Furthermore we studied several types of oxidative stress related responses such as induction of heme oxygenase I or formation of protein carbonyls. In summary, our data demonstrate that even low doses of SNP exerted adverse effects in human macrophages.

  2. Cellular uptake and intracellular fate of engineered nanoparticles: a review on the application of imaging techniques.

    Science.gov (United States)

    Tantra, Ratna; Knight, Alex

    2011-09-01

    The use of imaging tools to probe nanoparticle-cell interactions will be crucial to elucidating the mechanisms of nanoparticle-induced toxicity. Of particular interest are mechanisms associated with cell penetration, translocation and subsequent accumulation inside the cell, or in cellular compartments. The objective of the present paper is to review imaging techniques that have been previously used in order to assess such interactions, and new techniques with the potential to be useful in this area. In order to identify the most suitable techniques, they were evaluated and matched against a list of evaluation criteria. We conclude that limitations exist with all of the techniques and the ultimate choice will thus depend on the needs of end users, and their particular application. The state-of-the-art techniques appear to have the least limitations, despite the fact that they are not so well established and still far from being routine. For example, super-resolution microscopy techniques appear to have many advantages for understanding the details of the interactions between nanoparticles and cells. Future research should concentrate on further developing or improving such novel techniques, to include the development of standardized methods and appropriate reference materials.

  3. Mannosylated Chitosan Nanoparticles Based Macrophage-Targeting Gene Delivery System Enhanced Cellular Uptake and Improved Transfection Efficiency.

    Science.gov (United States)

    Peng, Yixing; Yao, Wenjun; Wang, Bo; Zong, Li

    2015-04-01

    Gene transfer mediated by mannosylated chitosan (MCS) is a safe and promising approach for gene and vaccine delivery. MCS nanoparticles based gene delivery system showed high in vivo delivery efficiency and elicited strong immune responses in mice. However, little knowledge about the cell binding, transfection efficiency and intracellular trafficking of MCS nanoparticles had been acquired. In this study, using gastrin-releasing peptide as a model plasmid (pGRP), the binding of MCS/pGRP nanoparticles to macrophages and the intracellular trafficking of MCS/pGRP nanoparticles in macrophages were investigated. MCS-mediated transfection efficiency in macrophages was also evaluated using pGL-3 as a reporter gene. The results showed that the binding and transfection efficiency of MCS nanoparticles in macrophages was higher than that of CS, which was attributed to the interaction between mannose ligands in MCS and mannose receptors on the surface of macrophages. Observation with a confocal laser scanning microscope indicated the cellular uptake of MCS/pGRP nanoparticles were more than that of CS/pGRP nanoparticles in macrophages. MCS/pGRP nanoparticles were taken up by macrophages and most of them were entrapped in endosomal/lysosomal compartments. After the nanoparticles escaping from endosomal/lysosomal compartments, naked pGRP entered the nucleus, and a few MCS might enter the nucleus in terms of nanoparticles. Overall, MCS has the potential to be an excellent macrophage-targeting gene delivery carrier.

  4. Ultrasensitive electrochemiluminescent immunoassay for morphine using a gold electrode modified with CdS quantum dots, polyamidoamine, and gold nanoparticles

    International Nuclear Information System (INIS)

    Fei, Wenjuan; Chen, Feifei; Sun, Li; Li, Qianhua; Wu, Ying; Yang, Jianping

    2014-01-01

    We report on a novel electrochemiluminescent (ECL) immunoassay for the ultrasensitive determination of morphine by making use of a gold electrode which was modified with a nanocomposite film containing self-assembled polyamidoamine (PAMAM) CdS quantum dots and electrodeposited gold nanoparticles (Au-NPs). The highly uniform and well-dispersed quantum dots were capped with PAMAM dendrimers. Due to the synergistic effect of the modified quantum dots and the electrodeposited Au-NPs, the ECL response is dramatically enhanced. Under optimal experimental conditions, the immunoreaction between morphine and anti-morphine antibody resulted in a decrease of the ECL signal because of steric hindrance. The calibration plot is linear in the morphine concentration range from 0.2 to 180 ng•mL −1 , with a detection limit as low as 67 pg•mL −1 . The sensor was successfully applied to the determination of morphine in blood plasma. This kind of assay is expected to pave new avenues in label-free drug assays. (author)

  5. Effect of surface charge and agglomerate degree of magnetic iron oxide nanoparticles on KB cellular uptake in vitro.

    Science.gov (United States)

    Ge, Yuqing; Zhang, Yu; Xia, Jingguang; Ma, Ming; He, Shiying; Nie, Fang; Gu, Ning

    2009-10-15

    We synthesized three types of magnetic iron oxide nanoparticles (MNPs), which were meso-2,3-dimercaptosuccinic acid (DMSA) coated MNPs (DMSA@MNPs, 17.3+/-4.8 nm, negative charge), chitosan (CS) coated MNPs (CS@MNPs, 16.5+/-6.1 nm, positive charge) and magnetic nanoparticles agglomerates, formed by electronic aggregation between DMSA@MNPs and CS (CS-DMSA@MNPs, 85.7+/-72.9 nm, positive charge) respectively. The interactions of these MNPs with Oral Squamous Carcinoma Cell KB were investigated. The results showed that cellular uptakes of MNPs were on the dependence of incubation time, nanoparticles concentration and nanoparticles properties such as surface charge, size, etc. The cellular uptake was enhanced with the increase of incubation time and nanoparticles concentration. Although all MNPs could enter to cells, we observed apparent differences in the magnitude of nanoparticles uptaken. The cellular uptake of CS-DMSA@MNPs by KB cells was the highest and that of DMSA@MNPs was the lowest among the three types of MNPs. The same conclusions were drawn via the reduction of water proton relaxation times T(2)(*), resulting from the different iron load of labeled cells using a 1.5T clinical MR imager. The finding of this study will have implications in the chemical design of nanomaterials for biomedical applications.

  6. A facile method to prepare fluorescent carbon dots and their application in selective colorimetric sensing of silver ion through the formation of silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ayaz Ahmed, Khan Behlol; P, Suresh Kumar; Veerappan, Anbazhagan, E-mail: anbazhagan@scbt.sastra.edu

    2016-09-15

    Herein, we report a laboratory convenient method for the preparation of blue color emitting fluorescent carbon dots (C-dots) in 60 min by boiling the alkaline solution of pectin. The C-dots derived from pectin detects selectively silver ion by forming silver nanoparticles (AgNPs) without any irradiation or heating or additional reducing agents. As prepared AgNPs appears yellow in color and showed the characteristic surface plasmon resonance maximum at 410 nm. Transmission electron microscopy (TEM) revealed crystalline, spherical AgNPs with size range from 10–15 nm. Cyclic voltammetry study revealed that the lower reduction potential of C-dots than that of silver ion favors the reduction of Ag{sup +} to Ag°. Electrochemical impedance spectroscopy showed the charge transfer value for the redox reaction of C-dots as 200 Ωcm{sup 2}. In the presence of Ag{sup +}, C-dots fluorescence emission was turned from blue to cyan to green to colorless, accompanying the quenching and red shift in emission maximum at 450 nm. Interference study clearly showed that the C-dots have high preference for Ag{sup +} ion than the other interfering metal ions. The proposed sensor system selectively senses Ag{sup +} ion in water at micromolar concentration and also offers an easy procedure to prepare AgNPs in the presence of other interfering metal ions. - Highlights: • Blue color emitting C-dots was prepared by boiling alkaline pectin solution. • C-dots sense silver ion at micromolar concentration. • C-dots recognize silver ion in the presence of interfering metal ions. • Reduction potential of C-dots was estimated by cyclic voltammeter as – 0.2 V.

  7. Carnauba wax nanoparticles enhance strong systemic and mucosal cellular and humoral immune responses to HIV-gp140 antigen.

    Science.gov (United States)

    Arias, Mauricio A; Loxley, Andrew; Eatmon, Christy; Van Roey, Griet; Fairhurst, David; Mitchnick, Mark; Dash, Philip; Cole, Tom; Wegmann, Frank; Sattentau, Quentin; Shattock, Robin

    2011-02-01

    Induction of humoral responses to HIV at mucosal compartments without inflammation is important for vaccine design. We developed charged wax nanoparticles that efficiently adsorb protein antigens and are internalized by DC in the absence of inflammation. HIV-gp140-adsorbed nanoparticles induced stronger in vitro T-cell proliferation responses than antigen alone. Such responses were greatly enhanced when antigen was co-adsorbed with TLR ligands. Immunogenicity studies in mice showed that intradermal vaccination with HIV-gp140 antigen-adsorbed nanoparticles induced high levels of specific IgG. Importantly, intranasal immunization with HIV-gp140-adsorbed nanoparticles greatly enhanced serum and vaginal IgG and IgA responses. Our results show that HIV-gp140-carrying wax nanoparticles can induce strong cellular/humoral immune responses without inflammation and may be of potential use as effective mucosal adjuvants for HIV vaccine candidates. Copyright © 2010 Elsevier Ltd. All rights reserved.

  8. Quantum-dot nanoprobes and AOTF based cross talk eliminated six color imaging of biomolecules in cellular system

    International Nuclear Information System (INIS)

    Park, Solji; Arumugam, Parthasarathy; Purushothaman, Baskaran; Kim, Sung-Yon; Min, Dal-Hee; Jeon, Noo Li; Song, Joon Myong

    2017-01-01

    Primary cell cultures mimic the physiology and genetic makeup of in-vivo tissue of origin, nonetheless, a complication in the derivation and propagation of primary cell culture limits its use in biological research. However, in-vitro models using primary cells might be a complement model to mimic in vivo response. But, conventional techniques such as western blot and PCR employed to study the expression and activation of proteins requires a large number of cells, hence repeated establishment and maintenance of primary culture are unavoidable. Quantum dot (Q-dot) and acousto-optic tunable filters (AOTF) based multiplex imaging system is a viable alternative choice to evaluate multiple signaling molecules by using a small number of cells. Q-dots have broad excitation and narrow emission spectra, which allows to simultaneously excite multiple Q-dots by using single excitation wavelength. The use of AOTF in the fluorescence detection system enables to scan the fluorescence emission intensity of a Q-dot at their central wavelength, this phenomenon effectively avoids spectral overlap among the neighboring Q-dots. When Q-dots are conjugated with antibodies it acts as effective sensing probes. To validate this, the expression pattern of p-JNK-1, p-GSK3β, p-IRS1ser, p-IRS1tyr, p-FOXO1, and PPAR-γ, involved in the insulin resistance were concurrently monitored in adipocyte and HepG2 co-cell culture model. The observed results clearly indicate that PPAR-γ is the critical component in the development of insulin resistance. Moreover, the results proved that developed Q-dot based AOTF imaging methodology is a sensible choice to concurrently monitor multiple signaling molecules with limited cell population. - Highlights: • Quantum dot (Q-dot) and acousto-optic tunable filters (AOTF) based six-colour imaging. • Expression of PPAR-γ in adipocyte regulates insulin resistance in hepatic (HepG2) cells. • Aspirin improved insulin sensitivity in adipocytes and HepG2 co

  9. Targeting dendritic cells through gold nanoparticles: A review on the cellular uptake and subsequent immunological properties.

    Science.gov (United States)

    Ahmad, Suhana; Zamry, Anes Ateqah; Tan, Hern-Tze Tina; Wong, Kah Keng; Lim, JitKang; Mohamud, Rohimah

    2017-11-01

    Gold nanoparticles (NPs) have been proposed as a highly potential tool in immunotherapies due to its advantageous properties including customizable size and shapes, surface functionality and biocompatibility. Dendritic cells (DCs), the sentinels of immune response, have been of interest to be manipulated by using gold NPs for targeted delivery of immunotherapeutic agent. Researches done especially in human DCs showed a variation of gold NPs effects on cellular uptake and internalization, DC maturation and subsequent T cells priming as well as cytotoxicity. In this review, we describe the synthesis and physiochemical properties of gold NPs as well as the importance of gold NPs in immunotherapies through their actions on human DCs. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Gold nanoparticles conjugating recombinant influenza hemagglutinin trimers and flagellin enhanced mucosal cellular immunity.

    Science.gov (United States)

    Wang, Chao; Zhu, Wandi; Luo, Yuan; Wang, Bao-Zhong

    2018-04-09

    The immunogenicity of subunit vaccines can be augmented by formulating them into nanoparticles. We conjugated recombinant trimetric influenza A/Aichi/2/68(H3N2) hemagglutinin (HA) onto functionalized gold nanoparticles (AuNPs) surfaces in a repetitive, oriented configuration. To further improve the immunogenicity, we generated Toll-like receptor 5 (TLR5) agonist flagellin (FliC)-coupled AuNPs as particulate adjuvants. Intranasal immunizations with an AuNP-HA and AuNP-FliC particle mixture elicited strong mucosal and systemic immune responses that protected hosts against lethal influenza challenges. Compared with the AuNP-HA alone group, the addition of AuNP-FliC improved mucosal B cell responses as characterized by elevated influenza specific IgA and IgG levels in nasal, tracheal, and lung washes. AuNP-HA/AuNP-FliC also stimulated antigen-specific interferon-γ (IFN-γ)-secreting CD4 + cell proliferation and induced strong effector CD8 + T cell activation. Our results indicate that intranasal co-delivery of antigen and adjuvant-displaying AuNPs enhanced vaccine efficacy by inducing potent cellular immune responses. Copyright © 2018. Published by Elsevier Inc.

  11. Fabrication of curcumin-loaded bovine serum albumin (BSA)-dextran nanoparticles and the cellular antioxidant activity.

    Science.gov (United States)

    Fan, Yuting; Yi, Jiang; Zhang, Yuzhu; Yokoyama, Wallace

    2018-01-15

    Bovine serum albumin (BSA)-dextran conjugate was prepared with glycation. Self-assembly nanoparticles were synthesized with a green, and facile approach. The effects of dry-heating time on the fabrication and characteristics of BSA-dextran conjugate nanoparticles were examined. Stable nanoparticles (dextran was grafted onto the BSA to provide significant steric hindrance. Particle size decreased with the increase of dry-heating time and the lowest particle size (51.2nm) was obtained after 24h dry-heating. The nanoparticles were stable in a wide pH range (pH 2.0-7.0). The particle size of nanoparticles increased to 115nm after curcumin incorporation and was stable even after one-month storage. TEM results demonstrated that curcumin-loaded nanoparticles displayed a spherical structure and were homogeneously dispersed. Curcumin in BSA-dextran nanoparticle showed better stability, compared to free curcumin. In addition, BSA-dextran nanoparticles can improve the cellular antioxidant activity of curcumin in Caco-2 cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Measuring in vitro cellular uptake of nanoparticles by transmission electron microscopy

    International Nuclear Information System (INIS)

    Brown, A P; Brydson, R M D; Hondow, N S

    2014-01-01

    Biomedical application of engineered nanoparticles (NPs) is a growing area of research and development. Uncertainty remains as to the mode of action of many NP types and TEM is a tool capable of addressing this if used in conjunction with standard cellular response assays. We will demonstrate imaging of thin sections of fixed, plastic embedded cells by analytical TEM to identify: superparamagnetic iron oxide NP translocation into cell compartments such as endosomes; amorphous silica NP penetration through a cell membrane without membrane encapsulation and zinc oxide NP degradation in cell compartments. We will then discuss how the in vitro cellular responses to a dose of NPs exposed to cell lines can be correlated to the internalized dose per cell section noting however that quantification of the latter requires random sampling procedures or correlation to higher throughout techniques to measure a population of whole cells. Similarly, analytical TEM measures of NP degradation within intracellular compartments will require a more appropriate sample preparation such as cryo-fixation

  13. Molecular design and nanoparticle-mediated intracellular delivery of functional proteins to target cellular pathways

    Science.gov (United States)

    Shah, Dhiral Ashwin

    Intracellular delivery of specific proteins and peptides represents a novel method to influence stem cells for gain-of-function and loss-of-function. Signaling control is vital in stem cells, wherein intricate control of and interplay among critical pathways directs the fate of these cells into either self-renewal or differentiation. The most common route to manipulate cellular function involves the introduction of genetic material such as full-length genes and shRNA into the cell to generate (or prevent formation of) the target protein, and thereby ultimately alter cell function. However, viral-mediated gene delivery may result in relatively slow expression of proteins and prevalence of oncogene insertion into the cell, which can alter cell function in an unpredictable fashion, and non-viral delivery may lead to low efficiency of genetic delivery. For example, the latter case plagues the generation of induced pluripotent stem cells (iPSCs) and hinders their use for in vivo applications. Alternatively, introducing proteins into cells that specifically recognize and influence target proteins, can result in immediate deactivation or activation of key signaling pathways within the cell. In this work, we demonstrate the cellular delivery of functional proteins attached to hydrophobically modified silica (SiNP) nanoparticles to manipulate specifically targeted cell signaling proteins. In the Wnt signaling pathway, we have targeted the phosphorylation activity of glycogen synthase kinase-3beta (GSK-3beta) by designing a chimeric protein and delivering it in neural stem cells. Confocal imaging indicates that the SiNP-chimeric protein conjugates were efficiently delivered to the cytosol of human embryonic kidney cells and rat neural stem cells, presumably via endocytosis. This uptake impacted the Wnt signaling cascade, indicated by the elevation of beta-catenin levels, and increased transcription of Wnt target genes, such as c-MYC. The results presented here suggest that

  14. Ambient-Processed Colloidal Quantum Dot Solar Cells via Individual Pre-Encapsulation of Nanoparticles

    KAUST Repository

    Debnath, Ratan; Tang, Jiang; Barkhouse, D. Aaron; Wang, Xihua; Pattantyus-Abraham, Andras G.; Brzozowski, Lukasz; Levina, Larissa; Sargent, Edward H.

    2010-01-01

    We report colloidal quantum dot solar cells fabricated under ambient atmosphere with an active area of 2.9 mm2 that exhibit 3.6% solar power conversion efficiency. The devices are based on PbS tuned via the quantum size effect to have a first excitonic peak at 950 nm. Because the formation of native oxides and sulfates on PbS leads to p-type doping and deep trap formation and because such dopants and traps dramatically influence device performance, prior reports of colloidal quantum dot solar cells have insisted on processing under an inert atmosphere. Here we report a novel ligand strategy in which we first encapsulate the quantum dots in the solution phase with the aid of a strongly bound N-2,4,6-trimethylphenyl-N-methyldithiocarbamate ligand. This allows us to carry out film formation and all subsequent device fabrication under an air atmosphere. © 2010 American Chemical Society.

  15. Ambient-Processed Colloidal Quantum Dot Solar Cells via Individual Pre-Encapsulation of Nanoparticles

    KAUST Repository

    Debnath, Ratan

    2010-05-05

    We report colloidal quantum dot solar cells fabricated under ambient atmosphere with an active area of 2.9 mm2 that exhibit 3.6% solar power conversion efficiency. The devices are based on PbS tuned via the quantum size effect to have a first excitonic peak at 950 nm. Because the formation of native oxides and sulfates on PbS leads to p-type doping and deep trap formation and because such dopants and traps dramatically influence device performance, prior reports of colloidal quantum dot solar cells have insisted on processing under an inert atmosphere. Here we report a novel ligand strategy in which we first encapsulate the quantum dots in the solution phase with the aid of a strongly bound N-2,4,6-trimethylphenyl-N-methyldithiocarbamate ligand. This allows us to carry out film formation and all subsequent device fabrication under an air atmosphere. © 2010 American Chemical Society.

  16. Directly deposited quantum dot solids using a colloidally stable nanoparticle ink

    KAUST Repository

    Fischer, Armin H.; Rollny, Lisa R.; Pan, Jun; Carey, Graham H.; Thon, Susanna; Hoogland, Sjoerd H.; Voznyy, Oleksandr; Zhitomirsky, David; Kim, Jinyoung; Bakr, Osman; Sargent, E. H.

    2013-01-01

    We develop a photovoltaic colloidal quantum dot ink that allows for lossless, single-step coating of large areas in a manufacturing-compatible process. Our materials strategy involves a solution-phase ligand exchange to transport compatible linkers that yield 1-thioglycerol-capped PbS quantum dots in dimethyl sulfoxide with a photoluminescence quantum yield of 24%. A proof-of-principle solar cell made from the ink exhibits 2.1% power conversion efficiency. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Directly deposited quantum dot solids using a colloidally stable nanoparticle ink

    KAUST Repository

    Fischer, Armin H.

    2013-08-12

    We develop a photovoltaic colloidal quantum dot ink that allows for lossless, single-step coating of large areas in a manufacturing-compatible process. Our materials strategy involves a solution-phase ligand exchange to transport compatible linkers that yield 1-thioglycerol-capped PbS quantum dots in dimethyl sulfoxide with a photoluminescence quantum yield of 24%. A proof-of-principle solar cell made from the ink exhibits 2.1% power conversion efficiency. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Dual-Mode SERS-Fluorescence Immunoassay Using Graphene Quantum Dot Labeling on One-Dimensional Aligned Magnetoplasmonic Nanoparticles.

    Science.gov (United States)

    Zou, Fengming; Zhou, Hongjian; Tan, Tran Van; Kim, Jeonghyo; Koh, Kwangnak; Lee, Jaebeom

    2015-06-10

    A novel dual-mode immunoassay based on surface-enhanced Raman scattering (SERS) and fluorescence was designed using graphene quantum dot (GQD) labels to detect a tuberculosis (TB) antigen, CFP-10, via a newly developed sensing platform of linearly aligned magnetoplasmonic (MagPlas) nanoparticles (NPs). The GQDs were excellent bilabeling materials for simultaneous Raman scattering and photoluminescence (PL). The one-dimensional (1D) alignment of MagPlas NPs simplified the immunoassay process and enabled fast, enhanced signal transduction. With a sandwich-type immunoassay using dual-mode nanoprobes, both SERS signals and fluorescence images were recognized in a highly sensitive and selective manner with a detection limit of 0.0511 pg mL(-1).

  19. Cellular trafficking of quantum dot-ligand bioconjugates and their induction of changes in normal routing of unconjugated ligands

    DEFF Research Database (Denmark)

    Tekle, Christina; van Deurs, Bo; Sandvig, Kirsten

    2008-01-01

    Can quantum dots (Qdots) act as relevant intracellular probes to investigate routing of ligands in live cells? The intracellular trafficking of Qdots that were coupled to the plant toxin ricin, Shiga toxin, or the ligand transferrin (Tf) was studied by confocal fluorescence microscopy. The Tf...

  20. Determination of gold nanoparticles in environmental water samples by second-order optical scattering using dithiotreitol-functionalized CdS quantum dots after cloud point extraction

    International Nuclear Information System (INIS)

    Mandyla, Spyridoula P.; Tsogas, George Z.; Vlessidis, Athanasios G.; Giokas, Dimosthenis L.

    2017-01-01

    Highlights: • A new method has been developed to determine gold nanoparticles in water samples. • Extraction was achieved by cloud point extraction. • A nano-hybrid assembly between AuNPs and dithiol-coated quantum dots was formulated. • Detection was accomplished at pico-molar levels by second-order light scattering. • The method was selective against ionic gold and other nanoparticle species. - Abstract: This work presents a new method for the sensitive and selective determination of gold nanoparticles in water samples. The method combines a sample preparation and enrichment step based on cloud point extraction with a new detection motif that relies on the optical incoherent light scattering of a nano-hybrid assembly that is formed by hydrogen bond interactions between gold nanoparticles and dithiotreitol-functionalized CdS quantum dots. The experimental parameters affecting the extraction and detection of gold nanoparticles were optimized and evaluated to the analysis of gold nanoparticles of variable size and surface coating. The selectivity of the method against gold ions and other nanoparticle species was also evaluated under different conditions reminiscent to those usually found in natural water samples. The developed method was applied to the analysis of gold nanoparticles in natural waters and wastewater with satisfactory results in terms of sensitivity (detection limit at the low pmol L −1 levels), recoveries (>80%) and reproducibility (<9%). Compared to other methods employing molecular spectrometry for metal nanoparticle analysis, the developed method offers improved sensitivity and it is easy-to-operate thus providing an additional tool for the monitoring and the assessment of nanoparticles toxicity and hazards in the environment.

  1. Determination of gold nanoparticles in environmental water samples by second-order optical scattering using dithiotreitol-functionalized CdS quantum dots after cloud point extraction

    Energy Technology Data Exchange (ETDEWEB)

    Mandyla, Spyridoula P.; Tsogas, George Z.; Vlessidis, Athanasios G.; Giokas, Dimosthenis L., E-mail: dgiokas@cc.uoi.gr

    2017-02-05

    Highlights: • A new method has been developed to determine gold nanoparticles in water samples. • Extraction was achieved by cloud point extraction. • A nano-hybrid assembly between AuNPs and dithiol-coated quantum dots was formulated. • Detection was accomplished at pico-molar levels by second-order light scattering. • The method was selective against ionic gold and other nanoparticle species. - Abstract: This work presents a new method for the sensitive and selective determination of gold nanoparticles in water samples. The method combines a sample preparation and enrichment step based on cloud point extraction with a new detection motif that relies on the optical incoherent light scattering of a nano-hybrid assembly that is formed by hydrogen bond interactions between gold nanoparticles and dithiotreitol-functionalized CdS quantum dots. The experimental parameters affecting the extraction and detection of gold nanoparticles were optimized and evaluated to the analysis of gold nanoparticles of variable size and surface coating. The selectivity of the method against gold ions and other nanoparticle species was also evaluated under different conditions reminiscent to those usually found in natural water samples. The developed method was applied to the analysis of gold nanoparticles in natural waters and wastewater with satisfactory results in terms of sensitivity (detection limit at the low pmol L{sup −1} levels), recoveries (>80%) and reproducibility (<9%). Compared to other methods employing molecular spectrometry for metal nanoparticle analysis, the developed method offers improved sensitivity and it is easy-to-operate thus providing an additional tool for the monitoring and the assessment of nanoparticles toxicity and hazards in the environment.

  2. Intracellular bimodal nanoparticles based on quantum dots for high-field MRI at 21.1 T.

    Science.gov (United States)

    Rosenberg, Jens T; Kogot, Joshua M; Lovingood, Derek D; Strouse, Geoffrey F; Grant, Samuel C

    2010-09-01

    Multimodal, biocompatible contrast agents for high magnetic field applications represent a new class of nanomaterials with significant potential for tracking of fluorescence and MR in vitro and vivo. Optimized for high-field MR applications-including biomedical imaging at 21.1 T, the highest magnetic field available for MRI-these nanoparticles capitalize on the improved performance of chelated Dy(3+) with increasing magnetic field coupled to a noncytotoxic Indium Phosphide/Zinc Sulfide (InP/ZnS) quantum dot that provides fluorescence detection, MR responsiveness, and payload delivery. By surface modifying the quantum dot with a cell-penetrating peptide sequence coupled to an MR contrast agent, the bimodal nanomaterial functions as a self-transfecting high-field MR/optical contrast agent for nonspecific intracellular labeling. Fluorescent images confirm sequestration in perinuclear vesicles of labeled cells, with no apparent cytotoxicity. These techniques can be extended to impart cell selectivity or act as a delivery vehicle for genetic or pharmaceutical interventions. 2010 Wiley-Liss, Inc.

  3. A high-throughput homogeneous immunoassay based on Förster resonance energy transfer between quantum dots and gold nanoparticles

    International Nuclear Information System (INIS)

    Qian, Jing; Wang, Chengquan; Pan, Xiaohu; Liu, Songqin

    2013-01-01

    Graphical abstract: A Förster resonance energy transfer system by using polyclonal goat anti-CEA antibody labeled luminescent CdTe quantum dots (QDs) as donor and monoclonal goat anti-CEA antibody labeled gold nanoparticles (AuNPs) as acceptor for sensitive detection of tumor marker was proposed. Highlights: ► A homogeneous immunosensing strategy based on FRET for detection of tumor marker was proposed. ► Close of QDs and AuNPs allow the occurrence of quenching the photoluminescence of nano-bio-probes. ► Signal quenching was monitored by a self-developed image analyzer. ► The fluorometric assay format is attractive for widespread carcinoma screening and even field use. -- Abstract: A novel homogeneous immunoassay based on Förster resonance energy transfer for sensitive detection of tumor, e.g., marker with carcinoembryonic antigen (CEA), was proposed. The assay was consisted of polyclonal goat anti-CEA antibody labeled luminescent CdTe quantum dots (QDs) as donor and monoclonal goat anti-CEA antibody labeled gold nanoparticles (AuNPs) as acceptor. In presence of CEA, the bio-affinity between antigen and antibody made the QDs and AuNPs close enough, thus the photoluminescence (PL) quenching of CdTe QDs occurred. The PL properties could be transformed into the fluorometric variation, corresponding to the target antigen concentration, and could be easily monitored and analyzed with the home-made image analysis software. The fluorometric results indicated a linear detection range of 1–110 ng mL −1 for CEA, with a detection limit of 0.3 ng mL −1 . The proposed assay configuration was attractive for carcinoma screening or single sample in point-of-care testing, and even field use. In spite of the limit of available model analyte, this approach could be easily extended to detection of a wide range of biomarkers

  4. A high-throughput homogeneous immunoassay based on Förster resonance energy transfer between quantum dots and gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Jing [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); School of Chemistry and Chemical Engineering, Jiangsu University, Zhengjiang 212013 (China); Wang, Chengquan [Changzhou College of Information Technology, Changzhou 213164 (China); Pan, Xiaohu [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Liu, Songqin, E-mail: liusq@seu.edu.cn [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China)

    2013-02-06

    Graphical abstract: A Förster resonance energy transfer system by using polyclonal goat anti-CEA antibody labeled luminescent CdTe quantum dots (QDs) as donor and monoclonal goat anti-CEA antibody labeled gold nanoparticles (AuNPs) as acceptor for sensitive detection of tumor marker was proposed. Highlights: ► A homogeneous immunosensing strategy based on FRET for detection of tumor marker was proposed. ► Close of QDs and AuNPs allow the occurrence of quenching the photoluminescence of nano-bio-probes. ► Signal quenching was monitored by a self-developed image analyzer. ► The fluorometric assay format is attractive for widespread carcinoma screening and even field use. -- Abstract: A novel homogeneous immunoassay based on Förster resonance energy transfer for sensitive detection of tumor, e.g., marker with carcinoembryonic antigen (CEA), was proposed. The assay was consisted of polyclonal goat anti-CEA antibody labeled luminescent CdTe quantum dots (QDs) as donor and monoclonal goat anti-CEA antibody labeled gold nanoparticles (AuNPs) as acceptor. In presence of CEA, the bio-affinity between antigen and antibody made the QDs and AuNPs close enough, thus the photoluminescence (PL) quenching of CdTe QDs occurred. The PL properties could be transformed into the fluorometric variation, corresponding to the target antigen concentration, and could be easily monitored and analyzed with the home-made image analysis software. The fluorometric results indicated a linear detection range of 1–110 ng mL{sup −1} for CEA, with a detection limit of 0.3 ng mL{sup −1}. The proposed assay configuration was attractive for carcinoma screening or single sample in point-of-care testing, and even field use. In spite of the limit of available model analyte, this approach could be easily extended to detection of a wide range of biomarkers.

  5. Nonpeturbative cavity-QED between a single quantum dot and a metal nanoparticle

    DEFF Research Database (Denmark)

    Van Vlack, C.; Kristensen, Philip Trøst; Hughes, S.

    2012-01-01

    modes. The vacuum Rabi doublet becomes a rich spectral quartet with two of the four peaks anticrossing, and surviving in spite of significant non-radiative decays. We also discuss the role of optical quenching and highlight the importance of accounting for photon transport from the dot to the detector...

  6. Comparison of cellular toxicity between multi-walled carbon nanotubes and onion-like shell-shaped carbon nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Seunghyon [Seoul National University, School of Mechanical and Aerospace Engineering (Korea, Republic of); Kim, Ji-Eun [Korea Research Institute of Standard and Science, Center for NanoSafety Metrology, Division of Convergence Technology (Korea, Republic of); Kim, Daegyu [LG Electronics (Korea, Republic of); Woo, Chang Gyu [Korea Institute of Machinery and Materials, Environmental and Energy Systems Research Division (Korea, Republic of); Pikhitsa, Peter V. [Seoul National University, School of Mechanical and Aerospace Engineering (Korea, Republic of); Cho, Myung-Haing, E-mail: mchotox@snu.ac.kr [Seoul National University, Laboratory of Toxicology, College of Veterinary Medicine (Korea, Republic of); Choi, Mansoo, E-mail: mchoi@snu.ac.kr [Seoul National University, School of Mechanical and Aerospace Engineering (Korea, Republic of)

    2015-09-15

    The cellular toxicity of multi-walled carbon nanotubes (MWCNTs) and onion-like shell-shaped carbon nanoparticles (SCNPs) was investigated by analyzing the comparative cell viability. For the reasonable comparison, physicochemical characteristics were controlled thoroughly such as crystallinity, carbon bonding characteristic, hydrodynamic diameter, and metal contents of the particles. To understand relation between cellular toxicity of the particles and generation of reactive oxygen species (ROS), we measured unpaired singlet electrons of the particles and intracellular ROS, and analyzed cellular toxicity with/without the antioxidant N-acetylcysteine (NAC). Regardless of the presence of NAC, the cellular toxicity of SCNPs was found to be lower than that of MWCNTs. Since both particles show similar crystallinity, hydrodynamic size, and Raman signal with negligible contribution of remnant metal particles, the difference in cell viability would be ascribed to the difference in morphology, i.e., spherical shape (aspect ratio of one) for SCNP and elongated shape (high aspect ratio) for MWCNT.

  7. Comparison of cellular toxicity between multi-walled carbon nanotubes and onion-like shell-shaped carbon nanoparticles

    International Nuclear Information System (INIS)

    Kang, Seunghyon; Kim, Ji-Eun; Kim, Daegyu; Woo, Chang Gyu; Pikhitsa, Peter V.; Cho, Myung-Haing; Choi, Mansoo

    2015-01-01

    The cellular toxicity of multi-walled carbon nanotubes (MWCNTs) and onion-like shell-shaped carbon nanoparticles (SCNPs) was investigated by analyzing the comparative cell viability. For the reasonable comparison, physicochemical characteristics were controlled thoroughly such as crystallinity, carbon bonding characteristic, hydrodynamic diameter, and metal contents of the particles. To understand relation between cellular toxicity of the particles and generation of reactive oxygen species (ROS), we measured unpaired singlet electrons of the particles and intracellular ROS, and analyzed cellular toxicity with/without the antioxidant N-acetylcysteine (NAC). Regardless of the presence of NAC, the cellular toxicity of SCNPs was found to be lower than that of MWCNTs. Since both particles show similar crystallinity, hydrodynamic size, and Raman signal with negligible contribution of remnant metal particles, the difference in cell viability would be ascribed to the difference in morphology, i.e., spherical shape (aspect ratio of one) for SCNP and elongated shape (high aspect ratio) for MWCNT

  8. Screening Applications to Test Cellular Fitness in Transwell® Models After Nanoparticle Treatment.

    Science.gov (United States)

    Christ, Bastian; Fey, Christina; Cubukova, Alevtina; Walles, Heike; Dembski, Sofia; Metzger, Marco

    2017-01-01

    Nanoparticles (NPs) in biotechnology hold great promise for revolutionizing medical treatments and therapies. In order to bring NPs into clinical application there is a number of preclinical in vitro and in vivo tests, which have to be applied before. The initial in vitro evaluation includes a detailed physicochemical characterization as well as biocompatibility tests, among others. For determination of biocompatibility at the cellular level, the correct choice of the in vitro assay as well as NP pretreatment is absolutely essential. There are a variety of assay technologies available that use standard plate readers to measure metabolic markers to estimate the number of viable cells in culture. Each cell viability assay has its own set of advantages and disadvantages. Regardless of the assay method chosen, the major factors critical for reproducibility and success include: (1) choosing the right assay after comparing optical NP properties with the read-out method of the assay, (2) verifying colloidal stability of NPs in cell culture media, (3) preparing a sterile and stable NP dispersion in cell culture media used in the assay, (4) using a tightly controlled and consistent cell model allowing appropriate characterization of NPs. This chapter will briefly summarize these different critical points, which can occur during biocompatibility screening applications of NPs.

  9. Kinetics of cellular uptake of viruses and nanoparticles via clathrin-mediated endocytosis

    Science.gov (United States)

    Banerjee, Anand; Berezhkovskii, Alexander; Nossal, Ralph

    2016-02-01

    Several viruses exploit clathrin-mediated endocytosis to gain entry into host cells. This process is also used extensively in biomedical applications to deliver nanoparticles (NPs) to diseased cells. The internalization of these nano-objects is controlled by the assembly of a clathrin-containing protein coat on the cytoplasmic side of the plasma membrane, which drives the invagination of the membrane and the formation of a cargo-containing endocytic vesicle. Current theoretical models of receptor-mediated endocytosis of viruses and NPs do not explicitly take coat assembly into consideration. In this paper we study cellular uptake of viruses and NPs with a focus on coat assembly. We characterize the internalization process by the mean time between the binding of a particle to the membrane and its entry into the cell. Using a coarse-grained model which maps the stochastic dynamics of coat formation onto a one-dimensional random walk, we derive an analytical formula for this quantity. A study of the dependence of the mean internalization time on NP size shows that there is an upper bound above which this time becomes extremely large, and an optimal size at which it attains a minimum. Our estimates of these sizes compare well with experimental data. We also study the sensitivity of the obtained results on coat parameters to identify factors which significantly affect the internalization kinetics.

  10. Cellular uptake of fluorophore-labeled glyco-DNA–gold nanoparticles

    International Nuclear Information System (INIS)

    Witten, Katrin G.; Ruff, Julie; Mohr, Anne; Görtz, Dieter; Recker, Tobias; Rinis, Natalie; Rech, Claudia; Elling, Lothar; Müller-Newen, Gerhard; Simon, Ulrich

    2013-01-01

    DNA-functionalized gold nanoparticles (AuNP–DNA) were hybridized with complementary di-N-acetyllactosamine-(di-LacNAc, [3Gal(β1-4)GlcNAc(β1-]2)-modified oligonucleotides to form glycol-functionalized particles, AuNP–DNA–di-LacNAc. While AuNP–DNA are known to be taken up by cells via scavenger receptors, glycol-functionalized particles have shown to be taken up via asialoglycoprotein receptors (ASGP-R). In this work, the interaction of these new particles with HepG2 cells was analyzed, which express scavenger receptors class B type I (SR-BI) and ASGP-R. To study the contribution of these receptors as potential mediators for cellular uptake, receptor-blocking experiments were performed with d-lactose, a ligand for ASGP-R, Fucoidan, a putative ligand for SR-BI, and a SR-BI blocking antibody. Labeling with Cy5-modified DNA ligands enabled us to monitor the particle uptake by confocal fluorescence microscopy and flow cytometry, in order to discriminate the two putative pathways by competitive binding studies. While SR-BI-antibody and d-lactose had no inhibiting effects on particle uptake Fucoidan led to a complete inhibition. Thus, a receptor-mediated uptake by the two receptors studied could not be proven and therefore other uptake mechanisms have to be considered

  11. Agglomeration, sedimentation, and cellular toxicity of alumina nanoparticles in cell culture medium

    International Nuclear Information System (INIS)

    Yoon, Dokyung; Woo, Daekwang; Kim, Jung Heon; Kim, Moon Ki; Kim, Taesung; Hwang, Eung-Soo; Baik, Seunghyun

    2011-01-01

    The cytotoxicity of alumina nanoparticles (NPs) was investigated for a wide range of concentration (25–200 μg/mL) and incubation time (0–72 h) using floating cells (THP-1) and adherent cells (J774A.1, A549, and 293). Alumina NPs were gradually agglomerated over time although a significant portion of sedimentation occurred at the early stage within 6 h. A decrease of the viability was found in floating (THP-1) and adherent (J774A.1 and A549) cells in a dose-dependent manner. However, the time-dependent decrease in cell viability was observed only in adherent cells (J774A.1 and A549), which is predominantly related with the sedimentation of alumina NPs in cell culture medium. The uptake of alumina NPs in macrophages and an increased cell-to-cell adhesion in adherent cells were observed. There was no significant change in the viability of 293 cells. This in vitro test suggests that the agglomeration and sedimentation of alumina NPs affected cellular viability depending on cell types such as monocytes (THP-1), macrophages (J774A.1), lung carcinoma cells (A549), and embryonic kidney cells (293).

  12. Agglomeration, sedimentation, and cellular toxicity of alumina nanoparticles in cell culture medium

    Science.gov (United States)

    Yoon, Dokyung; Woo, Daekwang; Kim, Jung Heon; Kim, Moon Ki; Kim, Taesung; Hwang, Eung-Soo; Baik, Seunghyun

    2011-06-01

    The cytotoxicity of alumina nanoparticles (NPs) was investigated for a wide range of concentration (25-200 μg/mL) and incubation time (0-72 h) using floating cells (THP-1) and adherent cells (J774A.1, A549, and 293). Alumina NPs were gradually agglomerated over time although a significant portion of sedimentation occurred at the early stage within 6 h. A decrease of the viability was found in floating (THP-1) and adherent (J774A.1 and A549) cells in a dose-dependent manner. However, the time-dependent decrease in cell viability was observed only in adherent cells (J774A.1 and A549), which is predominantly related with the sedimentation of alumina NPs in cell culture medium. The uptake of alumina NPs in macrophages and an increased cell-to-cell adhesion in adherent cells were observed. There was no significant change in the viability of 293 cells. This in vitro test suggests that the agglomeration and sedimentation of alumina NPs affected cellular viability depending on cell types such as monocytes (THP-1), macrophages (J774A.1), lung carcinoma cells (A549), and embryonic kidney cells (293).

  13. Cellular uptake of fluorophore-labeled glyco-DNA-gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Witten, Katrin G.; Ruff, Julie [RWTH Aachen University, Institute of Inorganic Chemistry and JARA - Fundamentals of Future Information Technology (Germany); Mohr, Anne; Goertz, Dieter; Recker, Tobias; Rinis, Natalie [RWTH Aachen University, Institute of Biochemistry and Molecular Biology, University Hospital Aachen (Germany); Rech, Claudia; Elling, Lothar [RWTH Aachen University, Laboratory for Biomaterials, Institute of Biotechnology and Helmholtz-Institute for Biomedical Engineering (Germany); Mueller-Newen, Gerhard [RWTH Aachen University, Institute of Biochemistry and Molecular Biology, University Hospital Aachen (Germany); Simon, Ulrich, E-mail: ulrich.simon@ac.rwth-aachen.de [RWTH Aachen University, Institute of Inorganic Chemistry and JARA - Fundamentals of Future Information Technology (Germany)

    2013-10-15

    DNA-functionalized gold nanoparticles (AuNP-DNA) were hybridized with complementary di-N-acetyllactosamine-(di-LacNAc, [3Gal({beta}1-4)GlcNAc({beta}1-]2)-modified oligonucleotides to form glycol-functionalized particles, AuNP-DNA-di-LacNAc. While AuNP-DNA are known to be taken up by cells via scavenger receptors, glycol-functionalized particles have shown to be taken up via asialoglycoprotein receptors (ASGP-R). In this work, the interaction of these new particles with HepG2 cells was analyzed, which express scavenger receptors class B type I (SR-BI) and ASGP-R. To study the contribution of these receptors as potential mediators for cellular uptake, receptor-blocking experiments were performed with d-lactose, a ligand for ASGP-R, Fucoidan, a putative ligand for SR-BI, and a SR-BI blocking antibody. Labeling with Cy5-modified DNA ligands enabled us to monitor the particle uptake by confocal fluorescence microscopy and flow cytometry, in order to discriminate the two putative pathways by competitive binding studies. While SR-BI-antibody and d-lactose had no inhibiting effects on particle uptake Fucoidan led to a complete inhibition. Thus, a receptor-mediated uptake by the two receptors studied could not be proven and therefore other uptake mechanisms have to be considered.

  14. Fluorescent determination of poly(hexamethylene guanidine) via the aggregates it forms with quantum dots and magnetic nanoparticles

    International Nuclear Information System (INIS)

    Likhachev, Konstantin V.; Beklemishev, Mikhail K.; Ovcharenko, Elena O.; Dityuk, Alexander I.; Efimov, Konstantin M.; Abramchuk, Sergei S.

    2016-01-01

    The authors report that the cationic polymer-oligomer poly(hexamethylene guanidine) (PHMG) in the form of its hydrochloride induces the formation of mixed aggregates composed of anionic magnetic nanoparticles (magNPs), PHMG and anionic quantum dots (QDs). The magNPs consisted of polymer-coated magnetite nanoparticles, and the QDs consisted of polymer-coated CdSe-CdS/ZnS nanoparticles with an emission maximum at 617 nm. This finding is exploited in a semi-quantitative method for the determination of PHMG. The protocol includes magnetic separation of the mixed aggregates (magNPs/PHMG/QDs) from the sample and excess QDs, redispersion of the aggregates in water, and measurement of fluorescence intensity. The signal is proportional to the concentration of PHMG in the 0.05 to 0.2 mg L"−"1 concentration range, with intra-day RSDs of up to 27 %. The limit of detection (LOD) of PHMG in spiked run-off waters, swimming pool water and wastewater is 23 μg L"−"1. This PHMG assay is selective in that high concentrations of surfactants and inorganic salts are tolerated. Polyethyleneimine and poly(diallyldimethylammonium chloride) also cause the formation of mixed aggregates but only at higher concentrations. Both a fluorometer and a digital camera (using a 365-nm LED as a light source) were used to measure fluorescence. In case of using a digital camera, the LOD is 40 μg L"−"1 and the intraday RSDs are up to 23 %. The method is sensitive, fairly selective and rather simple. (author)

  15. A Novel DNA Nanosensor Based on CdSe/ZnS Quantum Dots and Synthesized Fe3O4 Magnetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Roozbeh Hushiarian

    2014-04-01

    Full Text Available Although nanoparticle-enhanced biosensors have been extensively researched, few studies have systematically characterized the roles of nanoparticles in enhancing biosensor functionality. This paper describes a successful new method in which DNA binds directly to iron oxide nanoparticles for use in an optical biosensor. A wide variety of nanoparticles with different properties have found broad application in biosensors because their small physical size presents unique chemical, physical, and electronic properties that are different from those of bulk materials. Of all nanoparticles, magnetic nanoparticles are proving to be a versatile tool, an excellent case in point being in DNA bioassays, where magnetic nanoparticles are often used for optimization of the hybridization and separation of target DNA. A critical step in the successful construction of a DNA biosensor is the efficient attachment of biomolecules to the surface of magnetic nanoparticles. To date, most methods of synthesizing these nanoparticles have led to the formation of hydrophobic particles that require additional surface modifications. As a result, the surface to volume ratio decreases and nonspecific bindings may occur so that the sensitivity and efficiency of the device deteriorates. A new method of large-scale synthesis of iron oxide (Fe3O4 nanoparticles which results in the magnetite particles being in aqueous phase, was employed in this study. Small modifications were applied to design an optical DNA nanosensor based on sandwich hybridization. Characterization of the synthesized particles was carried out using a variety of techniques and CdSe/ZnS core-shell quantum dots were used as the reporter markers in a spectrofluorophotometer. We showed conclusively that DNA binds to the surface of ironoxide nanoparticles without further surface modifications and that these magnetic nanoparticles can be efficiently utilized as biomolecule carriers in biosensing devices.

  16. Engineering the lipid layer of lipid-PLGA hybrid nanoparticles for enhanced in vitro cellular uptake and improved stability.

    Science.gov (United States)

    Hu, Yun; Hoerle, Reece; Ehrich, Marion; Zhang, Chenming

    2015-12-01

    Lipid-polymer hybrid nanoparticles (NPs), consisting of a polymeric core and a lipid shell, have been intensively examined as delivery systems for cancer drugs, imaging agents, and vaccines. For applications in vaccine particularly, the hybrid NPs need to be able to protect the enclosed antigens during circulation, easily be up-taken by dendritic cells, and possess good stability for prolonged storage. However, the influence of lipid composition on the performance of hybrid NPs has not been well studied. In this study, we demonstrate that higher concentrations of cholesterol in the lipid layer enable slower and more controlled antigen release from lipid-poly(lactide-co-glycolide) acid (lipid-PLGA) NPs in human serum and phosphate buffered saline (PBS). Higher concentrations of cholesterol also promoted in vitro cellular uptake of hybrid NPs, improved the stability of the lipid layer, and protected the integrity of the hybrid structure during long-term storage. However, stabilized hybrid structures of high cholesterol content tended to fuse with each other during storage, resulting in significant size increase and lowered cellular uptake. Additional experiments demonstrated that PEGylation of NPs could effectively minimize fusion-caused size increase after long term storage, leading to improved cellular uptake, although excessive PEGylation will not be beneficial and led to reduced improvement. This paper reports the engineering of the lipid layer that encloses a polymeric nanoparticle, which can be used as a carrier for drug and vaccine molecules for targeted delivery. We demonstrated that the concentration of cholesterol is critical for the stability and uptake of the hybrid nanoparticles by dendritic cells, a targeted cell for the delivery of immune effector molecules. However, we found that hybrid nanoparticles with high cholesterol concentration tend to fuse during storage resulting in larger particles with decreased cellular uptake. This problem is

  17. Naringenin-loaded solid lipid nanoparticles: preparation, controlled delivery, cellular uptake, and pulmonary pharmacokinetics

    Directory of Open Access Journals (Sweden)

    Ji P

    2016-03-01

    Full Text Available Peng Ji, Tong Yu, Ying Liu, Jie Jiang, Jie Xu, Ying Zhao, Yanna Hao, Yang Qiu, Wenming Zhao, Chao WuCollege of Pharmacy, Liaoning Medical University, Jinzhou, Liaoning Province, People’s Republic of ChinaAbstract: Naringenin (NRG, a flavonoid compound, had been reported to exhibit extensive pharmacological effects, but its water solubility and oral bioavailability are only ~46±6 µg/mL and 5.8%, respectively. The purpose of this study is to design and develop NRG-loaded solid lipid nanoparticles (NRG-SLNs to provide prolonged and sustained drug release, with improved stability, involving nontoxic nanocarriers, and increase the bioavailability by means of pulmonary administration. Initially, a group contribution method was used to screen the best solid lipid matrix for the preparation of SLNs. NRG-SLNs were prepared by an emulsification and low-temperature solidification method and optimized using an orthogonal experiment approach. The morphology was examined by transmission electron microscopy, and the particle size and zeta potential were determined by photon correlation spectroscopy. The total drug content of NRG-SLNs was measured by high-performance liquid chromatography, and the encapsulation efficiency (EE was determined by Sephadex gel-50 chromatography and high-performance liquid chromatography. The in vitro NRG release studies were carried out using a dialysis bag. The best cryoprotectant to prepare NRG-SLN lyophilized powder for future structural characterization was selected using differential scanning calorimetry, powder X-ray diffraction, and Fourier transform infrared spectroscopy. The short-term stability, 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyl-tetrazolium bromide (MTT assay, cellular uptake, and pharmacokinetics in rats were studied after pulmonary administration of NRG-SLN lyophilized powder. Glycerol monostearate was selected to prepare SLNs, and the optimal formulation of NRG-SLNs was spherical in shape, with a particle

  18. Delivery of kinesin spindle protein targeting siRNA in solid lipid nanoparticles to cellular models of tumor vasculature

    International Nuclear Information System (INIS)

    Ying, Bo; Campbell, Robert B.

    2014-01-01

    Highlights: • siRNA-lipid nanoparticles are solid particles not lipid bilayers with aqueous core. • High, but not low, PEG content can prevent nanoparticle encapsulation of siRNA. • PEG reduces cellular toxicity of cationic nanoparticles in vitro. • PEG reduces zeta potential while improving gene silencing of siRNA nanoparticles. • Kinesin spindle protein can be an effective target for tumor vascular targeting. - Abstract: The ideal siRNA delivery system should selectively deliver the construct to the target cell, avoid enzymatic degradation, and evade uptake by phagocytes. In the present study, we evaluated the importance of polyethylene glycol (PEG) on lipid-based carrier systems for encapsulating, and delivering, siRNA to tumor vessels using cellular models. Lipid nanoparticles containing different percentage of PEG were evaluated based on their physical chemical properties, density compared to water, siRNA encapsulation, toxicity, targeting efficiency and gene silencing in vitro. siRNA can be efficiently loaded into lipid nanoparticles (LNPs) when DOTAP is included in the formulation mixture. However, the total amount encapsulated decreased with increase in PEG content. In the presence of siRNA, the final formulations contained a mixed population of particles based on density. The major population which contains the majority of siRNA exhibited a density of 4% glucose, and the minor fraction associated with a decreased amount of siRNA had a density less than PBS. The inclusion of 10 mol% PEG resulted in a greater amount of siRNA associated with the minor fraction. Finally, when kinesin spindle protein (KSP) siRNA was encapsulated in lipid nanoparticles containing a modest amount of PEG, the proliferation of endothelial cells was inhibited due to the efficient knock down of KSP mRNA. The presence of siRNA resulted in the formation of solid lipid nanoparticles when prepared using the thin film and hydration method. LNPs with a relatively modest amount of

  19. The toxicity of plastic nanoparticles to green algae as influenced by surface modification, medium hardness and cellular adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Nolte, Tom M., E-mail: T.Nolte@science.ru.nl [Department of Environmental Engineering, Technical University of Denmark, Miljøvej, B113, 2800 Kgs. Lyngby (Denmark); Radboud University Nijmegen, Institute for Water and Wetland Research, Department of Environmental Science, P.O. Box 9010, NL-6500 GL, Nijmegen (Netherlands); Hartmann, Nanna B. [Department of Environmental Engineering, Technical University of Denmark, Miljøvej, B113, 2800 Kgs. Lyngby (Denmark); Kleijn, J. Mieke [Physical Chemistry Soft Matter, Wageningen University, Stippeneng 4, NL-6708WE Wageningen (Netherlands); Garnæs, Jørgen [Danish Fundamental Metrology, Matematiktorvet 307, 2800 Kgs. Lyngby (Denmark); Meent, Dik van de [Radboud University Nijmegen, Institute for Water and Wetland Research, Department of Environmental Science, P.O. Box 9010, NL-6500 GL, Nijmegen (Netherlands); National Institute of Public Health and the Environment RIVM, P.O. Box 1, 3720 BA, Bilthoven (Netherlands); Jan Hendriks, A. [Radboud University Nijmegen, Institute for Water and Wetland Research, Department of Environmental Science, P.O. Box 9010, NL-6500 GL, Nijmegen (Netherlands); Baun, Anders [Department of Environmental Engineering, Technical University of Denmark, Miljøvej, B113, 2800 Kgs. Lyngby (Denmark)

    2017-02-15

    Highlights: • P. subcapitata cultures were exposed to plastic nanoparticles in adsorption assays. • UV/Vis and AFM showed ionic strength and surface chemistry influence adsorption of anionic and neutral nanoplastics. • Growth inhibition of algae is antagonistically influenced by carboxylate-modified polystyrene and calcium. • Physico-chemical characterization and proper dose metrics can be used to predict ecotoxicity. - Abstract: To investigate processes possibly underlying accumulation and ecological effects of plastic nano-particles we have characterized their interaction with the cell wall of green algae. More specifically, we have investigated the influence of particle surface functionality and water hardness (Ca{sup 2+} concentration) on particle adsorption to algae cell walls. Polystyrene nanoparticles with different functional groups (non-functionalized, −COOH and −NH{sub 2}) as well as coated (starch and PEG) gold nanoparticles were applied in these studies. Depletion measurements and atomic force microscopy (AFM) showed that adsorption of neutral and positively charged plastic nanoparticles onto the cell wall of P. subcapitata was stronger than that of negatively charged plastic particles. Results indicated that binding affinity is a function of both inter-particle and particle-cell wall interactions which are in turn influenced by the medium hardness and particle concentration. Physicochemical modelling using DLVO theory was used to interpret the experimental data, using also values for interfacial surface free energies. Our study shows that material properties and medium conditions play a crucial role in the rate and state of nanoparticle bio-adsorption for green algae. The results show that the toxicity of nanoparticles can be better described and assessed by using appropriate dose metrics including material properties, complexation/agglomeration behavior and cellular attachment and adsorption. The applied methodology provides an efficient

  20. The toxicity of plastic nanoparticles to green algae as influenced by surface modification, medium hardness and cellular adsorption

    International Nuclear Information System (INIS)

    Nolte, Tom M.; Hartmann, Nanna B.; Kleijn, J. Mieke; Garnæs, Jørgen; Meent, Dik van de; Jan Hendriks, A.; Baun, Anders

    2017-01-01

    Highlights: • P. subcapitata cultures were exposed to plastic nanoparticles in adsorption assays. • UV/Vis and AFM showed ionic strength and surface chemistry influence adsorption of anionic and neutral nanoplastics. • Growth inhibition of algae is antagonistically influenced by carboxylate-modified polystyrene and calcium. • Physico-chemical characterization and proper dose metrics can be used to predict ecotoxicity. - Abstract: To investigate processes possibly underlying accumulation and ecological effects of plastic nano-particles we have characterized their interaction with the cell wall of green algae. More specifically, we have investigated the influence of particle surface functionality and water hardness (Ca"2"+ concentration) on particle adsorption to algae cell walls. Polystyrene nanoparticles with different functional groups (non-functionalized, −COOH and −NH_2) as well as coated (starch and PEG) gold nanoparticles were applied in these studies. Depletion measurements and atomic force microscopy (AFM) showed that adsorption of neutral and positively charged plastic nanoparticles onto the cell wall of P. subcapitata was stronger than that of negatively charged plastic particles. Results indicated that binding affinity is a function of both inter-particle and particle-cell wall interactions which are in turn influenced by the medium hardness and particle concentration. Physicochemical modelling using DLVO theory was used to interpret the experimental data, using also values for interfacial surface free energies. Our study shows that material properties and medium conditions play a crucial role in the rate and state of nanoparticle bio-adsorption for green algae. The results show that the toxicity of nanoparticles can be better described and assessed by using appropriate dose metrics including material properties, complexation/agglomeration behavior and cellular attachment and adsorption. The applied methodology provides an efficient and

  1. Ascorbic acid prevents cellular uptake and improves biocompatibility of chitosan nanoparticles.

    Science.gov (United States)

    Elshoky, Hisham A; Salaheldin, Taher A; Ali, Maha A; Gaber, Mohamed H

    2018-04-11

    Chitosan nanoparticles have many applications, such as gene and drug delivery, due to their biocompatibility. Chitosan nanoparticles are currently produced by dissolution in acetic acid that affects the biocompatibility at acidic pH. Here, we synthesized and characterized chitosan (CS) and ascorbate chitosan (AsCS) nanoparticles and investigated their cytotoxic effects, internalization, and distribution in the human colon carcinoma cell line using confocal laser scanning microscopy (CLSM). The CS and AsCS nanoparticles were spherical with average particle sizes of 44±8.4nm and 87±13.6nm, respectively. CS nanoparticles were taken up by the cells and showed dose-dependent cytotoxicity. By contrast, AsCS nanoparticles were not internalized and showed no cytotoxicity. Therefore, AsCS nanoparticles are more biocompatible than CS nanoparticles and may be more suitable for extracellular drug delivery. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Nitrogen and phosphorus co-doped graphene quantum dots: synthesis from adenosine triphosphate, optical properties, and cellular imaging.

    Science.gov (United States)

    Ananthanarayanan, Arundithi; Wang, Yue; Routh, Parimal; Sk, Mahasin Alam; Than, Aung; Lin, Ming; Zhang, Jie; Chen, Jie; Sun, Handong; Chen, Peng

    2015-05-07

    Graphene quantum dots (GQDs) are emerging zero-dimensional materials promising a wide spectrum of applications, particularly, as superior fluorescent reporters for bio-imaging and optical sensing. Heteroatom doping can endow GQDs with new or improved photoluminescence properties. Here, we demonstrate a simple strategy for the synthesis of nitrogen and phosphorus co-doped GQDs from a single biomolecule precursor (adenosine triphosphate - ATP). Such ATP-GQDs exhibit high fluorescence quantum yield, strong two-photon upconversion, small molecular weight, high photostability, and good biocompatibility. Furthermore, transferrin conjugated ATP-GQDs have been used for imaging and real-time tracking of transferrin receptors in live cells.

  3. Nanostructured submicron block copolymer dots by sacrificial stamping: a potential preconcentration platform for locally resolved sensing, chemistry and cellular interactions

    OpenAIRE

    Hou, Peilong; Han, Weijia; Philippi, Michael; Schäfer, Helmut; Steinhart, Martin

    2018-01-01

    Classical contact lithography involves patterning of surfaces by embossing or by transfer of ink. We report direct lithographic transfer of parts of sacrificial stamps onto counterpart surfaces. Using sacrificial stamps consisting of the block copolymer polystyrene-block-poly(2-pyridine) (PS-b-P2VP), we deposited arrays of nanostructured submicron PS-b-P2VP dots with heights of about 100 nm onto silicon wafers and glass slides. The sacrificial PS-b-P2VP stamps were topographically patterned w...

  4. Investigating uptake of water-dispersible CdSe/ZnS quantum dot nanoparticles by Arabidopsis thaliana plants

    International Nuclear Information System (INIS)

    Navarro, Divina A.; Bisson, Mary A.; Aga, Diana S.

    2012-01-01

    Graphical abstract: This study highlights the importance of quantum dot (QD) structural stability in preventing phytotoxicity. Overall, there is no evidence that Arabidopsis thaliana plants can internalize intact QDs within 1–7 days of exposure, with or without humic acids. Highlights: ► Potential uptake of water-dispersible CdSe/ZnS QDs by Arabidopsis was demonstrated. ► QDs were not internalized by Arabidopsis as intact particles. ► Plants exposed to Cd-, Se-, and QD + HA suspensions experienced oxidative stress. ► An effective LC–MS method proves detection of low levels of glutathione in plants. ► Uptake of Cd and/or Se leached from QDs is of major concern. - Abstract: Interest on the environmental impacts of engineered nanomaterials has rapidly increased over the past years because it is expected that these materials will eventually be released into the environment. The present work investigates the potential root uptake of water-dispersible CdSe/ZnS quantum dots (QDs) by the model plant species, Arabidopsis thaliana. Experiments revealed that Arabidopsis exposed to QDs that are dispersed in Hoagland's solution for 1–7 days did not internalize intact QDs. Analysis of Cd and Se concentrations in roots and leaves by inductively-coupled plasma mass spectrometry indicated that Cd and Se from QD-treated plants were not translocated into the leaves, and remained in the root system of Arabidopsis. Furthermore, fluorescence microscopy showed strong evidence that the QDs were generally on the outside surfaces of the roots, where the amount of QDs adsorbed is dependent on the stability of the QDs in suspension. Despite no evidence of nanoparticle internalization, the ratio of reduced glutathione levels (GSH) relative to the oxidized glutathione (GSSG) in plants decreased when plants were exposed to QD dispersions containing humic acids, suggesting that QDs caused oxidative stress on the plant at this condition.

  5. Quantum dot bio-conjugate: as a western blot probe for highly sensitive detection of cellular proteins

    Energy Technology Data Exchange (ETDEWEB)

    Kale, Sonia [Agharkar Research Institute (India); Kale, Anup [University of Alabama, Center for Materials for Information Technology (United States); Gholap, Haribhau; Rana, Abhimanyu [National Chemical Laboratory, Physical and Materials Chemistry Division (India); Desai, Rama [National Centre for Cell Science (India); Banpurkar, Arun [University of Pune, Department of Physics (India); Ogale, Satishchandra, E-mail: sb.ogale@ncl.res.in [National Chemical Laboratory, Physical and Materials Chemistry Division (India); Shastry, Padma, E-mail: padma@nccs.res.in [National Centre for Cell Science (India)

    2012-03-15

    In the present study, we report a quantum dot (QD)-tailored western blot analysis for a sensitive, rapid and flexible detection of the nuclear and cytoplasmic proteins. Highly luminescent CdTe and (CdTe)ZnS QDs are synthesized by aqueous method. High resolution transmission electron microscopy, Raman spectroscopy, fourier transform infrared spectroscopy, fluorescence spectroscopy and X-ray diffraction are used to characterize the properties of the quantum dots. The QDs are functionalized with antibodies of prostate apoptosis response-4 (Par-4), poly(ADP-ribose) polymerases and {beta} actin to specifically bind with the proteins localized in the nucleus and cytoplasm of the cells, respectively. The QD-conjugated antibodies are used to overcome the limitations of conventional western blot technique. The sensitivity and rapidity of protein detection in QD-based approach is very high, with detection limits up to 10 pg of protein. In addition, these labels provide the capability of enhanced identification and localization of marker proteins in intact cells by confocal laser scanning microscopy.

  6. Study on the enhanced cellular uptake effect of daunorubicin on leukemia cells mediated via functionalized nickel nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Guo Dadong; Wu Chunhui; Hu Hongli; Wang Xuemei [State Key Lab of Bioelectronics (Chien-Shiung Wu Lab), Southeast University, Nanjing 210096 (China); Li Xiaomao [Department of Physics, University of Saarland, D-66041 Saarbruecken (Germany); Chen Baoan, E-mail: xuewang@seu.edu.c [Zhongda Hospital, School of Clinical Medical, Southeast University, Nanjing 210096 (China)

    2009-04-15

    The success of cancer chemotherapy is largely dependent on the efficient anticancer drug accumulation in target tumor tissues and cells so as to inhibit the proliferation of the cancer cells. Recently, some biocompatible nanomaterials have been utilized as drug target delivery systems and have shown the great potential to effectively afford the sustained drug delivery for the target cancer cells. In this study, we have explored the possibility for the bio-application of the functionalized nickel (Ni) nanoparticles and the efficiency of the functionalized Ni nanoparticles on drug permeability, and cellular uptake of leukemia K562 cells in vitro has been probed via atomic force microscopy, inverted fluorescence microscopy and confocal microscopy, electrochemical study and MTT (3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl-tetrazolium bromide) assay. It is observed that the presence of relevant Ni nanoparticles could induce the membrane structure change of target cells and efficiently improve the permeability of the cell membrane so that the combination of these Ni nanoparticles with anticancer drug daunorubicin could have a synergistic effect on the efficient cytotoxicity suppression in leukemia cancer cells. These observations indicate the great potential of Ni nanoparticles in the future biomedical application including target cancer diagnosis and chemotherapy.

  7. Effect of surface modification of silica nanoparticles on toxicity and cellular uptake by human peripheral blood lymphocytes in vitro.

    Science.gov (United States)

    Lankoff, Anna; Arabski, Michal; Wegierek-Ciuk, Aneta; Kruszewski, Marcin; Lisowska, Halina; Banasik-Nowak, Anna; Rozga-Wijas, Krystyna; Wojewodzka, Maria; Slomkowski, Stanislaw

    2013-05-01

    Silica nanoparticles have an interesting potential in drug delivery, gene therapy and molecular imaging due to the possibility of tailoring their surface reactivity that can be obtained by surface modification. Despite these potential benefits, there is concern that exposure of humans to certain types of silica nanomaterials may lead to significant adverse health effects. The motivation of this study was to determine the kinetics of cellular binding/uptake of the vinyl- and the aminopropyl/vinyl-modified silica nanoparticles into peripheral blood lymphocytes in vitro, to explore their genotoxic and cytotoxic properties and to compare the biological properties of modified silica nanoparticles with those of the unmodified ones. Size of nanoparticles determined by SEM varied from 10 to 50 nm. The average hydrodynamic diameter and zeta potential also varied from 176.7 nm (+18.16 mV) [aminopropyl/vinyl-modified] and 235.4 nm (-9.49 mV) [vinyl-modified] to 266.3 (-13.32 mV) [unmodified]. Surface-modified silica particles were internalized by lymphocytes with varying efficiency and expressed no cytotoxic nor genotoxic effects, as determined by various methods (cell viability, apoptosis/necrosis, oxidative DNA damage, chromosome aberrations). However, they affected the proliferation of the lymphocytes as indicated by a decrease in mitotic index value and cell cycle progression. In contrast, unmodified silica nanoparticles exhibited cytotoxic and genotoxic properties at high doses as well as interfered with cell cycle.

  8. The toxicity of plastic nanoparticles to green algae as influenced by surface modification, medium hardness and cellular adsorption.

    Science.gov (United States)

    Nolte, Tom M; Hartmann, Nanna B; Kleijn, J Mieke; Garnæs, Jørgen; van de Meent, Dik; Jan Hendriks, A; Baun, Anders

    2017-02-01

    To investigate processes possibly underlying accumulation and ecological effects of plastic nano-particles we have characterized their interaction with the cell wall of green algae. More specifically, we have investigated the influence of particle surface functionality and water hardness (Ca 2+ concentration) on particle adsorption to algae cell walls. Polystyrene nanoparticles with different functional groups (non-functionalized, -COOH and -NH 2 ) as well as coated (starch and PEG) gold nanoparticles were applied in these studies. Depletion measurements and atomic force microscopy (AFM) showed that adsorption of neutral and positively charged plastic nanoparticles onto the cell wall of P. subcapitata was stronger than that of negatively charged plastic particles. Results indicated that binding affinity is a function of both inter-particle and particle-cell wall interactions which are in turn influenced by the medium hardness and particle concentration. Physicochemical modelling using DLVO theory was used to interpret the experimental data, using also values for interfacial surface free energies. Our study shows that material properties and medium conditions play a crucial role in the rate and state of nanoparticle bio-adsorption for green algae. The results show that the toxicity of nanoparticles can be better described and assessed by using appropriate dose metrics including material properties, complexation/agglomeration behavior and cellular attachment and adsorption. The applied methodology provides an efficient and feasible approach for evaluating potential accumulation and hazardous effects of nanoparticles to algae caused by particle interactions with the algae cell walls. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Cellular uptake of magnetite nanoparticles enhanced by NdFeB magnets in staggered arrangement

    Science.gov (United States)

    Lu, Yi-Ching; Chang, Fan-Yu; Tu, Shu-Ju; Chen, Jyh-Ping; Ma, Yunn-Hwa

    2017-04-01

    Magnetic force may greatly enhance uptake of magnetic nanoparticles (MNPs) by cultured cells; however, the effects of non-uniformity of magnetic field/ magnetic gradient on MNP internalization in culture has not been elucidated. Cellular uptake of polyacrylic acid coated-MNP by LN229 cells was measured with cylindrical NdFeB magnets arranged in a staggered pattern. The magnetic field generated by placing a magnet underneath (H-field) elicited a homogenous distribution of MNPs on the cells in culture; whereas the field without magnet underneath (L-field) resulted in MNP distribution along the edge of the wells. Cell-associated MNP (MNPcell) appeared to be magnetic field- and concentration-dependent. In H-field, MNPcell reached plateau within one hour of exposure to MNP with only one-min application of the magnetic force in the beginning of incubation; continuous presence of the magnet for 2 h did not further increase MNPcell, suggesting that magnetic force-induced uptake may be primarily contributed to enhanced MNP sedimentation. Although MNP distribution was much inhomogeneous in L-field, averaged MNPcell in the L-field may reach as high as 80% of that in H-field during 1-6 h incubation, suggesting high capacity of MNP internalization. In addition, no significant difference was observed in MNPcell analyzed by flow cytometry with the application of H-field of staggered plate vs. filled magnet plate. Therefore, biological variation may dominate MNP internalization even under relatively uniformed magnetic field; whereas non-uniformed magnetic field may serve as a model for tumor targeting with MNPs in vivo.

  10. Scavenger receptor B1 facilitates macrophage uptake of silver nanoparticles and cellular activation

    Energy Technology Data Exchange (ETDEWEB)

    Aldossari, Abdullah A.; Shannahan, Jonathan H. [The University of Colorado Anschutz Medical Campus, Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences (United States); Podila, Ramakrishna [Clemson University, Department of Physics and Astronomy (United States); Brown, Jared M., E-mail: jared.brown@ucdenver.edu [The University of Colorado Anschutz Medical Campus, Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences (United States)

    2015-07-15

    Due to increased use of silver nanoparticles (AgNPs) for their antimicrobial activity, concerns have risen regarding potential adverse human health effects. Scavenger receptor B1 (SR-B1), a major receptor for high-density lipoprotein (HDL), is expressed by macrophages and has also been reported to play a role in recognition of negatively charged particles. We, therefore, hypothesized that SR-B1 mediates macrophage uptake of AgNPs and inflammatory activation. To test this hypothesis, we exposed a mouse macrophage cell line RAW264.7 (RAW) and bone marrow-derived macrophages (BMDM) to 20 nm citrate-suspended AgNPs. To verify the role of the SR-B1 receptor, we utilized a SR-B1 inhibitor (Blt2). In vitro studies demonstrated uptake of AgNPs and HDL-coated AgNPs by macrophages which were significantly reduced following pretreatment with Blt2. Inflammatory cytokine arrays revealed that macrophages exposed to AgNPs up-regulated expression of Tnf-α, Oncostatin m (OSM), Ccl4, Il17f, Ccl7, and Ccl2, whereas Il16 was found to be down-regulated. Macrophage activation was observed following AgNP and HDL-coated AgNP exposure as measured by OSM protein production and increased surface expression of CD86. These markers of activation were reduced with Blt2 pretreatment. The in vitro findings were confirmed in vivo through pulmonary instillation of AgNPs in mice. Pulmonary instillation of AgNPs resulted in a recruitment of inflammatory cells that were reduced in SR-B1-deficient mice or following Blt2 pretreatment. This study suggests that SR-B1 plays a major role in cellular recognition of AgNPs and the induction of cell responses that could contribute to inflammation caused by AgNP exposure.

  11. Scavenger receptor B1 facilitates macrophage uptake of silver nanoparticles and cellular activation

    Science.gov (United States)

    Aldossari, Abdullah A.; Shannahan, Jonathan H.; Podila, Ramakrishna; Brown, Jared M.

    2015-07-01

    Due to increased use of silver nanoparticles (AgNPs) for their antimicrobial activity, concerns have risen regarding potential adverse human health effects. Scavenger receptor B1 (SR-B1), a major receptor for high-density lipoprotein (HDL), is expressed by macrophages and has also been reported to play a role in recognition of negatively charged particles. We, therefore, hypothesized that SR-B1 mediates macrophage uptake of AgNPs and inflammatory activation. To test this hypothesis, we exposed a mouse macrophage cell line RAW264.7 (RAW) and bone marrow-derived macrophages (BMDM) to 20 nm citrate-suspended AgNPs. To verify the role of the SR-B1 receptor, we utilized a SR-B1 inhibitor (Blt2). In vitro studies demonstrated uptake of AgNPs and HDL-coated AgNPs by macrophages which were significantly reduced following pretreatment with Blt2. Inflammatory cytokine arrays revealed that macrophages exposed to AgNPs up-regulated expression of Tnf- α, Oncostatin m (OSM), Ccl4, Il17f, Ccl7, and Ccl2, whereas Il16 was found to be down-regulated. Macrophage activation was observed following AgNP and HDL-coated AgNP exposure as measured by OSM protein production and increased surface expression of CD86. These markers of activation were reduced with Blt2 pretreatment. The in vitro findings were confirmed in vivo through pulmonary instillation of AgNPs in mice. Pulmonary instillation of AgNPs resulted in a recruitment of inflammatory cells that were reduced in SR-B1-deficient mice or following Blt2 pretreatment. This study suggests that SR-B1 plays a major role in cellular recognition of AgNPs and the induction of cell responses that could contribute to inflammation caused by AgNP exposure.

  12. Glycated hemoglobin biosensing integration formed on Au nanoparticle-dotted tubular TiO{sub 2} nanoarray

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Utkarsh [Amity Institute of Nanotechnology, Amity University, Noida, 201303, Uttar Pradesh (India); Singh, Anamika [Department of Biotechnology, UIET, Kurukshetra University, Kurukshetra, 136 119, Haryana (India); Kuchhal, Naresh Kumar [Clinical Biochemistry Department, Bio-Diagnostics, Rohini, Delhi, 110085 (India); Chauhan, Nidhi, E-mail: nidhichauhan2007@rediffmail.com [Amity Institute of Nanotechnology, Amity University, Noida, 201303, Uttar Pradesh (India)

    2016-11-16

    Excessive glucose present in the blood of diabetic patients binds with the hemoglobin of red blood cells resulting in the formation of glycated hemoglobin (HbA{sub 1c}). Measurement of HbA{sub 1c} levels may help in identifying the efficacy of the ongoing treatment and hence provide a better control over the disease. In the present study, we have synthesized a sensitive and stable scaffold, which consists of Au nanoparticles (GNPs)-dotted tubular TiO{sub 2}, for the construction of an electrochemical HbA{sub 1c} biosensor. 12-phosphotungstic acid has been used as a reducer after depositing well-dispersed GNPs on TiO{sub 2} nanotubes (TiO{sub 2} NTs) and an electron mediator by accelerating the electron transfer between the conductor and protein. The fabricated electrode was characterized using scanning electron microscopy (SEM), cyclic voltammetry (CV), Fourier transform infrared spectroscopy (FTIR) and electrochemical impedance spectroscopic analysis (EIS). Biosensor exhibited low detection limit (0.5 μM), fast response time (3 s) and wide linearity (from 0.5 to 2000 μM). The working electrode was used 100 times over 4 months, when stored at 4 °C. The HbA1c biosensor was then effectively used to measure the % of HbA{sub 1c} in the blood of apparently healthy persons and diabetic patients. - Highlights: • Fabrication of a highly sensitive and stable sensing interface consisting of gold nanoparticles (GNPs) and tubular TiO2. • Biosensor exhibited low detection limit (0.5 μM). • The half life of electrode was 4 months. • Biosensor was suitable for detection of glycated hemoglobin in whole blood.

  13. Aptamer-Based electrochemiluminescent detection of MCF-7 cancer cells based on carbon quantum dots coated mesoporous silica nanoparticles

    International Nuclear Information System (INIS)

    Su, Min; Liu, Heng; Ge, Lei; Wang, Yanhu; Ge, Shenguang; Yu, Jinghua; Yan, Mei

    2014-01-01

    Graphical abstract: - Highlights: • Aptamers have many advantages over antibodies, such as low molecular weight, easy but reproducible production and low cost. • Mesoporous silica nanoparticles (MSNs) were prepared to load more CQDs for signal amplification which has a large surface area and high pore volume, ordered porous channels, a uniform and tunable pore structure, and a great diversity in surface functionalization • 3D-GR@AuNPs was prepared as biointerface for the immobilization of cancer cells due to their good biological compatibility, excellent conductivity and large surface area. • This new aptasensor may be quite promising, with potential broad applications in cancer early diagnosis due to the excellent analytical performance. - Abstract: In this work, we developed a novel electrochemiluminescence (ECL) platform for ultrasensitive and selective detection of MCF-7 cancer cells. To construct the platform, three-dimensional macroporous AuNPs@graphene complex was prepared through freeze drying process to modify glassy carbon electrode, which provided an effective matrix for concanavalin A to capture cancer cells due to its high surface area-to-weight ratio and excellent mechanical properties. The carbon quantum dots (CQDs) coated mesoporous silica nanoparticles were used as excellent ECL tracers due to their low cytotoxicity and good biocompatibility. Then, the prepared tracers were conjugated with mucin1 aptamer to specifically bind mucin1 on cancer cells with high stability and bioactivity. Structure characterization was obtained by means of transmission electron microscopy and scanning electron microscopy images. The proposed method showed a good analytical performance for the detection of MCF-7 cancer cells ranging from 500 to 2 × 10 7 cells·mL −1 with a detection limit of 230 cells mL −1 . The as-proposed device has the advantages of high sensitivity, nice specificity, and good stability and could offer great promise for sensitive

  14. Understanding the self-assembly of proteins onto gold nanoparticles and quantum dots driven by metal-histidine coordination.

    Science.gov (United States)

    Aldeek, Fadi; Safi, Malak; Zhan, Naiqian; Palui, Goutam; Mattoussi, Hedi

    2013-11-26

    Coupling of polyhistidine-appended biomolecules to inorganic nanocrystals driven by metal-affinity interactions is a greatly promising strategy to form hybrid bioconjugates. It is simple to implement and can take advantage of the fact that polyhistidine-appended proteins and peptides are routinely prepared using well established molecular engineering techniques. A few groups have shown its effectiveness for coupling proteins onto Zn- or Cd-rich semiconductor quantum dots (QDs). Expanding this conjugation scheme to other metal-rich nanoparticles (NPs) such as AuNPs would be of great interest to researchers actively seeking effective means for interfacing nanostructured materials with biology. In this report, we investigated the metal-affinity driven self-assembly between AuNPs and two engineered proteins, a His7-appended maltose binding protein (MBP-His) and a fluorescent His6-terminated mCherry protein. In particular, we investigated the influence of the capping ligand affinity to the nanoparticle surface, its density, and its lateral extension on the AuNP-protein self-assembly. Affinity gel chromatography was used to test the AuNP-MPB-His7 self-assembly, while NP-to-mCherry-His6 binding was evaluated using fluorescence measurements. We also assessed the kinetics of the self-assembly between AuNPs and proteins in solution, using time-dependent changes in the energy transfer quenching of mCherry fluorescent proteins as they immobilize onto the AuNP surface. This allowed determination of the dissociation rate constant, Kd(-1) ∼ 1-5 nM. Furthermore, a close comparison of the protein self-assembly onto AuNPs or QDs provided additional insights into which parameters control the interactions between imidazoles and metal ions in these systems.

  15. NANOPARTICLES IN NUCLEAR IMAGING

    Directory of Open Access Journals (Sweden)

    Dr. Vicky V Mody PhD

    2011-01-01

    Full Text Available The present review article summarizes the current state radiolabeled nanoparticles for molecular imaging applications mainly targeting cancer. Due to their enormous flexibility, and versatility the radiolabeled nanoparticles have shown their potential in the diagnosis and therapy. As the matter of fact, these radiolabeled imaging agents enable the visualization of the cellular function and the follow-up of the molecular process in living organisms. Moreover, the rapidly advancing field of nanotechnology has provided various innovative radionuclides and delivery systems, such as liposomes, magnetic agents, polymers, dendrimers, quantum dots, and carbon nanotubes to cope up with the hurdles which have been posed by various disease states.

  16. A cellular uptake and cytotoxicity properties study of gallic acid-loaded mesoporous silica nanoparticles on Caco-2 cells

    Science.gov (United States)

    Rashidi, Ladan; Vasheghani-Farahani, Ebrahim; Soleimani, Masoud; Atashi, Amir; Rostami, Khosrow; Gangi, Fariba; Fallahpour, Masoud; Tahouri, Mohammad Taher

    2014-03-01

    In this study, the effects of intracellular delivery of various concentrations of gallic acid (GA) as a semistable antioxidant, gallic acid-loaded mesoporous silica nanoparticles (MSNs-GA), and cellular uptake of nanoparticles into Caco-2 cells were investigated. MSNs were synthesized and loaded with GA, then characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, N2 adsorption isotherms, X-ray diffraction, and thermal gravimetric analysis. The cytotoxicity of MSNs and MSNs-GA at low and high concentrations were studied by means of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test and flow cytometry. MSNs did not show significant toxicity in various concentrations (0-500 μg/ml) on Caco-2 cells. For MSNs-GA, cell viability was reduced as a function of incubation time and different concentrations of nanoparticles. The in vitro GA release from MSNs-GA exhibited the same antitumor properties as free GA on Caco-2 cells. Flow cytometry results confirmed those obtained using MTT assay. TEM and fluorescent microscopy confirmed the internalization of MSNs by Caco-2 cells through nonspecific cellular uptake. MSNs can easily internalize into Caco-2 cells without deleterious effects on cell viability. The cell viability of Caco-2 cells was affected during MSNs-GA uptake. MSNs could be designed as suitable nanocarriers for antioxidants delivery.

  17. Multi-functionality Redefined with Colloidal Carotene Carbon Nanoparticles for Synchronized Chemical Imaging, Enriched Cellular Uptake and Therapy

    Science.gov (United States)

    Misra, Santosh K.; Mukherjee, Prabuddha; Chang, Huei-Huei; Tiwari, Saumya; Gryka, Mark; Bhargava, Rohit; Pan, Dipanjan

    2016-07-01

    Typically, multiplexing high nanoparticle uptake, imaging, and therapy requires careful integration of three different functions of a multiscale molecular-particle assembly. Here, we present a simpler approach to multiplexing by utilizing one component of the system for multiple functions. Specifically, we successfully synthesized and characterized colloidal carotene carbon nanoparticle (C3-NP), in which a single functional molecule served a threefold purpose. First, the presence of carotene moieties promoted the passage of the particle through the cell membrane and into the cells. Second, the ligand acted as a potent detrimental moiety for cancer cells and, finally, the ligands produced optical contrast for robust microscopic detection in complex cellular environments. In comparative tests, C3-NP were found to provide effective intracellular delivery that enables both robust detection at cellular and tissue level and presents significant therapeutic potential without altering the mechanism of intracellular action of β-carotene. Surface coating of C3 with phospholipid was used to generate C3-Lipocoat nanoparticles with further improved function and biocompatibility, paving the path to eventual in vivo studies.

  18. Silver nanoparticles in combination with acetic acid and zinc oxide quantum dots for antibacterial activities improvement—A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Sedira, Sofiane, E-mail: sofianebilel@gmail.com [Ceramic Laboratory, University of Constantine1, Constantine (Algeria); Ayachi, Ahmed Abdelhakim, E-mail: ayachi-med@hotmail.fr [Ceramic Laboratory, University of Constantine1, Constantine (Algeria); Lakehal, Sihem, E-mail: lakehal.lakehal@gmail.com [Ceramic Laboratory, University of Constantine1, Constantine (Algeria); Fateh, Merouane, E-mail: merouane.fateh@gmail.com [Microbiological Laboratory Engineering and Application, University of Constantine1, Constantine (Algeria); Achour, Slimane, E-mail: achourslimane11@yahoo.fr [Ceramic Laboratory, University of Constantine1, Constantine (Algeria)

    2014-08-30

    Graphical abstract: - Highlights: • Ag NPs and ZnO Qds were synthesized using polyol and hydrothermal method. • Ag NPs exert their bactericidal effect mainly by Ag{sup +} ions. • CH{sub 3}COOH addition to Ag NPs improves bactericidal effect more than ZnO Qds addition. • E. coli and P. aeruginosa are more sensitive to NPs than K. pneumonia and S. aureus. - Abstract: Due to their remarkable antibacterial/antivirus properties, silver nanoparticles (Ag NPs) and zinc oxide quantum dots (ZnO Qds) have been widely used in the antimicrobial field. The mechanism of action of Ag NPs on bacteria was recently studied and it has been proven that Ag NPs exerts their antibacterial activities mainly by the released Ag{sup +}. In this work, Ag NPs and ZnO Qds were synthesized using polyol and hydrothermal method, respectively. It was demonstrated that Ag NPs can be oxidized easily in aqueous solution and the addition of acetic acid can increase the Ag{sup +} release which improves the antibacterial activity of Ag NPs. A comparative study between bactericidal effect of Ag NPs/acetic acid and Ag NPs/ZnO Qds on Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia and Staphylococcus aureus was undertaken using agar diffusion method. The obtained colloids were characterized using UV–vis spectroscopy, Raman spectrometry, X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM)

  19. Application of CuInS{sub 2} and ZnO nanoparticles in colloidal quantum dot photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Scheunemann, Dorothea; Wilken, Sebastian; Frevert, Katja; Witt, Florian; Borchert, Holger; Parisi, Juergen [University of Oldenburg, Department of Physics, Energy and Semiconductor Research Laboratory, 26111 Oldenburg (Germany)

    2013-07-01

    Colloidal quantum dots (CQD) are attractive for photovoltaics because of their solution processability and spectral tunability due to quantum size effects. Rapid advances in CQD photovoltaics in the recent years have led to high power conversion efficiencies. Previous works mainly focused on highly toxic materials containing cadmium or lead which might limit their possible application. One promising alternative material is CuInS{sub 2} (CIS) which has shown attractive device performance in thin film solar cells. Here, we present solution processed CIS nanoparticles as absorber layer in nanocrystal based solar cells. In order to achieve efficient charge separation we use a heterojunction based on a bilayer structure of CIS and intrinsically n-doped ZnO nanocrystals. One issue in thin film photovoltaics is the optimization of the absorber thickness, taking into account light absorption as well as charge carrier collection. Therefore, we determined the absorption coefficient and transport properties which can serve as input parameters into an electro-optical simulation in order to determine the optimal absorber thickness.

  20. Application on Gold Nanoparticles-Dotted 4-Nitrophenylazo Graphene in a Label-Free Impedimetric Deoxynivalenol Immunosensor

    Directory of Open Access Journals (Sweden)

    Christopher Edozie Sunday

    2015-02-01

    Full Text Available In this paper, we report a new concept to construct a label-free electrochemical inhibition-based immunosensor for the detection of the mycotoxin deoxynivalenol (DON in cereal samples. The electrochemical impedance spectroscopy of tris(bipyridine ruthenium (II chloride was used as a marker enhanced with gold nanoparticles-dotted 4-nitrophenylazo functionalized graphene (AuNp/G/PhNO2 nanocatalyst mediated in Nafion on a glassy carbon electrode. Under the optimized conditions, the formation of immunocomplexes inhibited electron flow and increased the charge transfer resistance of the sensing interface linearly. The change in impedance was proportional to DON concentrations in the range of 6–30 ng/mL with a sensitivity and detection limit of 32.14 ΩL/ng and 0.3 µg/mL, respectively, which compares favorably with the ELISA result. The proposed sensor had a stability of 80.3%, good precision and selectivity in DON standard solution containing different interfering agents, indicating promising application prospect for this strategy in designing impedimetric, electrochemiluminescent, voltammetric or amperometric sensors.

  1. Efficient Fluorescence Resonance Energy Transfer between Quantum Dots and Gold Nanoparticles Based on Porous Silicon Photonic Crystal for DNA Detection.

    Science.gov (United States)

    Zhang, Hongyan; Lv, Jie; Jia, Zhenhong

    2017-05-10

    A novel assembled biosensor was prepared for detecting 16S rRNA, a small-size persistent specific for Actinobacteria. The mechanism of the porous silicon (PS) photonic crystal biosensor is based on the fluorescence resonance energy transfer (FRET) between quantum dots (QDs) and gold nanoparticles (AuNPs) through DNA hybridization, where QDs act as an emission donor and AuNPs serve as a fluorescence quencher. Results showed that the photoluminescence (PL) intensity of PS photonic crystal was drastically increased when the QDs-conjugated probe DNA was adhered to the PS layer by surface modification using a standard cross-link chemistry method. The PL intensity of QDs was decreased when the addition of AuNPs-conjugated complementary 16S rRNA was dropped onto QDs-conjugated PS. Based on the analysis of different target DNA concentration, it was found that the decrease of the PL intensity showed a good linear relationship with complementary DNA concentration in a range from 0.25 to 10 μM, and the detection limit was 328.7 nM. Such an optical FRET biosensor functions on PS-based photonic crystal for DNA detection that differs from the traditional FRET, which is used only in liquid. This method will benefit the development of a new optical FRET label-free biosensor on Si substrate and has great potential in biochips based on integrated optical devices.

  2. Nanodiamond-based nanostructures for coupling nitrogen-vacancy centres to metal nanoparticles and semiconductor quantum dots.

    Science.gov (United States)

    Gong, Jianxiao; Steinsultz, Nat; Ouyang, Min

    2016-06-08

    The ability to control the interaction between nitrogen-vacancy centres in diamond and photonic and/or broadband plasmonic nanostructures is crucial for the development of solid-state quantum devices with optimum performance. However, existing methods typically employ top-down fabrication, which restrict scalable and feasible manipulation of nitrogen-vacancy centres. Here, we develop a general bottom-up approach to fabricate an emerging class of freestanding nanodiamond-based hybrid nanostructures with external functional units of either plasmonic nanoparticles or excitonic quantum dots. Precise control of the structural parameters (including size, composition, coverage and spacing of the external functional units) is achieved, representing a pre-requisite for exploring the underlying physics. Fine tuning of the emission characteristics through structural regulation is demonstrated by performing single-particle optical studies. This study opens a rich toolbox to tailor properties of quantum emitters, which can facilitate design guidelines for devices based on nitrogen-vacancy centres that use these freestanding hybrid nanostructures as building blocks.

  3. Carbon-dot-based dual-emission silica nanoparticles as a ratiometric fluorescent probe for vanadium(V) detection in mineral water samples

    Science.gov (United States)

    He, Lijun; Zhang, Heng; Fan, Huanhuan; Jiang, Xiuming; Zhao, Wenjie; Xiang, Guo Qiang

    2018-01-01

    Herein, we propose a simple and effective strategy for designing a ratiometric fluorescent nanosensor. We designed and developed a carbon dots (CDs) based dual-emission nanosensor for vanadium(V) by coating the surface of dye-doped silica nanoparticles with CDs. The fluorescence of dual-emission silica nanoparticles was quenched in acetic acid through potassium bromate (KBrO3) oxidation. V(V) could catalyze KBrO3 oxidation reaction process, resulting in the ratiometric fluorescence quenching of dual-emission silica nanoparticles. We investigated several important parameters affecting the performance of the nanosensor. Under the optimized conditions, the detection limit of this nanosensor reached 1.1 ng mL- 1 and the linear range from 10 to 800 ng mL- 1. Furthermore, we found that the sensor was suitable for determination of V(V) in different mineral water samples with satisfactory results.

  4. Role of toll-like receptors 3, 4 and 7 in cellular uptake and response to titanium dioxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Peng Chen, Koki Kanehira and Akiyoshi Taniguchi

    2013-01-01

    Full Text Available Innate immune response is believed to be among the earliest provisional cellular responses, and mediates the interactions between microbes and cells. Toll-like receptors (TLRs are critical to these interactions. We hypothesize that TLRs also play an important role in interactions between nanoparticles (NPs and cells, although little information has been reported concerning such an interaction. In this study, we investigated the role of TLR3, TLR4 and TLR7 in cellular uptake of titanium dioxide NP (TiO2 NP agglomerates and the resulting inflammatory responses to these NPs. Our data indicate that TLR4 is involved in the uptake of TiO2 NPs and promotes the associated inflammatory responses. The data also suggest that TLR3, which has a subcellular location distinct from that of TLR4, inhibits the denaturation of cellular protein caused by TiO2 NPs. In contrast, the unique cellular localization of TLR7 has middle-ground functional roles in cellular response after TiO2 NP exposure. These findings are important for understanding the molecular interaction mechanisms between NPs and cells.

  5. Deposition kinetics of quantum dots and polystyrene latex nanoparticles onto alumina: role of water chemistry and particle coating.

    Science.gov (United States)

    Quevedo, Ivan R; Olsson, Adam L J; Tufenkji, Nathalie

    2013-03-05

    A clear understanding of the factors controlling the deposition behavior of engineered nanoparticles (ENPs), such as quantum dots (QDs), is necessary for predicting their transport and fate in natural subsurface environments and in water filtration processes. A quartz crystal microbalance with dissipation monitoring (QCM-D) was used to study the effect of particle surface coatings and water chemistry on the deposition of commercial QDs onto Al2O3. Two carboxylated QDs (CdSe and CdTe) with different surface coatings were compared with two model nanoparticles: sulfate-functionalized (sPL) and carboxyl-modified (cPL) polystyrene latex. Deposition rates were assessed over a range of ionic strengths (IS) in simple electrolyte (KCl) and in electrolyte supplemented with two organic molecules found in natural waters; namely, humic acid and rhamnolipid. The Al2O3 collector used here is selected to be representative of oxide patches found on the surface of aquifer or filter grains. Deposition studies showed that ENP deposition rates on bare Al2O3 generally decreased with increasing salt concentration, with the exception of the polyacrylic-acid (PAA) coated CdTe QD which exhibited unique deposition behavior due to changes in the conformation of the PAA coating. QD deposition rates on bare Al2O3 were approximately 1 order of magnitude lower than those of the polystyrene latex nanoparticles, likely as a result of steric stabilization imparted by the QD surface coatings. Adsorption of humic acid or rhamnolipid on the Al2O3 surface resulted in charge reversal of the collector and subsequent reduction in the deposition rates of all ENPs. Moreover, the ratio of the two QCM-D output parameters, frequency and dissipation, revealed key structural information of the ENP-collector interface; namely, on bare Al2O3, the latex particles were rigidly attached as compared to the more loosely attached QDs. This study emphasizes the importance of considering the nature of ENP coatings as well

  6. Evaluation of in-vitro cytotoxicity and cellular uptake efficiency of zidovudine-loaded solid lipid nanoparticles modified with Aloe Vera in glioma cells.

    Science.gov (United States)

    K S, Joshy; Sharma, Chandra P; Kalarikkal, Nandakumar; Sandeep, K; Thomas, Sabu; Pothen, Laly A

    2016-09-01

    Zidovudine loaded solid lipid nanoparticles of stearic acid modified with Aloe Vera (AV) have been prepared via simple emulsion solvent evaporation method which showed excellent stability at room temperature and refrigerated condition. The nanoparticles were examined by Fourier transform infrared spectroscopy (FT-IR), which revealed the overlap of the AV absorption peak with the absorption peak of modified stearic acid nanoparticles. The inclusion of AV to stearic acid decreased the crystallinity and improved the hydrophilicity of lipid nanoparticles and thereby improved the drug loading efficacy of lipid nanoparticles. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) imaging revealed that, the average particle size of unmodified (bare) nanoparticles was 45.66±12.22nm and modified solid lipid nanoparticles showed an average size of 265.61±80.44nm. Solid lipid nanoparticles with well-defined morphology were tested in vitro for their possible application in drug delivery. Cell culture studies using C6 glioma cells on the nanoparticles showed enhanced growth and proliferation of cells without exhibiting any toxicity. In addition, normal cell morphology and improved uptake were observed by fluorescence microscopy images of rhodamine labeled modified solid lipid nanoparticles compared with unmodified nanoparticles. The cellular uptake study suggested that these nanoparticles could be a promising drug delivery system to enhance the uptake of antiviral drug by brain cells and it could be a suitable drug carrier system for the treatment of HIV. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Cellular and molecular responses of E. fetida cœlomocytes exposed to TiO2 nanoparticles

    Science.gov (United States)

    Bigorgne, Emilie; Foucaud, Laurent; Caillet, Céline; Giambérini, Laure; Nahmani, Johanne; Thomas, Fabien; Rodius, François

    2012-07-01

    An in vitro approach using cœlomocytes of Eisenia fetida was investigated to evaluate toxicity of TiO2 nanoparticles. Cœlomocytes were exposed to well-dispersed suspension of small aggregates (130 nm) of TiO2 nanoparticles (1-25 μg/ml) during 4, 12 and 24 h. Intracellular localisation suggested that the main route of uptake was endocytosis. Cellular responses showed that TiO2 nanoparticles were not cytotoxic and had no effect on phagocytosis at any of the four concentrations for each time tested. Concerning molecular responses, an increase of fetidin and metallothionein mRNA expression was observed starting from 4 h of exposure. In contrast, expression of coelomic cytolytic factor mRNA decreased for 10 and 25 μg/ml after 4 h. Superoxide dismutase, catalase and glutathione-S-transferase expression were not modified suggesting that oxidative stress was not induced by TiO2 in our experimental conditions. This in vitro approach showed that TiO2 nanoparticles were taken up by cœlomocytes and they could modify the molecular response of immune and detoxification system.

  8. Quantitative characterization of nanoparticle agglomeration within biological media

    International Nuclear Information System (INIS)

    Hondow, Nicole; Brydson, Rik; Wang, Peiyi; Holton, Mark D.; Brown, M. Rowan; Rees, Paul; Summers, Huw D.; Brown, Andy

    2012-01-01

    Quantitative analysis of nanoparticle dispersion state within biological media is essential to understanding cellular uptake and the roles of diffusion, sedimentation, and endocytosis in determining nanoparticle dose. The dispersion of polymer-coated CdTe/ZnS quantum dots in water and cell growth medium with and without fetal bovine serum was analyzed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. Characterization by TEM of samples prepared by plunge freezing the blotted solutions into liquid ethane was sensitive to the dispersion state of the quantum dots and enabled measurement of agglomerate size distributions even in the presence of serum proteins where DLS failed. In addition, TEM showed a reduced packing fraction of quantum dots per agglomerate when dispersed in biological media and serum compared to just water, highlighting the effect of interactions between the media, serum proteins, and the quantum dots. The identification of a heterogeneous distribution of quantum dots and quantum dot agglomerates in cell growth medium and serum by TEM will enable correlation with the previously reported optical metrology of in vitro cellular uptake of this quantum dot dispersion. In this paper, we present a comparative study of TEM and DLS and show that plunge-freeze TEM provides a robust assessment of nanoparticle agglomeration state.

  9. Cellular uptake of magnetite nanoparticles enhanced by NdFeB magnets in staggered arrangement

    International Nuclear Information System (INIS)

    Lu, Yi-Ching; Chang, Fan-Yu; Tu, Shu-Ju; Chen, Jyh-Ping; Ma, Yunn-Hwa

    2017-01-01

    Magnetic force may greatly enhance uptake of magnetic nanoparticles (MNPs) by cultured cells; however, the effects of non-uniformity of magnetic field/ magnetic gradient on MNP internalization in culture has not been elucidated. Cellular uptake of polyacrylic acid coated-MNP by LN229 cells was measured with cylindrical NdFeB magnets arranged in a staggered pattern. The magnetic field generated by placing a magnet underneath (H-field) elicited a homogenous distribution of MNPs on the cells in culture; whereas the field without magnet underneath (L-field) resulted in MNP distribution along the edge of the wells. Cell-associated MNP (MNP cell ) appeared to be magnetic field- and concentration-dependent. In H-field, MNP cell reached plateau within one hour of exposure to MNP with only one-min application of the magnetic force in the beginning of incubation; continuous presence of the magnet for 2 h did not further increase MNP cell , suggesting that magnetic force-induced uptake may be primarily contributed to enhanced MNP sedimentation. Although MNP distribution was much inhomogeneous in L-field, averaged MNP cell in the L-field may reach as high as 80% of that in H-field during 1–6 h incubation, suggesting high capacity of MNP internalization. In addition, no significant difference was observed in MNP cell analyzed by flow cytometry with the application of H-field of staggered plate vs. filled magnet plate. Therefore, biological variation may dominate MNP internalization even under relatively uniformed magnetic field; whereas non-uniformed magnetic field may serve as a model for tumor targeting with MNPs in vivo. - Graphical abstract: Averaged MNP uptake by glioma cells in the low and non-uniformed magnetic field reached as high as 80% of that in uniformed magnetic field, which is probably due to both heterogeneous distributions of MNPs in the non-uniformed magnetic field and high capacity of the MNP uptake by these cells. - Highlights: • Enhanced sedimentation

  10. Cellular uptake of magnetite nanoparticles enhanced by NdFeB magnets in staggered arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yi-Ching; Chang, Fan-Yu [Department of Physiology and Pharmacology & Healthy Aging Research Center, Guishan, Taoyuan City 33302, Taiwan, ROC (China); Tu, Shu-Ju [Department of Medical Imaging and Radiological Sciences, Chang Gung University, Guishan, Taoyuan City 33302, Taiwan, ROC (China); Chen, Jyh-Ping [Department of Chemical and Materials Engineering, Chang Gung University, Guishan, Taoyuan City 33302, Taiwan, ROC (China); Ma, Yunn-Hwa, E-mail: yhma@mail.cgu.edu.tw [Department of Physiology and Pharmacology & Healthy Aging Research Center, Guishan, Taoyuan City 33302, Taiwan, ROC (China); Department of Neurology, Chang Gung Memorial Hospital, Guishan, Taoyuan City 33305, Taiwan, ROC (China)

    2017-04-01

    Magnetic force may greatly enhance uptake of magnetic nanoparticles (MNPs) by cultured cells; however, the effects of non-uniformity of magnetic field/ magnetic gradient on MNP internalization in culture has not been elucidated. Cellular uptake of polyacrylic acid coated-MNP by LN229 cells was measured with cylindrical NdFeB magnets arranged in a staggered pattern. The magnetic field generated by placing a magnet underneath (H-field) elicited a homogenous distribution of MNPs on the cells in culture; whereas the field without magnet underneath (L-field) resulted in MNP distribution along the edge of the wells. Cell-associated MNP (MNP{sub cell}) appeared to be magnetic field- and concentration-dependent. In H-field, MNP{sub cell} reached plateau within one hour of exposure to MNP with only one-min application of the magnetic force in the beginning of incubation; continuous presence of the magnet for 2 h did not further increase MNP{sub cell}, suggesting that magnetic force-induced uptake may be primarily contributed to enhanced MNP sedimentation. Although MNP distribution was much inhomogeneous in L-field, averaged MNP{sub cell} in the L-field may reach as high as 80% of that in H-field during 1–6 h incubation, suggesting high capacity of MNP internalization. In addition, no significant difference was observed in MNP{sub cell} analyzed by flow cytometry with the application of H-field of staggered plate vs. filled magnet plate. Therefore, biological variation may dominate MNP internalization even under relatively uniformed magnetic field; whereas non-uniformed magnetic field may serve as a model for tumor targeting with MNPs in vivo. - Graphical abstract: Averaged MNP uptake by glioma cells in the low and non-uniformed magnetic field reached as high as 80% of that in uniformed magnetic field, which is probably due to both heterogeneous distributions of MNPs in the non-uniformed magnetic field and high capacity of the MNP uptake by these cells. - Highlights:

  11. Glycosaminoglycan-functionalized poly-lactide-co-glycolide nanoparticles: synthesis, characterization, cytocompatibility, and cellular uptake

    Directory of Open Access Journals (Sweden)

    Lamichhane SP

    2015-01-01

    Full Text Available Surya P Lamichhane,1 Neha Arya,1,2 Nirdesh Ojha,3 Esther Kohler,1 V Prasad Shastri1,2,41Institute for Macromolecular Chemistry, University of Freiburg, Freiburg, 2Helmholtz Virtual Institute on “Multifunctional Biomaterials for Medicine”, 3Laboratory for Process Technology, Department of Microsystems Engineering, University of Freiburg, Freiburg, 4Centre for Biological Signaling Studies (BIOSS, University of Freiburg, Freiburg, GermanyAbstract: The efficient delivery of chemotherapeutics to the tumor via nanoparticle (NP-based delivery systems remains a significant challenge. This is compounded by the fact that the tumor is highly dynamic and complex environment composed of a plurality of cell types and extracellular matrix. Since glycosaminoglycan (GAG production is altered in many diseases (or pathologies, NPs bearing GAG moieties on the surface may confer some unique advantages in interrogating the tumor microenvironment. In order to explore this premise, in the study reported here poly-lactide-co-glycolide (PLGA NPs in the range of 100–150 nm bearing various proteoglycans were synthesized by a single-step nanoprecipitation and characterized. The surface functionalization of the NPs with GAG moieties was verified using zeta potential measurements and X-ray photoelectron spectroscopy. To establish these GAG-bearing NPs as carriers of therapeutics, cellular toxicity assays were undertaken in lung epithelial adenocarcinoma (A549 cells, human pulmonary microvascular endothelial cells (HPMEC, and renal proximal tubular epithelial cells. In general NPs were well tolerated over a wide concentration range (100–600 µg/mL by all cell types and were taken up to appreciable extents without any adverse cell response in A549 cells and HPMEC. Further, GAG-functionalized PLGA NPs were taken up to different extents in A459 cells and HPMEC. In both cell systems, the uptake of heparin-modified NPs was diminished by 50%–65% in comparison to that of

  12. Mixed-valence molecular four-dot unit for quantum cellular automata: Vibronic self-trapping and cell-cell response.

    Science.gov (United States)

    Tsukerblat, Boris; Palii, Andrew; Clemente-Juan, Juan Modesto; Coronado, Eugenio

    2015-10-07

    Our interest in this article is prompted by the vibronic problem of charge polarized states in the four-dot molecular quantum cellular automata (mQCA), a paradigm for nanoelectronics, in which binary information is encoded in charge configuration of the mQCA cell. Here, we report the evaluation of the electronic levels and adiabatic potentials of mixed-valence (MV) tetra-ruthenium (2Ru(ii) + 2Ru(iii)) derivatives (assembled as two coupled Creutz-Taube complexes) for which molecular implementations of quantum cellular automata (QCA) was proposed. The cell based on this molecule includes two holes shared among four spinless sites and correspondingly we employ the model which takes into account the two relevant electron transfer processes (through the side and through the diagonal of the square) as well as the difference in Coulomb energies for different instant positions of localization of the hole pair. The combined Jahn-Teller (JT) and pseudo JT vibronic coupling is treated within the conventional Piepho-Krauzs-Schatz model adapted to a bi-electronic MV species with the square-planar topology. The adiabatic potentials are evaluated for the low lying Coulomb levels in which the antipodal sites are occupied, the case just actual for utilization in mQCA. The conditions for the vibronic self-trapping in spin-singlet and spin-triplet states are revealed in terms of the two actual transfer pathways parameters and the strength of the vibronic coupling. Spin related effects in degrees of the localization which are found for spin-singlet and spin-triplet states are discussed. The polarization of the cell is evaluated and we demonstrate how the partial delocalization caused by the joint action of the vibronic coupling and electron transfer processes influences polarization of a four-dot cell. The results obtained within the adiabatic approach are compared with those based on the numerical solution of the dynamic vibronic problem. Finally, the Coulomb interaction between

  13. Non-Enzymatic Glucose Sensing Using Carbon Quantum Dots Decorated with Copper Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Houcem Maaoui

    2016-10-01

    Full Text Available Perturbations in glucose homeostasis is critical for human health, as hyperglycemia (defining diabetes leads to premature death caused by macrovascular and microvascular complications. However, the simple and accurate detection of glucose in the blood at low cost remains a challenging task, although it is of great importance for the diagnosis and therapy of diabetic patients. In this work, carbon quantum dots decorated with copper oxide nanostructures (CQDs/Cu2O are prepared by a simple hydrothermal approach, and their potential for electrochemical non-enzymatic glucose sensing is evaluated. The proposed sensor exhibits excellent electrocatalytic activity towards glucose oxidation in alkaline solutions. The glucose sensor is characterized by a wide concentration range from 6 µM to 6 mM, a sensitivity of 2.9 ± 0.2 µA·µM−1·cm−2, and a detection limit of 6 µM at a signal-to-noise ratio S/N = 3. The sensors are successfully applied for glucose determination in human serum samples, demonstrating that the CQDs/Cu2O-based glucose sensor satisfies the requirements of complex sample detection with adapted potential for therapeutic diagnostics.

  14. Quantum dot nanoparticle for optimization of breast cancer diagnostics and therapy in a clinical setting.

    Science.gov (United States)

    Radenkovic, Dina; Kobayashi, Hisataka; Remsey-Semmelweis, Ernö; Seifalian, Alexander M

    2016-08-01

    Breast cancer is the most common cancer in the world. Sentinel lymph node (SLN) biopsy is used for staging of axillary lymph nodes. Organic dyes and radiocolloid are currently used for SLN mapping, but expose patients to ionizing radiation, are unstable during surgery and cause local tissue damage. Quantum dots (QD) could be used for SLN mapping without the need for biopsy. Surgical resection of the primary tumor is the optimal treatment for early-diagnosed breast cancer, but due to difficulties in defining tumor margins, cancer cells often remain leading to reoccurrences. Functionalized QD could be used for image-guided tumor resection to allow visualization of cancer cells. Near Infrared QD are photostable and have improved deep tissue penetration. Slow elimination of QD raises concerns of potential accumulation. Nevertheless, promising findings with cadmium-free QD in recent in vivo studies and first in-human trial suggest huge potential for cancer diagnostic and therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Green synthesis of carbon dots functionalized silver nanoparticles for the colorimetric detection of phoxim.

    Science.gov (United States)

    Zheng, Mingda; Wang, Chenge; Wang, Yingying; Wei, Wei; Ma, Shuang; Sun, Xiaohan; He, Jiang

    2018-08-01

    In this work, Lycii Fructus as raw materials for green synthesis of fluorescent carbon dots (CDs) reduce AgNO 3 . The CDs-AgNPs were synthesized by one-step method. CDs were applied to stabilize AgNPs due to abundant functional groups on the surface of CDs. In presence of phoxim, the dispersed CDs-AgNPs get aggregated and the absorption peak with red shift from 400 nm to 525 nm, resulting in the color changed from yellow to red. Under optimized conditions, the absorbance ratio at A 525 nm /A 400 nm was related linearly to the concentrations of phoxim in the range of 0.1-100 μM. The detection limit was calculated to 0.04 μM, which is lower than maximum residue limits of phoxim in samples in China. The colorimetric sensor was successfully utilized to monitoring phoxim in environmental and fruit samples with good recoveries ranges from 87% to 110.0%. These results showed the sensor had a promising application prospect in real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Histidine-functionalized carbon-based dot-Zinc(II) nanoparticles as a novel stabilizer for Pickering emulsion synthesis of polystyrene microspheres.

    Science.gov (United States)

    Ruiyi, Li; Zaijun, Li; Junkang, Liu

    2017-05-01

    Carbon-based dots (CDs) are nanoparticles with size-dependent optical and electronic properties that have been widely applied in energy-efficient displays and lighting, photovoltaic devices and biological markers. However, conventional CDs are difficult to be used as ideal stabilizer for Pickering emulsion due to its irrational amphiphilic structure. The study designed and synthesized a new histidine-functionalized carbon dot-Zinc(II) nanoparticles, which is termed as His-CD-Zn. The His-CD was made via one-step hydrothermal treatment of histidine and maleic acid. The His-CD reacted with Zn 2+ to form His-CD-Zn. The as-prepared His-CD-Zn was used as a solid particle surfactant for stabilizing styrene-in-water emulsion. The Pickering emulsion exhibits high stability and sensitive pH-switching behaviour. The introduction of S 2 O 8 2- triggers the emulsion polymerization of styrene. The resulted polystyrene microsphere was well coated with His-CDs on the surface. It was successfully used as an ideal adsorbent for removal of heavy metallic ions from water with high adsorption capacity. The study also provides a prominent approach for fabrication of amphiphilic carbon-based nanoparticles for stabilizing Pickering emulsion. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Cellular Internalization and Biocompatibility of Periodic Mesoporous Organosilica Nanoparticles with Tunable Morphologies: From Nanospheres to Nanowires

    KAUST Repository

    Fatieiev, Yevhen; Croissant, Jonas G.; Alamoudi, Kholod; Khashab, Niveen M.

    2017-01-01

    This work describes the sol-gel syntheses of para-substituted phenylene-bridged periodic mesoporous organosilica (PMO) nanoparticles (NPs) with tunable morphologies ranging from nanowires to nanospheres. The findings show the key role

  18. Effect of surface charge on the cellular uptake of fluorescent magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kralj, Slavko, E-mail: slavko.kralj@ijs.si [Jozef Stefan Institute, Department for Materials Synthesis (Slovenia); Rojnik, Matija [University of Ljubljana, Faculty of Pharmacy (Slovenia); Romih, Rok [University of Ljubljana, Faculty of Medicine, Institute of Cell Biology (Slovenia); Jagodic, Marko [Institute of Mathematics, Physics and Mechanics (Slovenia); Kos, Janko [University of Ljubljana, Faculty of Pharmacy (Slovenia); Makovec, Darko [Jozef Stefan Institute, Department for Materials Synthesis (Slovenia)

    2012-10-15

    We report on the nanoparticle uptake into MCF10A neoT and PC-3 cells using flow cytometry, confocal microscopy, SQUID magnetometry, and transmission electron microscopy. The aim was to evaluate the influence of the nanoparticles' surface charge on the uptake efficiency. The surface of the superparamagnetic, silica-coated, maghemite nanoparticles was modified using amino functionalization for the positive surface charge (CNPs), and carboxyl functionalization for the negative surface charge (ANPs). The CNPs and ANPs exhibited no significant cytotoxicity in concentrations up to 500 {mu}g/cm{sup 3} in 24 h. The CNPs, bound to a plasma membrane, were intensely phagocytosed, while the ANPs entered cells through fluid-phase endocytosis in a lower internalization degree. The ANPs and CNPs were shown to be co-localized with a specific lysosomal marker, thus confirming their presence in lysosomes. We showed that tailoring the surface charge of the nanoparticles has a great impact on their internalization.

  19. Cellular Interaction and Tumoral Penetration Properties of Cyclodextrin Nanoparticles on 3D Breast Tumor Model

    Directory of Open Access Journals (Sweden)

    Gamze Varan

    2018-01-01

    Full Text Available Amphiphilic cyclodextrins are biocompatible oligosaccharides that can be used for drug delivery especially for the delivery of drugs with solubility problems thanks to their unique molecular structures. In this paper, Paclitaxel was used as a model anticancer drug to determine the inclusion complex properties of amphiphilic cyclodextrins with different surface charge. Paclitaxel-loaded cyclodextrin nanoparticles were characterized in terms of mean particle diameter, zeta potential, encapsulation efficacy, drug release profile and cell culture studies. It was determined that the nanoparticles prepared from the inclusion complex according to characterization studies have a longer release profile than the conventionally prepared nanoparticles. In order to mimic the tumor microenvironment, breast cancer cells and healthy fibroblast cells were used in 3-dimensional (3D cell culture studies. It was determined that the activities of nanoparticles prepared by conventional methods behave differently in 2-dimensional (2D and 3D cell cultures. In addition, it was observed that the nanoparticles prepared from the inclusion complex have a stronger anti-tumoral activity in the 3D multicellular tumor model than the drug solution. Furthermore, polycationic amphiphilic cyclodextrin nanoparticles can diffuse and penetrate through multilayer cells in a 3D tumor model, which is crucial for an eventual antitumor effect.

  20. Synthesis, solubilization, and surface functionalization of highly fluorescent quantum dots for cellular targeting through a small molecule

    Science.gov (United States)

    Galloway, Justin F.

    To achieve long-term fluorescence imaging with quantum dots (QDs), a CdSe core/shell must first be synthesized. The synthesis of bright CdSe QDs is not trivial and as a consequence, the role of surfactant in nucleation and growth was investigated. It was found that the type of surfactant used, either phosphonic or fatty acid, played a pivotal role in the size of the CdSe core. The study of surfactant on CdSe synthesis, ultimately led to an electrical passivation method that utilized a short-chained phosphonic acid and highly reactive organometallic precursors to achieve high quantum yield (QY) as has been previously described. The synthesis of QDs using organometallic precursors and a phosphonic acid for passivation resulted in 4 out of 9 batches of QDs achieving QYs greater than 50% and 8 out of 9 batches with QYs greater than 35%. The synthesis of CdSe QDs was done in organic solutions rendering the surface of the particle hydrophobic. To perform cell-targeting experiments, QDs must be transferred to water. The transfer of QDs to water was successfully accomplished by using single acyl chain lipids. A systematic study of different lipid combinations and coatings demonstrated that 20-40 mol% single acyl chained lipids were able to transfer QDs to water resulting in monodispersed, stable QDs without adversely affecting the QY. The advantage to water solubilization using single acyl chain lipids is that the QD have a hydrodynamic radius less than 15 nm, QYs that can exceed 50% and additional surface functionalization can be down using the reactive sites incorporated into the lipid bilayer. QDs that are bright and stable in water were studied for the purpose of targeting G protein-coupled Receptors (GPCR). GPCRs are transmembrane receptors that internalize extracellular cues, and thus mediate signal transduction. The cyclic Adenosine Monophosphate Receptor 1 of the model organism Dictyostelium disodium was the receptor of interest. The Halo protein, a genetically

  1. Curcumin Encapsulated into Methoxy Poly(Ethylene Glycol) Poly(ε-Caprolactone) Nanoparticles Increases Cellular Uptake and Neuroprotective Effect in Glioma Cells.

    Science.gov (United States)

    Marslin, Gregory; Sarmento, Bruno Filipe Carmelino Cardoso; Franklin, Gregory; Martins, José Alberto Ribeiro; Silva, Carlos Jorge Ribeiro; Gomes, Andreia Ferreira Castro; Sárria, Marisa Passos; Coutinho, Olga Maria Fernandes Pereira; Dias, Alberto Carlos Pires

    2017-03-01

    Curcumin is a natural polyphenolic compound isolated from turmeric ( Curcuma longa ) with well-demonstrated neuroprotective and anticancer activities. Although curcumin is safe even at high doses in humans, it exhibits poor bioavailability, mainly due to poor absorption, fast metabolism, and rapid systemic elimination. To overcome these issues, several approaches, such as nanoparticle-mediated targeted delivery, have been undertaken with different degrees of success. The present study was conducted to compare the neuroprotective effect of curcumin encapsulated in poly( ε -caprolactone) and methoxy poly(ethylene glycol) poly( ε -caprolactone) nanoparticles in U251 glioblastoma cells. Prepared nanoparticles were physically characterized by laser doppler anemometry, transmission electron microscopy, and X-ray diffraction. The results from laser doppler anemometry confirmed that the size of poly( ε -caprolactone) and poly(ethylene glycol) poly( ε -caprolactone) nanoparticles ranged between 200-240 nm for poly( ε -caprolactone) nanoparticles and 30-70 nm for poly(ethylene glycol) poly( ε -caprolactone) nanoparticles, and transmission electron microscopy images revealed their spherical shape. Treatment of U251 glioma cells and zebrafish embryos with poly( ε -caprolactone) and poly(ethylene glycol) poly( ε -caprolactone) nanoparticles loaded with curcumin revealed efficient cellular uptake. The cellular uptake of poly(ethylene glycol) poly( ε -caprolactone) nanoparticles was higher in comparison to poly( ε -caprolactone) nanoparticles. Moreover, poly(ethylene glycol) poly( ε -caprolactone) di-block copolymer-loaded curcumin nanoparticles were able to protect the glioma cells against tBHP induced-oxidative damage better than free curcumin. Together, our results show that curcumin-loaded poly(ethylene glycol) poly( ε -caprolactone) di-block copolymer nanoparticles possess significantly stronger neuroprotective effect in U251 human glioma cells compared to

  2. Using silicon-coated gold nanoparticles to enhance the fluorescence of CdTe quantum dot and improve the sensing ability of mercury (II)

    Science.gov (United States)

    Zhu, Jian; Chang, Hui; Li, Jian-Jun; Li, Xin; Zhao, Jun-Wu

    2018-01-01

    The effect of silicon-coated gold nanoparticles with different gold core diameter and silica shell thickness on the fluorescence emission of CdTe quantum dots (QDs) was investigated. For gold nanoparticles with a diameter of 15 nm, silica coating can only results in fluorescence recover of the bare gold nanoparticle-induced quenching of QDs. However, when the size of gold nanoparticle is increased to 60 nm, fluorescence enhancement of the QDs could be obtained by silica coating. Because of the isolation of the silica shell-reduced quenching effect and local electric field effect, the fluorescence of QDs gets intense firstly and then decreases. The maximum fluorescence enhancement takes place as the silica shell has a thickness of 30 nm. This enhanced fluorescence from silicon-coated gold nanoparticles is demonstrated for sensing of Hg2 +. Under optimal conditions, the enhanced fluorescence intensity decreases linearly with the concentration of Hg2 + ranging from 0 to 200 ng/mL. The limit of detection for Hg2 + is 1.25 ng/mL. Interference test and real samples detection indicate that the influence from other metal ions could be neglected, and the Hg2 + could be specifically detected.

  3. Photovoltaic performance enhancement of CdS quantum dot-sensitized TiO2 photoanodes with plasmonic gold nanoparticles

    International Nuclear Information System (INIS)

    Liu, Aiping; Ren, Qinghua; Zhao, Ming; Xu, Tao; Yuan, Ming; Zhao, Tingyu; Tang, Weihua

    2014-01-01

    Highlights: • CdS QD-sensitized TiO 2 porous photoanode with plasmonic gold. • A prominent light absorption enhancement of hybrid was attained by gold plasmon. • The photovoltaic response of hybrid was tunable by CdS amount. • The Au/TiO 2 /CdS hybrid had a potential application in energy conversion devices. -- Abstract: The CdS quantum dot-sensitized TiO 2 films with plasmonic gold nanoparticles were designed as photoanodes by the electrodeposition of gold combined with the “successive ionic layer adsorption and reaction” (SILAR) method for CdS deposition on porous TiO 2 films. A prominent enhancement in light absorption of Au/TiO 2 /CdS hybrid was attained by efficient light scattering of gold plasmons as sub-wavelength antennas and concentrators. The photogenerated electron formed in the near-surface region of TiO 2 and CdS were facilitated to transfer to the plasmonic gold, resulting in the enhancement of photocurrent and incident photon-to-current conversion efficiency of hybrid photoanode upon photoirradiation. Furthermore, the photovoltaic response of hybrid was highly tunable with respect to the number of SILAR cycles applied to deposit CdS. The thicker absorber layer with less porous structure and larger CdS crystals might limit the electrolyte diffusion into the hybrid electrode and impose a barrier for electron tunneling and transferring. The highly versatile and tunable properties of Au/TiO 2 /CdS photoanodes demonstrated their potential application in energy conversion devices

  4. Carbon-Dots-Based Lab-On-a-Nanoparticle Approach for the Detection and Differentiation of Antibiotics.

    Science.gov (United States)

    Qiao, Li'na; Qian, Sihua; Wang, Yuhui; Yan, Shifeng; Lin, Hengwei

    2018-03-26

    Fluorescent carbon dots (CDs) have received considerable attention in recent years due to their superior optical properties. To take further advantages of these unique features, herein, a CDs-based "lab-on-a-nanoparticle" approach for the detection and discrimination of antibiotics is developed. The sensing platform was designed based on the different channel's fluorescence recoveries or further quenching of the full-color emissive CDs (F-CDs) and metal ion ensembles upon the addition of antibiotics. The F-CDs exhibited unusually comparable emission intensity nearly across the entire visible spectrum even as the excitation wavelength is shifted, making it very suitable for the construction of multi-channel sensing systems. The sensing platform was fabricated on the basis of the competing interaction of metal ions with the F-CDs and antibiotics. Three metal ions (i.e., Cu 2+ , Ce 3+ and Eu 3+ ) can efficiently quench the fluorescence of the F-CDs. Upon the addition of antibiotics, the fluorescent intensities either recovered at different emission wavelengths or were further quenched to various degrees. The fluorescence response patterns at different emission wavelength were characteristic for each antibiotic and can be quantitatively differentiated by standard statistical methods (e.g., hierarchical clustering analysis and principal component analysis). Moreover, as an example, the proposed method was applied for quantitative detection of oxytetracycline with a limit of detection to be 0.06 μm. Finally, the sensing system was successfully employed for residual antibiotics detection and identification in real food samples. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Enhancement of the optical Kerr effect exhibited by an integrated configuration of silicon quantum dots and silver nanoparticles

    International Nuclear Information System (INIS)

    Lopez-Suarez, A; Benami, A; Tamayo-Rivera L; Reyes-Esqueda, J A; Cheang-Wong, J C; Rodriguez-Fernandez, L; Crespo-Sosa, A; Oliver, A; R Rangel-Rojo; Torres-Torres, C

    2011-01-01

    We present nonlinear refractive results for three different systems produced by ion implantation: high purity silica substrates with silicon quantum dots (Si-QDs), silver nanoparticles (Ag-NPs), and one sample containing both. We used a femtosecond optical Kerr gate (OKG) with 80 fs pulses at 830 nm to investigate the magnitude and response time of their nonlinear response. The Ag-NPs samples were prepared implanting 2 MeV Ag 2+ ions at different fluencies. A sample with 1x10 17 ions/cm 2 showed no discernible Kerr signal, while for one with 2.4x10 17 ions/cm 2 we measured |χ (3) | 1111 = 5.1x10 -11 esu. The Si-QDs sample required irradiation with 1.5 MeV Si 2+ ions, at a 2.5x10 17 ions/cm 2 fluence in order that the OKG results for this sample yielded a similar |χ (3) | 1111 value. The sample containing the Si-QDs was then irradiated by 1 MeV Ag2+ ions at a 4.44 x 10 16 ions/cm 2 fluence and thermally treated, for which afterward we measured |χ (3) | 1111 1.7x10 -10 esu. In all cases the response time was quasi-instantaneous. These results imply that the inclusion of Ag-NPs at low fluence, enhances the nonlinearity of the composite by a factor of around three, and that this is purely electronic in nature. Pump-probe results show that there is not any nonlinear absorption present. We estimate that the confinement effect of the Si-QDs in the sample plays an important role for the excitation of the Surface Plasmon Resonance (SPR) related to the Ag-NPs. A theoretical model that describes the modification of the third order nonlinearity is also presented.

  6. Adder design using a 5-input majority gate in a novel “multilayer gate design paradigm” for quantum dot cellular automata circuits

    International Nuclear Information System (INIS)

    Kumar, Rohit; Ghosh, Bahniman; Gupta, Shoubhik

    2015-01-01

    This paper proposes a novel design paradigm for circuits designed in quantum dot cellular automata (QCA) technology. Previously reported QCA circuits in the literature have generally been designed in a single layer which is the main logical block in which the inverter and majority gate are on the base layer, except for the parts where multilayer wire crossing was used. In this paper the concept of multilayer wire crossing has been extended to design logic gates in multilayers. Using a 5-input majority gate in a multilayer, a 1-bit and 2-bit adder have been designed in the proposed multilayer gate design paradigm. A comparison has been made with some adders reported previously in the literature and it has been shown that circuits designed in the proposed design paradigm are much more efficient in terms of area, the requirement of QCA cells in the design and the input–output delay of the circuit. Over all, the availability of one additional spatial dimension makes the design process much more flexible and there is scope for the customizability of logic gate designs to make the circuit compact. (paper)

  7. Metal Dependence of Signal Transmission through MolecularQuantum-Dot Cellular Automata (QCA: A Theoretical Studyon Fe, Ru, and Os Mixed-Valence Complexes

    Directory of Open Access Journals (Sweden)

    Ken Tokunaga

    2010-08-01

    Full Text Available Dynamic behavior of signal transmission through metal complexes [L5M-BL-ML5]5+ (M=Fe, Ru, Os, BL=pyrazine (py, 4,4’-bipyridine (bpy, L=NH3, which are simplified models of the molecular quantum-dot cellular automata (molecular QCA, is discussed from the viewpoint of one-electron theory, density functional theory. It is found that for py complexes, the signal transmission time (tst is Fe(0.6 fs < Os(0.7 fs < Ru(1.1 fs and the signal amplitude (A is Fe(0.05 e < Os(0.06 e < Ru(0.10 e. For bpy complexes, tst and A are Fe(1.4 fs < Os(1.7 fs < Ru(2.5 fs and Os(0.11 e < Ru(0.12 e

  8. Human Aortic Endothelial Cell Labeling with Positive Contrast Gadolinium Oxide Nanoparticles for Cellular Magnetic Resonance Imaging at 7 Tesla

    Directory of Open Access Journals (Sweden)

    Yasir Loai

    2012-03-01

    Full Text Available Positive T1 contrast using gadolinium (Gd contrast agents can potentially improve detection of labeled cells on magnetic resonance imaging (MRI. Recently, gadolinium oxide (Gd2O3 nanoparticles have shown promise as a sensitive T1 agent for cell labeling at clinical field strengths compared to conventional Gd chelates. The objective of this study was to investigate Gado CELLTrack, a commercially available Gd2O3 nanoparticle, for cell labeling and MRI at 7 T. Relaxivity measurements yielded r1 = 4.7 s−1 mM−1 and r2/r1 = 6.2. Human aortic endothelial cells were labeled with Gd2O3 at various concentrations and underwent MRI from 1 to 7 days postlabeling. The magnetic resonance relaxation times T1 and T2 of labeled cell pellets were measured. Cellular contrast agent uptake was quantified by inductively coupled plasma–atomic emission spectroscopy, which showed very high uptake compared to conventional Gd compounds. MRI demonstrated significant positive T1 contrast and stable labeling on cells. Enhancement was optimal at low Gd concentrations, attained in the 0.02 to 0.1 mM incubation concentration range (corresponding cell uptake was 7.26 to 34.1 pg Gd/cell. Cell viability and proliferation were unaffected at the concentrations tested and up to at least 3 days postlabeling. Gd2O3 is a promising sensitive and stable positive contrast agent for cellular MRI at 7 T.

  9. Dual-drug delivery by porous silicon nanoparticles for improved cellular uptake, sustained release, and combination therapy.

    Science.gov (United States)

    Wang, Chang-Fang; Mäkilä, Ermei M; Kaasalainen, Martti H; Hagström, Marja V; Salonen, Jarno J; Hirvonen, Jouni T; Santos, Hélder A

    2015-04-01

    Dual-drug delivery of antiangiogenic and chemotherapeutic drugs can enhance the therapeutic effect for cancer therapy. Conjugation of methotrexate (MTX) to porous silicon (PSi) nanoparticles (MTX-PSi) with positively charged surface can improve the cellular uptake of MTX and inhibit the proliferation of cancer cells. Herein, MTX-PSi conjugates sustained the release of MTX up to 96 h, and the released fragments including MTX were confirmed by mass spectrometry. The intracellular distribution of the MTX-PSi nanoparticles was confirmed by transmission electron microscopy. Compared to pure MTX, the MTX-PSi achieved similar inhibition of cell proliferation in folate receptor (FR) over-expressing U87 MG cancer cells, and a higher effect in low FR-expressing EA.hy926 cells. Nuclear fragmentation analysis demonstrated programmed cell apoptosis of MTX-PSi in the high/low FR-expressing cancer cells, whereas PSi alone at the same dose had a minor effect on cell apoptosis. Finally, the porous structure of MTX-PSi enabled a successful concomitant loading of another anti-angiogenic hydrophobic drug, sorafenib, and considerably enhanced the dissolution rate of sorafenib. Overall, the MTX-PSi nanoparticles can be used as a platform for combination chemotherapy by simultaneously enhancing the dissolution rate of a hydrophobic drug and sustaining the release of a conjugated chemotherapeutic drug. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. Quantum dot sensitized solar cells fabricated by means of a novel inorganic spinel nanoparticle

    Science.gov (United States)

    Jalali-Moghadam, Elnaz; Shariatinia, Zahra

    2018-05-01

    A novel inorganic spinel compound with formula Zn0.5184La0.7859Ce0.3994Al1.0026O4 (ZLCA) was synthesized by the gel combustion method and its exact formula was approved by the XPS analysis. The TEM image exhibited that the ZLCA NPs were very fine, spherical and slightly agglomerated particles with their particle size changed in the range of ∼5-20 nm. Then, several quantum dot-sensitized solar cells (QDSSCs) were fabricated using this new compound which was doped into the TiO2 pastes of photoanodes and subsequently the CdS, CdS and ZnS layers were deposited on the ZLCA-doped TiO2 layer by the SILAR and the CBD methods. Results indicated that the photovoltaic parameters of the optimized cell (η = 3.50%, JSC = 11.690 mA·cm-2) were boosted compared with those of the reference cell which was free of ZLCA NPs (η = 2.14%, JSC = 7.075 mA·cm-2) indicating rather high improvements of approximately 64 and 65% in the efficiency and short-circuit current density, respectively. The UV-Vis absorption spectra of all nanocomposite photoanodes revealed broad absorption bands between ∼320 and 600 nm. The lowest intensity of the photoluminescence peak for the CdSe cell fabricated using 0.6%ZLCA suggested that it had the least charge recombination and the easiest electron transfer which was confirmed by the J-V and efficiency results. The Electrochemical impedance spectra (EIS) illustrated that the charge transfer resistances (RCT) of cells were dropped by addition of the ZLCA into the TiO2 compared with that of the cell made without using ZLCA NPs. The RCT resistance was 1900 Ω for pure TiO2 but it was decreased to 81.6 Ω in the optimized cell containing 0.6%wt of ZLCA. Thus, it could be decided that doping 0.6%wt ZLCA was appropriate to attain suitable photocurrent efficiency for the QDSSCs because it was used in a minimum quantity to accelerate the electron transport, decrease the recombination and increase the cell efficiency.

  11. Effects of cell culture media on the dynamic formation of protein-nanoparticle complexes and influence on the cellular response.

    Science.gov (United States)

    Maiorano, Gabriele; Sabella, Stefania; Sorce, Barbara; Brunetti, Virgilio; Malvindi, Maria Ada; Cingolani, Roberto; Pompa, Pier Paolo

    2010-12-28

    The development of appropriate in vitro protocols to assess the potential toxicity of the ever expanding range of nanoparticles represents a challenging issue, because of the rapid changes of their intrinsic physicochemical properties (size, shape, reactivity, surface area, etc.) upon dispersion in biological fluids. Dynamic formation of protein coating around nanoparticles is a key molecular event, which may strongly impact the biological response in nanotoxicological tests. In this work, by using citrate-capped gold nanoparticles (AuNPs) of different sizes as a model, we show, by several spectroscopic techniques (dynamic light scattering, UV-visible, plasmon resonance light scattering), that proteins-NP interactions are differently mediated by two widely used cellular media (i.e., Dulbecco Modified Eagle's medium (DMEM) and Roswell Park Memorial Institute medium (RPMI), supplemented with fetal bovine serum). We found that, while DMEM elicits the formation of a large time-dependent protein corona, RPMI shows different dynamics with reduced protein coating. Characterization of these nanobioentities was also performed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and mass spectroscopy, revealing that the average composition of protein corona does not reflect the relative abundance of serum proteins. To evaluate the biological impact of such hybrid bionanostructures, several comparative viability assays onto two cell lines (HeLa and U937) were carried out in the two media, in the presence of 15 nm AuNPs. We observed that proteins/NP complexes formed in RPMI are more abundantly internalized in cells as compared to DMEM, overall exerting higher cytotoxic effects. These results show that, beyond an in-depth NPs characterization before cellular experiments, a detailed understanding of the effects elicited by cell culture media on NPs is crucial for standardized nanotoxicology tests.

  12. Synthesis of fluorescent carbon dots via microwave carbonization of citric acid in presence of tetraoctylammonium ion, and their application to cellular bioimaging

    International Nuclear Information System (INIS)

    Bhaisare, Mukesh Lavkush; Talib, Abou; Khan, M. Shahnawaz; Pandey, Sunil; Wu, Hui-Fen

    2015-01-01

    A jelly-like form of carbon dots (C-dots) was prepared by microwave-assisted synthesis from citric acid in the presence of tetraoctylammonium bromide. The effect of the concentration of tetraoctylammonium bromide was examined. The synthesized carbon dots were characterized by UV–vis, XRD, FTIR, fluorescence and HR-TEM. Fluorescence extends from 350 to 600 nm, and the corresponding excitation wavelengths range from 300 to 460 nm. Quantum yields are at around 0.11. A cytotoxicity study showed carbon dots to be cell permeable and biocompatible which renders them appropriate for imaging applications. The dots were used to image HeLa cell lines via the blue fluorescence of the dots. (author)

  13. Correlation of particle properties with cytotoxicity and cellular uptake of hydroxyapatite nanoparticles in human gastric cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Xinhui [State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237 (China); Liang, Tong [Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Liu, Changsheng [State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237 (China); Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Yuan, Yuan, E-mail: yyuan@ecust.edu.cn [Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Qian, Jiangchao, E-mail: jiangchaoqian@ecust.edu.cn [State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2016-10-01

    Three types of hydroxyapatite nanoparticles (HAPNs) were synthesized employing a sonochemistry-assisted microwave method by changing microwave power (from 200 to 300 W) or using calcination treatment: L200 (200 W, lyophilization), L300 (300 W, lyophilization) and C200 (200 W, lyophilization & calcination). Their physiochemical properties were characterized and correlated with cytotoxicity to human gastric cancer cells (MGC80-3). The major differences among these HAPN preparations were their size and specific surface area, with the L200 showing a smaller size and higher specific surface area. Although all HAPNs inhibited cell proliferation and induced apoptosis of cancer cells, L200 exhibited the greatest toxicity. All types of HAPNs were internalized through energy-dependent pathways, but the L200 nanoparticles were more efficiently uptaken by MGC80-3 cells. Inhibitor studies with dynasore and methyl-β-cyclodextrin suggested that caveolae-mediated endocytosis and, to a much lesser extent, clathrin-mediated endocytosis, were involved in cellular uptake of the various preparations, whereas the inhibition of endocytosis was more obvious for L200. Using fluorescein isothiocyanate-labeled HAPNs and laser-scanning confocal microscopy, we found that all forms of nanoparticles were present in the cytoplasm, and some L200 HAPNs were even found within nuclei. Treatment with all HAPN preparations led to the increase in the intracellular calcium level with the highest level detected for L200. - Highlights: • Three types of HAPNs (L200, L300 and C200) were synthesized employing a sonochemistry-assisted microwave method. • L200 exhibited the greatest cytotoxicity to human gastric cancer (MGC80-3) cells. • L200 showed a smaller size and higher specific surface area. • The L200 nanoparticles were more efficiently uptaken by MGC80-3 cells through energy-dependent pathways. • L200 caused the most significant increase in the intracellular calcium level.

  14. Assessing cellular toxicities in fibroblasts upon exposure to lipid-based nanoparticles: a high content analysis approach

    Science.gov (United States)

    Solmesky, Leonardo J.; Shuman, Michal; Goldsmith, Meir; Weil, Miguel; Peer, Dan

    2011-12-01

    Lipid-based nanoparticles (LNPs) are widely used for the delivery of drugs and nucleic acids. Although most of them are considered safe, there is confusing evidence in the literature regarding their potential cellular toxicities. Moreover, little is known about the recovery process cells undergo after a cytotoxic insult. We have previously studied the systemic effects of common LNPs with different surface charge (cationic, anionic, neutral) and revealed that positively charged LNPs ((+)LNPs) activate pro-inflammatory cytokines and induce interferon response by acting as an agonist of Toll-like receptor 4 on immune cells. In this study, we focused on the response of human fibroblasts exposed to LNPs and their cellular recovery process. To this end, we used image-based high content analysis (HCA). Using this strategy, we were able to show simultaneously, in several intracellular parameters, that fibroblasts can recover from the cytotoxic effects of (+)LNPs. The use of HCA opens new avenues in understanding cellular response and nanotoxicity and may become a valuable tool for screening safe materials for drug delivery and tissue engineering.

  15. Assessing cellular toxicities in fibroblasts upon exposure to lipid-based nanoparticles: a high content analysis approach

    International Nuclear Information System (INIS)

    Solmesky, Leonardo J; Weil, Miguel; Shuman, Michal; Goldsmith, Meir; Peer, Dan

    2011-01-01

    Lipid-based nanoparticles (LNPs) are widely used for the delivery of drugs and nucleic acids. Although most of them are considered safe, there is confusing evidence in the literature regarding their potential cellular toxicities. Moreover, little is known about the recovery process cells undergo after a cytotoxic insult. We have previously studied the systemic effects of common LNPs with different surface charge (cationic, anionic, neutral) and revealed that positively charged LNPs ((+)LNPs) activate pro-inflammatory cytokines and induce interferon response by acting as an agonist of Toll-like receptor 4 on immune cells. In this study, we focused on the response of human fibroblasts exposed to LNPs and their cellular recovery process. To this end, we used image-based high content analysis (HCA). Using this strategy, we were able to show simultaneously, in several intracellular parameters, that fibroblasts can recover from the cytotoxic effects of (+)LNPs. The use of HCA opens new avenues in understanding cellular response and nanotoxicity and may become a valuable tool for screening safe materials for drug delivery and tissue engineering.

  16. Probing the cellular damage in bacteria induced by GaN nanoparticles using confocal laser Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, Prasana, E-mail: prasanasahoo@gmail.com [Indira Gandhi Center for Atomic Research, Surface and Nanoscience Division (India); Murthy, P. Sriyutha [Bhabha Atomic Research Centre, Biofouling and Biofilm Processes Section, Water and Steam Chemistry Division (India); Dhara, S., E-mail: dhara@igcar.gov.in [Indira Gandhi Center for Atomic Research, Surface and Nanoscience Division (India); Venugopalan, V. P. [Bhabha Atomic Research Centre, Biofouling and Biofilm Processes Section, Water and Steam Chemistry Division (India); Das, A.; Tyagi, A. K. [Indira Gandhi Center for Atomic Research, Surface and Nanoscience Division (India)

    2013-08-15

    Understanding the mechanism of nanoparticle (NP) induced toxicity in microbes is of potential importance to a variety of disciplines including disease diagnostics, biomedical implants, and environmental analysis. In this context, toxicity to bacterial cells and inhibition of biofilm formation by GaN NPs and their functional derivatives have been investigated against gram positive and gram negative bacterial species down to single cellular level. High levels of inhibition of biofilm formation (>80 %) was observed on treatments with GaN NPs at sub-micro molar concentrations. These results were substantiated with morphological features investigated with field emission scanning electron microscope, and the observed changes in vibrational modes of microbial cells using Raman spectroscopy. Raman spectra provided molecular interpretation of cell damage by registering signatures of molecular vibrations of individual living microbial cells and mapping the interplay of proteins at the cell membrane. As compared to the untreated cells, Raman spectra of NP-treated cells showed an increase in the intensities of characteristic protein bands, which confirmed membrane damage and subsequent release of cellular contents outside the cells. Raman spectral mapping at single cellular level can facilitate understanding of the mechanistic aspect of toxicity of GaN NPs. The effect may be correlated to passive diffusion causing mechanical damage to the membrane or ingress of Ga{sup 3+} (ionic radius {approx}0.076 nm) which can potentially interfere with bacterial metabolism, as it resembles Fe{sup 2+} (ionic radius {approx}0.077 nm), which is essential for energy metabolism.

  17. Probing the cellular damage in bacteria induced by GaN nanoparticles using confocal laser Raman spectroscopy

    International Nuclear Information System (INIS)

    Sahoo, Prasana; Murthy, P. Sriyutha; Dhara, S.; Venugopalan, V. P.; Das, A.; Tyagi, A. K.

    2013-01-01

    Understanding the mechanism of nanoparticle (NP) induced toxicity in microbes is of potential importance to a variety of disciplines including disease diagnostics, biomedical implants, and environmental analysis. In this context, toxicity to bacterial cells and inhibition of biofilm formation by GaN NPs and their functional derivatives have been investigated against gram positive and gram negative bacterial species down to single cellular level. High levels of inhibition of biofilm formation (>80 %) was observed on treatments with GaN NPs at sub-micro molar concentrations. These results were substantiated with morphological features investigated with field emission scanning electron microscope, and the observed changes in vibrational modes of microbial cells using Raman spectroscopy. Raman spectra provided molecular interpretation of cell damage by registering signatures of molecular vibrations of individual living microbial cells and mapping the interplay of proteins at the cell membrane. As compared to the untreated cells, Raman spectra of NP-treated cells showed an increase in the intensities of characteristic protein bands, which confirmed membrane damage and subsequent release of cellular contents outside the cells. Raman spectral mapping at single cellular level can facilitate understanding of the mechanistic aspect of toxicity of GaN NPs. The effect may be correlated to passive diffusion causing mechanical damage to the membrane or ingress of Ga 3+ (ionic radius ∼0.076 nm) which can potentially interfere with bacterial metabolism, as it resembles Fe 2+ (ionic radius ∼0.077 nm), which is essential for energy metabolism

  18. Comparison of Cellular Uptake and Inflammatory Response via Toll-Like Receptor 4 to Lipopolysaccharide and Titanium Dioxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Akiyoshi Taniguchi

    2013-06-01

    Full Text Available The innate immune response is the earliest cellular response to infectious agents and mediates the interactions between microbes and cells. Toll-like receptors (TLRs play an important role in these interactions. We have already shown that TLRs are involved with the uptake of titanium dioxide nanoparticles (TiO2 NPs and promote inflammatory responses. In this paper, we compared role of cellular uptake and inflammatory response via TLR 4 to lipopolysaccharide (LPS and TiO2 NPs. In the case of LPS, LPS binds to LPS binding protein (LBP and CD 14, and then this complex binds to TLR 4. In the case of TiO2 NPs, the necessity of LBP and CD 14 to induce the inflammatory response and for uptake by cells was investigated using over-expression, antibody blocking, and siRNA knockdown experiments. Our results suggested that for cellular uptake of TiO2 NPs, TLR 4 did not form a complex with LBP and CD 14. In the TiO2 NP-mediated inflammatory response, TLR 4 acted as the signaling receptor without protein complex of LPS, LBP and CD 14. The results suggested that character of TiO2 NPs might be similar to the complex of LPS, LBP and CD 14. These results are important for development of safer nanomaterials.

  19. ZnO nanoparticles sensitized by CuInZnxS2+x quantum dots as highly efficient solar light driven photocatalysts

    Directory of Open Access Journals (Sweden)

    Florian Donat

    2017-05-01

    Full Text Available Alloyed CuInZnxS2+x (ZCIS quantum dots (QDs were successfully associated to ZnO nanoparticles by a thermal treatment at 400 °C for 15 min. The ZnO/ZCIS composite was characterized by TEM, SEM, XRD, XPS and UV–vis absorption spectroscopy. ZCIS QDs, with an average diameter of ≈4.5 nm, were found to be homogeneously distributed at the surface of ZnO nanoparticles. ZCIS-sensitized ZnO nanoparticles exhibit a high photocatalytic activity under simulated solar light irradiation for the degradation of Orange II dye (>95% degradation after 180 min of irradiation at an intensity of 5 mW/cm2. The heterojunction built between the ZnO nanoparticle and ZCIS QDs not only extends the light adsorption range by the photocatalyst but also acts to decrease electron/hole recombination. Interestingly, the ZnO/ZCIS composite was found to produce increased amounts of H2O2 and singlet oxygen 1O2 compared to ZnO, suggesting that these reactive oxygen species play a key role in the photodegradation mechanism. The activity of the ZnO/ZCIS composite is retained at over 90% of its original value after ten successive photocatalytic runs, indicating its high stability and its potential for practical photocatalytic applications.

  20. TiN nanoparticles on CNT-graphene hybrid support as noble-metal-free counter electrode for quantum-dot-sensitized solar cells.

    Science.gov (United States)

    Youn, Duck Hyun; Seol, Minsu; Kim, Jae Young; Jang, Ji-Wook; Choi, Youngwoo; Yong, Kijung; Lee, Jae Sung

    2013-02-01

    The development of an efficient noble-metal-free counter electrode is crucial for possible applications of quantum-dot-sensitized solar cells (QDSSCs). Herein, we present TiN nanoparticles on a carbon nanotube (CNT)-graphene hybrid support as a noble-metal-free counter electrode for QDSSCs employing a polysulfide electrolyte. The resulting TiN/CNT-graphene possesses an extremely high surface roughness, a good metal-support interaction, and less aggregation relative to unsupported TiN; it also has superior solar power conversion efficiency (4.13 %) when applying a metal mask, which is much higher than that of the state-of-the-art Au electrode (3.35 %). Based on electrochemical impedance spectroscopy measurements, the enhancement is ascribed to a synergistic effect between TiN nanoparticles and the CNT-graphene hybrid, the roles of which are to provide active sites for the reduction of polysulfide ions and electron pathways to TiN nanoparticles, respectively. The combination of graphene and CNTs leads to a favorable morphology that prevents stacking of graphene or bundling of CNTs, which maximizes the contact of the support with TiN nanoparticles and improves electron-transfer capability relative to either carbon material alone. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. A Novel Nanomaterial of Graphene Oxide Dotted with Ni Nanoparticles Produced by Supercritical CO2-Assisted Deposition for Reducing Friction and Wear.

    Science.gov (United States)

    Meng, Yuan; Su, Fenghua; Chen, Yangzhi

    2015-06-03

    Graphene oxide dotted with nickel nanoparticles (Sc-Ni/GO) was synthesized by chemical deposition with the assistance of supercritical carbon dioxide (scCO2). The deposited Ni nanoparticles with diameters less than 5 nm are uniformly anchored on the surfaces of GO nanosheets. The as-prepared Sc-Ni/GO composites were employed as lubricating additives in paraffin oil and their tribological properties were tested using a four-ball tribometer. The results demonstrate that the Sc-Ni/GO composites are efficient lubricant additives. Adding 0.08 wt % Sc-Ni/GO into paraffin oil can reduce the friction coefficient and wear scar diameter by 32 and 42%, respectively, in comparison with the pure oil. In addition, Sc-Ni/GO composites exhibit superior lubricating performances than nano-Ni, GO nanosheets, and Ni/GO composites produced without the aid of scCO2. Such excellent lubricating properties of the Sc-Ni/GO composites derive from the synergistic lubricating actions of Ni nanoparticles and GO nanosheets during the rubbing process. The synergistic lubricating actions are closely related to the microstructure of the nanocomposites and the characteristic features of transfer film formed on the contact steel balls. The anchored Ni nanoparticles with smaller size and more uniform distribution on GO surfaces and the thin transfer film formed on the contact balls favor the full play of the synergistic actions.

  2. Evaluation of in-vitro cytotoxicity and cellular uptake efficiency of zidovudine-loaded solid lipid nanoparticles modified with Aloe Vera in glioma cells

    Energy Technology Data Exchange (ETDEWEB)

    Joshy, K.S. [Department of Chemistry, CMS College Kottayam, Kerala (India); International and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); Sharma, Chandra P. [Division of Biosurface Technology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Science and Technology, Poojappura, Thiruvananthapuram, Kerala (India); Kalarikkal, Nandakumar [International and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); Sandeep, K. [International and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); Thomas, Sabu, E-mail: sabuchathukulam@yahoo.co.uk [International and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); Pothen, Laly A. [Department of Chemistry, Bishop Moore College, Mavelikkara, Kerala (India)

    2016-09-01

    Zidovudine loaded solid lipid nanoparticles of stearic acid modified with Aloe Vera (AV) have been prepared via simple emulsion solvent evaporation method which showed excellent stability at room temperature and refrigerated condition. The nanoparticles were examined by Fourier transform infrared spectroscopy (FT-IR), which revealed the overlap of the AV absorption peak with the absorption peak of modified stearic acid nanoparticles. The inclusion of AV to stearic acid decreased the crystallinity and improved the hydrophilicity of lipid nanoparticles and thereby improved the drug loading efficacy of lipid nanoparticles. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) imaging revealed that, the average particle size of unmodified (bare) nanoparticles was 45.66 ± 12.22 nm and modified solid lipid nanoparticles showed an average size of 265.61 ± 80.44 nm. Solid lipid nanoparticles with well-defined morphology were tested in vitro for their possible application in drug delivery. Cell culture studies using C6 glioma cells on the nanoparticles showed enhanced growth and proliferation of cells without exhibiting any toxicity. In addition, normal cell morphology and improved uptake were observed by fluorescence microscopy images of rhodamine labeled modified solid lipid nanoparticles compared with unmodified nanoparticles. The cellular uptake study suggested that these nanoparticles could be a promising drug delivery system to enhance the uptake of antiviral drug by brain cells and it could be a suitable drug carrier system for the treatment of HIV. - Highlights: • SLN of AZT-SA, AZT-SA-AV was developed • Better drug loading efficacy • Good uptake.

  3. Evaluation of in-vitro cytotoxicity and cellular uptake efficiency of zidovudine-loaded solid lipid nanoparticles modified with Aloe Vera in glioma cells

    International Nuclear Information System (INIS)

    Joshy, K.S.; Sharma, Chandra P.; Kalarikkal, Nandakumar; Sandeep, K.; Thomas, Sabu; Pothen, Laly A.

    2016-01-01

    Zidovudine loaded solid lipid nanoparticles of stearic acid modified with Aloe Vera (AV) have been prepared via simple emulsion solvent evaporation method which showed excellent stability at room temperature and refrigerated condition. The nanoparticles were examined by Fourier transform infrared spectroscopy (FT-IR), which revealed the overlap of the AV absorption peak with the absorption peak of modified stearic acid nanoparticles. The inclusion of AV to stearic acid decreased the crystallinity and improved the hydrophilicity of lipid nanoparticles and thereby improved the drug loading efficacy of lipid nanoparticles. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) imaging revealed that, the average particle size of unmodified (bare) nanoparticles was 45.66 ± 12.22 nm and modified solid lipid nanoparticles showed an average size of 265.61 ± 80.44 nm. Solid lipid nanoparticles with well-defined morphology were tested in vitro for their possible application in drug delivery. Cell culture studies using C6 glioma cells on the nanoparticles showed enhanced growth and proliferation of cells without exhibiting any toxicity. In addition, normal cell morphology and improved uptake were observed by fluorescence microscopy images of rhodamine labeled modified solid lipid nanoparticles compared with unmodified nanoparticles. The cellular uptake study suggested that these nanoparticles could be a promising drug delivery system to enhance the uptake of antiviral drug by brain cells and it could be a suitable drug carrier system for the treatment of HIV. - Highlights: • SLN of AZT-SA, AZT-SA-AV was developed • Better drug loading efficacy • Good uptake

  4. The cytotoxicity of polycationic iron oxide nanoparticles: Common endpoint assays and alternative approaches for improved understanding of cellular response mechanism

    Directory of Open Access Journals (Sweden)

    Hoskins Clare

    2012-04-01

    Full Text Available Abstract Background Iron oxide magnetic nanoparticles (MNP's have an increasing number of biomedical applications. As such in vitro characterisation is essential to ensure the bio-safety of these particles. Little is known on the cellular interaction or effect on membrane integrity upon exposure to these MNPs. Here we synthesised Fe3O4 and surface coated with poly(ethylenimine (PEI and poly(ethylene glycol (PEG to achieve particles of varying surface positive charges and used them as model MNP's to evaluate the relative utility and limitations of cellular assays commonly applied for nanotoxicity assessment. An alternative approach, atomic force microscopy (AFM, was explored for the analysis of membrane structure and cell morphology upon interacting with the MNPs. The particles were tested in vitro on human SH-SY5Y, MCF-7 and U937 cell lines for reactive oxygen species (ROS production and lipid peroxidation (LPO, LDH leakage and their overall cytotoxic effect. These results were compared with AFM topography imaging carried out on fixed cell lines. Results Successful particle synthesis and coating were characterised using FTIR, PCS, TEM and ICP. The particle size from TEM was 30 nm (−16.9 mV which increased to 40 nm (+55.6 mV upon coating with PEI and subsequently 50 nm (+31.2 mV with PEG coating. Both particles showed excellent stability not only at neutral pH but also in acidic environment of pH 4.6 in the presence of sodium citrate. The higher surface charge MNP-PEI resulted in increased cytotoxic effect and ROS production on all cell lines compared with the MNP-PEI-PEG. In general the effect on the cell membrane integrity was observed only in SH-SY5Y and MCF-7 cells by MNP-PEI determined by LDH leakage and LPO production. AFM topography images showed consistently that both the highly charged MNP-PEI and the less charged MNP-PEI-PEG caused cell morphology changes possibly due to membrane disruption and cytoskeleton remodelling. Conclusions

  5. Enhancement of the optical Kerr effect exhibited by an integrated configuration of silicon quantum dots and silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Suarez, A; Benami, A; Tamayo-Rivera L; Reyes-Esqueda, J A; Cheang-Wong, J C; Rodriguez-Fernandez, L; Crespo-Sosa, A; Oliver, A [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, D. F. 04510 (Mexico); R Rangel-Rojo [Departamento de Optica, Centro de Investigacion CientIfica y de Educacion Superior de Ensenada, Apartado Postal 2732, Ensenada, BC 22860 (Mexico); Torres-Torres, C, E-mail: rrangel@cicese.mx [Seccion de Estudios de Posgrado e Investigacion, ESIME-Z, Instituto Politecnico Nacional, D.F. 07738 (Mexico)

    2011-01-01

    We present nonlinear refractive results for three different systems produced by ion implantation: high purity silica substrates with silicon quantum dots (Si-QDs), silver nanoparticles (Ag-NPs), and one sample containing both. We used a femtosecond optical Kerr gate (OKG) with 80 fs pulses at 830 nm to investigate the magnitude and response time of their nonlinear response. The Ag-NPs samples were prepared implanting 2 MeV Ag{sup 2+} ions at different fluencies. A sample with 1x10{sup 17} ions/cm{sup 2} showed no discernible Kerr signal, while for one with 2.4x10{sup 17} ions/cm{sup 2} we measured |{chi}{sup (3)}|{sub 1111} = 5.1x10{sup -11} esu. The Si-QDs sample required irradiation with 1.5 MeV Si{sup 2+} ions, at a 2.5x10{sup 17} ions/cm{sup 2} fluence in order that the OKG results for this sample yielded a similar |{chi}{sup (3)}|{sub 1111} value. The sample containing the Si-QDs was then irradiated by 1 MeV Ag2+ ions at a 4.44 x 10{sup 16} ions/cm{sup 2} fluence and thermally treated, for which afterward we measured |{chi}{sup (3)}|{sub 1111} 1.7x10{sup -10} esu. In all cases the response time was quasi-instantaneous. These results imply that the inclusion of Ag-NPs at low fluence, enhances the nonlinearity of the composite by a factor of around three, and that this is purely electronic in nature. Pump-probe results show that there is not any nonlinear absorption present. We estimate that the confinement effect of the Si-QDs in the sample plays an important role for the excitation of the Surface Plasmon Resonance (SPR) related to the Ag-NPs. A theoretical model that describes the modification of the third order nonlinearity is also presented.

  6. Free-radical sensing by using naphthalimide based mesoporous silica (MCM-41) nanoparticles: A combined fluorescence and cellular imaging study

    Science.gov (United States)

    Jha, Gaurav; Roy, Subhasis; Sahu, Prabhat Kumar; Banerjee, Somnath; Anoop, N.; Rahaman, Abdur; Sarkar, Moloy

    2018-01-01

    Keeping in mind the advantages of material-based systems over simple molecule-based systems, we have designed and developed three inorganic-organic hybrid systems by anchoring 1,8-naphthalimide derivatives to mesoporous silica nanoparticles for detection of free radicals. Prior to photophysical study, systems are characterized by spectroscopic, microscopic and thermo-gravimetric techniques. Steady state and time-resolved fluorescence studies demonstrate that the hydrazine based system is senstive towards detection of various free radicals. Cellular imaging study reveals cell permeability and toxicity study demonstrates the non-toxic nature of the material. These studies have suggested that present system has the potential to be used in various biological applications.

  7. Ru(II)-polypyridyl surface functionalised gold nanoparticles as DNA targeting supramolecular structures and luminescent cellular imaging agents.

    Science.gov (United States)

    Martínez-Calvo, Miguel; Orange, Kim N; Elmes, Robert B P; la Cour Poulsen, Bjørn; Williams, D Clive; Gunnlaugsson, Thorfinnur

    2016-01-07

    The development of Ru(II) functionalized gold nanoparticles 1–3·AuNP is described. These systems were found to be mono-disperse with a hydrodynamic radius of ca. 15 nm in water but gave rise to the formation of higher order structures in buffered solution. The interaction of 1–3·AuNP with DNA was also studied by spectroscopic and microscopic methods and suggested the formation of large self-assembly structures in solution. The uptake of 1–3·AuNP by cancer cells was studied using both confocal fluorescence as well as transmission electron microscopy (TEM), with the aim of investigating their potential as tools for cellular biology. These systems displaying a non-toxic profile with favourable photophysical properties may have application across various biological fields including diagnostics and therapeutics.

  8. Trojan-horse mechanism in the cellular uptake of silver nanoparticles verified by direct intra- and extracellular silver speciation analysis.

    Science.gov (United States)

    Hsiao, I-Lun; Hsieh, Yi-Kong; Wang, Chu-Fang; Chen, I-Chieh; Huang, Yuh-Jeen

    2015-03-17

    The so-called "Trojan-horse" mechanism, in which nanoparticles are internalized within cells and then release high levels of toxic ions, has been proposed as a behavior in the cellular uptake of Ag nanoparticles (AgNPs). While several reports claim to have proved this mechanism by measuring AgNPs and Ag ions (I) in cells, it cannot be fully proven without examining those two components in both intra- and extracellular media. In our study, we found that even though cells take up AgNPs similarly to (microglia (BV-2)) or more rapidly than (astrocyte (ALT)) Ag (I), the ratio of AgNPs to total Ag (AgNPs+Ag (I)) in both cells was lower than that in outside media. It could be explained that H2O2, a major intracellular reactive oxygen species (ROS), reacts with AgNPs to form more Ag (I). Moreover, the major speciation of Ag (I) in cells was Ag(cysteine) and Ag(cysteine)2, indicating the possible binding of monomer cysteine or vital thiol proteins/peptides to Ag ions. Evidence we found indicates that the Trojan-horse mechanism really exists.

  9. Smart pH-responsive upconversion nanoparticles for enhanced tumor cellular internalization and near-infrared light-triggered photodynamic therapy.

    Science.gov (United States)

    Wang, Sheng; Zhang, Lei; Dong, Chunhong; Su, Lin; Wang, Hanjie; Chang, Jin

    2015-01-01

    A smart pH-responsive photodynamic therapy system based on upconversion nanoparticle loaded PEG coated polymeric lipid vesicles (RB-UPPLVs) was designed and prepared. These RB-UPPLVs which are promising agents for deep cancer photodynamic therapy applications can achieve enhanced tumor cellular internalization and near-infrared light-triggered photodynamic therapy.

  10. Cellular Interactions and Biological Responses to Titanium Dioxide Nanoparticles in HepG2 and BEAS-2B Cells: Role of Cell Culture Media

    Science.gov (United States)

    ABSTRACT We have shown previously that the composition of the biological medium used in vitro can affect the cellular interaction and biological response of titanium dioxide nanoparticles (nano-TiO2) in human lung epithelial cells. However, it is unclear if these effects are co...

  11. Fluorescent quenching immune chromatographic strips with quantum dots and upconversion nanoparticles as fluorescent donors for visual detection of sulfaquinoxaline in foods of animal origin

    International Nuclear Information System (INIS)

    Hu, Gaoshuang; Sheng, Wei; Li, Jingmin; Zhang, Yan; Wang, Junping; Wang, Shuo

    2017-01-01

    In this study, two novel fluorescence quenching immune chromatographic strips (FQICS) were developed to detect sulfaquinoxaline (SQX) in foods of animal origin. These proposed FQICSs were based on fluorescence resonance energy transfer (FRET) from fluorescence donors (quantum dots or upconversion nanoparticles) to fluorescence acceptors (colloidal gold nanoparticles). Compared with traditional colloidal gold-based immune chromatographic strips (ICS), these FQICSs showed positive correlation between the fluorescent signals and the targets, and allowed user to get test results from weak fluorescent signals. The visual detection limits of these two FQICSs were both 1 ng mL −1 in standard solution and 8 μg kg −1 in samples, while the visual detection limit of the colloidal gold-based ICS was 10 ng mL −1 in standard solution and 80 μg kg −1 in samples. Besides, the results we obtained by the use of FQICS showed high agreement with those obtained by the use of commercial ELISA kits, indicating the good accuracy of these strips. As a conclusion, these proposed FQICS based on quantum dots and upconversion nanoparticles can be applied in sensitive, rapid and on-site detection of SQX in foods of animal origin. - Highlights: • Two novel FQICS based on FRET were developed for the first time. • QDs and UCNPs were used as fluorescent donors in the FQICS. • The proposed FQICS showed low LOD compared with traditional ICS. • The proposed FQICS were applied in real samples analysis. • The proposed FQICS were verified by commercial ELISA kits.

  12. Core–shell Fe3O4–Au magnetic nanoparticles based nonenzymatic ultrasensitive electrochemiluminescence immunosensor using quantum dots functionalized graphene sheet as labels

    International Nuclear Information System (INIS)

    Liu, Weiyan; Zhang, Yan; Ge, Shenguang; Song, Xianrang; Huang, Jiadong; Yan, Mei; Yu, Jinghua

    2013-01-01

    Graphical abstract: Core–shell Fe 3 O 4 –Au magnetic nanoparticles and P-GS@QDs were prepared to immobilize Ab 1 and Ab 2 respectively and combined to fabricate a novel sandwich-type ECL immunosensor for detecting CA125 at low concentration. Highlights: ► ECL immunosensor for CA125 based on a microfluidic strategy with a homemade ECL cell was proposed. ► Core–shell Fe 3 O 4 –Au magnetic nanoparticles were employed as the carriers of the primary antibodies. ► CdTe quantum dots functionalized graphene sheet were used for signal amplification. -- Abstract: In this paper, a novel, low-cost electrochemiluminescence (ECL) immunosensor using core–shell Fe 3 O 4 –Au magnetic nanoparticles (AuMNPs) as the carriers of the primary antibody of carbohydrate antigen 125 (CA125) was designed. Graphene sheet (GS) with property of good conductivity and large surface area was a captivating candidate to amplify ECL signal. We successively synthesized functionalized GS by loading large amounts of quantum dots (QDs) onto the poly (diallyldimethyl-ammonium chloride) (PDDA) coated graphene sheet (P-GS@QDs) via self-assembly electrostatic reactions, which were used to label secondary antibodies. The ECL immunosensors coupled with a microfluidic strategy exhibited a wide detection range (0.005–50 U mL −1 ) and a low detection limit (1.2 mU mL −1 ) with the help of an external magnetic field to gather immunosensors. The method was evaluated with clinical serum sample, receiving good correlation with results from commercially available analytical procedure

  13. Multifunctional organic–inorganic hybrid nanoparticles and nanosheets based on chitosan derivative and layered double hydroxide: cellular uptake mechanism and application for topical ocular drug delivery

    Science.gov (United States)

    Chi, Huibo; Gu, Yan; Xu, Tingting; Cao, Feng

    2017-01-01

    To study the cellular uptake mechanism of multifunctional organic–inorganic hybrid nanoparticles and nanosheets, new chitosan–glutathione–valine–valine-layered double hydroxide (CG-VV-LDH) nanosheets with active targeting to peptide transporter-1 (PepT-1) were prepared, characterized and further compared with CG-VV-LDH nanoparticles. Both organic–inorganic hybrid nanoparticles and nanosheets showed a sustained release in vitro and prolonged precorneal retention time in vivo, but CG-VV-LDH nanoparticles showed superior permeability in the isolated cornea of rabbits than CG-VV-LDH nanosheets. Furthermore, results of cellular uptake on human corneal epithelial primary cells (HCEpiC) and retinal pigment epithelial (ARPE-19) cells indicated that both clathrin-mediated endocytosis and active transport of PepT-1 are involved in the internalization of CG-VV-LDH nanoparticles and CG-VV-LDH nanosheets. In summary, the CG-VV-LDH nanoparticle may be a promising carrier as a topical ocular drug delivery system for the treatment of ocular diseases of mid-posterior segments, while the CG-VV-LDH nanosheet may be suitable for the treatment of ocular surface diseases. PMID:28280329

  14. Comparison of cellular effects of starch-coated SPIONs and poly(lactic-co-glycolic acid) matrix nanoparticles on human monocytes.

    Science.gov (United States)

    Gonnissen, Dominik; Qu, Ying; Langer, Klaus; Öztürk, Cengiz; Zhao, Yuliang; Chen, Chunying; Seebohm, Guiscard; Düfer, Martina; Fuchs, Harald; Galla, Hans-Joachim; Riehemann, Kristina

    Within the last years, progress has been made in the knowledge of the properties of medically used nanoparticles and their toxic effects, but still, little is known about their influence on cellular processes of immune cells. The aim of our comparative study was to present the influence of two different nanoparticle types on subcellular processes of primary monocytes and the leukemic monocyte cell line MM6. We used core-shell starch-coated superparamagnetic iron oxide nanoparticles (SPIONs) and matrix poly(lactic-co-glycolic acid) (PLGA) nanoparticles for our experiments. In addition to typical biocompatibility testing like the detection of necrosis or secretion of interleukins (ILs), we investigated the impact of these nanoparticles on the actin cytoskeleton and the two voltage-gated potassium channels Kv1.3 and Kv7.1. Induction of necrosis was not seen for PLGA nanoparticles and SPIONs in primary monocytes and MM6 cells. Likewise, no alteration in secretion of IL-1β and IL-10 was detected under the same experimental conditions. In contrast, IL-6 secretion was exclusively downregulated in primary monocytes after contact with both nanoparticles. Two-electrode voltage clamp experiments revealed that both nanoparticles reduce currents of the aforementioned potassium channels. The two nanoparticles differed significantly in their impact on the actin cytoskeleton, demonstrated via atomic force microscopy elasticity measurement and phalloidin staining. While SPIONs led to the disruption of the respective cytoskeleton, PLGA did not show any influence in both experimental setups. The difference in the effects on ion channels and the actin cytoskeleton suggests that nanoparticles affect these subcellular components via different pathways. Our data indicate that the alteration of the cytoskeleton and the effect on ion channels are new parameters that describe the influence of nanoparticles on cells. The results are highly relevant for medical application and further

  15. Cellular imaging using biocompatible dendrimer-functionalized graphene oxide-based fluorescent probe anchored with magnetic nanoparticles

    International Nuclear Information System (INIS)

    Wate, Prateek S; Banerjee, Shashwat S; Mascarenhas, Russel R; Zope, Khushbu R; Khandare, Jayant; Jalota-Badhwar, Archana; Misra, R Devesh K

    2012-01-01

    We describe a novel multicomponent graphene nanostructured system that is biocompatible, and has strong NIR optical absorbance and superparamagnetic properties. The fabrication of the multicomponent nanostructure system involves the covalent attachment of 3 components; Fe 3 O 4 (Fe) nanoparticles, PAMAM-G4-NH 2 (G4) dendrimer and Cy5 (Cy) on a graphene oxide (GO) surface to synthesize a biologically relevant multifunctional system. The resultant GO-G4-Fe-Cy nanosystem exhibits high dispersion in an aqueous medium, and is magnetically responsive and fluorescent. In vitro experiments provide a clear indication of successful uptake of the GO-G4-Fe-Cy nanosystem by MCF-7 breast cancer cells, and it is seen to behave as a bright and stable fluorescent marker. The study also reveals varied cellular distribution kinetics profile for the GO nanostructured system compared to free Cy. Furthermore, the newly developed GO nanostructured system is observed to be non-toxic to MDA-MB-231 cell growth, in striking contrast to free G4 dendrimer and GO-G4 conjugate. The GO-G4-Fe-Cy nanostructured system characterized by multifunctionality suggests the merits of graphene for cellular bioimaging and the delivery of bioactives. (paper)

  16. Cellular processing of gold nanoparticles: CE-ICP-MS evidence for the speciation changes in human cytosol.

    Science.gov (United States)

    Legat, Joanna; Matczuk, Magdalena; Timerbaev, Andrei R; Jarosz, Maciej

    2018-01-01

    The cellular uptake of gold nanoparticles (AuNPs) may (or may not) affect their speciation, but information on the chemical forms in which the particles exist in the cell remains obscure. An analytical method based on the use of capillary electrophoresis hyphenated with inductively coupled plasma mass spectrometry (ICP-MS) has been proposed to shed light on the intracellular processing of AuNPs. It was observed that when being introduced into normal cytosol, the conjugates of 10-50 nm AuNPs with albumin evolved in human serum stayed intact. On the contrary, under simulated cancer cytosol conditions, the nanoconjugates underwent decomposition, the rate of which and the resulting metal speciation patterns were strongly influenced by particle size. The new peaks that appeared in ICP-MS electropherograms could be ascribed to nanosized species, as upon ultracentrifugation, they quantitatively precipitated whereas the supernatant showed only trace Au signals. Our present study is the first step to unravel a mystery of the cellular chemistry for metal-based nanomedicines.

  17. Poly(methyl vinyl ether-alt-maleic acid)-functionalized porous silicon nanoparticles for enhanced stability and cellular internalization.

    Science.gov (United States)

    Shahbazi, Mohammad-Ali; Almeida, Patrick V; Mäkilä, Ermei; Correia, Alexandra; Ferreira, Mónica P A; Kaasalainen, Martti; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

    2014-03-01

    Currently, developing a stable nanocarrier with high cellular internalization and low toxicity is a key bottleneck in nanomedicine. Here, we have developed a successful method to covalently conjugate poly(methyl vinyl ether-co-maleic acid) (PMVE-MA) copolymer on the surface of (3-aminopropyl)triethoxysilane-functionalized thermally carbonized porous silicon nanoparticles (APSTCPSi NPs), forming a surface negatively charged nanovehicle with unique properties. This polymer conjugated NPs could modify surface smoothness, charge, and hydrophilicity of the developed NPs, leading to considerable improvement in the colloidal and plasma stabilities via enhanced suspensibility and charge repulsion. Furthermore, despite the surface negative charge of the polymer-conjugated NPs, the cellular internalization was increased in both MDA-MB-231 and MCF-7 breast cancer cells. These results provide a proof-of-concept evidence that such polymer-based PSi nanocomposite can be extensively used as a promising candidate for intracellular drug delivery. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Comparative Iron Oxide Nanoparticle Cellular Dosimetry and Response in Mice by the Inhalation and Liquid Cell Culture Exposure Routes

    Energy Technology Data Exchange (ETDEWEB)

    Teeguarden, Justin G.; Mikheev, Vladimir B.; Minard, Kevin R.; Forsythe, William C.; Wang, Wei; Sharma, Gaurav; Karin, Norman J.; Tilton, Susan C.; Waters, Katrina M.; Asgharian, Bahman; Price, Owen; Pounds, Joel G.; Thrall, Brian D.

    2014-01-01

    testing the rapidly growing number of nanomaterials requires large scale use of in vitro systems under the presumption that these systems are sufficiently predictive or descriptive of responses in in vivo systems for effective use in hazard ranking. We hypothesized that improved relationships between in vitro and in vivo models of experimental toxicology for nanomaterials would result from placing response data in vitro and in vivo on the same dose scale, the amount of material associated with cells (target cell dose). Methods: Balb/c mice were exposed nose-only to an aerosol of 12.8 nm (68.6 nm CMD, 19.9 mg/m3, 4 hours) super paramagnetic iron oxide particles, target cell doses were calculated and biomarkers of response anchored with histological evidence were identified by global transcriptomics. Representative murine epithelial and macrophage cell types were exposed in vitro to the same material in liquid suspension for four hours and levels nanoparticle regulated cytokine transcripts identified in vivo were quantified as a function of measured nanoparticle cellular dose. Results. Target tissue doses of 0.009-0.4 μg SPIO/cm2 lung led to an inflammatory response in the alveolar region characterized by interstitial inflammation and macrophage infiltration. In vitro, higher target tissue doses of ~1.2-4 μg SPIO/ cm2 of cells were required to induce transcriptional regulation of markers of inflammation, CXCL2 CCL3, in C10 lung epithelial cells. Estimated in vivo macrophage SPIO nanoparticle doses ranged from 1-100 pg/cell, and induction of inflammatory markers was observed in vitro in macrophages at doses of 8-35 pg/cell. Conclusions: Application of target tissue dosimetry revealed good correspondence between target cell doses triggering inflammatory processes in vitro and in vivo in the alveolar macrophage population, but not in the epithelial cells of the alveolar region. These findings demonstrate the potential for target tissue dosimetry to enable the more

  19. Characterization of the cellular response triggered by gold nanoparticle-mediated laser manipulation.

    Science.gov (United States)

    Kalies, Stefan; Keil, Sebastian; Sender, Sina; Hammer, Susanne C; Antonopoulos, Georgios C; Schomaker, Markus; Ripken, Tammo; Murua Escobar, Hugo; Meyer, Heiko; Heinemann, Dag

    2015-11-01

    Laser-based transfection techniques have proven high applicability in several cell biologic applications. The delivery of different molecules using these techniques has been extensively investigated. In particular, new high-throughput approaches such as gold nanoparticle–mediated laser transfection allow efficient delivery of antisense molecules or proteins into cells preserving high cell viabilities. However, the cellular response to the perforation procedure is not well understood. We herein analyzed the perforation kinetics of single cells during resonant gold nanoparticle–mediated laser manipulation with an 850-ps laser system at a wavelength of 532 nm. Inflow velocity of propidium iodide into manipulated cells reached a maximum within a few seconds. Experiments based on the inflow of FM4-64 indicated that the membrane remains permeable for a few minutes for small molecules. To further characterize the cellular response postmanipulation, we analyzed levels of oxidative heat or general stress. Although we observed an increased formation of reactive oxygen species by an increase of dichlorofluorescein fluorescence, heat shock protein 70 was not upregulated in laser-treated cells. Additionally, no evidence of stress granule formation was visible by immunofluorescence staining. The data provided in this study help to identify the cellular reactions to gold nanoparticle–mediated laser manipulation.

  20. Biomechanics and Thermodynamics of Nanoparticle Interactions with Plasma and Endosomal Membrane Lipids in Cellular Uptake and Endosomal Escape

    Science.gov (United States)

    2015-01-01

    To be effective for cytoplasmic delivery of therapeutics, nanoparticles (NPs) taken up via endocytic pathways must efficiently transport across the cell membrane and subsequently escape from the secondary endosomes. We hypothesized that the biomechanical and thermodynamic interactions of NPs with plasma and endosomal membrane lipids are involved in these processes. Using model plasma and endosomal lipid membranes, we compared the interactions of cationic NPs composed of poly(d,l-lactide-co-glycolide) modified with the dichain surfactant didodecyldimethylammonium bromide (DMAB) or the single-chain surfactant cetyltrimethylammonium bromide (CTAB) vs anionic unmodified NPs of similar size. We validated our hypothesis in doxorubicin-sensitive (MCF-7, with relatively fluid membranes) and resistant breast cancer cells (MCF-7/ADR, with rigid membranes). Despite their cationic surface charges, DMAB- and CTAB-modified NPs showed different patterns of biophysical interaction: DMAB-modified NPs induced bending of the model plasma membrane, whereas CTAB-modified NPs condensed the membrane, thereby resisted bending. Unmodified NPs showed no effects on bending. DMAB-modified NPs also induced thermodynamic instability of the model endosomal membrane, whereas CTAB-modified and unmodified NPs had no effect. Since bending of the plasma membrane and destabilization of the endosomal membrane are critical biophysical processes in NP cellular uptake and endosomal escape, respectively, we tested these NPs for cellular uptake and drug efficacy. Confocal imaging showed that in both sensitive and resistant cells DMAB-modified NPs exhibited greater cellular uptake and escape from endosomes than CTAB-modified or unmodified NPs. Further, paclitaxel-loaded DMAB-modified NPs induced greater cytotoxicity even in resistant cells than CTAB-modified or unmodified NPs or drug in solution, demonstrating the potential of DMAB-modified NPs to overcome the transport barrier in resistant cells. In

  1. Increased cellular uptake of lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles due to surface modification with folic acid.

    Science.gov (United States)

    Feuser, Paulo Emilio; Arévalo, Juan Marcelo Carpio; Junior, Enio Lima; Rossi, Gustavo Rodrigues; da Silva Trindade, Edvaldo; Rocha, Maria Eliane Merlin; Jacques, Amanda Virtuoso; Ricci-Júnior, Eduardo; Santos-Silva, Maria Claudia; Sayer, Claudia; de Araújo, Pedro H Hermes

    2016-12-01

    Lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles surface modified with folic acid were synthesized by miniemulsion polymerization in just one step. In vitro biocompatibility and cytotoxicity assays on L929 (murine fibroblast), human red blood, and HeLa (uterine colon cancer) cells were performed. The effect of folic acid at the nanoparticles surface was evaluated through cellular uptake assays in HeLa cells. Results showed that the presence of folic acid did not affect substantially the polymer particle size (~120 nm), the superparamagnetic behavior, the encapsulation efficiency of lauryl gallate (~87 %), the Zeta potential (~38 mV) of the polymeric nanoparticles or the release profile of lauryl gallate. The release profile of lauryl gallate from superparamagnetic poly(methyl methacrylate) nanoparticles presented an initial burst effect (0-1 h) followed by a slow and sustained release, indicating a biphasic release system. Lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles with folic acid did not present cytotoxicity effects on L929 and human red blood cells. However, free lauryl gallate presented significant cytotoxic effects on L929 and human red blood cells at all tested concentrations. The presence of folic acid increased the cytotoxicity of lauryl gallate loaded in nanoparticles on HeLa cells due to a higher cellular uptake when HeLa cells were incubated at 37 °C. On the other hand, when the nanoparticles were incubated at low temperature (4 °C) cellular uptake was not observed, suggesting that the uptake occurred by folate receptor mediated energy-dependent endocytosis. Based on presented results our work suggests that this carrier system can be an excellent alternative in targeted drug delivery by folate receptor.

  2. Differential cellular responses in healthy mice and in mice with established airway inflammation when exposed to hematite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Åsa, E-mail: asa.gustafsson@foi.se [Swedish Defence Research Agency, Division of CBRN Defence and Security, Umeå (Sweden); Dept of Public Health and Clinical Medicine, Umeå University (Sweden); Bergström, Ulrika [Swedish Defence Research Agency, Division of CBRN Defence and Security, Umeå (Sweden); Dept of Organismal Biology, Uppsala University, SE-751 Uppsala (Sweden); Ågren, Lina [Swedish Defence Research Agency, Division of CBRN Defence and Security, Umeå (Sweden); Österlund, Lars [Dept of Engineering Sciences, The Ångström Laboratory, Uppsala University, SE-751 Uppsala (Sweden); Sandström, Thomas [Dept of Public Health and Clinical Medicine, Umeå University (Sweden); Bucht, Anders [Swedish Defence Research Agency, Division of CBRN Defence and Security, Umeå (Sweden); Dept of Public Health and Clinical Medicine, Umeå University (Sweden)

    2015-10-01

    The aim of this study was to investigate the inflammatory and immunological responses in airways and lung-draining lymph nodes (LDLNs), following lung exposure to iron oxide (hematite) nanoparticles (NPs). The responses to the hematite NPs were evaluated in both healthy non-sensitized mice, and in sensitized mice with an established allergic airway disease. The mice were exposed intratracheally to either hematite NPs or to vehicle (PBS) and the cellular responses were evaluated on days 1, 2, and 7, post-exposure. Exposure to hematite NPs increased the numbers of neutrophils, eosinophils, and lymphocytes in the airways of non-sensitized mice on days 1 and 2 post-exposure; at these time points the number of lymphocytes was also elevated in the LDLNs. In contrast, exposing sensitized mice to hematite NPs induced a rapid and unspecific cellular reduction in the alveolar space on day 1 post-exposure; a similar decrease of lymphocytes was also observed in the LDLN. The results indicate that cells in the airways and in the LDLN of individuals with established airway inflammation undergo cell death when exposed to hematite NPs. A possible explanation for this toxic response is the extensive generation of reactive oxygen species (ROS) in the pro-oxidative environment of inflamed airways. This study demonstrates how sensitized and non-sensitized mice respond differently to hematite NP exposure, and it highlights the importance of including individuals with respiratory disorders when evaluating health effects of inhaled nanomaterials. - Highlights: • Hematite NPs induce differential responses in airways of healthy and allergic mice. • Hematite induced an airway inflammation in healthy mice. • Hematite induced cellular reduction in the alveolus and lymph nodes of allergic mice. • Cell death is possible due to extensive pro-oxidative environment in allergic mice. • It is important to include sensitive individuals when valuing health effects of NPs.

  3. The effect of nanoparticle uptake on cellular behavior: disrupting or enabling functions?

    Directory of Open Access Journals (Sweden)

    Miserocchi G

    2012-09-01

    Full Text Available Alice Panariti, Giuseppe Miserocchi, Ilaria RivoltaDepartment of Experimental Medicine, University of Milano Bicocca, Monza, ItalyAbstract: Nanoparticles (NPs are materials with overall dimensions in the nanoscale range. They have unique physicochemical properties, and have emerged as important players in current research in modern medicine. In the last few decades, several types of NPs and microparticles have been synthesized and proposed for use as contrast agents for diagnostics and imaging and for drug delivery; for example, in cancer therapy. Yet specific targeting that will improve their delivery still represents an unsolved challenge. The mechanism by which NPs enter the cell has important implications not only for their fate but also for their impact on biological systems. Several papers in the literature discuss the potential risks related to NP exposure, and more recently the concept that even sublethal doses of NPs may elicit a cell response has been proposed. In this review, we intend to present an overall view of cell mechanisms that may be perturbed by cell–NP interaction. Published data, in fact, emphasize that NPs should no longer be viewed only as simple carriers for biomedical applications, but that they can also play an active role in mediating biological effects.Keywords: nanoparticles, uptake, intracellular trafficking, bio compatibility

  4. Detection of stiff nanoparticles within cellular structures by contact resonance atomic force microscopy subsurface nanomechanical imaging.

    Science.gov (United States)

    Reggente, Melania; Passeri, Daniele; Angeloni, Livia; Scaramuzzo, Francesca Anna; Barteri, Mario; De Angelis, Francesca; Persiconi, Irene; De Stefano, Maria Egle; Rossi, Marco

    2017-05-04

    Detecting stiff nanoparticles buried in soft biological matrices by atomic force microscopy (AFM) based techniques represents a new frontier in the field of scanning probe microscopies, originally developed as surface characterization methods. Here we report the detection of stiff (magnetic) nanoparticles (NPs) internalized in cells by using contact resonance AFM (CR-AFM) employed as a potentially non-destructive subsurface characterization tool. Magnetite (Fe 3 O 4 ) NPs were internalized in microglial cells from cerebral cortices of mouse embryos of 18 days by phagocytosis. Nanomechanical imaging of cells was performed by detecting the contact resonance frequencies (CRFs) of an AFM cantilever held in contact with the sample. Agglomerates of NPs internalized in cells were visualized on the basis of the local increase in the contact stiffness with respect to the surrounding biological matrix. A second AFM-based technique for nanomechanical imaging, i.e., HarmoniX™, as well as magnetic force microscopy and light microscopy were used to confirm the CR-AFM results. Thus, CR-AFM was demonstrated as a promising technique for subsurface imaging of nanomaterials in biological samples.

  5. Carbon-Dot and Quantum-Dot-Coated Dual-Emission Core-Satellite Silica Nanoparticles for Ratiometric Intracellular Cu(2+) Imaging.

    Science.gov (United States)

    Zou, Chenchen; Foda, Mohamed Frahat; Tan, Xuecai; Shao, Kang; Wu, Long; Lu, Zhicheng; Bahlol, Hagar Shendy; Han, Heyou

    2016-07-19

    Copper (Cu(2+)) is physiologically essential, but excessive Cu(2+) may cause potential risk to plants and animals due to the bioaccumulative properties. Hence, sensitive recognition is crucial to avoid overintake of Cu(2+), and visual recognition is more favored for practical application. In this work, a dual-emission ratiometric fluorescent nanoprobe was developed possessing the required intensity ratio, which can facilitate the sensitive identification of Cu(2+) by the naked eye. The probe hybridizes two fluorescence nanodots (quantum dots (QDs) and carbon dots (CDs)). Although both of them can be viable fluorescence probes for metal ion detection, rarely research has coupled this two different kinds of fluorescence material in one nanosensor to fabricate a selectively ratiometric fluorescence probe for intracellular imaging. The red emitting CdTe/CdS QDs were capped around the silica microsphere to serve as the response signal label, and the blue-emitting CDs, which is insensitive to the analyte, were covalently attached to the QDs surface to act as the reference signal. This core-satellite hybrid sphere not only improves the stability and brightness of QDs significantly but also decreases the cytotoxicity toward HeLa cells tremendously. Moreover, the Cu(2+) could quench the QDs emission effectively but have no ability for reduction of the CDs emission. Accordingly, a simple, efficient, and precise method for tracing Cu(2+) was proposed. The increase of Cu(2+) concentration in the series of 0-3 × 10(-6) M was in accordance with linearly decrease of the F650/F425 ratio. As for practical application, this nanosensor was utilized to the ratiometric fluorescence imaging of copper ions in HeLa cells.

  6. Bufalin-loaded mPEG-PLGA-PLL-cRGD nanoparticles: preparation, cellular uptake, tissue distribution, and anticancer activity

    Directory of Open Access Journals (Sweden)

    Duan YR

    2012-07-01

    Full Text Available Peihao Yin,1,* Yan Wang,1,* YanYan Qiu,1 LiLi Hou,1 Xuan Liu,1 Jianmin Qin,1 Yourong Duan,2 Peifeng Liu,2 Ming Qiu,3 Qi Li11Department of Clinical Oncology, Putuo Hospital and Interventional Cancer Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China; 2Shanghai Cancer Institute, Jiaotong University, Shanghai, China; 3Department of General Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China *These authors contributed equally to this workBackground: Recent studies have shown that bufalin has a good antitumor effect but has high toxicity, poor water solubility, a short half-life, a narrow therapeutic window, and a toxic dose that is close to the therapeutic dose, which all limit its clinical application. This study aimed to determine the targeting efficacy of nanoparticles (NPs made of methoxy polyethylene glycol (mPEG, polylactic-co-glycolic acid (PLGA, poly-L-lysine (PLL, and cyclic arginine-glycine-aspartic acid (cRGD loaded with bufalin, ie, bufalin-loaded mPEG-PLGA-PLL-cRGD nanoparticles (BNPs, in SW620 colon cancer-bearing mice.Methods: BNPs showed uniform size. The size, shape, zeta potential, drug loading, encapsulation efficiency, and release of these nanoparticles were studied in vitro. The tumor targeting, cellular uptake, and growth-inhibitory effect of BNPs in vivo were tested.Results: BNPs were of uniform size with an average particle size of 164 ± 84 nm and zeta potential of 2.77 mV. The encapsulation efficiency was 81.7% ± 0.89%, and the drug load was 3.92% ± 0.16%. The results of in vitro cytotoxicity studies showed that although the blank NPs were nontoxic, they enhanced the cytotoxicity of bufalin in BNPs. Drug release experiments showed that the release of the drug was prolonged and sustained. The results of confocal laser scanning microscopy indicated that BNPs could effectively bind to human umbilical vein endothelial cells. In the SW620

  7. Exploring cellular uptake of iron oxide nanoparticles associated with rhodium citrate in breast cancer cells.

    Science.gov (United States)

    Chaves, Natalia L; Estrela-Lopis, Irina; Böttner, Julia; Lopes, Cláudio Ap; Guido, Bruna C; de Sousa, Aparecido R; Báo, Sônia N

    2017-01-01

    Nanocarriers have the potential to improve the therapeutic index of currently available drugs by improving their efficacy and achieving therapeutic steady-state levels over an extended period. The association of maghemite-rhodium citrate (MRC) nanoparticles (NPs) has the potential to increase specificity of the cytotoxic action. However, the interaction of these NPs with cells, their uptake mechanism, and subcellular localization need to be elucidated. This work evaluates the uptake mechanism of MRC NPs in metastatic and nonmetastatic breast cancer-cell models, comparing them to a nontumor cell line. MRC NPs uptake in breast cancer cells was more effective than in normal cells, with regard to both the amount of internalized material and the achievement of more strategic intracellular distribution. Moreover, this process occurred through a clathrin-dependent endocytosis pathway with different basal expression levels of this protein in the cell lines tested.

  8. Cellular toxicity and bioaccumulationof silver nanoparticles in the marine polychaete, Nereis diversicolor

    DEFF Research Database (Denmark)

    cong, Yi; Banta, Gary Thomas; Selck, Henriette

    (comet assay) and bioaccumulation as endpoints. Prior to the toxicity experiment, the physical-chemical properties of Ag NPs were fully characterized. The nominal concentrations used in all exposure scenarios were 0, 5, 10, 25, 50 and 100 µg Ag/g dry weight (dw) sediment. Lysosomal membrane stability...... of Nereis coelomocytes, which was measured by neutral red retention time (NRRT), decreased in a concentration-dependent manner in all Ag treatments, indicating increased permeability of lysosomal membranes. Comet assay results showed that Ag was able to cause DNA damage in Nereis coelomocytes regardless......In this study, the toxicities of commercial silver nanoparticles (Ag NPs, 20 and 80 nm) were compared with the toxicities of Ag+ ions in the marine sediment-dwelling polychaete, Nereis diversicolor, after 10 d of sediment exposure, using lysosomal membrane stability (neutral red assay), DNA damage...

  9. Long-term exposure of CdTe quantum dots on PC12 cellular activity and the determination of optimum non-toxic concentrations for biological use

    Directory of Open Access Journals (Sweden)

    Gérard Valérie A

    2010-03-01

    Full Text Available Abstract Background The unique and tuneable photonic properties of Quantum Dots (QDs have made them potentially useful tools for imaging biological entities. However, QDs though attractive diagnostic and therapeutic tools, have a major disadvantage due to their inherent cytotoxic nature. The cellular interaction, uptake and resultant toxic influence of CdTe QDs (gelatinised and non-gelatinised Thioglycolic acid (TGA capped have been investigated with pheochromocytoma 12 (PC12 cells. In conjunction to their analysis by confocal microscopy, the QD - cell interplay was explored as the QD concentrations were varied over extended (up to 72 hours co-incubation times. Coupled to this investigation, cell viability, DNA quantification and cell proliferation assays were also performed to compare and contrast the various factors leading to cell stress and ultimately death. Results Thioglycolic acid (TGA stabilised CdTe QDs (gel and non - gel were co-incubated with PC12 cells and investigated as to how their presence influenced cell behaviour and function. Cell morphology was analysed as the QD concentrations were varied over co-incubations up to 72 hours. The QDs were found to be excellent fluorophores, illuminating the cytoplasm of the cells and no deleterious effects were witnessed at concentrations of ~10-9 M. Three assays were utilised to probe how individual cell functions (viability, DNA quantification and proliferation were affected by the presence of the QDs at various concentrations and incubation times. Cell response was found to not only be concentration dependant but also influenced by the surface environment of the QDs. Gelatine capping on the surface acts as a barrier towards the leaking of toxic atoms, thus reducing the negative impact of the QDs. Conclusion This study has shown that under the correct conditions, QDs can be routinely used for the imaging of PC12 cells with minimal adverse effects. We have found that PC12 cells are highly

  10. Cytotoxicity and cellular mechanisms involved in the toxicity of CdS quantum dots in hemocytes and gill cells of the mussel Mytilus galloprovincialis

    Energy Technology Data Exchange (ETDEWEB)

    Katsumiti, A. [CBET Research Group, Dept. Zoology and Animal Cell Biology, Faculty of Science and Technology and Research Centre for Experimental Marine Biology and Biotechnology PIE, University of the Basque Country UPV/EHU, Basque Country (Spain); Gilliland, D. [EU Commission–Joint Research Centre, Institute of Health and Consumer Protection, NSB Unit, Ispra (Italy); Arostegui, I. [Department of Applied Mathematics, Statistics and Operations Research, Faculty of Science and Technology, University of the Basque Country UPV/EHU, Leioa (Spain); Cajaraville, M.P., E-mail: mirenp.cajaraville@ehu.es [CBET Research Group, Dept. Zoology and Animal Cell Biology, Faculty of Science and Technology and Research Centre for Experimental Marine Biology and Biotechnology PIE, University of the Basque Country UPV/EHU, Basque Country (Spain)

    2014-08-15

    Highlights: • CdS QDs were cytotoxic for mussel hemocytes and gill cells in vitro. • Ionic Cd was the most toxic form, followed by CdS QDs and bulk CdS. • CdS QDs altered oxidative balance and caused DNA damage in mussel cells. • CdS QDs caused a particle-specific immunostimulation on phagocytosis of hemocytes. • Conceptual models for cellular handling and toxicity of CdS QDs are proposed. - Abstract: CdS quantum dots (QDs) show a great promise for treatment and diagnosis of cancer and for targeted drug delivery, due to their size-tunable fluorescence and ease of functionalization for tissue targeting. In spite of their advantages it is important to determine if CdS QDs can exert toxicity on biological systems. In the present work, cytotoxicity of CdS QDs (5 nm) at a wide range of concentrations (0.001–100 mg Cd/L) was screened using neutral red (NR) and thiazolyl blue tetrazolium bromide (MTT) assays in isolated hemocytes and gill cells of mussels (Mytilus galloprovincialis). The mechanisms of action of CdS QDs were assessed at sublethal concentrations (0.31–5 mg Cd/L) in the same cell types through a series of functional in vitro assays: production of reactive oxygen species (ROS), catalase (CAT) activity, DNA damage, lysosomal acid phosphatase (AcP) activity, multixenobiotic resistance (MXR) transport activity, Na-K-ATPase activity (only in gill cells) and phagocytic activity and damage to actin cytoskeleton (only in hemocytes). Exposures to CdS QDs lasted for 24 h and were performed in parallel with exposures to bulk CdS and ionic Cd. Ionic Cd was the most toxic form to both cell types, followed by CdS QDs and bulk CdS. ROS production, DNA damage, AcP activity and MXR transport were significantly increased in both cell types exposed to the 3 forms of Cd. CAT activity increased in hemocytes exposed to the three forms of Cd while in gill cells only in those exposed to ionic Cd. No effects were found on hemocytes cytoskeleton integrity. Effects on

  11. Long-term exposure of CdTe quantum dots on PC12 cellular activity and the determination of optimum non-toxic concentrations for biological use

    LENUS (Irish Health Repository)

    Prasad, Babu R

    2010-03-25

    Abstract Background The unique and tuneable photonic properties of Quantum Dots (QDs) have made them potentially useful tools for imaging biological entities. However, QDs though attractive diagnostic and therapeutic tools, have a major disadvantage due to their inherent cytotoxic nature. The cellular interaction, uptake and resultant toxic influence of CdTe QDs (gelatinised and non-gelatinised Thioglycolic acid (TGA) capped) have been investigated with pheochromocytoma 12 (PC12) cells. In conjunction to their analysis by confocal microscopy, the QD - cell interplay was explored as the QD concentrations were varied over extended (up to 72 hours) co-incubation times. Coupled to this investigation, cell viability, DNA quantification and cell proliferation assays were also performed to compare and contrast the various factors leading to cell stress and ultimately death. Results Thioglycolic acid (TGA) stabilised CdTe QDs (gel and non - gel) were co-incubated with PC12 cells and investigated as to how their presence influenced cell behaviour and function. Cell morphology was analysed as the QD concentrations were varied over co-incubations up to 72 hours. The QDs were found to be excellent fluorophores, illuminating the cytoplasm of the cells and no deleterious effects were witnessed at concentrations of ~10-9 M. Three assays were utilised to probe how individual cell functions (viability, DNA quantification and proliferation) were affected by the presence of the QDs at various concentrations and incubation times. Cell response was found to not only be concentration dependant but also influenced by the surface environment of the QDs. Gelatine capping on the surface acts as a barrier towards the leaking of toxic atoms, thus reducing the negative impact of the QDs. Conclusion This study has shown that under the correct conditions, QDs can be routinely used for the imaging of PC12 cells with minimal adverse effects. We have found that PC12 cells are highly susceptible to

  12. The effect of neutral-surface iron oxide nanoparticles on cellular uptake and signaling pathways

    Directory of Open Access Journals (Sweden)

    Kim E

    2016-09-01

    Full Text Available Eunjoo Kim,1 Joon Mee Kim,2 Lucia Kim,2 Suk Jin Choi,2 In Suh Park,2 Jee Young Han,2 Young Chae Chu,2 Eun Sook Choi,1 Kun Na,3 Soon-Sun Hong4 1Division of Nano and Energy Convergence Research, Daegu Gyeongbuk Institute of Science and Technology (DGIST, Daegu, 2Department of Pathology, Inha University College of Medicine, Incheon, 3Department of Biotechnology, Catholic University of Korea, Bucheon, 4Department of Biomedical Sciences, Inha University College of Medicine, Incheon, South Korea Abstract: In recent years, iron oxide nanoparticles (IONPs have been applied widely to biomedical fields. However, the relationship between the physicochemical properties of IONPs and their biological behavior is not fully understood yet. We prepared 3-methacryloxypropyl­trimethoxysilane (MPS-coated IONPs, which have a neutral hydrophobic surface, and compared their biological behavior to that of Resovist (ferucarbotran, a commercialized IONP formulation modified with carboxymethyl dextran. The rate of MPS-IONP uptake by human aortic endothelial cells (HAoECs was higher than ferucarbotran uptake, indicating that the neutral hydrophobic nature of MPS-IONPs allowed them to be absorbed more readily through the plasma membrane. However, the signaling pathways activated by MPS-IONPs and ferucarbotran were comparable, suggesting that surface charge is not a key factor for inducing changes in HAoECs. In vivo fate analysis showed that MPS-IONPs accumulated for longer periods in tissues than hydrophilic ferucarbotran. These findings could enlarge our understanding of NP behavior for advanced applications in the biomedical field. Keywords: iron oxide nanoparticles, neutral hydrophobic surface, signaling pathway, uptake, accumulation, reactive oxygen species (ROS

  13. The cellular responses and antibacterial activities of silver nanoparticles stabilized by different polymers

    Science.gov (United States)

    Lin, Jiang-Jen; Lin, Wen-Chun; Dong, Rui-Xuan; Hsu, Shan-hui

    2012-02-01

    Silver nanoparticles (AgNPs) are known for their excellent antibacterial activities. The possible toxicity, however, is a major concern for their applications. Three types of AgNPs were prepared in this study by chemical processes. Each was stabilized by a polymer surfactant, which was expected to reduce the exposure of cells to AgNPs and therefore their cytotoxicity. The polymer stabilizers included poly(oxyethylene)-segmented imide (POEM), poly(styrene-co-maleic anhydride)-grafting poly(oxyalkylene) (SMA) and poly(vinyl alcohol) (PVA). The cytotoxicity of these chemically produced AgNPs to mouse skin fibroblasts (L929), human hepatocarcinoma cells (HepG2), and mouse monocyte macrophages (J774A1) was compared to that of physically produced AgNPs and gold nanoparticles (AuNPs) as well as the standard reference material RM8011 AuNPs. Results showed that SMA-AgNPs were the least cytotoxic among all materials, but cytotoxicity was still observed at higher silver concentrations (>30 ppm). Macrophages demonstrated the inflammatory response with cell size increase and viability decrease upon exposure to 10 ppm of the chemically produced AgNPs. SMA-AgNPs did not induce hemolysis at a silver concentration below 1.5 ppm. Regarding the antibacterial activity, POEM-AgNPs and SMA-AgNPs at 1 ppm silver content showed 99.9% and 99.3% growth inhibition against E. coli, while PVA-AgNPs at the same silver concentration displayed 79.1% inhibition. Overall, SMA-AgNPs demonstrated better safety in vitro and greater antibacterial effects than POEM-AgNPs and PVA-AgNPs. This study suggested that polymer stabilizers may play an important role in determining the toxicity of AgNPs.

  14. Influence of TiO{sub 2} nanoparticles on cellular antioxidant defense and its involvement in genotoxicity in HepG2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Petkovic, Jana; Zegura, Bojana; Filipic, Metka, E-mail: metka.filipic@nib.si [Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, SI-1000 Ljubljana (Slovenia)

    2011-07-06

    We investigated the effects of two types of TiO{sub 2} nanoparticles (<25 nm anatase, TiO{sub 2}-An; <100 nm rutile, TiO{sub 2}-Ru) on cellular antioxidant defense in HepG2 cells. We previously showed that in HepG2 cells, TiO{sub 2} nanoparticles are not toxic, although they induce oxidative DNA damage, production of intracellular reactive oxygen species, and up-regulation of mRNA expression of DNA-damage-responsive genes (p53, p21, gadd45{alpha} and mdm2). In the present study, we measured changes in mRNA expression of several antioxidant enzymes: catalase, superoxide dismutase, glutathione peroxidase, nitric oxide synthase, glutathione reductase and glutamate-cysteine ligase. As reduced glutathione has a central role in cellular antioxidant defense, we determined the effects of TiO{sub 2} nanoparticles on changes in the intracellular glutathione content. To confirm a role for glutathione in protection against TiO{sub 2}-nanoparticle-induced DNA damage, we compared the extent of TiO{sub 2}-nanoparticle-induced DNA damage in HepG2 cells that were glutathione depleted with buthionine-(S,R)-sulfoximine pretreatment and in nonglutathione-depleted cells. Our data show that both types of TiO{sub 2} nanoparticles up-regulate mRNA expression of oxidative-stress-related genes, with TiO{sub 2}-Ru being a stronger inducer than TiO{sub 2}-An. Both types of TiO{sub 2} nanoparticles also induce dose-dependent increases in intracellular glutathione levels, and in glutathione-depleted cells, TiO{sub 2}-nanoparticle-induced DNA damage was significantly greater than in nonglutathione-depleted cells. Interestingly, the glutathione content and the extent of DNA damage were significantly higher in TiO{sub 2}-An- than TiO{sub 2}-Ru-exposed cells. Thus, we show that TiO{sub 2} nanoparticles cause activation of cellular antioxidant processes, and that intracellular glutathione has a critical role in defense against this TiO{sub 2}-nanoparticle-induced DNA damage.

  15. An ultrasensitive electrochemical biosensor for glucose using CdTe-CdS core-shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle

    International Nuclear Information System (INIS)

    Gu Zhiguo; Yang Shuping; Li Zaijun; Sun Xiulan; Wang Guangli; Fang Yinjun; Liu Junkang

    2011-01-01

    Graphical abstract: We first reported an ultrasensitive electrochemical biosensor for glucose using CdTe-CdS core-shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle. Since promising their electrocatalytic synergy towards glucose was achieved, the biosensor showed high sensitivity (5762.8 nA nM -1 cm -2 ), low detection limit (S/N = 3) (3 x 10 -12 M) and fast response time (0.045 s). - Abstract: The paper reported an ultrasensitive electrochemical biosensor for glucose which was based on CdTe-CdS core-shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle. Since efficient electron transfer between glucose oxidase and the electrode was achieved, the biosensor showed high sensitivity (5762.8 nA nM -1 cm -2 ), low detection limit (S/N = 3) (3 x 10 -12 M), fast response time (0.045 s), wide calibration range (from 1 x 10 -11 M to 1 x 10 -8 M) and good long-term stability (26 weeks). The apparent Michaelis-Menten constant of the glucose oxidase on the medium, 5.24 x 10 -6 mM, indicates excellent bioelectrocatalytic activity of the immobilized enzyme towards glucose oxidation. Moreover, the effects of omitting graphene-gold nanocomposite, CdTe-CdS core-shell quantum dot and gold nanoparticle were also investigated. The result showed sensitivity of the biosensor is 7.67-fold better if graphene-gold nanocomposite, CdTe-CdS core-shell quantum dot and gold nanoparticle are used. This could be ascribed to improvement of the conductivity between graphene nanosheets due to introduction of gold nanoparticles, ultrafast charge transfer from CdTe-CdS core-shell quantum dot to graphene nanosheets and gold nanoparticle due to unique electrochemical properties of the CdTe-CdS core-shell quantum dot and good biocompatibility of gold nanoparticle for glucose oxidase. The biosensor is of best sensitivity in all glucose biosensors based on graphene nanomaterials up to

  16. An ultrasensitive electrochemical biosensor for glucose using CdTe-CdS core-shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle

    Energy Technology Data Exchange (ETDEWEB)

    Gu Zhiguo; Yang Shuping [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China); Li Zaijun, E-mail: zaijunli@263.net [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China); Sun Xiulan [School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China); Wang Guangli [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China); Fang Yinjun [Zhejiang Zanyu Technology Co., Ltd., Hangzhou 310009 (China); Liu Junkang [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China)

    2011-10-30

    Graphical abstract: We first reported an ultrasensitive electrochemical biosensor for glucose using CdTe-CdS core-shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle. Since promising their electrocatalytic synergy towards glucose was achieved, the biosensor showed high sensitivity (5762.8 nA nM{sup -1} cm{sup -2}), low detection limit (S/N = 3) (3 x 10{sup -12} M) and fast response time (0.045 s). - Abstract: The paper reported an ultrasensitive electrochemical biosensor for glucose which was based on CdTe-CdS core-shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle. Since efficient electron transfer between glucose oxidase and the electrode was achieved, the biosensor showed high sensitivity (5762.8 nA nM{sup -1} cm{sup -2}), low detection limit (S/N = 3) (3 x 10{sup -12} M), fast response time (0.045 s), wide calibration range (from 1 x 10{sup -11} M to 1 x 10{sup -8} M) and good long-term stability (26 weeks). The apparent Michaelis-Menten constant of the glucose oxidase on the medium, 5.24 x 10{sup -6} mM, indicates excellent bioelectrocatalytic activity of the immobilized enzyme towards glucose oxidation. Moreover, the effects of omitting graphene-gold nanocomposite, CdTe-CdS core-shell quantum dot and gold nanoparticle were also investigated. The result showed sensitivity of the biosensor is 7.67-fold better if graphene-gold nanocomposite, CdTe-CdS core-shell quantum dot and gold nanoparticle are used. This could be ascribed to improvement of the conductivity between graphene nanosheets due to introduction of gold nanoparticles, ultrafast charge transfer from CdTe-CdS core-shell quantum dot to graphene nanosheets and gold nanoparticle due to unique electrochemical properties of the CdTe-CdS core-shell quantum dot and good biocompatibility of gold nanoparticle for glucose oxidase. The biosensor is of best sensitivity in all glucose

  17. Morphology controllable time-dependent CoS nanoparticle thin films as efficient counter electrode for quantum dot-sensitized solar cells

    Science.gov (United States)

    Reddy, Araveeti Eswar; Rao, S. Srinivasa; Gopi, Chandu V. V. M.; Anitha, Tarugu; Thulasi-Varma, Chebrolu Venkata; Punnoose, Dinah; Kim, Hee-Je

    2017-11-01

    Cobalt sulfide (CoS) agglomerated nanoparticle thin films obtained by a facile chemical bath method at different deposition times. The CoS counter electrode (CE) deposited at 3 h deposition time (CC-3h) based quantum dot sensitized solar cells (QDSSCs) achieves higher power conversion efficiency (η) of 3.67% than those of CC-2h (1.83%), CC-4h (2.52%), and Pt (1.48%) CEs, under one sun illumination (100 mW cm-2, AM 1.5 G). The electrochemical analysis revealed that CC-3h CE shows a smaller charge transfer resistance (9.22 Ω) at the CE/electrolyte interface than the CC-2h (23.34 Ω), CC-4h (19.73 Ω) and Pt (139.92 Ω) CEs, respectively.

  18. Cellular uptake of nanoparticles as determined by particle properties, experimental conditions, and cell type.

    Science.gov (United States)

    Kettler, Katja; Veltman, Karin; van de Meent, Dik; van Wezel, Annemarie; Hendriks, A Jan

    2014-03-01

    The increased application of nanoparticles (NPs) is increasing the risk of their release into the environment. Although many toxicity studies have been conducted, the environmental risk is difficult to estimate, because uptake mechanisms are often not determined in toxicity studies. In the present study, the authors review dominant uptake mechanisms of NPs in cells, as well as the effect of NP properties, experimental conditions, and cell type on NP uptake. Knowledge of NP uptake is crucial for risk assessment and is essential to predict the behavior of NPs based on their physical-chemical properties. Important uptake mechanisms for eukaryotic cells are macropinocytosis, receptor-mediated endocytosis, and phagocytosis in specialized mammalian cells. The studies reviewed demonstrate that uptake into nonphagocytic cells depends strongly on NP size, with an uptake optimum at an NP diameter of approximately 50 nm. Increasing surface charges, either positive or negative, have been shown to increase particle uptake in comparison with uncharged NPs. Another important factor is the degree of (homo-) aggregation. Results regarding shape have been ambiguous. Difficulties in the production of NPs, with 1 property changed at a time, call for a full characterization of NP properties. Only then will it be possible to draw conclusions as to which property affected the uptake. © 2013 SETAC.

  19. The prospective protective effect of selenium nanoparticles against chromium-induced oxidative and cellular damage in rat thyroid

    Directory of Open Access Journals (Sweden)

    Hassanin KMA

    2013-05-01

    Full Text Available Kamel MA Hassanin,1 Samraa H Abd El-Kawi,2 Khalid S Hashem1 1Department of Biochemistry, Faculty of Veterinary Medicine, 2Department of Histology, Faculty of Medicine, Beni-Suef University, Beni-Suef, Egypt Background: Nanotechnology has enabled researchers to synthesize nanosize particles that possess increased surface areas. Compared to conventional microparticles, it has resulted in increased interactions with biological targets. Objective: The objective of this study was to determine the protective ability of selenium nanoparticles against hexavalent chromium-induced thyrotoxicity. Design: Twenty male rats were used in the study, and arbitrarily assigned to four groups. Group 1 was the control group, and was given phosphate-buffered saline. Group 2 was the chromium-treated group and was given K2Cr2O7 60 µg/kg body weight intraperitoneally as a single dose on the third day of administration. Group 3 was the nano-selenium-treated group and was given selenium nanoparticles (size 3–20 nm 0.5 mg/kg body weight intraperitoneally daily for 5 consecutive days. Group 4 was the nano-selenium chromium-treated group, which received selenium nanoparticles for 5 days and a single dose of K2Cr2O7 on the third day of administration. Materials and methods: Blood samples were collected from rats for measuring thyroid hormones (free triiodothyronine [T3] and free thyroxine [T4] and oxidative and antioxidant parameters (malondialdehyde [MDA], reduced glutathione [GSH], catalase, and superoxide dismutase [SOD]. Upon dissection, thyroid glands were taken for histopathological examination by using paraffin preparations stained with hematoxylin and eosin (H&E and Masson’s trichrome. Immunohistochemical staining was performed for detecting cellular proliferation using Ki67 antibodies. Results: The present study shows that K2Cr2O7 has a toxic effect on the thyroid gland as a result of inducing a marked oxidative damage and release of reactive oxygen species

  20. Multifunctional organic–inorganic hybrid nanoparticles and nanosheets based on chitosan derivative and layered double hydroxide: cellular uptake mechanism and application for topical ocular drug delivery

    Directory of Open Access Journals (Sweden)

    Chi H

    2017-02-01

    Full Text Available Huibo Chi,1,2,* Yan Gu,1,* Tingting Xu,1 Feng Cao1 1Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing, 2State Key Laboratory of Drug Delivery Technology and Pharmacokinetics, Tianjin Institute of Pharmaceutical Research Co., Ltd., Tianjin, People’s Republic of China *These authors contributed equally to this work Abstract: To study the cellular uptake mechanism of multifunctional organic–inorganic hybrid nanoparticles and nanosheets, new chitosan–glutathione–valine–valine-layered double hydroxide (CG-VV-LDH nanosheets with active targeting to peptide transporter-1 (PepT-1 were prepared, characterized and further compared with CG-VV-LDH nanoparticles. Both organic–inorganic hybrid nanoparticles and nanosheets showed a sustained release in vitro and prolonged precorneal retention time in vivo, but CG-VV-LDH nanoparticles showed superior permeability in the isolated cornea of rabbits than CG-VV-LDH nanosheets. Furthermore, results of cellular uptake on human corneal epithelial primary cells (HCEpiC and retinal pigment epithelial (ARPE-19 cells indicated that both clathrin-mediated endocytosis and active transport of PepT-1 are involved in the internalization of CG-VV-LDH nanoparticles and CG-VV-LDH nanosheets. In summary, the CG-VV-LDH nanoparticle may be a promising carrier as a topical ocular drug delivery system for the treatment of ocular diseases of mid-posterior segments, while the CG-VV-LDH nanosheet may be suitable for the treatment of ocular surface diseases. Keywords: LDH nanoparticles, LDH nanosheets, ocular drug delivery, human corneal epithelial primary cell, retinal pigment cell, ARPE-19, active targeting

  1. Spontaneous emission spectra and quantum light-matter interactions from a strongly coupled quantum dot metal-nanoparticle system

    DEFF Research Database (Denmark)

    Van Vlack, C.; Kristensen, Philip Trøst; Hughes, S.

    2012-01-01

    the dot to the detector, we demonstrate that the strong-coupling regime should be observable in the far-field spontaneous emission spectrum, even at room temperature. The vacuum-induced emission spectra show that the usual vacuum Rabi doublet becomes a rich spectral triplet or quartet with two of the four...

  2. Simple method for sub-diffraction resolution imaging of cellular structures on standard confocal microscopes by three-photon absorption of quantum dots.

    Directory of Open Access Journals (Sweden)

    Anje Sporbert

    Full Text Available This study describes a simple technique that improves a recently developed 3D sub-diffraction imaging method based on three-photon absorption of commercially available quantum dots. The method combines imaging of biological samples via tri-exciton generation in quantum dots with deconvolution and spectral multiplexing, resulting in a novel approach for multi-color imaging of even thick biological samples at a 1.4 to 1.9-fold better spatial resolution. This approach is realized on a conventional confocal microscope equipped with standard continuous-wave lasers. We demonstrate the potential of multi-color tri-exciton imaging of quantum dots combined with deconvolution on viral vesicles in lentivirally transduced cells as well as intermediate filaments in three-dimensional clusters of mouse-derived neural stem cells (neurospheres and dense microtubuli arrays in myotubes formed by stacks of differentiated C2C12 myoblasts.

  3. Microglial cells (BV-2) internalize titanium dioxide (TiO2) nanoparticles: toxicity and cellular responses.

    Science.gov (United States)

    Rihane, Naima; Nury, Thomas; M'rad, Imen; El Mir, Lassaad; Sakly, Mohsen; Amara, Salem; Lizard, Gérard

    2016-05-01

    Because of their whitening and photocatalytic effects, titanium dioxide nanoparticles (TiO2-NPs) are widely used in daily life. These NPs can be found in paints, plastics, papers, sunscreens, foods, medicines (pills), toothpastes, and cosmetics. However, the biological effect of TiO2-NPs on the human body, especially on the central nervous system, is still unclear. Many studies have demonstrated that the brain is one of the target organs in acute or chronic TiO2-NPs toxicity. The present study aimed to investigate the effect of TiO2-NPs at different concentrations (0.1 to 200 μg/mL) on murine microglial cells (BV-2) to assess their activity on cell growth and viability, as well as their neurotoxicity. Different parameters were measured: cell viability, cell proliferation and DNA content (SubG1 peak), mitochondrial depolarization, overproduction of reactive oxygen species (especially superoxide anions), and ultrastructural changes. Results showed that TiO2-NPs induced some cytotoxic effects with a slight inhibition of cell growth. Thus, at high concentrations, TiO2-NPs were not only able to inhibit cell adhesion but also enhanced cytoplasmic membrane permeability to propidium iodide associated with a loss of mitochondrial transmembrane potential and an overproduction of superoxide anions. No induction of apoptosis based on the presence of a SubG1 peak was detected. The microscopic observations also indicated that small groups of nanosized particles and micron-sized aggregates were engulfed by the BV-2 cells and sequestered as intracytoplasmic aggregates after 24-h exposure to TiO2-NPs. Altogether, our data show that the accumulation TiO2-NPs in microglial BV-2 cells favors mitochondrial dysfunctions and oxidative stress.

  4. Biological Properties of Iron Oxide Nanoparticles for Cellular and Molecular Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Claus-Christian Glüer

    2010-12-01

    Full Text Available Superparamagnetic iron-oxide particles (SPIO are used in different ways as contrast agents for magnetic resonance imaging (MRI: Particles with high nonspecific uptake are required for unspecific labeling of phagocytic cells whereas those that target specific molecules need to have very low unspecific cellular uptake. We compared iron-oxide particles with different core materials (magnetite, maghemite, different coatings (none, dextran, carboxydextran, polystyrene and different hydrodynamic diameters (20–850 nm for internalization kinetics, release of internalized particles, toxicity, localization of particles and ability to generate contrast in MRI. Particle uptake was investigated with U118 glioma cells und human umbilical vein endothelial cells (HUVEC, which exhibit different phagocytic properties. In both cell types, the contrast agents Resovist, B102, non-coated Fe3O4 particles and microspheres were better internalized than dextran-coated Nanomag particles. SPIO uptake into the cells increased with particle/iron concentrations. Maximum intracellular accumulation of iron particles was observed between 24 h to 36 h of exposure. Most particles were retained in the cells for at least two weeks, were deeply internalized, and only few remained adsorbed at the cell surface. Internalized particles clustered in the cytosol of the cells. Furthermore, all particles showed a low toxicity. By MRI, monolayers consisting of 5000 Resovist-labeled cells could easily be visualized. Thus, for unspecific cell labeling, Resovist and microspheres show the highest potential, whereas Nanomag particles are promising contrast agents for target-specific labeling.

  5. An apolipoprotein-enriched biomolecular corona switches the cellular uptake mechanism and trafficking pathway of lipid nanoparticles.

    Science.gov (United States)

    Digiacomo, L; Cardarelli, F; Pozzi, D; Palchetti, S; Digman, M A; Gratton, E; Capriotti, A L; Mahmoudi, M; Caracciolo, G

    2017-11-16

    Following exposure to biological milieus (e.g. after systemic administration), nanoparticles (NPs) get covered by an outer biomolecular corona (BC) that defines many of their biological outcomes, such as the elicited immune response, biodistribution, and targeting abilities. In spite of this, the role of BC in regulating the cellular uptake and the subcellular trafficking properties of NPs has remained elusive. Here, we tackle this issue by employing multicomponent (MC) lipid NPs, human plasma (HP) and HeLa cells as models for nanoformulations, biological fluids, and target cells, respectively. By conducting confocal fluorescence microscopy experiments and image correlation analyses, we quantitatively demonstrate that the BC promotes a neat switch of the cell entry mechanism and subsequent intracellular trafficking, from macropinocytosis to clathrin-dependent endocytosis. Nano-liquid chromatography tandem mass spectrometry identifies apolipoproteins as the most abundant components of the BC tested here. Interestingly, this class of proteins target the LDL receptors, which are overexpressed in clathrin-enriched membrane domains. Our results highlight the crucial role of BC as an intrinsic trigger of specific NP-cell interactions and biological responses and set the basis for a rational exploitation of the BC for targeted delivery.

  6. Coupled elasticity-diffusion model for the effects of cytoskeleton deformation on cellular uptake of cylindrical nanoparticles.

    Science.gov (United States)

    Wang, Jizeng; Li, Long

    2015-01-06

    Molecular dynamic simulations and experiments have recently demonstrated how cylindrical nanoparticles (CNPs) with large aspect ratios penetrate animal cells and inevitably deform cytoskeletons. Thus, a coupled elasticity-diffusion model was adopted to elucidate this interesting biological phenomenon by considering the effects of elastic deformations of cytoskeleton and membrane, ligand-receptor binding and receptor diffusion. The mechanism by which the binding energy drives the CNPs with different orientations to enter host cells was explored. This mechanism involved overcoming the resistance caused by cytoskeleton and membrane deformations and the change in configurational entropy of the ligand-receptor bonds and free receptors. Results showed that deformation of the cytoskeleton significantly influenced the engulfing process by effectively slowing down and even hindering the entry of the CNPs. Additionally, the engulfing depth was determined quantitatively. CNPs preferred or tended to vertically attack target cells until they were stuck in the cytoskeleton as implied by the speed of vertically oriented CNPs that showed much faster initial engulfing speeds than horizontally oriented CNPs. These results elucidated the most recent molecular dynamics simulations and experimental observations on the cellular uptake of carbon nanotubes and phagocytosis of filamentous Escherichia coli bacteria. The most efficient engulfment showed the stiffness-dependent optimal radius of the CNPs. Cytoskeleton stiffness exhibited more significant influence on the optimal sizes of the vertical uptake than the horizontal uptake. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  7. Coupled elasticity–diffusion model for the effects of cytoskeleton deformation on cellular uptake of cylindrical nanoparticles

    Science.gov (United States)

    Wang, Jizeng; Li, Long

    2015-01-01

    Molecular dynamic simulations and experiments have recently demonstrated how cylindrical nanoparticles (CNPs) with large aspect ratios penetrate animal cells and inevitably deform cytoskeletons. Thus, a coupled elasticity–diffusion model was adopted to elucidate this interesting biological phenomenon by considering the effects of elastic deformations of cytoskeleton and membrane, ligand–receptor binding and receptor diffusion. The mechanism by which the binding energy drives the CNPs with different orientations to enter host cells was explored. This mechanism involved overcoming the resistance caused by cytoskeleton and membrane deformations and the change in configurational entropy of the ligand–receptor bonds and free receptors. Results showed that deformation of the cytoskeleton significantly influenced the engulfing process by effectively slowing down and even hindering the entry of the CNPs. Additionally, the engulfing depth was determined quantitatively. CNPs preferred or tended to vertically attack target cells until they were stuck in the cytoskeleton as implied by the speed of vertically oriented CNPs that showed much faster initial engulfing speeds than horizontally oriented CNPs. These results elucidated the most recent molecular dynamics simulations and experimental observations on the cellular uptake of carbon nanotubes and phagocytosis of filamentous Escherichia coli bacteria. The most efficient engulfment showed the stiffness-dependent optimal radius of the CNPs. Cytoskeleton stiffness exhibited more significant influence on the optimal sizes of the vertical uptake than the horizontal uptake. PMID:25411410

  8. Cotransporting Ion is a Trigger for Cellular Endocytosis of Transporter-Targeting Nanoparticles: A Case Study of High-Efficiency SLC22A5 (OCTN2)-Mediated Carnitine-Conjugated Nanoparticles for Oral Delivery of Therapeutic Drugs.

    Science.gov (United States)

    Kou, Longfa; Yao, Qing; Sun, Mengchi; Wu, Chunnuan; Wang, Jia; Luo, Qiuhua; Wang, Gang; Du, Yuqian; Fu, Qiang; Wang, Jian; He, Zhonggui; Ganapathy, Vadivel; Sun, Jin

    2017-09-01

    OCTN2 (SLC22A5) is a Na + -coupled absorption transporter for l-carnitine in small intestine. This study tests the potential of this transporter for oral delivery of therapeutic drugs encapsulated in l-carnitine-conjugated poly(lactic-co-glycolic acid) (PLGA) nanoparticles (LC-PLGA NPs) and discloses the molecular mechanism for cellular endocytosis of transporter-targeting nanoparticles. Conjugation of l-carnitine to a surface of PLGA-NPs enhances the cellular uptake and intestinal absorption of encapsulated drug. In both cases, the uptake process is dependent on cotransporting ion Na + . Computational OCTN2 docking analysis shows that the presence of Na + is important for the formation of the energetically stable intermediate complex of transporter-Na + -LC-PLGA NPs, which is also the first step in cellular endocytosis of nanoparticles. The transporter-mediated intestinal absorption of LC-PLGA NPs occurs via endocytosis/transcytosis rather than via the traditional transmembrane transport. The portal blood versus the lymphatic route is evaluated by the plasma appearance of the drug in the control and lymph duct-ligated rats. Absorption via the lymphatic system is the predominant route in the oral delivery of the NPs. In summary, LC-PLGA NPs can effectively target OCTN2 on the enterocytes for enhancing oral delivery of drugs and the critical role of cotransporting ions should be noticed in designing transporter-targeting nanoparticles. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. A novel enzyme-mimic nanosensor based on quantum dot-Au nanoparticle@silica mesoporous microsphere for the detection of glucose

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yang; Ma, Qiang; Liu, Ziping [Department of Analytical Chemistry, College of Chemistry, Jilin University, Qianjin Street 2699, Changchun 130012 (China); Wang, Xinyan [Changchun Institute of Applied Chemistry Chinese Academy of Sciences, Changchun 130022 (China); Su, Xingguang, E-mail: suxg@jlu.edu.cn [Department of Analytical Chemistry, College of Chemistry, Jilin University, Qianjin Street 2699, Changchun 130012 (China)

    2014-08-20

    Highlights: • Design QD-Au NP@silica mesoporous microspheres as a novel enzyme-mimic nanosensor. • Composition of two kinds of nanoparticle can be controlled through silica layers coating. • Our nanosensor for glucose detection has high sensitivity and selectivity. - Abstract: QD-Au NP@silica mesoporous microspheres have been fabricated as a novel enzyme-mimic nanosensor. CdTe quantum dots (QDs) were loaded into the core, and Au nanoparticles (NPs) were encapsulated in the outer mesoporous shell. QDs and Au NPs were separated in the different space of the nanosensor, which prevent the potential energy or electron transfer process between QDs and Au NPs. As biomimetic catalyst, Au NPs in the mesoporous silica shell can catalytically oxidize glucose as glucose oxidase (GOx)-mimicking. The resultant hydrogen peroxide can quench the photoluminescence (PL) signal of QDs in the microsphere core. Therefore the nanosensor based on the decrease of the PL intensity of QDs was established for the glucose detection. The linear range for glucose was in the range of 5–200 μM with a detection limit (3σ) of 1.32 μM.

  10. Graphene quantum dots decorated with magnetic nanoparticles: Synthesis, electrodeposition, characterization and application as an electrochemical sensor towards determination of some amino acids at physiological pH

    International Nuclear Information System (INIS)

    Hasanzadeh, Mohammad; Karimzadeh, Ayub; Shadjou, Nasrin; Mokhtarzadeh, Ahad; Bageri, Leyla; Sadeghi, Sattar; Mahboob, Soltanali

    2016-01-01

    This study reports on the synthesis and characterization of a novel nano-composite, Fe 3 O 4 magnetic nanoparticles/graphene quantum dots (Fe 3 O 4 MNP-GQDs), for sensing of some amino acids. For the first time, as-synthesized GQDs and Fe 3 O 4 MNPs-GQDs was electrodeposited on the glassy carbon electrode (GCE) by cyclic voltammetry (CV) regime in the potential range from − 1.0 to 1.0 V. Fe 3 O 4 MNP-GQDs is engineered to specifically and effectively capture and enhancement the electrochemical signals of some amino acids at physiological pH due to the synergy among GQDs and magnetic nanoparticles. We have illustrated that the obtained Fe 3 O 4 MNPs-GQDs exhibited a much higher electroactivity individual GQDs and Fe 3 O 4 MNPs for the electrooxidation and detection of amino acid which was about 10 fold higher than for GQDs. Magnetic and specific properties of the Fe 3 O 4 MNP-GQDs can be exploited to capture and pre-concentration the amino acids onto its surface, which are important for detection of multi-amino acids. - Highlights: • Electrooxidation of amino acids was performed using Fe 3 O 4 MNP-GQDs. • Modified electrode shows new advantages as an amino acids sensor. • Excellent electrocatalytic activity was obtained for amino acids oxidation.

  11. A layer-by-layer ZnO nanoparticle-PbS quantum dot self-assembly platform for ultrafast interfacial electron injection

    KAUST Repository

    Eita, Mohamed Samir

    2014-08-28

    Absorbent layers of semiconductor quantum dots (QDs) are now used as material platforms for low-cost, high-performance solar cells. The semiconductor metal oxide nanoparticles as an acceptor layer have become an integral part of the next generation solar cell. To achieve sufficient electron transfer and subsequently high conversion efficiency in these solar cells, however, energy-level alignment and interfacial contact between the donor and the acceptor units are needed. Here, the layer-by-layer (LbL) technique is used to assemble ZnO nanoparticles (NPs), providing adequate PbS QD uptake to achieve greater interfacial contact compared with traditional sputtering methods. Electron injection at the PbS QD and ZnO NP interface is investigated using broadband transient absorption spectroscopy with 120 femtosecond temporal resolution. The results indicate that electron injection from photoexcited PbS QDs to ZnO NPs occurs on a time scale of a few hundred femtoseconds. This observation is supported by the interfacial electronic-energy alignment between the donor and acceptor moieties. Finally, due to the combination of large interfacial contact and ultrafast electron injection, this proposed platform of assembled thin films holds promise for a variety of solar cell architectures and other settings that principally rely on interfacial contact, such as photocatalysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Collective optical Kerr effect exhibited by an integrated configuration of silicon quantum dots and gold nanoparticles embedded in ion-implanted silica

    International Nuclear Information System (INIS)

    Torres-Torres, C; López-Suárez, A; Oliver, A; Can-Uc, B; Rangel-Rojo, R; Tamayo-Rivera, L

    2015-01-01

    The study of the third-order optical nonlinear response exhibited by a composite containing gold nanoparticles and silicon quantum dots nucleated by ion implantation in a high-purity silica matrix is presented. The nanocomposites were explored as an integrated configuration containing two different ion-implanted distributions. The time-resolved optical Kerr gate and z-scan techniques were conducted using 80 fs pulses at a 825 nm wavelength; while the nanosecond response was investigated by a vectorial two-wave mixing method at 532 nm with 1 ns pulses. An ultrafast purely electronic nonlinearity was associated to the optical Kerr effect for the femtosecond experiments, while a thermal effect was identified as the main mechanism responsible for the nonlinear optical refraction induced by nanosecond pulses. Comparative experimental tests for examining the contribution of the Au and Si distributions to the total third-order optical response were carried out. We consider that the additional defects generated by consecutive ion irradiations in the preparation of ion-implanted samples do not notably modify the off-resonance electronic optical nonlinearities; but they do result in an important change for near-resonant nanosecond third-order optical phenomena exhibited by the closely spaced nanoparticle distributions. (paper)

  13. The effect of agglomeration state of silver and titanium dioxide nanoparticles on cellular response of HepG2, A549 and THP-1 cells.

    Science.gov (United States)

    Lankoff, Anna; Sandberg, Wiggo J; Wegierek-Ciuk, Aneta; Lisowska, Halina; Refsnes, Magne; Sartowska, Bożena; Schwarze, Per E; Meczynska-Wielgosz, Sylwia; Wojewodzka, Maria; Kruszewski, Marcin

    2012-02-05

    Nanoparticles (NPs) occurring in the environment rapidly agglomerate and form particles of larger diameters. The extent to which this abates the effects of NPs has not been clarified. The motivation of this study was to examine how the agglomeration/aggregation state of silver (20nm and 200nm) and titanium dioxide (21nm) nanoparticles may affect the kinetics of cellular binding/uptake and ability to induce cytotoxic responses in THP1, HepG2 and A549 cells. Cellular binding/uptake, metabolic activation and cell death were assessed by the SSC flow cytometry measurements, the MTT-test and the propidium iodide assay. The three types of particles were efficiently taken up by the cells, decreasing metabolic activation and increasing cell death in all the cell lines. The magnitude of the studied endpoints depended on the agglomeration/aggregation state of particles, their size, time-point and cell type. Among the three cell lines tested, A549 cells were the most sensitive to these particles in relation to cellular binding/uptake. HepG2 cells showed a tendency to be more sensitive in relation to metabolic activation. THP-1 cells were the most resistant to all three types of particles in relation to all endpoints tested. Our findings suggest that particle features such as size and agglomeration status as well as the type of cells may contribute to nanoparticles biological impact. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  14. Hydroxyl radicals ({center_dot}OH) are associated with titanium dioxide (TiO{sub 2}) nanoparticle-induced cytotoxicity and oxidative DNA damage in fish cells

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, James F.; Davies, Simon J.; Dodd, Nicholas J.F. [School of Biological Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Jha, Awadhesh N. [School of Biological Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)], E-mail: a.jha@plymouth.ac.uk

    2008-04-02

    TiO{sub 2} nanoparticles (<100 nm diameter) have been reported to cause oxidative stress related effects, including inflammation, cytotoxicity and genomic instability, either alone or in the presence of UVA irradiation in mammalian studies. Despite the fact that the aquatic environment is often the ultimate recipient of all contaminants there is a paucity of data pertaining to the potential detrimental effects of nanoparticles on aquatic organisms. Therefore, these investigations aimed to evaluate the potential cytotoxic and genotoxic effects of TiO{sub 2} nanoparticles on goldfish skin cells (GFSk-S1), either alone or in combination with UVA. Whilst neutral red retention (NRR) assay (a measure of lysosomal membrane integrity) was used to evaluate cell viability, a modified Comet assay using bacterial lesion-specific repair endonucleases (Endo-III, Fpg) was employed to specifically target oxidative DNA damage. Additionally, electron spin resonance (ESR) studies with different spin traps were carried out for qualitative analysis of free radical generation. For cell viability, TiO{sub 2} alone (0.1-1000 {mu}g ml{sup -1}) had little effect whereas co-exposure with UVA (0.5-2.0 kJ m{sup -2}) caused a significant dose-dependent decrease which was dependent on both the concentration of TiO{sub 2} and the dose of UVA administered. For the Comet assay, doses of 1, 10 and 100 {mu}g ml{sup -1} in the absence of UVA caused elevated levels of Fpg-sensitive sites, indicating the oxidation of purine DNA bases (i.e. guanine) by TiO{sub 2}. UVA irradiation of TiO{sub 2}-treated cells caused further increases in DNA damage. ESR studies revealed that the observed toxic effects of nanoparticulate TiO{sub 2} were most likely due to hydroxyl radical ({center_dot}OH) formation.

  15. Enhanced Electroluminescence from Silicon Quantum Dots Embedded in Silicon Nitride Thin Films Coupled with Gold Nanoparticles in Light Emitting Devices

    Directory of Open Access Journals (Sweden)

    Ana Luz Muñoz-Rosas

    2018-03-01

    Full Text Available Nowadays, the use of plasmonic metal layers to improve the photonic emission characteristics of several semiconductor quantum dots is a booming tool. In this work, we report the use of silicon quantum dots (SiQDs embedded in a silicon nitride thin film coupled with an ultra-thin gold film (AuNPs to fabricate light emitting devices. We used the remote plasma enhanced chemical vapor deposition technique (RPECVD in order to grow two types of silicon nitride thin films. One with an almost stoichiometric composition, acting as non-radiative spacer; the other one, with a silicon excess in its chemical composition, which causes the formation of silicon quantum dots imbibed in the silicon nitride thin film. The ultra-thin gold film was deposited by the direct current (DC-sputtering technique, and an aluminum doped zinc oxide thin film (AZO which was deposited by means of ultrasonic spray pyrolysis, plays the role of the ohmic metal-like electrode. We found that there is a maximum electroluminescence (EL enhancement when the appropriate AuNPs-spacer-SiQDs configuration is used. This EL is achieved at a moderate turn-on voltage of 11 V, and the EL enhancement is around four times bigger than the photoluminescence (PL enhancement of the same AuNPs-spacer-SiQDs configuration. From our experimental results, we surmise that EL enhancement may indeed be due to a plasmonic coupling. This kind of silicon-based LEDs has the potential for technology transfer.

  16. A label-free fluorescence biosensor for highly sensitive detection of lectin based on carboxymethyl chitosan-quantum dots and gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ziping; Liu, Hua; Wang, Lei; Su, Xingguang, E-mail: suxg@jlu.edu.cn

    2016-08-17

    In this work, we report a novel label-free fluorescence “turn off-on” biosensor for lectin detection. The highly sensitive and selective sensing system is based on the integration of carboxymethyl chitosan (CM-CHIT), CuInS{sub 2} quantum dots (QDs) and Au nanoparticles (NPs). Firstly, CuInS{sub 2} QDs featuring carboxyl groups were directly synthesized via a hydrothermal synthesis method. Then, the carboxyl groups on the CuInS{sub 2} QDs surface were interacted with the amino groups (−NH{sub 2}), carboxyl groups (−COOH) and hydroxyl groups (−OH) within CM-CHIT polymeric chains via electrostatic interactions and hydrogen bonding to form CM-CHIT-QDs assemblies. Introduction of Au NPs could quench the fluorescence of CM-CHIT-QDs through electron and energy transfer. In the presence of lectin, lectin could bind exclusively with CM-CHIT-QDs by means of specific multivalent carbohydrate-protein interaction. Thus, the electron and energy transfer process between CM-CHIT-QDs and Au NPs was inhibited, and as a result, the fluorescence of CM-CHIT-QDs was effectively “turned on”. Under the optimum conditions, there was a good linear relationship between the fluorescence intensity ratio I/I{sub 0} (I and I{sub 0} were the fluorescence intensity of CM-CHIT-QDs-Au NPs in the presence and absence of lectin, respectively) and lectin concentration in the range of 0.2–192.5 nmol L{sup −1}, And the detection limit could be down to 0.08 nmol L{sup −1}. Furthermore, the proposed biosensor was employed for the determination of lectin in fetal bovine serum samples with satisfactory results. - Graphical abstract: A label-free fluorescence biosensor for highly sensitive detection of lectin based on the integration of carboxymethyl chitosan, CuInS{sub 2} quantum dots and gold nanoparticles. - Highlights: • A label-free near-infrared fluorescence “turn off-on” biosensor for detection of lectin was established. • The highly sensitive biosensor was based on the

  17. A label-free fluorescence biosensor for highly sensitive detection of lectin based on carboxymethyl chitosan-quantum dots and gold nanoparticles

    International Nuclear Information System (INIS)

    Liu, Ziping; Liu, Hua; Wang, Lei; Su, Xingguang

    2016-01-01

    In this work, we report a novel label-free fluorescence “turn off-on” biosensor for lectin detection. The highly sensitive and selective sensing system is based on the integration of carboxymethyl chitosan (CM-CHIT), CuInS_2 quantum dots (QDs) and Au nanoparticles (NPs). Firstly, CuInS_2 QDs featuring carboxyl groups were directly synthesized via a hydrothermal synthesis method. Then, the carboxyl groups on the CuInS_2 QDs surface were interacted with the amino groups (−NH_2), carboxyl groups (−COOH) and hydroxyl groups (−OH) within CM-CHIT polymeric chains via electrostatic interactions and hydrogen bonding to form CM-CHIT-QDs assemblies. Introduction of Au NPs could quench the fluorescence of CM-CHIT-QDs through electron and energy transfer. In the presence of lectin, lectin could bind exclusively with CM-CHIT-QDs by means of specific multivalent carbohydrate-protein interaction. Thus, the electron and energy transfer process between CM-CHIT-QDs and Au NPs was inhibited, and as a result, the fluorescence of CM-CHIT-QDs was effectively “turned on”. Under the optimum conditions, there was a good linear relationship between the fluorescence intensity ratio I/I_0 (I and I_0 were the fluorescence intensity of CM-CHIT-QDs-Au NPs in the presence and absence of lectin, respectively) and lectin concentration in the range of 0.2–192.5 nmol L"−"1, And the detection limit could be down to 0.08 nmol L"−"1. Furthermore, the proposed biosensor was employed for the determination of lectin in fetal bovine serum samples with satisfactory results. - Graphical abstract: A label-free fluorescence biosensor for highly sensitive detection of lectin based on the integration of carboxymethyl chitosan, CuInS_2 quantum dots and gold nanoparticles. - Highlights: • A label-free near-infrared fluorescence “turn off-on” biosensor for detection of lectin was established. • The highly sensitive biosensor was based on the inner filter effect of Au NPs on CM

  18. An ultrasensitive hydrogen peroxide biosensor based on electrocatalytic synergy of graphene-gold nanocomposite, CdTe-CdS core-shell quantum dots and gold nanoparticles

    International Nuclear Information System (INIS)

    Gu Zhiguo; Yang Shuping; Li Zaijun; Sun Xiulan; Wang Guangli; Fang Yinjun; Liu Junkang

    2011-01-01

    Graphical abstract: We first reported an ultrasensitive hydrogen peroxide biosensor in this work, which was fabricated by coating graphene-gold nanocomposite, CdTe-CdS core-shell quantum dots, gold nanoparticles and horseradish peroxidase in sequence on the surface of gold electrode. Since a promising their electrocatalytic synergy towards hydrogen peroxide was achieved, the biosensor displayed very high sensitivity, low detection limit (S/N = 3) (3.2 x 10 -11 M) and good long-term stability (20 weeks). Highlights: · We for the first time integrated novel hydrogen peroxide biosensor based on G-AuNP, CdTe-CdS and AuNPs. · Three nanomaterials show remarkable synergistic electrocatalysis towards hydrogen peroxide. · The biosensor provides the best sensitivity in all biosensors based on graphene for detection of glucose up to now. - Abstract: We first reported an ultrasensitive hydrogen peroxide biosensor in this work. The biosensor was fabricated by coating graphene-gold nanocomposite (G-AuNP), CdTe-CdS core-shell quantum dots (CdTe-CdS), gold nanoparticles (AuNPs) and horseradish peroxidase (HRP) in sequence on the surface of gold electrode (GE). Cyclic voltammetry and differential pulse voltammetry were used to investigate electrochemical performances of the biosensor. Since promising electrocatalytic synergy of G-AuNP, CdTe-CdS and AuNPs towards hydrogen peroxide was achieved, the biosensor displayed a high sensitivity, low detection limit (S/N = 3) (3.2 x 10 -11 M), wide calibration range (from 1 x 10 -10 M to 1.2 x 10 -8 M) and good long-term stability (20 weeks). Moreover, the effects of omitting G-AuNP, CdTe-CdS and AuNP were also examined. It was found that sensitivity of the biosensor is more 11-fold better if G-AuNP, CdTe-CdS and AuNPs are used. This could be ascribed to improvement of the conductivity between graphene nanosheets in the G-AuNP due to introduction of the AuNPs, ultrafast charge transfer from CdTe-CdS to the graphene sheets and AuNP due to

  19. Microfluidic bead-based multienzyme-nanoparticle amplification for detection of circulating tumor cells in the blood using quantum dots labels

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, He, E-mail: mzhang_he@126.com; Fu, Xin; Hu, Jiayi; Zhu, Zhenjun

    2013-05-24

    Graphical abstract: A microfluidic beads-based nucleic acid sensor for sensitive detection of circulating tumor cells (CTCs) in the blood using multienzyme-nanoparticle amplification and quantum dots labels was developed. The chip-based CTCs analysis could detect reverse transcription-polymerase chain reaction (RT-PCR) products of tumor cell as low as 1 tumor cell (e.g. CEA expressing cell) in 1 mL blood sample. This microfluidic beads-based nucleic acid sensor is a promising platform for disease-related nucleic acid molecules at the lowest level at their earliest incidence. -- Highlights: •Combination of microfluidic bead-based platform and enzyme–probe–AuNPs is proposed. •The developed nucleic acid sensor could respond to 5 fM of tumor associated DNA. •Microfluidic platform and multienzyme-labeled AuNPs greatly enhanced sensitivity. •The developed nucleic acid sensor could respond to RT-PCR products of tumor cell as low as 1 tumor cell in 1 mL blood sample. •We report a sensitive nucleic acid sensor for detection of circulating tumor cells. -- Abstract: This study reports the development of a microfluidic bead-based nucleic acid sensor for sensitive detection of circulating tumor cells in blood samples using multienzyme-nanoparticle amplification and quantum dot labels. In this method, the microbeads functionalized with the capture probes and modified electron rich proteins were arrayed within a microfluidic channel as sensing elements, and the gold nanoparticles (AuNPs) functionalized with the horseradish peroxidases (HRP) and DNA probes were used as labels. Hence, two signal amplification approaches are integrated for enhancing the detection sensitivity of circulating tumor cells. First, the large surface area of Au nanoparticle carrier allows several binding events of HRP on each nanosphere. Second, enhanced mass transport capability inherent from microfluidics leads to higher capture efficiency of targets because continuous flow within micro

  20. Graphene quantum dots decorated with magnetic nanoparticles: Synthesis, electrodeposition, characterization and application as an electrochemical sensor towards determination of some amino acids at physiological pH

    Energy Technology Data Exchange (ETDEWEB)

    Hasanzadeh, Mohammad, E-mail: mhmmd_hasanzadeh@yahoo.com [Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz 51664 (Iran, Islamic Republic of); Pharmaceutical Analysis Research Center, Tabriz University of Medical Sciences, Tabriz 51664 (Iran, Islamic Republic of); Karimzadeh, Ayub [Department of Biochemistry, Higher Education Institute of Rab-Rashid, Tabriz (Iran, Islamic Republic of); School of Medicine, Gonabad University of Medical Sciences, Gonabad (Iran, Islamic Republic of); Shadjou, Nasrin [Department of Nanochemistry, Nano Technology Research Center, Urmia University, Urmia 57154 (Iran, Islamic Republic of); Department of Nano Technology, Faculty of Science, Urmia University, Urmia 57154 (Iran, Islamic Republic of); Mokhtarzadeh, Ahad [School of Medicine, Gonabad University of Medical Sciences, Gonabad (Iran, Islamic Republic of); Department of Biochemistry, Higher Education Institute of Rab-Rashid, Tabriz (Iran, Islamic Republic of); Bageri, Leyla [Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz 51664 (Iran, Islamic Republic of); Sadeghi, Sattar; Mahboob, Soltanali [Department of Biochemistry, Higher Education Institute of Rab-Rashid, Tabriz (Iran, Islamic Republic of)

    2016-11-01

    This study reports on the synthesis and characterization of a novel nano-composite, Fe{sub 3}O{sub 4} magnetic nanoparticles/graphene quantum dots (Fe{sub 3}O{sub 4} MNP-GQDs), for sensing of some amino acids. For the first time, as-synthesized GQDs and Fe{sub 3}O{sub 4} MNPs-GQDs was electrodeposited on the glassy carbon electrode (GCE) by cyclic voltammetry (CV) regime in the potential range from − 1.0 to 1.0 V. Fe{sub 3}O{sub 4} MNP-GQDs is engineered to specifically and effectively capture and enhancement the electrochemical signals of some amino acids at physiological pH due to the synergy among GQDs and magnetic nanoparticles. We have illustrated that the obtained Fe{sub 3}O{sub 4} MNPs-GQDs exhibited a much higher electroactivity individual GQDs and Fe{sub 3}O{sub 4} MNPs for the electrooxidation and detection of amino acid which was about 10 fold higher than for GQDs. Magnetic and specific properties of the Fe{sub 3}O{sub 4} MNP-GQDs can be exploited to capture and pre-concentration the amino acids onto its surface, which are important for detection of multi-amino acids. - Highlights: • Electrooxidation of amino acids was performed using Fe{sub 3}O{sub 4} MNP-GQDs. • Modified electrode shows new advantages as an amino acids sensor. • Excellent electrocatalytic activity was obtained for amino acids oxidation.

  1. The surface chemistry determines the spatio-temporal interaction dynamics of quantum dots in atherosclerotic lesions.

    Science.gov (United States)

    Uhl, Bernd; Hirn, Stephanie; Mildner, Karina; Coletti, Raffaele; Massberg, Steffen; Reichel, Christoph A; Rehberg, Markus; Zeuschner, Dagmar; Krombach, Fritz

    2018-03-01

    To optimize the design of nanoparticles for diagnosis or therapy of vascular diseases, it is mandatory to characterize the determinants of nano-bio interactions in vascular lesions. Using ex vivo and in vivo microscopy, we analyzed the interactive behavior of quantum dots with different surface functionalizations in atherosclerotic lesions of ApoE-deficient mice. We demonstrate that quantum dots with different surface functionalizations exhibit specific interactive behaviors with distinct molecular and cellular components of the injured vessel wall. Moreover, we show a role for fibrinogen in the regulation of the spatio-temporal interaction dynamics in atherosclerotic lesions. Our findings emphasize the relevance of surface chemistry-driven nano-bio interactions on the differential in vivo behavior of nanoparticles in diseased tissue.

  2. Effect of Treatment Media on the Agglomeration of Titanium Dioxide Nanoparticles: Impact on Genotoxicity, Cellular Interaction, and Cell Cycle

    Science.gov (United States)

    ABSTRACT The widespread use of titanium dioxide (TiO2) nanoparticles in consumer products increases the probability of exposure to humans and the environment. Although TiO2 nanoparticles have been shown to induce DNA damage (comet assay) and chromosome damage (micronucleus ass...

  3. A paper-based resonance energy transfer nucleic acid hybridization assay using upconversion nanoparticles as donors and quantum dots as acceptors.

    Science.gov (United States)

    Doughan, Samer; Uddayasankar, Uvaraj; Krull, Ulrich J

    2015-06-09

    Monodisperse aqueous upconverting nanoparticles (UCNPs) were covalently immobilized on aldehyde modified cellulose paper via reduction amination to develop a luminescence resonance energy transfer (LRET)-based nucleic acid hybridization assay. This first account of covalent immobilization of UCNPs on paper for a bioassay reports an optically responsive method that is sensitive, reproducible and robust. The immobilized UCNPs were decorated with oligonucleotide probes to capture HPRT1 housekeeping gene fragments, which in turn brought reporter conjugated quantum dots (QDs) in close proximity to the UCNPs for LRET. This sandwich assay could detect unlabeled oligonucleotide target, and had a limit of detection of 13 fmol and a dynamic range spanning nearly 3 orders of magnitude. The use of QDs, which are excellent LRET acceptors, demonstrated improved sensitivity, limit of detection, dynamic range and selectivity compared to similar assays that have used molecular fluorophores as acceptors. The selectivity of the assay was attributed to the decoration of the QDs with polyethylene glycol to eliminate non-specific adsorption. The kinetics of hybridization were determined to be diffusion limited and full signal development occurred within 3 min. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Enhancing the Performance of Quantum Dot Light-Emitting Diodes Using Room-Temperature-Processed Ga-Doped ZnO Nanoparticles as the Electron Transport Layer

    KAUST Repository

    Cao, Sheng

    2017-04-19

    Colloidal ZnO nanoparticle (NP) films are recognized as efficient electron transport layers (ETLs) for quantum dot light-emitting diodes (QD-LEDs) with good stability and high efficiency. However, because of the inherently high work function of such films, spontaneous charge transfer occurs at the QD/ZnO interface in such a QD-LED, thus leading to reduced performance. Here, to improve the QD-LED performance, we prepared Ga-doped ZnO NPs with low work functions and tailored band structures via a room-temperature (RT) solution process without the use of bulky organic ligands. We found that the charge transfer at the interface between the CdSe/ZnS QDs and the doped ZnO NPs was significantly weakened because of the incorporated Ga dopants. Remarkably, the as-assembled QD-LEDs, with Ga-doped ZnO NPs as the ETLs, exhibited superior luminances of up to 44 000 cd/m2 and efficiencies of up to 15 cd/A, placing them among the most efficient red-light QD-LEDs ever reported. This discovery provides a new strategy for fabricating high-performance QD-LEDs by using RT-processed Ga-doped ZnO NPs as the ETLs, which could be generalized to improve the efficiency of other optoelectronic devices.

  5. Amphiphilic Quantum Dots with Asymmetric, Mixed Polymer Brush Layers: From Single Core-Shell Nanoparticles to Salt-Induced Vesicle Formation

    Directory of Open Access Journals (Sweden)

    Brian R. Coleman

    2018-03-01

    Full Text Available A mixed micelle approach is used to produce amphiphilic brush nanoparticles (ABNPs with cadmium sulfide quantum dot (QD cores and surface layers of densely grafted (σ = ~1 chain/nm2 and asymmetric (fPS = 0.9 mixed polymer brushes that contain hydrophobic polystyrene (PS and hydrophilic poly(methyl methacrylate (PMAA chains (PS/PMAA-CdS. In aqueous media, the mixed brushes undergo conformational rearrangements that depend strongly on prior salt addition, giving rise to one of two pathways to fluorescent and morphologically disparate QD-polymer colloids. (A In the absence of salt, centrosymmetric condensation of PS chains forms individual core-shell QD-polymer colloids. (B In the presence of salt, non-centrosymmetric condensation of PS chains forms Janus particles, which trigger anisotropic interactions and amphiphilic self-assembly into the QD-polymer vesicles. To our knowledge, this is the first example of an ABNP building block that can form either discrete core-shell colloids or self-assembled superstructures in water depending on simple changes to the chemical conditions (i.e., salt addition. Such dramatic and finely tuned morphological variation could inform numerous applications in sensing, biolabeling, photonics, and nanomedicine.

  6. Hybrid nanostructures of well-organized arrays of colloidal quantum dots and a self-assembled monolayer of gold nanoparticles for enhanced fluorescence

    Science.gov (United States)

    Liu, Xiaoying; McBride, Sean P.; Jaeger, Heinrich M.; Nealey, Paul F.

    2016-07-01

    Hybrid nanomaterials comprised of well-organized arrays of colloidal semiconductor quantum dots (QDs) in close proximity to metal nanoparticles (NPs) represent an appealing system for high-performance, spectrum-tunable photon sources with controlled photoluminescence. Experimental realization of such materials requires well-defined QD arrays and precisely controlled QD-metal interspacing. This long-standing challenge is tackled through a strategy that synergistically combines lateral confinement and vertical stacking. Lithographically generated nanoscale patterns with tailored surface chemistry confine the QDs into well-organized arrays with high selectivity through chemical pattern directed assembly, while subsequent coating with a monolayer of close-packed Au NPs introduces the plasmonic component for fluorescence enhancement. The results show uniform fluorescence emission in large-area ordered arrays for the fabricated QD structures and demonstrate five-fold fluorescence amplification for red, yellow, and green QDs in the presence of the Au NP monolayer. Encapsulation of QDs with a silica shell is shown to extend the design space for reliable QD/metal coupling with stronger enhancement of 11 times through the tuning of QD-metal spatial separation. This approach provides new opportunities for designing hybrid nanomaterials with tailored array structures and multiple functionalities for applications such as multiplexed optical coding, color display, and quantum transduction.

  7. Rational Targeting of Cellular Cholesterol in Diffuse Large B-Cell Lymphoma (DLBCL) Enabled by Functional Lipoprotein Nanoparticles: A Therapeutic Strategy Dependent on Cell of Origin.

    Science.gov (United States)

    Rink, Jonathan S; Yang, Shuo; Cen, Osman; Taxter, Tim; McMahon, Kaylin M; Misener, Sol; Behdad, Amir; Longnecker, Richard; Gordon, Leo I; Thaxton, C Shad

    2017-11-06

    Cancer cells have altered metabolism and, in some cases, an increased demand for cholesterol. It is important to identify novel, rational treatments based on biology, and cellular cholesterol metabolism as a potential target for cancer is an innovative approach. Toward this end, we focused on diffuse large B-cell lymphoma (DLBCL) as a model because there is differential cholesterol biosynthesis driven by B-cell receptor (BCR) signaling in germinal center (GC) versus activated B-cell (ABC) DLBCL. To specifically target cellular cholesterol homeostasis, we employed high-density lipoprotein-like nanoparticles (HDL NP) that can generally reduce cellular cholesterol by targeting and blocking cholesterol uptake through the high-affinity HDL receptor, scavenger receptor type B-1 (SCARB1). As we previously reported, GC DLBCL are exquisitely sensitive to HDL NP as monotherapy, while ABC DLBCL are less sensitive. Herein, we report that enhanced BCR signaling and resultant de novo cholesterol synthesis in ABC DLBCL drastically reduces the ability of HDL NPs to reduce cellular cholesterol and induce cell death. Therefore, we combined HDL NP with the BCR signaling inhibitor ibrutinib and the SYK inhibitor R406. By targeting both cellular cholesterol uptake and BCR-associated de novo cholesterol synthesis, we achieved cellular cholesterol reduction and induced apoptosis in otherwise resistant ABC DLBCL cell lines. These results in lymphoma demonstrate that reduction of cellular cholesterol is a powerful mechanism to induce apoptosis. Cells rich in cholesterol require HDL NP therapy to reduce uptake and molecularly targeted agents that inhibit upstream pathways that stimulate de novo cholesterol synthesis, thus, providing a new paradigm for rationally targeting cholesterol metabolism as therapy for cancer.

  8. MO-FG-BRA-03: A Monte-Carlo Study of Cellular Dosimetry of Radioactive Gold-Palladium Nanoparticles

    International Nuclear Information System (INIS)

    Ma, Y; Michaud, F; Fortin, M; Beaulieu, L

    2015-01-01

    Purpose: Radioactive gold-palladium nanoparticles ("1"0"3Pd:Pd@Au NPs) are being developed for prostate cancer brachytherapy. Photons emitted by the radioisotope palladium (photon energy: 20.1 and 23.0 keV), interacting with gold-coating of NPs, lead to enhanced energy distribution in nucleus. Here, a simple cellular model was studied using detailed track-structure method. Methods: Geant4-DNA was used with auger electrons enabled. Biological cell was modeled as a sphere of radius r=5 µm that were immersed in a fluid containing large number of NPs at different concentrations (S=1, 2.15, 5.1, 17.2 mg-Au/g-H2O). Nucleus was modeled as a concentric sphere (r=3µm). Thickness of gold-coating on "1"0"3Pd core was 15nm, 20nm and 25nm, respectively. A scenario of NP diffusion was investigated, where S=5.1 mg-Au/g-H2O outside cell and S=1 mg-Au/g-H2O in cytoplasm. 10"1"0 "1"0"3Pd decays were simulated for each combination of NP concentration and gold-coating. Results: A uniform increase in energy deposition (Edep) is observed in cell nucleus and the energy enhancement ratio (EER) is 1.16, 1.22 and 1.3 for 15nm, 20nm and 25nm of gold -coatings, respectively. Edep at the center of nucleus is increased by a factor of 1.47, 2.51 and 5.54 when the NP concentration in the cytoplasm increases from 1 mg-Au/g-H2O to 2.15, 5.10 and 17.2 mg-Au/g-H2O, respectively. When NPs diffuse into cytoplasm, the mean value of Edep in nucleus increases from 0.42 to 1.13 MeV per 10"9 decays (GBq-Second) of "1"0"3Pd and the maximum value increases from 0.54 to 2.5 MeV per GBq-Second. Conclusion: These results suggest that "1"0"3Pd:Pd@Au NPs constitute a promising nanotherapeutic agent. Ongoing studies use transmission electron microscopy (TEM) images of prostate cancer

  9. The use of transmission electron microscopy in the quantification of nanoparticle dose

    International Nuclear Information System (INIS)

    Hondow, N; Brydson, R; Brown, A

    2014-01-01

    There are an increasing number of potential applications for nanoparticles in clinical medicine, including targeted drug delivery and contrast agents for biomedical imaging. Current in vitro studies are concerned with the biological impact of nanoparticles, with electron microscopy commonly employed to image their intracellular location. It is critical to quantify the absolute nanoparticle dose internalized by cells in a given exposure, and to understand the factors which affect this. In this work we are aiming to develop a full quantitative description of quantum dot uptake by an in vitro cell line. Transmission electron microscopy of thin cell sections provides the location and number of cellular vesicles per 2-D cell slice plus the number of quantum dots per vesicle. These results can then be correlated to other techniques to quantify the internalized nanoparticle dose distribution for whole cells

  10. Real-time cellular and molecular dynamics of bi-metallic self-therapeutic nanoparticle in cancer cells

    Science.gov (United States)

    Vishwakarma, Sandeep Kumar; Bardia, Avinash; Lakkireddy, Chandrakala; Paspala, Syed Ameer Basha; Habeeb, Md. Aejaz; Khan, Aleem Ahmed

    2018-02-01

    Since last decades various kinds of nanoparticles have been functionalized to improve their biomedical applications. However, the biological effect of un-modified/non-functionalized bi-metallic magnetic nanoparticles remains under investigated. Herein we demonstrate a multifaceted non-functionalized bi-metallic inorganic Gd-SPIO nanoparticle which passes dual high MRI contrast and can kill the cancer cells through several mechanisms. The results of the present study demonstrate that Gd-SPIO nanoparticles have potential to induce cancer cell death by production of reactive oxygen species and apoptotic events. Furthermore, Gd-SPIO nanoparticles also enhance the expression levels of miRNA-199a and miRNA-181a-7p which results in decreased levels of cancer markers such as C-met, TGF-β and hURP. One very interesting finding of this study reveals side scatter-based real-time analysis of nanoparticle uptake in cancer cells using flow cytometry analysis. In conclusion, this study paves a way for future investigation of un-modified inorganic nanoparticles to purport enhanced therapeutic effect in combination with potential anti-tumor drugs/molecules in cancer cells.

  11. Carbon nanotube surface modification with polyelectrolyte brushes endowed with quantum dots and metal oxide nanoparticles through in situ synthesis

    International Nuclear Information System (INIS)

    Llarena, Irantzu; Romero, Gabriela; Moya, Sergio E; Ziolo, Ronald F

    2010-01-01

    Carbon nanotubes (CNTs) have been successfully coated with a covalently bonded polymer brush of negatively charged poly(3-sulfopropylamino methacrylate) (PSPM) by in situ polymerization employing atomic transfer radical polymerization (ATRP) from initiating silanes attached to the CNTs before the polymerization. The CNT-bonded brush forms a polymer layer or shell-like structure around the CNTs and provides colloidal stabilization for the CNTs in aqueous media. In situ syntheses of nanocrystalline CdS and magnetic iron oxide in the polymer brushes lead to the formation of hybrid nanocomposites consisting of nanoparticle-containing PSPM-coated CNTs that remain readily dispersible and stable in aqueous media. The hybrid nanostructures are synthesized by ion exchange with the cations of the sulfonate groups of the PSPM followed by precipitation and were followed by stepwise zeta potential measurements and TEM. Such structures could have applications in the design of more complex structures and devices. The general synthetic scheme can be extended to include other nanoparticles as brush cargo to broaden the utility or functionality of the CNTs. TEM data shows nanocrystalline CdS in the range of 5-8 nm embedded in the PSPM brush and nanocrystalline iron oxide with a size between 2 and 4 nm, with the former consistent with UV-vis spectroscopy and fluorescence measurements.

  12. The toxicity of plastic nanoparticles to green algae as influenced by surface modification, medium hardness and cellular adsorption

    DEFF Research Database (Denmark)

    Nolte, Tom M.; Hartmann, Nanna B.; Kleijn, J. Mieke

    2017-01-01

    To investigate processes possibly underlying accumulation and ecological effects of plastic nano-particles we have characterized their interaction with the cell wall of green algae. More specifically, we have investigated the influence of particle surface functionality and water hardness (Ca2......+ concentration) on particle adsorption to algae cell walls. Polystyrene nanoparticles with different functional groups (non-functionalized, −COOH and −NH2) as well as coated (starch and PEG) gold nanoparticles were applied in these studies. Depletion measurements and atomic force microscopy (AFM) showed...... that adsorption of neutral and positively charged plastic nanoparticles onto the cell wall of P. subcapitata was stronger than that of negatively charged plastic particles. Results indicated that binding affinity is a function of both inter-particle and particle-cell wall interactions which are in turn influenced...

  13. The photovoltaic performance of Ag2S quantum dots-sensitized solar cells using plasmonic Au nanoparticles/TiO2 working electrodes

    Science.gov (United States)

    Badawi, Ali; Mostafa, Nasser Y.; Al-Hosiny, Najm M.; Merazga, Amar; Albaradi, Ateyyah M.; Abdel-Wahab, F.; Atta, A. A.

    2018-06-01

    The photovoltaic performance of silver sulfide (Ag2S) quantum dots-sensitized solar cells (QDSSCs) using different concentrations (0, 0.05, 0.1, 0.3 and 0.5 wt.%) of plasmonic Au nanoparticles (NPs)/titania (TiO2) electrodes has been investigated. Ag2S quantum dots (QDs) were adsorbed onto the Au NPs/titania electrodes using the successive ionic layer adsorption and reaction (SILAR) deposition technique. The morphological properties of the Au NPs and the prepared titania electrodes were characterized using transmission electron microscope (TEM) and scanning electron microscope (SEM), respectively. The energy-dispersive X-ray (EDX) spectra of the bare titania and Ag2S QDs-sensitized titania electrodes were recorded. The optical properties of the prepared Ag2S QDs-sensitized titania electrodes were measured using a UV-visible spectrophotometer. The estimated energy band gap of Ag2S QDs-sensitized titania electrodes is 1.96 eV. The photovoltaic performance of the assembled Ag2S QDSSCs was measured under 100 mW/cm2 solar illumination. The optimal photovoltaic parameters were obtained as follows: open circuit voltage Voc = 0.50 V, current density Jsc = 3.18 mA/cm2, fill factor (FF) = 0.35 and energy conversion efficiency η = 0.55% for 0.3 wt.% of Au NPs/titania electrode. These results are attributed to the enhancement in the absorption and decrease in the electron-hole pairs recombination rate. The open circuit voltage decay (OCVD) measurements of the assembled Ag2S QDSSCs were measured. The calculated electron lifetime (τ) in Ag2S QDSSCs with Au NPs/titania electrodes is at least one order of magnitude more than that with bare titania electrode. The cut-on-cut-off cycles of the solar illumination measurements show the rapid sensitivity and good reproducibility of the assembled Ag2S QDSSCs.

  14. Multi-functionality Redefined with Colloidal Carotene Carbon Nanoparticles for Synchronized Chemical Imaging, Enriched Cellular Uptake and Therapy

    OpenAIRE

    Misra, Santosh K.; Mukherjee, Prabuddha; Chang, Huei-Huei; Tiwari, Saumya; Gryka, Mark; Bhargava, Rohit; Pan, Dipanjan

    2016-01-01

    Typically, multiplexing high nanoparticle uptake, imaging, and therapy requires careful integration of three different functions of a multiscale molecular-particle assembly. Here, we present a simpler approach to multiplexing by utilizing one component of the system for multiple functions. Specifically, we successfully synthesized and characterized colloidal carotene carbon nanoparticle (C3-NP), in which a single functional molecule served a threefold purpose. First, the presence of carotene ...

  15. Quantum Dots

    Science.gov (United States)

    Tartakovskii, Alexander

    2012-07-01

    Part I. Nanostructure Design and Structural Properties of Epitaxially Grown Quantum Dots and Nanowires: 1. Growth of III/V semiconductor quantum dots C. Schneider, S. Hofling and A. Forchel; 2. Single semiconductor quantum dots in nanowires: growth, optics, and devices M. E. Reimer, N. Akopian, M. Barkelid, G. Bulgarini, R. Heeres, M. Hocevar, B. J. Witek, E. Bakkers and V. Zwiller; 3. Atomic scale analysis of self-assembled quantum dots by cross-sectional scanning tunneling microscopy and atom probe tomography J. G. Keizer and P. M. Koenraad; Part II. Manipulation of Individual Quantum States in Quantum Dots Using Optical Techniques: 4. Studies of the hole spin in self-assembled quantum dots using optical techniques B. D. Gerardot and R. J. Warburton; 5. Resonance fluorescence from a single quantum dot A. N. Vamivakas, C. Matthiesen, Y. Zhao, C.-Y. Lu and M. Atature; 6. Coherent control of quantum dot excitons using ultra-fast optical techniques A. J. Ramsay and A. M. Fox; 7. Optical probing of holes in quantum dot molecules: structure, symmetry, and spin M. F. Doty and J. I. Climente; Part III. Optical Properties of Quantum Dots in Photonic Cavities and Plasmon-Coupled Dots: 8. Deterministic light-matter coupling using single quantum dots P. Senellart; 9. Quantum dots in photonic crystal cavities A. Faraon, D. Englund, I. Fushman, A. Majumdar and J. Vukovic; 10. Photon statistics in quantum dot micropillar emission M. Asmann and M. Bayer; 11. Nanoplasmonics with colloidal quantum dots V. Temnov and U. Woggon; Part IV. Quantum Dot Nano-Laboratory: Magnetic Ions and Nuclear Spins in a Dot: 12. Dynamics and optical control of an individual Mn spin in a quantum dot L. Besombes, C. Le Gall, H. Boukari and H. Mariette; 13. Optical spectroscopy of InAs/GaAs quantum dots doped with a single Mn atom O. Krebs and A. Lemaitre; 14. Nuclear spin effects in quantum dot optics B. Urbaszek, B. Eble, T. Amand and X. Marie; Part V. Electron Transport in Quantum Dots Fabricated by

  16. Printer model for dot-on-dot halftone screens

    Science.gov (United States)

    Balasubramanian, Raja

    1995-04-01

    A printer model is described for dot-on-dot halftone screens. For a given input CMYK signal, the model predicts the resulting spectral reflectance of the printed patch. The model is derived in two steps. First, the C, M, Y, K dot growth functions are determined which relate the input digital value to the actual dot area coverages of the colorants. Next, the reflectance of a patch is predicted as a weighted combination of the reflectances of the four solid C, M, Y, K patches and their various overlays. This approach is analogous to the Neugebauer model, with the random mixing equations being replaced by dot-on-dot mixing equations. A Yule-Neilsen correction factor is incorporated to account for light scattering within the paper. The dot area functions and Yule-Neilsen parameter are chosen to optimize the fit to a set of training data. The model is also extended to a cellular framework, requiring additional measurements. The model is tested with a four color xerographic printer employing a line-on-line halftone screen. CIE L*a*b* errors are obtained between measurements and model predictions. The Yule-Neilsen factor significantly decreases the model error. Accuracy is also increased with the use of a cellular framework.

  17. Multifunctional molecular imaging probes for estrogen receptors. 99mTc labeled diethylstilbestrol (DES) conjugated, cuinp quantum dot nanoparticles (DESCIP)

    International Nuclear Information System (INIS)

    Payam Moharrami; Perihan Unak; Ozge Kozgus Guldu; Medine, E.I.; Gul Gumuser; Elvan Sayit Bilgin; Omer Aras

    2017-01-01

    A theranostic nanoparticle was synthesized based on diethylstilbestrol conjugated with phosphate, copper, and indium (DESCIP) and labelled with 99m Tc which can be used for SPECT imaging of ER-enriched cancers. In vitro biological activity of 99m Tc-DESCIP was examined in breast adenocarcinoma cells (MCF-7), prostatic carcinoma cells (PC-3), and pulmonary epithelial cells (A-549). In vivo lymph node imaging was performed in normal and receptor blocked female New Zealand rabbits. Results demonstrated that 99m Tc-DESCIP and DESCIP has potential for imaging ER-enriched tumors such as breast and prostate tumors, and their metastases in the lung, as well as improving management for their therapies. (author)

  18. Comparison of cellular effects of starch-coated SPIONs and poly(lactic-co-glycolic acid matrix nanoparticles on human monocytes

    Directory of Open Access Journals (Sweden)

    Gonnissen D

    2016-10-01

    Full Text Available Dominik Gonnissen,1 Ying Qu,1,2 Klaus Langer,3 Cengiz Öztürk,4 Yuliang Zhao,2 Chunying Chen,2 Guiscard Seebohm,5 Martina Düfer,6 Harald Fuchs,1 Hans-Joachim Galla,7 Kristina Riehemann11Center for Nanotechnology, Institute of Physics, University of Münster, Münster, Germany; 2National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, People’s Republic of China; 3Institute of Pharmaceutical Technology and Biopharmacy, University of Münster, Münster, 4chemicell GmbH, Berlin, 5Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases, University Hospital Münster, 6Department of Pharmacology, Institute of Pharmaceutical and Medicinal Chemistry, 7Department of Cell Biology/Biophysics, Institute of Biochemistry, University of Münster, Münster, GermanyAbstract: Within the last years, progress has been made in the knowledge of the properties of medically used nanoparticles and their toxic effects, but still, little is known about their influence on cellular processes of immune cells. The aim of our comparative study was to present the influence of two different nanoparticle types on subcellular processes of primary monocytes and the leukemic monocyte cell line MM6. We used core-shell starch-coated superparamagnetic iron oxide nanoparticles (SPIONs and matrix poly(lactic-co-glycolic acid (PLGA nanoparticles for our experiments. In addition to typical biocompatibility testing like the detection of necrosis or secretion of interleukins (ILs, we investigated the impact of these nanoparticles on the actin cytoskeleton and the two voltage-gated potassium channels Kv1.3 and Kv7.1. Induction of necrosis was not seen for PLGA nanoparticles and SPIONs in primary monocytes and MM6 cells. Likewise, no alteration in secretion of IL-1β and IL-10 was detected under the same experimental conditions. In contrast, IL-6 secretion was exclusively downregulated in primary monocytes after contact with both

  19. Quantum dots

    International Nuclear Information System (INIS)

    Kouwenhoven, L.; Marcus, C.

    1998-01-01

    Quantum dots are man-made ''droplets'' of charge that can contain anything from a single electron to a collection of several thousand. Their typical dimensions range from nanometres to a few microns, and their size, shape and interactions can be precisely controlled through the use of advanced nanofabrication technology. The physics of quantum dots shows many parallels with the behaviour of naturally occurring quantum systems in atomic and nuclear physics. Indeed, quantum dots exemplify an important trend in condensed-matter physics in which researchers study man-made objects rather than real atoms or nuclei. As in an atom, the energy levels in a quantum dot become quantized due to the confinement of electrons. With quantum dots, however, an experimentalist can scan through the entire periodic table by simply changing a voltage. In this article the authors describe how quantum dots make it possible to explore new physics in regimes that cannot otherwise be accessed in the laboratory. (UK)

  20. Synthesis of an excellent electrocatalyst for oxygen reduction reaction with supercritical fluid: Graphene cellular monolith with ultrafine and highly dispersive multimetallic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yazhou; Cheng, Xiaonong; Yen, Clive H.; Wai, Chien M.; Wang, Chongmin; Yang, Juan; Lin, Yuehe

    2017-04-01

    Graphene cellular monolith (GCM) can be used as an excellent support for nanoparticles in widespread applications. However, it's still a great challenge to deposit the desirable nanoparticles in GCM that have small size, controllable structure, composition, and high dispersion using the current methods. Here we demonstrate a green, efficient and large-scale method to address this challenge using supercritical fluid (SCF). By this superior method, graphene hydrogel can be transferred into GCM while being deposited with ultrafine and highly dispersive nanoparticles. Specifically, the bimetallic PtFe/GCM and the trimetallic PtFeCo/GCM catalysts are successfully synthesized, and their electrocatalytic performances toward oxygen reduction reaction (ORR) are also studied. The resultant PtFe/GCM shows the significant enhancement in ORR activity, including a factor of 8.47 enhancement in mass activity (0.72 A mgPt-1), and a factor of 7.67 enhancement in specific activity (0.92 mA cm-2), comparing with those of the commercial Pt/C catalyst (0.085 A mgPt-1, 0.12 mA cm-2). Importantly, by introducing the Co, the trimetallic PtFeCo/GCM exhibits the further improved ORR activities (1.28 A mgPt-1, 1.80 mA cm-2). The high ORR activity is probably attributed to the alloying structure, ultrafine size, highly dispersive, well-defined, and a better interface with 3D porous graphene support.

  1. Development and characterization of a magnetic bead-quantum dot nanoparticles based assay capable of Escherichia coli O157:H7 quantification

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gha-Young [Department of Civil Engineering, Auburn University, Auburn, AL 36849 (United States); Son, Ahjeong, E-mail: ason@auburn.edu [Department of Civil Engineering, Auburn University, Auburn, AL 36849 (United States)

    2010-09-10

    The development and characterization of a magnetic bead (MB)-quantum dot (QD) nanoparticles based assay capable of quantifying pathogenic bacteria is presented here. The MB-QD assay operates by having a capturing probe DNA selectively linked to the signaling probe DNA via the target genomic DNA (gDNA) during DNA hybridization. The signaling probe DNA is labeled with fluorescent QD{sub 565} which serves as a reporter. The capturing probe DNA is conjugated simultaneously to a MB and another QD{sub 655}, which serve as a carrier and an internal standard, respectively. Successfully captured target gDNA is separated using a magnetic field and is quantified via a spectrofluorometer. The use of QDs (i.e., QD{sub 565}/QD{sub 655}) as both a fluorescence label and an internal standard increased the sensitivity of the assay. The passivation effect and the molar ratio between QD and DNA were optimized. The MB-QD assay demonstrated a detection limit of 890 zeptomolar (i.e., 10{sup -21} mol L{sup -1}) concentration for the linear single stranded DNA (ssDNA). It also demonstrated a detection limit of 87 gene copies for double stranded DNA (dsDNA) eaeA gene extracted from pure Escherichia coli (E. coli) O157:H7 culture. Its corresponding dynamic range, sensitivity, and selectivity were also presented. Finally, the bacterial gDNA of E. coli O157:H7 was used to highlight the MB-QD assay's ability to detect below the minimum infective dose (i.e., 100 organisms) of E. coli O157:H7 in water environment.

  2. Photovoltaic performance enhancement of CdS quantum dot-sensitized TiO{sub 2} photoanodes with plasmonic gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Aiping, E-mail: liuaiping1979@gmail.com [Center for Optoelectronics Materials and Devices, Zhejiang Sci-Tech University, Hangzhou 310018 (China); State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Ren, Qinghua; Zhao, Ming; Xu, Tao; Yuan, Ming; Zhao, Tingyu [Center for Optoelectronics Materials and Devices, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Tang, Weihua [State Key Laboratory of Information Photonics and Optical Communication, Beijing University Posts and Telecommunications, Beijing 100876 (China)

    2014-03-15

    Highlights: • CdS QD-sensitized TiO{sub 2} porous photoanode with plasmonic gold. • A prominent light absorption enhancement of hybrid was attained by gold plasmon. • The photovoltaic response of hybrid was tunable by CdS amount. • The Au/TiO{sub 2}/CdS hybrid had a potential application in energy conversion devices. -- Abstract: The CdS quantum dot-sensitized TiO{sub 2} films with plasmonic gold nanoparticles were designed as photoanodes by the electrodeposition of gold combined with the “successive ionic layer adsorption and reaction” (SILAR) method for CdS deposition on porous TiO{sub 2} films. A prominent enhancement in light absorption of Au/TiO{sub 2}/CdS hybrid was attained by efficient light scattering of gold plasmons as sub-wavelength antennas and concentrators. The photogenerated electron formed in the near-surface region of TiO{sub 2} and CdS were facilitated to transfer to the plasmonic gold, resulting in the enhancement of photocurrent and incident photon-to-current conversion efficiency of hybrid photoanode upon photoirradiation. Furthermore, the photovoltaic response of hybrid was highly tunable with respect to the number of SILAR cycles applied to deposit CdS. The thicker absorber layer with less porous structure and larger CdS crystals might limit the electrolyte diffusion into the hybrid electrode and impose a barrier for electron tunneling and transferring. The highly versatile and tunable properties of Au/TiO{sub 2}/CdS photoanodes demonstrated their potential application in energy conversion devices.

  3. A label-free fluorescence biosensor for highly sensitive detection of lectin based on carboxymethyl chitosan-quantum dots and gold nanoparticles.

    Science.gov (United States)

    Liu, Ziping; Liu, Hua; Wang, Lei; Su, Xingguang

    2016-08-17

    In this work, we report a novel label-free fluorescence "turn off-on" biosensor for lectin detection. The highly sensitive and selective sensing system is based on the integration of carboxymethyl chitosan (CM-CHIT), CuInS2 quantum dots (QDs) and Au nanoparticles (NPs). Firstly, CuInS2 QDs featuring carboxyl groups were directly synthesized via a hydrothermal synthesis method. Then, the carboxyl groups on the CuInS2 QDs surface were interacted with the amino groups (NH2), carboxyl groups (COOH) and hydroxyl groups (OH) within CM-CHIT polymeric chains via electrostatic interactions and hydrogen bonding to form CM-CHIT-QDs assemblies. Introduction of Au NPs could quench the fluorescence of CM-CHIT-QDs through electron and energy transfer. In the presence of lectin, lectin could bind exclusively with CM-CHIT-QDs by means of specific multivalent carbohydrate-protein interaction. Thus, the electron and energy transfer process between CM-CHIT-QDs and Au NPs was inhibited, and as a result, the fluorescence of CM-CHIT-QDs was effectively "turned on". Under the optimum conditions, there was a good linear relationship between the fluorescence intensity ratio I/I0 (I and I0 were the fluorescence intensity of CM-CHIT-QDs-Au NPs in the presence and absence of lectin, respectively) and lectin concentration in the range of 0.2-192.5 nmol L(-1), And the detection limit could be down to 0.08 nmol L(-1). Furthermore, the proposed biosensor was employed for the determination of lectin in fetal bovine serum samples with satisfactory results. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Uptake, retention and internalization of quantum dots in Daphnia is influenced by particle surface functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Feswick, A., E-mail: afeswick@yahoo.ca [Center for Environmental and Human Toxicology, University of Florida, PO Box 110885, Gainesville, FL 32611 (United States); Canadian Rivers Institute, University of New Brunswick, PO Box 5050, Saint John NB, CA (United States); Griffitt, R.J., E-mail: joe.griffitt@usm.edu [Department of Coastal Sciences, University of Southern Mississippi, 703 East Beach Drive, Ocean Springs, MS 39564 (United States); Siebein, K., E-mail: kerry.siebein@nist.gov [Major Analytical Instrumentation Center, University of Florida, PO Box 116400, Gainesville, FL 32611 (United States); Barber, D.S., E-mail: barberd@vetmed.ufl.edu [Center for Environmental and Human Toxicology, University of Florida, PO Box 110885, Gainesville, FL 32611 (United States)

    2013-04-15

    Highlights: ► Daphnia underwent a waterborne exposure of PEG, NH{sub 2} and COOH functionalized quantum dot nanoparticles. ► There was preferential retention of COOH nanoparticles. ► TEM demonstrated that NH{sub 2} and COOH nanoparticles were internalized in cells adjacent to the GI tract. ► This cellular internalization was confirmed using energy dispersive spectroscopy. -- Abstract: Nanomaterials are a diverse group of compounds whose inevitable release into the environment warrants study of the fundamental processes that govern the ingestion, uptake and accumulation in aquatic organisms. Nanomaterials have the ability to transfer to higher trophic levels in aquatic ecosystems, and recent evidence suggests that the surface chemistry of both the nanoparticle and biological membrane can influence uptake kinetics. Therefore, our study investigates the effect of surface functionalization on uptake, internalization and depuration in Daphnia spp. Uncharged (polyethylene glycol; PEG), positively charged (amino-terminated: NH{sub 2}) and negatively charged (carboxyl-modified; COOH) cadmium selenide/zinc sulfide quantum dots were used to monitor ingestion, uptake and depuration of nanometals in Daphnia magna and Ceriodaphnia dubia over 24 h of exposure. These studies demonstrated that particles with higher negative charge (COOH quantum dots) were taken up to a greater extent by Daphnia (259.17 ± 17.70 RFU/20 Daphnia) than either the NH{sub 2} (150.01 ± 18.91) or PEG quantum dots (95.17 ± 9.78), however this is likely related to the functional groups attached to the nanoparticles as there were no real differences in zeta potential. Whole body fluorescence associates well with fluorescent microscopic images obtained at the 24 h timepoint. Confocal and electron microscopic analysis clearly demonstrated that all three types of quantum dots could cross the intestinal epithelial barrier and be translocated to other cells. Upon cessation of exposure, elimination of

  5. Improved performance of quantum dot light emitting diode by modulating electron injection with yttrium-doped ZnO nanoparticles

    Science.gov (United States)

    Li, Jingling; Guo, Qiling; Jin, Hu; Wang, Kelai; Xu, Dehua; Xu, Yongjun; Xu, Gang; Xu, Xueqing

    2017-10-01

    In a typical light emitting diode (QD-LED), with ZnO nanoparticles (NPs) serving as the electron transport layer (ETL) material, excessive electron injection driven by the matching conduction band maximum (CBM) between the QD and this oxide layer usually causes charge imbalance and degrades the device performance. To address this issue, the electronic structure of ZnO NPs is modified by the yttrium (Y) doping method. We demonstrate that the CBM of ZnO NPs has a strong dependence on the Y-doping concentration, which can be tuned from 3.55 to 2.77 eV as the Y doping content increases from 0% to 9.6%. This CBM variation generates an enlarged barrier between the cathode and this ZnO ETL benefits from the modulation of electron injection. By optimizing electron injection with the use of a low Y-doped (2%) ZnO to achieve charge balance in the QD-LED, device performance is significantly improved with maximum luminance, peak current efficiency, and maximal external quantum efficiency increase from 4918 cd/m2, 11.3 cd/A, and 4.5% to 11,171 cd/m2, 18.3 cd/A, and 7.3%, respectively. This facile strategy based on the ETL modification enriches the methodology of promoting QD-LED performance.

  6. High-resolution cellular MRI: gadolinium and iron oxide nanoparticles for in-depth dual-cell imaging of engineered tissue constructs.

    Science.gov (United States)

    Di Corato, Riccardo; Gazeau, Florence; Le Visage, Catherine; Fayol, Delphine; Levitz, Pierre; Lux, François; Letourneur, Didier; Luciani, Nathalie; Tillement, Olivier; Wilhelm, Claire

    2013-09-24

    Recent advances in cell therapy and tissue engineering opened new windows for regenerative medicine, but still necessitate innovative noninvasive imaging technologies. We demonstrate that high-resolution magnetic resonance imaging (MRI) allows combining cellular-scale resolution with the ability to detect two cell types simultaneously at any tissue depth. Two contrast agents, based on iron oxide and gadolinium oxide rigid nanoplatforms, were used to "tattoo" endothelial cells and stem cells, respectively, with no impact on cell functions, including their capacity for differentiation. The labeled cells' contrast properties were optimized for simultaneous MRI detection: endothelial cells and stem cells seeded together in a polysaccharide-based scaffold material for tissue engineering appeared respectively in black and white and could be tracked, at the cellular level, both in vitro and in vivo. In addition, endothelial cells labeled with iron oxide nanoparticles could be remotely manipulated by applying a magnetic field, allowing the creation of vessel substitutes with in-depth detection of individual cellular components.

  7. Probing intra-cellular drug release event using activatable (OFF/ON) CdS:Mn/ZnS quantum dots (Qdots): spectroscopic studies to investigate interaction of Qdots with quencher

    Science.gov (United States)

    Tharkur, Jeremy; Teblum, Andrew; Basumallick, Srijita; Shah, Rikhav; Cantarero, Karishma; Maity, Niharika; Rifai, Sara; Doshi, Mona; Gesquiere, Andre J.; Santra, Swadeshmukul

    2013-02-01

    In recent years, activatable Quantum Dots (AQdots) are gaining popularity in a number of chemical and biological sensing applications. A basic design of AQdot probes involves a suitable quencher which is capable of altering optical properties of the Qdots. In our previous studies we have shown that CdS:Mn/ZnS fluorescence can be effectively quenched using small molecule quenchers (such as dopamine, chemotherapeutic drug) as well as iron oxide nanoparticle via electron/energy transfer process. We have also shown that the quenched Qdot fluorescence can be restored when the Qdots are separated from the quencher. Using Qdot based activatable probes, we detected intracellular drug release event. Qdot fluorescence was restored upon interaction with the intracellular glutathione (GSH). In this paper, we report a GSH induced quenching of water-soluble N-Acetyl Cysteine (NAC) surface-conjugated Cds:Mn/ZnS Qdots. Quenching of NAC-Qdots was due to aggregation of Qdots in solution. This aggregation induced fluorescence quenching phenomenon resembles with the self-quenching phenomenon of traditional organic fluorescence dyes at high concentrations. UV-VIS and fluorescence emission spectroscopy data support the interaction and binding of GSH with the NAC-Qdots. Increase in particle size due to GSH induced aggregation of NAC-Qdots was confirmed by the Dynamic Light Scattering (DLS) data.

  8. Cytotoxicity of CdTe quantum dots in human umbilical vein endothelial cells: the involvement of cellular uptake and induction of pro-apoptotic endoplasmic reticulum stress

    Directory of Open Access Journals (Sweden)

    Yan M

    2016-02-01

    Full Text Available Ming Yan,1,* Yun Zhang,2,* Haiyan Qin,3 Kezhou Liu,1 Miao Guo,1 Yakun Ge,1 Mingen Xu,1 Yonghong Sun,4 Xiaoxiang Zheng4 1Department of Biomedical Engineering, College of Life Information Science and Instrument Engineering, Hangzhou Dianzi University, Hangzhou, 2Basic Medical Sciences, College of Medicine, Shaoxing University, Shaoxing, 3Department of Chemistry, Zhejiang University, 4Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Department of Biomedical Engineering, Zhejiang University, Hangzhou, People’s Republic of China *These authors contributed equally to this work Abstract: Cadmium telluride quantum dots (CdTe QDs have been proposed to induce oxidative stress, which plays a crucial role in CdTe QDs-mediated mitochondrial-dependent apoptosis in human umbilical vein endothelial cells (HUVECs. However, the direct interactions of CdTe QDs with HUVECs and their potential impairment of other organelles like endoplasmic reticulum (ER in HUVECs are poorly understood. In this study, we reported that the negatively charged CdTe QDs (–21.63±0.91 mV, with good dispersity and fluorescence stability, were rapidly internalized via endocytosis by HUVECs, as the notable internalization could be inhibited up to 95.52% by energy depletion (NaN3/deoxyglucose or low temperature. The endocytosis inhibitors (methyl-β-cyclodextrin, genistein, sucrose, chlorpromazine, and colchicine dramatically decreased the uptake of CdTe QDs by HUVECs, suggesting that both caveolae/raft- and clathrin-mediated endocytosis were involved in the endothelial uptake of CdTe QDs. Using immunocytochemistry, a striking overlap of the internalized CdTe QDs and ER marker was observed, which indicates that QDs may be transported to ER. The CdTe QDs also caused remarkable ER stress responses in HUVECs, confirmed by significant dilatation of ER cisternae, upregulation of ER stress markers GRP78/GRP94, and

  9. Cellular uptake of beta-carotene from protein stabilized solid lipid nano-particles prepared by homogenization-evaporation method

    Science.gov (United States)

    Using a homogenization-evaporation method, beta-carotene (BC) loaded nano-particles were prepared with different ratios of food-grade sodium caseinate (SC), whey protein isolate (WPI), or soy protein isolate (SPI) to BC and evaluated for their physiochemical stability, in vitro cytotoxicity, and cel...

  10. Methodology description for detection of cellular uptake of PVA coated superparamagnetic iron oxide nanoparticles (SPION) in synovial cells of sheep

    International Nuclear Information System (INIS)

    Schoepf, Bernhard; Neuberger, Tobias; Schulze, Katja; Petri, Alke; Chastellain, Matthieu; Hofmann, Margarete; Hofmann, Heinrich; Rechenberg, Brigitte von

    2005-01-01

    The detection of superparamagnetic iron oxide nanoparticles (SPION) in synoviocytes is reported. Synoviocytes were incubated for 2, 12, 24 and 48 h with 1.5 mg/ml of PVA coated SPION under the influence of magnets (12 h). Particles were well tolerated by the synoviocytes, were easily detected using the Turnbulls and Prussian blue reactions between 12 and 24 h

  11. Methodology description for detection of cellular uptake of PVA coated superparamagnetic iron oxide nanoparticles (SPION) in synovial cells of sheep

    Energy Technology Data Exchange (ETDEWEB)

    Schoepf, Bernhard [Musculoskeletal Research Unit, Equine Hospital, Vetsuisse Faculty Zurich, University of Zurich, Winterthurerstr. 260, 8057 Zurich (Switzerland); Neuberger, Tobias [Musculoskeletal Research Unit, Equine Hospital, Vetsuisse Faculty Zurich, University of Zurich, Winterthurerstr. 260, 8057 Zurich (Switzerland); Schulze, Katja [Musculoskeletal Research Unit, Equine Hospital, Vetsuisse Faculty Zurich, University of Zurich, Winterthurerstr. 260, 8057 Zurich (Switzerland); Petri, Alke [Powder Technology Laboratory, Institute of Materials, Swiss Federal Institute of Technology Lausanne, EPFL, MX-D Ecublens, 1015 Lausanne (Switzerland); Chastellain, Matthieu [Powder Technology Laboratory, Institute of Materials, Swiss Federal Institute of Technology Lausanne, EPFL, MX-D Ecublens, 1015 Lausanne (Switzerland); Hofmann, Margarete [MatSearch, Ch. Jean Pavillard 14, 1009 Pully (Switzerland); Hofmann, Heinrich [Powder Technology Laboratory, Institute of Materials, Swiss Federal Institute of Technology Lausanne, EPFL, MX-D Ecublens, 1015 Lausanne (Switzerland); Rechenberg, Brigitte von [Musculoskeletal Research Unit, Equine Hospital, Vetsuisse Faculty Zurich, University of Zurich, Winterthurerstr. 260, 8057 Zurich (Switzerland)]. E-mail: bvonrechenberg@vetclinics.unizh.ch

    2005-05-15

    The detection of superparamagnetic iron oxide nanoparticles (SPION) in synoviocytes is reported. Synoviocytes were incubated for 2, 12, 24 and 48 h with 1.5 mg/ml of PVA coated SPION under the influence of magnets (12 h). Particles were well tolerated by the synoviocytes, were easily detected using the Turnbulls and Prussian blue reactions between 12 and 24 h.

  12. The toxicity of plastic nanoparticles to green algae as influenced by surface modification, medium hardness and cellular adsorption

    NARCIS (Netherlands)

    Nolte, Tom M.; Hartmann, Nanna B.; Kleijn, Mieke; Garnæs, Jørgen; Meent, van de Dik; Jan Hendriks, A.; Baun, Anders

    2017-01-01

    To investigate processes possibly underlying accumulation and ecological effects of plastic nano-particles we have characterized their interaction with the cell wall of green algae. More specifically, we have investigated the influence of particle surface functionality and water hardness (Ca2+

  13. On the pathway of cellular uptake: new insight into the interaction between the cell membrane and very small nanoparticles

    Directory of Open Access Journals (Sweden)

    Claudia Messerschmidt

    2016-09-01

    Full Text Available For any living cell the exchange with its environment is vital. Therefore, many different kinds of cargo are able to enter cells via energy-dependent or -independent routes. Nanoparticles are no exemption. It is known that small silica nanoparticles with a diameter below 50 nm are taken up by cells and that their uptake exerts pronounced toxic effects beyond a certain concentration threshold. However, neither the exact uptake mechanism of these particles nor the actual reason for their toxicity has yet been elucidated. In this study we examined the uptake of silica nanoparticles with a diameter of 7, 12 and 22 nm by means of transmission electron microscopy, accompanied by toxicological assays. We show that for every particle diameter tested a different membrane morphology during uptake can be observed and that the amount of particles entering in one event is different for the three sizes. Silica particles with a diameter of 22 nm show single-particle internalization with a membrane wrapped around the particles in the cytosol, whereas 12 nm particles display row-like multi-particle uptake into elongated membrane structures and those with a diameter of 7 nm or less end up in tubular endocytic structures containing many particles. These membrane morphologies proved to be highly reproducible as we found them in five different cell lines. Additionally, we performed ATP and LDH assays to determine particle toxicity. Exceeding a certain concentration threshold the nanoparticles showed a high toxic potential both in the biochemical assay measurements and from morphological findings. We could not find any hint at the induction of apoptosis, neither morphologically nor biochemically. In this regard we discuss membrane damage and consumption as one possible mechanism of toxicity, linking morphological observations to toxicological findings to bridge the gap in understanding the mechanism of toxicity of small nanoparticles.

  14. Disregarded Effect of Biological Fluids in siRNA Delivery: Human Ascites Fluid Severely Restricts Cellular Uptake of Nanoparticles.

    Science.gov (United States)

    Dakwar, George R; Braeckmans, Kevin; Demeester, Joseph; Ceelen, Wim; De Smedt, Stefaan C; Remaut, Katrien

    2015-11-04

    Small interfering RNA (siRNA) offers a great potential for the treatment of various diseases and disorders. Nevertheless, inefficient in vivo siRNA delivery hampers its translation into the clinic. While numerous successful in vitro siRNA delivery stories exist in reduced-protein conditions, most studies so far overlook the influence of the biological fluids present in the in vivo environment. In this study, we compared the transfection efficiency of liposomal formulations in Opti-MEM (low protein content, routinely used for in vitro screening) and human undiluted ascites fluid obtained from a peritoneal carcinomatosis patient (high protein content, representing the in vivo situation). In Opti-MEM, all formulations are biologically active. In ascites fluid, however, the biological activity of all lipoplexes is lost except for lipofectamine RNAiMAX. The drop in transfection efficiency was not correlated to the physicochemical properties of the nanoparticles, such as premature siRNA release and aggregation of the nanoparticles in the human ascites fluid. Remarkably, however, all of the formulations except for lipofectamine RNAiMAX lost their ability to be taken up by cells following incubation in ascites fluid. To take into account the possible effects of a protein corona formed around the nanoparticles, we recommend always using undiluted biological fluids for the in vitro optimization of nanosized siRNA formulations next to conventional screening in low-protein content media. This should tighten the gap between in vitro and in vivo performance of nanoparticles and ensure the optimal selection of nanoparticles for further in vivo studies.

  15. Quantum dots and nanocomposites.

    Science.gov (United States)

    Mansur, Herman Sander

    2010-01-01

    Quantum dots (QDs), also known as semiconducting nanoparticles, are promising zero-dimensional advanced materials because of their nanoscale size and because they can be engineered to suit particular applications such as nonlinear optical devices (NLO), electro-optical devices, and computing applications. QDs can be joined to polymers in order to produce nanocomposites which can be considered a scientific revolution of the 21st century. One of the fastest moving and most exciting interfaces of nanotechnology is the use of QDs in medicine, cell and molecular biology. Recent advances in nanomaterials have produced a new class of markers and probes by conjugating semiconductor QDs with biomolecules that have affinities for binding with selected biological structures. The nanoscale of QDs ensures that they do not scatter light at visible or longer wavelengths, which is important in order to minimize optical losses in practical applications. Moreover, at this scale, quantum confinement and surface effects become very important and therefore manipulation of the dot diameter or modification of its surface allows the properties of the dot to be controlled. Quantum confinement affects the absorption and emission of photons from the dot. Thus, the absorption edge of a material can be tuned by control of the particle size. This paper reviews developments in the myriad of possibilities for the use of semiconductor QDs associated with molecules producing novel hybrid nanocomposite systems for nanomedicine and bioengineering applications.

  16. Theranostic carbon dots derived from garlic with efficient anti-oxidative effects towards macrophages

    DEFF Research Database (Denmark)

    Yang, Chuanxu; Ogaki, Ryosuke; Hansen, Line

    2015-01-01

    Luminescent garlic carbon dots with superior photostability are synthesized via microwave assisted heating. The garlic dots are biocompatible, have low toxicity and can be used as benign theranostic nanoparticles for bioimaging with efficient anti-oxidative effects towards macrophages....

  17. Quadra-quantum Dots and Related Patterns of Quantum Dot Molecules:

    Directory of Open Access Journals (Sweden)

    Somsak Panyakeow

    2010-10-01

    Full Text Available Abstract Laterally close-packed quantum dots (QDs called quantum dot molecules (QDMs are grown by modified molecular beam epitaxy (MBE. Quantum dots could be aligned and cross hatched. Quantum rings (QRs created from quantum dot transformation during thin or partial capping are used as templates for the formations of bi-quantum dot molecules (Bi-QDMs and quantum dot rings (QDRs. Preferable quantum dot nanostructure for quantum computation based on quantum dot cellular automata (QCA is laterally close-packed quantum dot molecules having four quantum dots at the corners of square configuration. These four quantum dot sets are called quadra-quantum dots (QQDs. Aligned quadra-quantum dots with two electron confinements work like a wire for digital information transmission by Coulomb repulsion force, which is fast and consumes little power. Combination of quadra-quantum dots in line and their cross-over works as logic gates and memory bits. Molecular Beam Epitaxial growth technique called ‘‘Droplet Epitaxy” has been developed for several quantum nanostructures such as quantum rings and quantum dot rings. Quantum rings are prepared by using 20 ML In-Ga (15:85 droplets deposited on a GaAs substrate at 390°C with a droplet growth rate of 1ML/s. Arsenic flux (7–8×10-6Torr is then exposed for InGaAs crystallization at 200°C for 5 min. During droplet epitaxy at a high droplet thickness and high temperature, out-diffusion from the centre of droplets occurs under anisotropic strain. This leads to quantum ring structures having non-uniform ring stripes and deep square-shaped nanoholes. Using these peculiar quantum rings as templates, four quantum dots situated at the corners of a square shape are regrown. Two of these four quantum dots are aligned either or , which are preferable crystallographic directions of quantum dot alignment in general.

  18. One-pot synthesis of fluorescent nitrogen-doped carbon dots with good biocompatibility for cell labeling.

    Science.gov (United States)

    Zhang, Zhengwei; Yan, Kun; Yang, Qiulian; Liu, Yanhua; Yan, Zhengyu; Chen, Jianqiu

    2017-12-01

    Here we report an easy and economical hydrothermal carbonization approach to synthesize the fluorescent nitrogen-doped carbon dots (N-CDs) that was developed using citric acid and triethanolamine as the precursors. The synthesis conditions were optimized to obtain the N-CDs with superior fluorescence performances. The as-prepared N-CDs are monodispersed sphere nanoparticles with good water solubility, and exhibited strong fluorescence, favourable photostability and excitation wavelength-dependent behavior. Furthermore, the in vitro cytotoxicity and cellular labeling of N-CDs were investigated using the rat glomerular mesangial cells. The results showed the N-CDs have more inconspicuous cytotoxicity and better biosafety in comparison with ZnSe quantum dots, although both targeted the cells successfully. Considering their admirable photostability, low toxicity and good compatibility, the as-obtained N-CDs could have potential applications in biosensors, cellular imaging, and other fields. Copyright © 2017 John Wiley & Sons, Ltd.

  19. A polymeric nanoparticle consisting of mPEG-PLA-Toco and PLMA-COONa as a drug carrier: improvements in cellular uptake and biodistribution.

    Science.gov (United States)

    Yi, Yilwoong; Kim, Jae Hong; Kang, Hye-Won; Oh, Hun Seung; Kim, Sung Wan; Seo, Min Hyo

    2005-02-01

    To evaluate a new polymeric nanoparticulate drug delivery formulation that consists of two components: i) an amphiphilic diblock copolymer having tocopherol moiety at the end of the hydrophobic block in which the hydrophobic tocopherol moiety increases stability of hydrophobic core of the nanoparticle in aqueous medium; and ii) a biodegradable copolyester having carboxylate end group that is capable of forming ionic complex with positively charged compounds such as doxorubicin. A doxourubicin-loaded polymeric nanoparticle (Dox-PNP) was prepared by solvent evaporation method. The entrapment efficiency, size distribution, and in vitro release profile at various pH conditions were characterized. In vitro cellular uptake was investigated by confocal microscopy, flow cytometry, and MTT assay using drug-sensitive and drug-resistant cell lines. Pharmacokinetics and biodistribution were evaluated in rats and tumor-bearing mice. Doxorubicin (Dox) was efficiently loaded into the PNP (higher than 95% of entrapment efficiency), and the diameter of Dox-PNP was in the range 20-25 nm with a narrow size distribution. In Vitro study showed that Dox-PNP exhibited higher cellular uptake into both human breast cancer cell (MCF-7) and human uterine cancer cell (MES-SA) than free doxorubicin solution (Free-Dox), especially into drug-resistant cells (MCF-7/ADR and MES-SA/Dx-5). In pharmacokinetics and tissue distribution study, the bioavailability of Dox-PNP calculated from the area under the blood concentration-time curve (AUC) was 69.8 times higher than that of Free-Dox in rats, and Dox-PNP exhibited 2 times higher bioavailability in tumor tissue of tumor-bearing mice. Dox-PNP exhibited enhanced cellular uptake of the drug. In the cytotoxic activity study, this improved cellular uptake was proved to be more advantageous in drug-resistant cell. Dox-PNP exhibited much higher bioavailability in blood plasma and more drug accumulation in tumor tissue than conventional doxorubicin

  20. In vitro evaluation of the cytotoxicity and cellular uptake of CMCht/PAMAM dendrimer nanoparticles by glioblastoma cell models

    Energy Technology Data Exchange (ETDEWEB)

    Pojo, M., E-mail: martapojo@ecsaude.uminho.pt; Cerqueira, S. R.; Mota, T.; Xavier-Magalhaes, A.; Ribeiro-Samy, S. [University of Minho, Life and Health Sciences Research Institute (ICVS), School of Health Sciences (Portugal); Mano, J. F.; Oliveira, J. M., E-mail: miguel.oliveira@dep.uminho.pt; Reis, R. L. [ICVS/3Bs, PT Government Associated Laboratory (Portugal); Sousa, N.; Costa, B. M.; Salgado, A. J. [University of Minho, Life and Health Sciences Research Institute (ICVS), School of Health Sciences (Portugal)

    2013-05-15

    Glioblastoma (GBM) is simultaneously the most common and most malignant subtype tumor of the central nervous system. These are particularly dramatic diseases ranking first among all human tumor types for tumor-related average years of life lost and for which curative therapies are not available. Recently, the use of nanoparticles as drug delivery systems (DDS) for tumor treatment has gained particular interest. In an attempt to evaluate the potential of carboxymethylchitosan/poly(amidoamine) (CMCht/PAMAM) dendrimer nanoparticles as a DDS, we aimed to evaluate its cytotoxicity and internalization efficiency in GBM cell models. CMCht/PAMAM-mediated cytotoxicity was evaluated in a GBM cell line (U87MG) and in human immortalized astrocytes (hTERT/E6/E7) by MTS and double-stranded DNA quantification. CMCht/PAMAM internalization was assessed by double fluorescence staining. Both cells lines present similar internalization kinetics when exposed to a high dose (400 {mu}g/mL) of these nanoparticles. However, the internalization rate was higher in tumor GBM cells as compared to immortalized astrocytes when cells were exposed to lower doses (200 {mu}g/mL) of CMCht/PAMAM for short periods (<24 h). After 48 h of exposure, both cell lines present {approx}100% of internalization efficiency for the tested concentrations. Importantly, short-term exposures (1, 6, 12, 24, and 48 h) did not show cytotoxicity, and long-term exposures (7 days) to CMCht/PAMAM induced only low levels of cytotoxicity in both cell lines ({approx}20% of decrease in metabolic activity). The high efficiency and rate of internalization of CMCht/PAMAM we show here suggest that these nanoparticles may be an attractive DDS for brain tumor treatment in the future.

  1. APPLICATION OF NANOPARTICLES IN BIOMEDICINE

    Directory of Open Access Journals (Sweden)

    P. G. Telegeeva

    2013-04-01

    Full Text Available The advances in nanotechnology, particularly, application in biomedicine are described in the review. The characteristic of the new drug delivery systems is given including lipid, protein and polymer nanoparticles which provide stable delivery of drugs to the target of distribution in the body and prevent their rapid degradation. The advantages of nanometer scale vectors were analyzed. Due to their small size, structure and large surface area, nanoscale materials acquire necessary physico-chemical properties. These properties allow the nanoparticles, containing specific agents, to overcome the limitations existing for the forms of large sizes. This significantly facilitates the intracellular transport to specific cellular targets. Controlled deli very to the place of action and reduction of exposure time on non-target tissues increases efficacy and reduces toxicity and other side effects, which improves the patient's overall health. Use of different ways to deliver nanoparticles allows to deliver low-molecular drugs, proteins, peptides or nucleic acids to specific tissues. Various ways of nanodrugs delivery to a cell and the possibility of modifying their surface by target ligands are discussed in the review. Types of drug delivery systems: microsponges, viruses, imunoconjugates, liposomes, metal nanoparticles and quantum dots, dendrimers, natural and synthetic polymeric nanoparticles, etc are discussed. A large variety of nanovectors, as well as their modification, and loading of various drugs (the methods of inclusion and adsorption are examined, control of their release into the cell, opens prospects for their wide application for visualization of biological processes, diagnosis and therapy of wide range of diseases.

  2. Quantum Dot Platform for Single-Cell Molecular Profiling

    Science.gov (United States)

    Zrazhevskiy, Pavel S.

    In-depth understanding of the nature of cell physiology and ability to diagnose and control the progression of pathological processes heavily rely on untangling the complexity of intracellular molecular mechanisms and pathways. Therefore, comprehensive molecular profiling of individual cells within the context of their natural tissue or cell culture microenvironment is essential. In principle, this goal can be achieved by tagging each molecular target with a unique reporter probe and detecting its localization with high sensitivity at sub-cellular resolution, primarily via microscopy-based imaging. Yet, neither widely used conventional methods nor more advanced nanoparticle-based techniques have been able to address this task up to date. High multiplexing potential of fluorescent probes is heavily restrained by the inability to uniquely match probes with corresponding molecular targets. This issue is especially relevant for quantum dot probes---while simultaneous spectral imaging of up to 10 different probes is possible, only few can be used concurrently for staining with existing methods. To fully utilize multiplexing potential of quantum dots, it is necessary to design a new staining platform featuring unique assignment of each target to a corresponding quantum dot probe. This dissertation presents two complementary versatile approaches towards achieving comprehensive single-cell molecular profiling and describes engineering of quantum dot probes specifically tailored for each staining method. Analysis of expanded molecular profiles is achieved through augmenting parallel multiplexing capacity with performing several staining cycles on the same specimen in sequential manner. In contrast to other methods utilizing quantum dots or other nanoparticles, which often involve sophisticated probe synthesis, the platform technology presented here takes advantage of simple covalent bioconjugation and non-covalent self-assembly mechanisms for straightforward probe

  3. Multiplex electrochemiluminescence DNA sensor for determination of hepatitis B virus and hepatitis C virus based on multicolor quantum dots and Au nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Linlin; Wang, Xinyan; Ma, Qiang; Lin, Zihan; Chen, Shufan; Li, Yang [Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun, 130012 (China); Lu, Lehui [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 (China); Qu, Hongping [Department of Biotechnology, College of Life Science, Jilin Normal University, Siping, 136000 (China); Su, Xingguang, E-mail: suxg@jlu.edu.cn [Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun, 130012 (China)

    2016-04-15

    In this work, a novel multiplex electrochemiluminescence (ECL) DNA sensor has been developed for determination of hepatitis B virus (HBV) and hepatitis C virus (HCV) based on multicolor CdTe quantum dots (CdTe QDs) and Au nanoparticles (Au NPs). The electrochemically synthesized graphene nanosheets (GNs) were selected as conducting bridge to anchor CdTe QDs{sub 551}-capture DNA{sub HBV} and CdTe QDs{sub 607}-capture DNA{sub HCV} on the glassy carbon electrode (GCE). Then, different concentrations of target DNA{sub HBV} and target DNA{sub HCV} were introduced to hybrid with complementary CdTe QDs-capture DNA. Au NPs-probe DNA{sub HBV} and Au NPs-probe DNA{sub HCV} were modified to the above composite film via hybrid with the unreacted complementary CdTe QDs-capture DNA. Au NPs could quench the electrochemiluminescence (ECL) intensity of CdTe QDs due to the inner filter effect. Therefore, the determination of target DNA{sub HBV} and target DNA{sub HCV} could be achieved by monitoring the ECL DNA sensor based on Au NPs-probe DNA/target DNA/CdTe QDs-capture DNA/GNs/GCE composite film. Under the optimum conditions, the ECL intensity of CdTe QDs{sub 551} and CdTe QDs{sub 607} and the concentration of target DNA{sub HBV} and target DNA{sub HCV} have good linear relationship in the range of 0.0005–0.5 nmol L{sup −1} and 0.001–1.0 nmol L{sup −1} respectively, and the limit of detection were 0.082 pmol L{sup −1} and 0.34 pmol L{sup −1} respectively (S/N = 3). The DNA sensor showed good sensitivity, selectivity, reproducibility and acceptable stability. The proposed DNA sensor has been employed for the determination of target DNA{sub HBV} and target DNA{sub HCV} in human serum samples with satisfactory results. - Highlights: • A novel electrochemiluminescence DNA sensor has been developed for the determination of target DNA{sub HBV} and target DNA{sub HCV}. • The DNA sensor shows good sensitivity, reproducibility and stability. • The ECL provided a

  4. Materials Research Society Symposium Proceedings. Volume 789. Held in Boston, Massachusetts, December 1-5 2003. Quantum Dots Nanoparticles and Nanowires

    National Research Council Canada - National Science Library

    Guyot-Sionnesi, P

    2004-01-01

    ... techniques A structural transformation in the nanoparticle core mediated purely by surface layer effects in the case of CdTe and a spontaneous self-organization of nanoparticles into nanorods in the case...

  5. Surface-anchored poly(acryloyl-L(D)-valine) with enhanced chirality-selective effect on cellular uptake of gold nanoparticles

    Science.gov (United States)

    Deng, Jun; Wu, Sai; Yao, Mengyun; Gao, Changyou

    2016-01-01

    Chirality is one of the ubiquitous phenomena in biological systems. The left handed (L-) amino acids and right handed (D-) sugars are normally found in proteins, and in RNAs and DNAs, respectively. The effect of chiral surfaces at the nanoscale on cellular uptake has, however, not been explored. This study reveals for the first time the molecular chirality on gold nanoparticles (AuNPs) functions as a direct regulator for cellular uptake. Monolayers of 2-mercaptoacetyl-L(D)-valine (L(D)-MAV) and poly(acryloyl-L(D)-valine (L(D)-PAV) chiral molecules were formed on AuNPs surface, respectively. The internalized amount of PAV-AuNPs was several times larger than that of MAV-AuNPs by A549 and HepG2 cells, regardless of the chirality difference. However, the D-PAV-AuNPs were internalized with significantly larger amount than the L-PAV-AuNPs. This chirality-dependent uptake effect is likely attributed to the preferable interaction between the L-phospholipid-based cell membrane and the D-enantiomers. PMID:27531648

  6. Core–shell Fe{sub 3}O{sub 4}–Au magnetic nanoparticles based nonenzymatic ultrasensitive electrochemiluminescence immunosensor using quantum dots functionalized graphene sheet as labels

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Weiyan; Zhang, Yan [Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Ge, Shenguang [Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, Jinan 250022 (China); Song, Xianrang [Cancer Research Center, Shandong Tumor Hospital, Jinan 250012 (China); Huang, Jiadong [Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Yan, Mei, E-mail: chm_yanm@ujn.edu.cn [Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Yu, Jinghua [Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China)

    2013-04-03

    Graphical abstract: Core–shell Fe{sub 3}O{sub 4}–Au magnetic nanoparticles and P-GS@QDs were prepared to immobilize Ab{sub 1} and Ab{sub 2} respectively and combined to fabricate a novel sandwich-type ECL immunosensor for detecting CA125 at low concentration. Highlights: ► ECL immunosensor for CA125 based on a microfluidic strategy with a homemade ECL cell was proposed. ► Core–shell Fe{sub 3}O{sub 4}–Au magnetic nanoparticles were employed as the carriers of the primary antibodies. ► CdTe quantum dots functionalized graphene sheet were used for signal amplification. -- Abstract: In this paper, a novel, low-cost electrochemiluminescence (ECL) immunosensor using core–shell Fe{sub 3}O{sub 4}–Au magnetic nanoparticles (AuMNPs) as the carriers of the primary antibody of carbohydrate antigen 125 (CA125) was designed. Graphene sheet (GS) with property of good conductivity and large surface area was a captivating candidate to amplify ECL signal. We successively synthesized functionalized GS by loading large amounts of quantum dots (QDs) onto the poly (diallyldimethyl-ammonium chloride) (PDDA) coated graphene sheet (P-GS@QDs) via self-assembly electrostatic reactions, which were used to label secondary antibodies. The ECL immunosensors coupled with a microfluidic strategy exhibited a wide detection range (0.005–50 U mL{sup −1}) and a low detection limit (1.2 mU mL{sup −1}) with the help of an external magnetic field to gather immunosensors. The method was evaluated with clinical serum sample, receiving good correlation with results from commercially available analytical procedure.

  7. Surface chemistry of gold nanoparticles determines the biocorona composition impacting cellular uptake, toxicity and gene expression profiles in human endothelial cells.

    Science.gov (United States)

    Chandran, Parwathy; Riviere, Jim E; Monteiro-Riviere, Nancy A

    2017-05-01

    This study investigated the role of nanoparticle size and surface chemistry on biocorona composition and its effect on uptake, toxicity and cellular responses in human umbilical vein endothelial cells (HUVEC), employing 40 and 80 nm gold nanoparticles (AuNP) with branched polyethyleneimine (BPEI), lipoic acid (LA) and polyethylene glycol (PEG) coatings. Proteomic analysis identified 59 hard corona proteins among the various AuNP, revealing largely surface chemistry-dependent signature adsorbomes exhibiting human serum albumin (HSA) abundance. Size distribution analysis revealed the relative instability and aggregation inducing potential of bare and corona-bound BPEI-AuNP, over LA- and PEG-AuNP. Circular dichroism analysis showed surface chemistry-dependent conformational changes of proteins binding to AuNP. Time-dependent uptake of bare, plasma corona (PC) and HSA corona-bound AuNP (HSA-AuNP) showed significant reduction in uptake with PC formation. Cell viability studies demonstrated dose-dependent toxicity of BPEI-AuNP. Transcriptional profiling studies revealed 126 genes, from 13 biological pathways, to be differentially regulated by 40 nm bare and PC-bound BPEI-AuNP (PC-BPEI-AuNP). Furthermore, PC formation relieved the toxicity of cationic BPEI-AuNP by modulating expression of genes involved in DNA damage and repair, heat shock response, mitochondrial energy metabolism, oxidative stress and antioxidant response, and ER stress and unfolded protein response cascades, which were aberrantly expressed in bare BPEI-AuNP-treated cells. NP surface chemistry is shown to play the dominant role over size in determining the biocorona composition, which in turn modulates cell uptake, and biological responses, consequently defining the potential safety and efficacy of nanoformulations.

  8. Multiplex electrochemiluminescence DNA sensor for determination of hepatitis B virus and hepatitis C virus based on multicolor quantum dots and Au nanoparticles

    International Nuclear Information System (INIS)

    Liu, Linlin; Wang, Xinyan; Ma, Qiang; Lin, Zihan; Chen, Shufan; Li, Yang; Lu, Lehui; Qu, Hongping; Su, Xingguang

    2016-01-01

    In this work, a novel multiplex electrochemiluminescence (ECL) DNA sensor has been developed for determination of hepatitis B virus (HBV) and hepatitis C virus (HCV) based on multicolor CdTe quantum dots (CdTe QDs) and Au nanoparticles (Au NPs). The electrochemically synthesized graphene nanosheets (GNs) were selected as conducting bridge to anchor CdTe QDs_5_5_1-capture DNA_H_B_V and CdTe QDs_6_0_7-capture DNA_H_C_V on the glassy carbon electrode (GCE). Then, different concentrations of target DNA_H_B_V and target DNA_H_C_V were introduced to hybrid with complementary CdTe QDs-capture DNA. Au NPs-probe DNA_H_B_V and Au NPs-probe DNA_H_C_V were modified to the above composite film via hybrid with the unreacted complementary CdTe QDs-capture DNA. Au NPs could quench the electrochemiluminescence (ECL) intensity of CdTe QDs due to the inner filter effect. Therefore, the determination of target DNA_H_B_V and target DNA_H_C_V could be achieved by monitoring the ECL DNA sensor based on Au NPs-probe DNA/target DNA/CdTe QDs-capture DNA/GNs/GCE composite film. Under the optimum conditions, the ECL intensity of CdTe QDs_5_5_1 and CdTe QDs_6_0_7 and the concentration of target DNA_H_B_V and target DNA_H_C_V have good linear relationship in the range of 0.0005–0.5 nmol L"−"1 and 0.001–1.0 nmol L"−"1 respectively, and the limit of detection were 0.082 pmol L"−"1 and 0.34 pmol L"−"1 respectively (S/N = 3). The DNA sensor showed good sensitivity, selectivity, reproducibility and acceptable stability. The proposed DNA sensor has been employed for the determination of target DNA_H_B_V and target DNA_H_C_V in human serum samples with satisfactory results. - Highlights: • A novel electrochemiluminescence DNA sensor has been developed for the determination of target DNA_H_B_V and target DNA_H_C_V. • The DNA sensor shows good sensitivity, reproducibility and stability. • The ECL provided a convenient, low-cost, sensitive, and specific method for target DNA

  9. Nuclear and Cytoplasmic Delivery of Lactoferrin in Glioma using Chitosan Nanoparticles: Cellular Location Dependent-Action of Lactoferrin.

    Science.gov (United States)

    Tammam, Salma N; Azzazy, Hassan M E; Lamprecht, Alf

    2018-05-23

    Lactoferrin (Lf) exerts anti-cancer effects on glioma, however, the exact mechanism remains unclear. Despite possessing a nuclear localization sequence (NLS), Lf was found to allocate only in the cytoplasm of glioma 261. Lf was therefore loaded into nuclear and cytoplasmic targeted nanoparticles (NPs) to determine whether nuclear delivery of Lf would enhance its anti-cancer effect. Upon treatment with 300 and 800 µg/mL Lf loaded chitosan NPs, nuclear targeted Lf-NPs showed 1.3 and 2.7 folds increase in cell viability, whereas cytoplasmic targeted Lf-NPs at 300 µg/mL decreased cell viability by 0.8 folds in comparison to free Lf and controls. Results suggest that the cytotoxicity of Lf on glioma is attributable to its cytoplasmic allocation. Nuclear delivery of Lf induced cell proliferation rather than cytotoxicity, indicating that the mode of action of Lf in glioma is cell location dependent. This calls for caution about the general use of Lf as an anti-cancer protein. Copyright © 2018. Published by Elsevier B.V.

  10. nanoparticles

    Science.gov (United States)

    Andreu-Cabedo, Patricia; Mondragon, Rosa; Hernandez, Leonor; Martinez-Cuenca, Raul; Cabedo, Luis; Julia, J. Enrique

    2014-10-01

    Thermal energy storage (TES) is extremely important in concentrated solar power (CSP) plants since it represents the main difference and advantage of CSP plants with respect to other renewable energy sources such as wind, photovoltaic, etc. CSP represents a low-carbon emission renewable source of energy, and TES allows CSP plants to have energy availability and dispatchability using available industrial technologies. Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 500°C. Their main drawbacks are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve thermal properties of fluids is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. In this work, solar salt used in CSP plants (60% NaNO3 + 40% KNO3) was doped with silica nanoparticles at different solid mass concentrations (from 0.5% to 2%). Specific heat was measured by means of differential scanning calorimetry (DSC). A maximum increase of 25.03% was found at an optimal concentration of 1 wt.% of nanoparticles. The size distribution of nanoparticle clusters present in the salt at each concentration was evaluated by means of scanning electron microscopy (SEM) and image processing, as well as by means of dynamic light scattering (DLS). The cluster size and the specific surface available depended on the solid content, and a relationship between the specific heat increment and the available particle surface area was obtained. It was proved that the mechanism involved in the specific heat increment is based on a surface phenomenon. Stability of samples was tested for several thermal cycles and thermogravimetric analysis at high temperature was carried out, the samples being stable.

  11. Scanning electron microscopy of individual nanoparticle bio-markers in liquid

    Energy Technology Data Exchange (ETDEWEB)

    Liv, Nalan, E-mail: n.liv@tudelft.nl; Lazić, Ivan; Kruit, Pieter; Hoogenboom, Jacob P.

    2014-08-01

    We investigated SEM imaging of nanoparticle biomarkers suspended below a thin membrane, with the ultimate goal of integrating functional fluorescence and structural SEM measurements of samples kept at ambient or hydrated conditions. In particular, we investigated how resolving power in liquid SEM is affected by the interaction of the electron beam with the membrane. Simulations with the Geant4-based Monte Carlo scheme developed by Kieft and Bosch (2008) [1] are compared to experimental results with suspended nanoparticles. For 20 nm and 50 nm thin membranes, we found a beam broadening of 1.5 nm and 3 nm, respectively, with an excellent agreement between simulations and experiments. 15 nm Au nanoparticles and bio-functionalized core-shell quantum dots can be individually resolved in denser clusters. We demonstrated the imaging of single EGF-conjugated quantum dots docked at filopodia during cellular uptake with both fluorescence microscopy and SEM simultaneously. These results open novel opportunities for correlating live fluorescence microscopy with structural electron microscopy. - Highlights: • We investigate the achievable resolution in liquid scanning electron microscopy (SEM). • We demonstrate liquid SEM imaging of individual fluorescent nanoparticle bio-markers • We show imaging of cellular QDot uptake with simultaneous fluorescence microscopy and SEM. • The positions of individual QDots can be resolved with details on cellular structure.

  12. Scanning electron microscopy of individual nanoparticle bio-markers in liquid

    International Nuclear Information System (INIS)

    Liv, Nalan; Lazić, Ivan; Kruit, Pieter; Hoogenboom, Jacob P.

    2014-01-01

    We investigated SEM imaging of nanoparticle biomarkers suspended below a thin membrane, with the ultimate goal of integrating functional fluorescence and structural SEM measurements of samples kept at ambient or hydrated conditions. In particular, we investigated how resolving power in liquid SEM is affected by the interaction of the electron beam with the membrane. Simulations with the Geant4-based Monte Carlo scheme developed by Kieft and Bosch (2008) [1] are compared to experimental results with suspended nanoparticles. For 20 nm and 50 nm thin membranes, we found a beam broadening of 1.5 nm and 3 nm, respectively, with an excellent agreement between simulations and experiments. 15 nm Au nanoparticles and bio-functionalized core-shell quantum dots can be individually resolved in denser clusters. We demonstrated the imaging of single EGF-conjugated quantum dots docked at filopodia during cellular uptake with both fluorescence microscopy and SEM simultaneously. These results open novel opportunities for correlating live fluorescence microscopy with structural electron microscopy. - Highlights: • We investigate the achievable resolution in liquid scanning electron microscopy (SEM). • We demonstrate liquid SEM imaging of individual fluorescent nanoparticle bio-markers • We show imaging of cellular QDot uptake with simultaneous fluorescence microscopy and SEM. • The positions of individual QDots can be resolved with details on cellular structure

  13. Using of Quantum Dots in Biology and Medicine.

    Science.gov (United States)

    Pleskova, Svetlana; Mikheeva, Elza; Gornostaeva, Ekaterina

    2018-01-01

    Quantum dots are nanoparticles, which due to their unique physical and chemical (first of all optical) properties, are promising in biology and medicine. There are many ways for quantum dots synthesis, both in the form of nanoislands self-forming on the surfaces, which can be used as single-photon emitters in electronics for storing information, and in the form of colloidal quantum dots for diagnostic and therapeutic purposes in living systems. The paper describes the main methods of quantum dots synthesis and summarizes medical and biological ways of their use. The main emphasis is laid on the ways of quantum dots surface modification. Influence of the size and form of nanoparticles, charge on the surfaces of quantum dots, and cover type on the efficiency of internalization by cells and cell compartments is shown. The main mechanisms of penetration are considered.

  14. Light-emitting diodes based on solution-processed nontoxic quantum dots: oxides as carrier-transport layers and introducing molybdenum oxide nanoparticles as a hole-inject layer.

    Science.gov (United States)

    Bhaumik, Saikat; Pal, Amlan J

    2014-07-23

    We report fabrication and characterization of solution-processed quantum dot light-emitting diodes (QDLEDs) based on a layer of nontoxic and Earth-abundant zinc-diffused silver indium disulfide (AIZS) nanoparticles as an emitting material. In the QDLEDs fabricated on indium tin oxide (ITO)-coated glass substrates, we use layers of oxides, such as graphene oxide (GO) and zinc oxide (ZnO) nanoparticles as a hole- and electron-transport layer, respectively. In addition, we introduce a layer of MoO3 nanoparticles as a hole-inject one. We report a comparison of the characteristics of different device architectures. We show that an inverted device architecture, ITO/ZnO/AIZS/GO/MoO3/Al, yields a higher electroluminescence (EL) emission, compared to direct ones, for three reasons: (1) the GO/MoO3 layers introduce barriers for electrons to reach the Al electrode, and, similarly, the ZnO layers acts as a barrier for holes to travel to the ITO electrode; (2) the introduction of a layer of MoO3 nanoparticles as a hole-inject layer reduces the barrier height for holes and thereby balances charge injection in the inverted structure; and (3) the wide-bandgap zinc oxide next to the ITO electrode does not absorb the EL emission during its exit from the device. In the QDLEDs with oxides as carrier inject and transport layers, the EL spectrum resembles the photoluminescence emission of the emitting material (AIZS), implying that excitons are formed in the quaternary nanocrystals and decay radiatively.

  15. Cellular and molecular responses of adult zebrafish after exposure to CuO nanoparticles or ionic copper.

    Science.gov (United States)

    Vicario-Parés, Unai; Lacave, Jose M; Reip, Paul; Cajaraville, Miren P; Orbea, Amaia

    2018-01-01

    Due to their antimicrobial, electrical and magnetic properties, copper nanoparticles (NPs) are suitable for a vast array of applications. Copper can be toxic to biota, making it necessary to assess the potential hazard of copper nanomaterials. Zebrafish (Danio rerio) were exposed to 10 µg Cu/L of CuO NPs of ≈100 nm (CuO-poly) or ionic copper to compare the effects provoked after 3 and 21 days of exposure and at 6 months post-exposure (mpe). At 21 days, significant copper accumulation was only detected in fish exposed to ionic copper. Exposure to both copper forms caused histopathological alterations that could reduce gill functionality, more markedly in the case of ionic copper. Nevertheless, at 6 mpe higher prevalences of gill lesions were detected in fish previously exposed to CuO-poly NPs. No relevant histological alterations were detected in liver, but the lysosomal membrane stability test showed significantly impaired general health status after exposure to both metal forms that lasted up to 6 mpe. 69 transcripts appeared regulated after 3 days of exposure to CuO-poly NPs, suggesting that NPs could produce oxidative stress and reduce metabolism and transport processes. Thirty transcripts were regulated after 21 days of exposure to ionic copper, indicating possible DNA damage. Genes of the circadian clock were identified as the key genes involved in time-dependent differences between the two copper forms. In conclusion, each copper form showed a distinct pattern of liver transcriptome regulation, but both caused gill histopathological alterations and long lasting impaired health status in adult zebrafish.

  16. Biocompatible fluorescent zein nanoparticles for simultaneous bioimaging and drug delivery application

    International Nuclear Information System (INIS)

    Girija Aswathy, Ravindran; Sivakumar, Balasubramanian; Brahatheeswaran, Dhandayudhapani; Fukuda, Takahiro; Yoshida, Yasuhiko; Maekawa, Toru; Sakthi Kumar, D

    2012-01-01

    We report the synthesis of 5-fluorouracil (5-FU) loaded biocompatible fluorescent zein nanoparticles. Zein is the storage protein in corn kernels that has a variety of unique characteristics and functionalities that makes zein valuable in various commercial applications. It is classified as generally recognized as safe (GRAS) by the Food and Drug Administration (FDA). We synthesized zein nanoparticles of around 800 nm in size and conjugated with quantum dot ZnS:Mn. The nanoparticle was in turn encapsulated with the drug 5-FU. The luminescent properties of these nanoparticles were studied by using fluorescence microscopy. The nanoparticles were characterized and the drug release profile was studied. The biocompatibility of zein nanoparticle and the cytotoxicity with drug-loaded nanoparticle was studied in L929 and MCF-7 cell lines. The nanoparticles were successfully employed for cellular imaging. In vitro drug release studies were also performed. The biocompatibility of the nanoparticle showed that nanoparticles at higher concentrations are compatible for cells and are expected to be promising agents for the targeted delivery of drugs in the near future

  17. Spectroscopic characteristics of carbon dots (C-dots) derived from carbon fibers and conversion to sulfur-bridged C-dots nanosheets.

    Science.gov (United States)

    Vinci, John C; Ferrer, Ivonne M; Guterry, Nathan W; Colón, Verónica M; Destino, Joel F; Bright, Frank V; Colón, Luis A

    2015-09-01

    We synthesized sub-10 nm carbon nanoparticles (CNPs) consistent with photoluminescent carbon dots (C-dots) from carbon fiber starting material. The production of different C-dots fractions was monitored over seven days. During the course of the reaction, one fraction of C-dots species with relatively high photoluminescence was short-lived, emerging during the first hour of reaction but disappearing after one day of reaction. Isolation of this species during the first hour of the reaction was crucial to obtaining higher-luminescent C-dots species. When the reaction proceeded for one week, the appearance of larger nanostructures was observed over time, with lateral dimensions approaching 200 nm. The experimental evidence suggests that these larger species are formed from small C-dot nanoparticles bridged together by sulfur-based moieties between the C-dot edge groups, as if the C-dots polymerized by cross-linking the edge groups through sulfur bridges. Their size can be tailored by controlling the reaction time. Our results highlight the variety of CNP products, from sub-10 nm C-dots to ~200 nm sulfur-containing carbon nanostructures, that can be produced over time during the oxidation reaction of the graphenic starting material. Our work provides a clear understanding of when to stop the oxidation reaction during the top-down production of C-dots to obtain highly photoluminescent species or a target average particle size.

  18. Interaction with culture medium components, cellular uptake and intracellular distribution of cobalt nanoparticles, microparticles and ions in Balb/3T3 mouse fibroblasts.

    Science.gov (United States)

    Sabbioni, Enrico; Fortaner, Salvador; Farina, Massimo; Del Torchio, Riccardo; Petrarca, Claudia; Bernardini, Giovanni; Mariani-Costantini, Renato; Perconti, Silvia; Di Giampaolo, Luca; Gornati, Rosalba; Di Gioacchino, Mario

    2014-02-01

    The mechanistic understanding of nanotoxicity requires the physico-chemical characterisation of nanoparticles (NP), and their comparative investigation relative to the corresponding ions and microparticles (MP). Following this approach, the authors studied the dissolution, interaction with medium components, bioavailability in culture medium, uptake and intracellular distribution of radiolabelled Co forms (CoNP, CoMP and Co(2+)) in Balb/3T3 mouse fibroblasts. Co(2+) first saturates the binding sites of molecules in the extracellular milieu (e.g., albumin and histidine) and on the cell surface. Only after saturation, Co(2+) is actively uptaken. CoNP, instead, are predicted to be internalised by endocytosis. Dissolution of Co particles allows the formation of Co compounds (CoNP-rel), whose mechanism of cellular internalisation is unknown. Co uptake (ranking CoMP > CoNP > Co(2+)) reached maximum at 4 h. Once inside the cell, CoNP spread into the cytosol and organelles. Consequently, massive amounts of Co ions and CoNP-rel can reach subcellular compartments normally unexposed to Co(2+). This could explain the fact that the nuclear and mitochondrial Co concentrations resulted significantly higher than those obtained with Co(2+).

  19. Surface modification of solid lipid nanoparticles for oral delivery of curcumin: Improvement of bioavailability through enhanced cellular uptake, and lymphatic uptake.

    Science.gov (United States)

    Baek, Jong-Suep; Cho, Cheong-Weon

    2017-08-01

    Curcumin has been reported to exhibit potent anticancer effects. However, poor solubility, bioavailability and stability of curcumin limit its in vivo efficacy for the cancer treatment. Solid lipid nanoparticles (SLN) are a promising delivery system for the enhancement of bioavailability of hydrophobic drugs. However, burst release of drug from SLN in acidic environment limits its usage as oral delivery system. Hence, we prepared N-carboxymethyl chitosan (NCC) coated curcumin-loaded SLN (NCC-SLN) to inhibit the rapid release of curcumin in acidic environment and enhance the bioavailability. The NCC-SLN exhibited suppressed burst release in simulated gastric fluid while sustained release was observed in simulated intestinal fluid. Furthermore, NCC-SLN exhibited increased cytotoxicity and cellular uptake on MCF-7 cells. The lymphatic uptake and oral bioavailability of NCC-SLN were found to be 6.3-fold and 9.5-fold higher than that of curcumin solution, respectively. These results suggest that NCC-SLN could be an efficient oral delivery system for curcumin. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Loading Cd0.5Zn0.5S Quantum Dots onto Onion-Like Carbon Nanoparticles to Boost Photocatalytic Hydrogen Generation.

    Science.gov (United States)

    Zhou, Xiaolong; Wang, Xina; Feng, Xi; Zhang, Kun; Peng, Xiaoniu; Wang, Hanbin; Liu, Chunlei; Han, Yibo; Wang, Hao; Li, Quan

    2017-07-12

    Carbon dots (C dots, size < 10 nm) have been conventionally decorated onto semiconductor matrixes for photocatalytic H 2 evolution, but the efficiency is largely limited by the low loading ratio of the C dots on the photocatalyst. Here, we propose an inverse structure of Cd 0.5 Zn 0.5 S quantum dots (QDs) loaded onto the onionlike carbon (OLC) matrix for noble metal-free photocatalytic H 2 evolution. Cd 0.5 Zn 0.5 S QDs (6.9 nm) were uniformly distributed on an OLC (30 nm) matrix with both upconverted and downconverted photoluminescence property. Such an inverse structure allows the full optimization of the QD/OLC interfaces for effective energy transfer and charge separation, both of which contribute to efficient H 2 generation. An optimized H 2 generation rate of 2018 μmol/h/g (under the irradiation of visible light) and 58.6 μmol/h/g (under the irradiation of 550-900 nm light) was achieved in the Cd 0.5 Zn 0.5 S/OLC composite samples. The present work shows that using the OLC matrix in such a reverse construction is a promising strategy for noble metal-free solar hydrogen production.

  1. PREPARATIONS AND APPLICATION OF METAL NANOPARTICLES

    OpenAIRE

    Adlim, Adlim

    2010-01-01

    Terminology of metal nanoparticles, the uniqueness properties in terms of the surface atom, the quantum dot, and the magnetism are described. The further elaboration was on the synthesis of nanoparticles. Applications of metal nanoparticles in electronic, ceramic medical and catalysis were overviewed. The bibliography includes 81 references with 99% are journal articles.   Keywords: metal nanoparticles

  2. PREPARATIONS AND APPLICATION OF METAL NANOPARTICLES

    Directory of Open Access Journals (Sweden)

    Adlim Adlim

    2010-06-01

    Full Text Available Terminology of metal nanoparticles, the uniqueness properties in terms of the surface atom, the quantum dot, and the magnetism are described. The further elaboration was on the synthesis of nanoparticles. Applications of metal nanoparticles in electronic, ceramic medical and catalysis were overviewed. The bibliography includes 81 references with 99% are journal articles.   Keywords: metal nanoparticles

  3. Biocompatible Quantum Dots for Biological Applications

    Science.gov (United States)

    Rosenthal, Sandra J.; Chang, Jerry C.; Kovtun, Oleg; McBride, James R.; Tomlinson, Ian D.

    2011-01-01

    Semiconductor quantum dots are quickly becoming a critical diagnostic tool for discerning cellular function at the molecular level. Their high brightness, long-lasting, sizetunable, and narrow luminescence set them apart from conventional fluorescence dyes. Quantum dots are being developed for a variety of biologically oriented applications, including fluorescent assays for drug discovery, disease detection, single protein tracking, and intracellular reporting. This review introduces the science behind quantum dots and describes how they are made biologically compatible. Several applications are also included, illustrating strategies toward target specificity, and are followed by a discussion on the limitations of quantum dot approaches. The article is concluded with a look at the future direction of quantum dots. PMID:21276935

  4. Optical properties of quantum-dot-doped liquid scintillators

    International Nuclear Information System (INIS)

    Aberle, C; Winslow, L; Li, J J; Weiss, S

    2013-01-01

    Semiconductor nanoparticles (quantum dots) were studied in the context of liquid scintillator development for upcoming neutrino experiments. The unique optical and chemical properties of quantum dots are particularly promising for the use in neutrinoless double-beta decay experiments. Liquid scintillators for large scale neutrino detectors have to meet specific requirements which are reviewed, highlighting the peculiarities of quantum-dot-doping. In this paper, we report results on laboratory-scale measurements of the attenuation length and the fluorescence properties of three commercial quantum dot samples. The results include absorbance and emission stability measurements, improvement in transparency due to filtering of the quantum dot samples, precipitation tests to isolate the quantum dots from solution and energy transfer studies with quantum dots and the fluorophore PPO

  5. Enhanced cellular uptake and phototoxicity of Verteporfin-conjugated gold nanoparticles as theranostic nanocarriers for targeted photodynamic therapy and imaging of cancers

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Linlin [Tianjin Key Laboratory for Photoelectric Materials and Devices, School of Materials Science & Engineering, Tianjin University of Technology, Tianjin 300384 (China); Graduate School of Energy Science and Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Kim, Tae-Hyun; Kim, Hae-Won [Department of Nanobiomedical Science, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN) & College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Ahn, Jin-Chul [Department of Biomedical Science, College of Medicine, Dankook University, Cheonan, 330-714 (Korea, Republic of); Kim, So Yeon, E-mail: kimsy@cnu.ac.kr [Graduate School of Energy Science and Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Department of Chemical Engineering Education, College of Education, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2016-10-01

    Activatable theranostics with the capacity to respond to a given stimulus have recently been intensively explored to develop more specific, individualized therapies for various diseases, and to combine diagnostic and therapeutic capabilities into a single agent. In this work, we designed tumor-targeting ligand-conjugated block copolymer-gold nanoparticle (AuNP) conjugates as multifunctional nanocarriers of the hydrophobic photosensitizer (PS), verteporfin (Verte), for simultaneous photodynamic therapy and imaging of cancers. Folic acid (FA)-conjugated block copolymers composed of polyethylene glycol (PEG) and poly-β-benzyl-L-aspartate (PBLA) were attached to citrate-stabilized AuNPs through a bidentate dihydrolipoic acid (DHLA) linker. The resulting AuNP conjugates (FA-PEG-P(Asp-Hyd)-DHLA-AuNPs) were significantly more stable than unmodified AuNPs, and their optical properties were not affected by pH. The hydrophobic PS, Verte, was covalently incorporated onto the surfaces of the AuNP conjugates through a pH-sensitive linkage, which increased the water solubility of Verte from < 1 μg/ml to > 2000 μg/ml. The size of FA-PEG-P(Asp-Hyd)-DHLA-AuNPs-Verte as determined by light-scattering measurements was about 110.3 nm, and FE-SEM and FE-TEM images showed that these nanoparticles were spherical and showed adequate dispersivity after modification. In particular, an in vitro cell study revealed high intracellular uptake of FA-PEG-P(Asp-Hyd)-DHLA-AuNPs-Verte (about 98.62%) and marked phototoxicity after laser irradiation compared with free Verte. These results suggest that FA-PEG-P(Asp-Hyd)-DHLA-AuNPs-Verte has great potential as an effective nanocarrier for dual imaging and photodynamic therapy. - Highlights: • We designed theranostic nanocarriers for photodynamic therapy and imaging of cancers. • AuNP conjugates had a spherical shape and a narrow size distribution with a mean diameter of 110.3 nm. • Cellular uptake of free Verte was 18.86%, whereas that of Au

  6. Cyto-molecular Tuning of Quantum Dots

    Science.gov (United States)

    Lee, Bong; Suresh, Sindhuja; Ekpenyong, Andrew

    Quantum dots (QDs) are semiconductor nanoparticles composed of groups II-VI or III-V elements, with physical dimensions smaller than the exciton Bohr radius, and between 1-10 nm. Their applications and promising myriad applications in photovoltaic cells, biomedical imaging, targeted drug delivery, quantum computing, etc, have led to much research on their interactions with other systems. For biological systems, research has focused on biocompatibility and cytotoxicity of QDs in the context of imaging/therapy. However, there is a paucity of work on how biological systems might be used to tune QDs. Here, we hypothesize that the photo-electronic properties of QDs can be tuned by biological macromolecules following controlled changes in cellular activities. Using CdSe/ZnS core-shell QDs, we perform spectroscopic analysis of optically excited colloidal QDs with and without promyelocytic HL60 cells. Preliminary results show shifts in the emission spectra of the colloidal dispersions with and without cells. We will present results for activated HL60-derived cells where specific macromolecules produced by these cells perturb the electric dipole moments of the excited QDs and the associated electric fields, in ways that constitute what we describe as cyto-molecular tuning. Startup funds from the College of Arts and Sciences, Creighton University (to AEE).

  7. Hyperbolic metamaterials based on quantum-dot plasmon-resonator nanocomposites

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Ozel, T.; Mutlugun, E.

    2014-01-01

    We theoretically demonstrate that nanocomposites made of colloidal semiconductor quantum dot monolayers placed between metal nanoparticle monolayers can function as multilayer hyperbolic metamaterials. Depending on the thickness of the spacer between the quantum dot and nanoparticle layers......, the effective permittivity tensor of the nanocomposite is shown to become indefinite, resulting in increased photonic density of states and strong enhancement of quantum dot luminescence. This explains the results of recent experiments [T. Ozel et al., ACS Nano 5, 1328 (2011)] and confirms that hyperbolic...

  8. Two-dimensional TiO_2-based nanosheets co-modified by surface-enriched carbon dots and Gd_2O_3 nanoparticles for efficient visible-light-driven photocatalysis

    International Nuclear Information System (INIS)

    Lu, Dingze; Fang, Pengfei; Ding, Junqian; Yang, Minchen; Cao, Yufei; Zhou, Yawei; Peng, Kui; Kondamareddy, Kiran Kumar; Liu, Min

    2017-01-01

    Highlights: • Gd-C-TNSs with high stability and recycle usability were prepared by two-pot method. • Gd_2O_3 loading results in the structure changes of TNSs and increase of the Ti"3"+ ions. • Modified CDs leads to obvious increase of optical absorption ability and red shift. • Appropriate amount of Gd_2O_3 nanoparticles and CDs improve the separation of charges. • Gd-C-TNSs exhibit excellent synergistic photocatalytic activity for Cr(VI) and RhB. - Abstract: Two-dimensional TiO_2-based nanosheets (TNSs) co-modified by surface-enriched carbon dots (CDs) and Gd_2O_3 nanoparticles: (Gd-C-TNSs), capable of exhibiting visible-light-driven photo catalysis were synthesized using a two-pot hydrothermal route. The samples had a sheet-like structure, thickness of approximately 3.6 nm, large specific surface area of 240–350 cm"2/g. The CDs (2–3 nm) and Gd_2O_3 nanoparticles (1–2 nm) were highly dispersed over the surface of the nanosheets. The co-modification by Gd_2O_3 nanoparticles and CDs influenced the crystallinity, crystal structure, and surface area of the TNSs, and improved the visible-light absorption. Surface photocurrent and fluorescence spectral studies revealed that the photo-generated charge carrier separation efficiency could be improved by an appropriate amount of modification. A very high efficiency was obtained using 0.5 at% Gd/Ti and 3.0 g/L of CDs. The visible-light-induced photocatalytic activity is enhanced under the isolated Cr(VI) system, isolated Rhodamin B (RhB) system, and the synergism between RhB degradation and Cr(VI) reduction for the Gd-C-TNSs photocatalysts. Initially, the photocatalytic activity gradually increased with an increase in the amount of CDs, and then decreased after attaining a maximum, in the case where 0.5 at% Gd/Ti and 3.0 g/L of CDs were used. The enhancement in the photocatalytic activity was attributed to the synergetic effect of the Gd_2O_3 nanoparticles, TNSs, and CDs in the Gd-C-TNSs composites. The

  9. Two-dimensional TiO{sub 2}-based nanosheets co-modified by surface-enriched carbon dots and Gd{sub 2}O{sub 3} nanoparticles for efficient visible-light-driven photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Dingze, E-mail: 1005116870@qq.com [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Fang, Pengfei, E-mail: fangpf@whu.edu.cn [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Ding, Junqian, E-mail: 630736958@qq.com [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Yang, Minchen, E-mail: 1023635028@qq.com [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Cao, Yufei, E-mail: 344541464@qq.com [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Zhou, Yawei, E-mail: 769107311@qq.com [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Peng, Kui, E-mail: 758007737@qq.com [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Kondamareddy, Kiran Kumar, E-mail: kokila_kkk@yahoo.co.in [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Liu, Min, E-mail: liumhb@126.com [State Grid Zhejiang Electric Power Research Institute, Hangzhou, Zhejiang 310007 (China)

    2017-02-28

    Highlights: • Gd-C-TNSs with high stability and recycle usability were prepared by two-pot method. • Gd{sub 2}O{sub 3} loading results in the structure changes of TNSs and increase of the Ti{sup 3+} ions. • Modified CDs leads to obvious increase of optical absorption ability and red shift. • Appropriate amount of Gd{sub 2}O{sub 3} nanoparticles and CDs improve the separation of charges. • Gd-C-TNSs exhibit excellent synergistic photocatalytic activity for Cr(VI) and RhB. - Abstract: Two-dimensional TiO{sub 2}-based nanosheets (TNSs) co-modified by surface-enriched carbon dots (CDs) and Gd{sub 2}O{sub 3} nanoparticles: (Gd-C-TNSs), capable of exhibiting visible-light-driven photo catalysis were synthesized using a two-pot hydrothermal route. The samples had a sheet-like structure, thickness of approximately 3.6 nm, large specific surface area of 240–350 cm{sup 2}/g. The CDs (2–3 nm) and Gd{sub 2}O{sub 3} nanoparticles (1–2 nm) were highly dispersed over the surface of the nanosheets. The co-modification by Gd{sub 2}O{sub 3} nanoparticles and CDs influenced the crystallinity, crystal structure, and surface area of the TNSs, and improved the visible-light absorption. Surface photocurrent and fluorescence spectral studies revealed that the photo-generated charge carrier separation efficiency could be improved by an appropriate amount of modification. A very high efficiency was obtained using 0.5 at% Gd/Ti and 3.0 g/L of CDs. The visible-light-induced photocatalytic activity is enhanced under the isolated Cr(VI) system, isolated Rhodamin B (RhB) system, and the synergism between RhB degradation and Cr(VI) reduction for the Gd-C-TNSs photocatalysts. Initially, the photocatalytic activity gradually increased with an increase in the amount of CDs, and then decreased after attaining a maximum, in the case where 0.5 at% Gd/Ti and 3.0 g/L of CDs were used. The enhancement in the photocatalytic activity was attributed to the synergetic effect of the Gd{sub 2}O

  10. DOT's CAFE rulemaking analysis.

    Science.gov (United States)

    2013-02-13

    Presentation discusses what DOT needs to consider in setting CAFE standards. How DOT's use of the CAFE Compliance and Effects Modeling System helps to analyze potential CAFE Standards. How DOT might approach the next round of CAFE standards for model...

  11. Cellular Response to Titanium Dioxide Nanoparticles in Intestinal Epithelial Caco-2 Cells is Dependent on Endocytosis-Associated Structures and Mediated by EGFR

    Science.gov (United States)

    Krüger, Kristin; Schrader, Katrin; Klempt, Martin

    2017-01-01

    Titanium dioxide (TiO2) is one of the most applied nanomaterials and widely used in food and non-food industries as an additive or coating material (E171). It has been shown that E171 contains up to 37% particles which are smaller than 100 nm and that TiO2 nanoparticles (NPs) induce cytotoxicity and inflammation. Using a nuclear factor Kappa-light-chain enhancer of activated B cells (NF-κB) reporter cell line (Caco-2nfkb-RE), Real time polymerase chain reaction (PCR), and inhibition of dynamin and clathrin, it was shown that cellular responses induced by 5 nm and 10 nm TiO2 NPs (nominal size) depends on endocytic processes. As endocytosis is often dependent on the epithelial growth factor receptor (EGFR), further investigations focused on the involvement of EGFR in the uptake of TiO2 NPs: (1) inhibition of EGFR reduced inflammatory markers of the cell (i.e., nuclear factor (NF)-κB activity, mRNA of IL8, CCL20, and CXCL10); and (2) exposure of Caco-2 cells to TiO2 NPs activated the intracellular EGFR cascade beginning with EGFR-mediated extracellular signal-regulated kinases (ERK)1/2, and including transcription factor ELK1. This was followed by the expression of ERK1/2 target genes CCL2 and CXCL3. We concluded that TiO2 NPs enter the cell via EGFR-associated endocytosis, followed by activation of the EGFR/ERK/ELK signaling pathway, which finally induces NF-κB. No changes in inflammatory response are observed in Caco-2 cells exposed to 32 nm and 490 nm TiO2 particles. PMID:28387727

  12. Cellular Response to Titanium Dioxide Nanoparticles in Intestinal Epithelial Caco-2 Cells is Dependent on Endocytosis-Associated Structures and Mediated by EGFR.

    Science.gov (United States)

    Krüger, Kristin; Schrader, Katrin; Klempt, Martin

    2017-04-07

    Titanium dioxide (TiO₂) is one of the most applied nanomaterials and widely used in food and non-food industries as an additive or coating material (E171). It has been shown that E171 contains up to 37% particles which are smaller than 100 nm and that TiO₂ nanoparticles (NPs) induce cytotoxicity and inflammation. Using a nuclear factor Kappa-light-chain enhancer of activated B cells (NF-κB) reporter cell line (Caco-2 nfkb-RE ), Real time polymerase chain reaction (PCR), and inhibition of dynamin and clathrin, it was shown that cellular responses induced by 5 nm and 10 nm TiO₂ NPs (nominal size) depends on endocytic processes. As endocytosis is often dependent on the epithelial growth factor receptor (EGFR), further investigations focused on the involvement of EGFR in the uptake of TiO₂ NPs: (1) inhibition of EGFR reduced inflammatory markers of the cell (i.e., nuclear factor (NF)-κB activity, mRNA of IL8, CCL20, and CXCL10); and (2) exposure of Caco-2 cells to TiO₂ NPs activated the intracellular EGFR cascade beginning with EGFR-mediated extracellular signal-regulated kinases (ERK)1/2, and including transcription factor ELK1. This was followed by the expression of ERK1/2 target genes CCL2 and CXCL3. We concluded that TiO₂ NPs enter the cell via EGFR-associated endocytosis, followed by activation of the EGFR/ERK/ELK signaling pathway, which finally induces NF-κB. No changes in inflammatory response are observed in Caco-2 cells exposed to 32 nm and 490 nm TiO₂ particles.

  13. Influence of ablation wavelength and time on optical properties of laser ablated carbon dots

    Science.gov (United States)

    Isnaeni, Hanna, M. Yusrul; Pambudi, A. A.; Murdaka, F. H.

    2017-01-01

    Carbon dots, which are unique and applicable materials, have been produced using many techniques. In this work, we have fabricated carbon dots made of coconut fiber using laser ablation technique. The purpose of this work is to evaluate two ablation parameters, which are ablation wavelength and ablation time. We used pulsed laser from Nd:YAG laser with emit wavelength at 355 nm, 532 nm and 1064 nm. We varied ablation time one hour and two hours. Photoluminescence and time-resolved photoluminescence setup were used to study the optical properties of fabricated carbon dots. In general, fabricated carbon dots emit bluish green color emission upon excitation by blue laser. We found that carbon dots fabricated using 1064 nm laser produced the highest carbon dots emission among other samples. The peak wavelength of carbon dots emission is between 495 nm until 505 nm, which gives bluish green color emission. Two hours fabricated carbon dots gave four times higher emission than one hour fabricated carbon dot. More emission intensity of carbon dots means more carbon dots nanoparticles were fabricated during laser ablation process. In addition, we also measured electron dynamics of carbon dots using time-resolved photoluminescence. We found that sample with higher emission has longer electron decay time. Our finding gives optimum condition of carbon dots fabrication from coconut fiber using laser ablation technique. Moreover, fabricated carbon dots are non-toxic nanoparticles that can be applied for health, bio-tagging and medical applications.

  14. Spray deposition of water-soluble multiwall carbon nanotube and Cu2ZnSnSe4 nanoparticle composites as highly efficient counter electrodes in a quantum dot-sensitized solar cell system

    Science.gov (United States)

    Zeng, Xianwei; Xiong, Dehua; Zhang, Wenjun; Ming, Liqun; Xu, Zhen; Huang, Zhanfeng; Wang, Mingkui; Chen, Wei; Cheng, Yi-Bing

    2013-07-01

    In this paper, low-cost counter electrodes (CEs) based on water-soluble multiwall carbon nanotube (MWCNT) and Cu2ZnSnSe4 nanoparticle (CZTSe NP) composites have been successfully introduced into a quantum dot-sensitized solar cell (QDSC) system. Suitable surface modification allows the MWCNTs and CZTSe NPs to be homogeneously dispersed in water, facilitating the subsequent low-temperature spray deposition of high quality composite films with different composite ratios. The electrochemical catalytic activity of the composite CEs has been critically compared by electrochemical impedance spectroscopy and Tafel-polarization analysis. It is found that the composite CE at the MWCNT : CZTSe ratio of 0.1 offers the best performance, leading to an optimal solar cell efficiency of 4.60%, which is 50.8% higher than that of the Pt reference CE. The as-demonstrated higher catalytic activity of the composite CEs compared to their single components could be ascribed to the combination of the fast electron transport of the MWCNTs and the high catalytic activity of CZTSe NPs.In this paper, low-cost counter electrodes (CEs) based on water-soluble multiwall carbon nanotube (MWCNT) and Cu2ZnSnSe4 nanoparticle (CZTSe NP) composites have been successfully introduced into a quantum dot-sensitized solar cell (QDSC) system. Suitable surface modification allows the MWCNTs and CZTSe NPs to be homogeneously dispersed in water, facilitating the subsequent low-temperature spray deposition of high quality composite films with different composite ratios. The electrochemical catalytic activity of the composite CEs has been critically compared by electrochemical impedance spectroscopy and Tafel-polarization analysis. It is found that the composite CE at the MWCNT : CZTSe ratio of 0.1 offers the best performance, leading to an optimal solar cell efficiency of 4.60%, which is 50.8% higher than that of the Pt reference CE. The as-demonstrated higher catalytic activity of the composite CEs compared to

  15. VCAM-1-targeted core/shell nanoparticles for selective adhesion and delivery to endothelial cells with lipopolysaccharide-induced inflammation under shear flow and cellular magnetic resonance imaging in vitro.

    Science.gov (United States)

    Yang, Hong; Zhao, Fenglong; Li, Ying; Xu, Mingming; Li, Li; Wu, Chunhui; Miyoshi, Hirokazu; Liu, Yiyao

    2013-01-01

    these VCAM-1-targeted Fe(3)O(4)@SiO2(FITC) nanoparticles targeted to inflammatory endothelial cells could be used in the transfer of therapeutic drugs/genes into these cells or for diagnosis of vascular disease at the molecular and cellular levels in the future.

  16. An Ultrasensitive Electrochemiluminescence Immunoassay for Carbohydrate Antigen 19-9 in Serum Based on Antibody Labeled Fe3O4 Nanoparticles as Capture Probes and Graphene/CdTe Quantum Dot Bionanoconjugates as Signal Amplifiers

    Science.gov (United States)

    Gan, Ning; Zhou, Jing; Xiong, Ping; Li, Tianhua; Jiang, Shan; Cao, Yuting; Jiang, Qianli

    2013-01-01

    The CdTe quantum dots (QDs), graphene nanocomposite (CdTe-G) and dextran–Fe3O4 magnetic nanoparticles have been synthesized for developing an ultrasensitive electrochemiluminescence (ECL) immunoassay for Carcinoembryonic antigen 19-9 (CA 19-9) in serums. Firstly, the capture probes (CA 19-9 Ab1/Fe3O4) for enriching CA 19-9 were synthesized by immobilizing the CA 19-9’s first antibody (CA 19-9 Ab1) on magnetic nanoparticles (dextran-Fe3O4). Secondly, the signal probes (CA 19-9 Ab2/CdTe-G), which can emit an ECL signal, were formed by attaching the secondary CA 19-9 antibody (CA 19-9 Ab2) to the surface of the CdTe-G. Thirdly, the above two probes were used for conjugating with a serial of CA 19-9 concentrations. Graphene can immobilize dozens of CdTe QDs on their surface, which can emit stronger ECL intensity than CdTe QDs. Based on the amplified signal, ultrasensitive antigen detection can be realized. Under the optimal conditions, the ECL signal depended linearly on the logarithm of CA 19-9 concentration from 0.005 to 100 pg/mL, and the detection limit was 0.002 pg/mL. Finally, five samples of human serum were tested, and the results were compared with a time-resolved fluorescence assay (TRFA). The novel immunoassay provides a stable, specific and highly sensitive immunoassay protocol for tumor marker detection at very low levels, which can be applied in early diagnosis of tumor. PMID:23685872

  17. Multimodality Imaging with Silica-Based Targeted Nanoparticle Platforms

    International Nuclear Information System (INIS)

    Lewis, Jason S.

    2012-01-01

    Objectives: To synthesize and characterize a C-Dot silica-based nanoparticle containing 'clickable' groups for the subsequent attachment of targeting moieties (e.g., peptides) and multiple contrast agents (e.g., radionuclides with high specific activity) (1,2). These new constructs will be tested in suitable tumor models in vitro and in vivo to ensure maintenance of target-specificity and high specific activity. Methods: Cy5 dye molecules are cross-linked to a silica precursor which is reacted to form a dye-rich core particle. This core is then encapsulated in a layer of pure silica to create the core-shell C-Dot (Figure 1) (2). A 'click' chemistry approach has been used to functionalize the silica shell with radionuclides conferring high contrast and specific activity (e.g. 64Cu and 89Zr) and peptides for tumor targeting (e.g. cRGD and octreotate) (3). Based on the selective Diels-Alder reaction between tetrazine and norbornene, the reaction is bioorthogonal, highyielding, rapid, and water-compatible. This radiolabeling approach has already been employed successfully with both short peptides (e.g. octreotate) and antibodies (e.g. trastuzumab) as model systems for the ultimate labeling of the nanoparticles (1). Results: PEGylated C-Dots with a Cy5 core and labeled with tetrazine have been synthesized (d = 55 nm, zeta potential = -3 mV) reliably and reproducibly and have been shown to be stable under physiological conditions for up to 1 month. Characterization of the nanoparticles revealed that the immobilized Cy5 dye within the C-Dots exhibited fluorescence intensities over twice that of the fluorophore alone. The nanoparticles were successfully radiolabeled with Cu-64. Efforts toward the conjugation of targeting peptides (e.g. cRGD) are underway. In vitro stability, specificity, and uptake studies as well as in vivo imaging and biodistribution investigations will be presented. Conclusions: C-Dot silica-based nanoparticles offer a robust, versatile, and multi

  18. Multimodality Imaging with Silica-Based Targeted Nanoparticle Platforms

    Energy Technology Data Exchange (ETDEWEB)

    Jason S. Lewis

    2012-04-09

    Objectives: To synthesize and characterize a C-Dot silica-based nanoparticle containing 'clickable' groups for the subsequent attachment of targeting moieties (e.g., peptides) and multiple contrast agents (e.g., radionuclides with high specific activity) [1,2]. These new constructs will be tested in suitable tumor models in vitro and in vivo to ensure maintenance of target-specificity and high specific activity. Methods: Cy5 dye molecules are cross-linked to a silica precursor which is reacted to form a dye-rich core particle. This core is then encapsulated in a layer of pure silica to create the core-shell C-Dot (Figure 1) [2]. A 'click' chemistry approach has been used to functionalize the silica shell with radionuclides conferring high contrast and specific activity (e.g. 64Cu and 89Zr) and peptides for tumor targeting (e.g. cRGD and octreotate) [3]. Based on the selective Diels-Alder reaction between tetrazine and norbornene, the reaction is bioorthogonal, highyielding, rapid, and water-compatible. This radiolabeling approach has already been employed successfully with both short peptides (e.g. octreotate) and antibodies (e.g. trastuzumab) as model systems for the ultimate labeling of the nanoparticles [1]. Results: PEGylated C-Dots with a Cy5 core and labeled with tetrazine have been synthesized (d = 55 nm, zeta potential = -3 mV) reliably and reproducibly and have been shown to be stable under physiological conditions for up to 1 month. Characterization of the nanoparticles revealed that the immobilized Cy5 dye within the C-Dots exhibited fluorescence intensities over twice that of the fluorophore alone. The nanoparticles were successfully radiolabeled with Cu-64. Efforts toward the conjugation of targeting peptides (e.g. cRGD) are underway. In vitro stability, specificity, and uptake studies as well as in vivo imaging and biodistribution investigations will be presented. Conclusions: C-Dot silica-based nanoparticles offer a robust

  19. A fluorescence resonance energy transfer (FRET) biosensor based on graphene quantum dots (GQDs) and gold nanoparticles (AuNPs) for the detection of mecA gene sequence of Staphylococcus aureus.

    Science.gov (United States)

    Shi, Jingyu; Chan, Chunyu; Pang, Yukting; Ye, Weiwei; Tian, Feng; Lyu, Jing; Zhang, Yu; Yang, Mo

    2015-05-15

    In this work, a novel fluorescence resonance energy transfer (FRET) biosensor based on graphene quantum dots (GQDs) and gold nanoparticles (AuNPs) pairs was developed for Staphylococcus aureus specific gene sequence detection. This FRET biosensor platform was realized by immobilization of capture probes on GQDs and conjugation of reporter probes on AuNPs. Target oligos then co-hybridized with capture probes and reporter probes to form a sandwich structure which brought GQDs and AuNPs to close proximity to trigger FRET effect. The fluorescence signals before and after addition of targets were measured and the fluorescence quenching efficiency could reach around 87% with 100 nM target oligo. The limit of detection (LOD) of this FRET biosensor was around 1 nM for S.aureus gene detection. Experiments with both single-base mismatched oligos and double-base mismatched oligos demonstrated the good sequence selectivity of this FRET biosensor. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Spray deposition of water-soluble multiwall carbon nanotube and Cu2ZnSnSe4 nanoparticle composites as highly efficient counter electrodes in a quantum dot-sensitized solar cell system.

    Science.gov (United States)

    Zeng, Xianwei; Xiong, Dehua; Zhang, Wenjun; Ming, Liqun; Xu, Zhen; Huang, Zhanfeng; Wang, Mingkui; Chen, Wei; Cheng, Yi-Bing

    2013-08-07

    In this paper, low-cost counter electrodes (CEs) based on water-soluble multiwall carbon nanotube (MWCNT) and Cu2ZnSnSe4 nanoparticle (CZTSe NP) composites have been successfully introduced into a quantum dot-sensitized solar cell (QDSC) system. Suitable surface modification allows the MWCNTs and CZTSe NPs to be homogeneously dispersed in water, facilitating the subsequent low-temperature spray deposition of high quality composite films with different composite ratios. The electrochemical catalytic activity of the composite CEs has been critically compared by electrochemical impedance spectroscopy and Tafel-polarization analysis. It is found that the composite CE at the MWCNT : CZTSe ratio of 0.1 offers the best performance, leading to an optimal solar cell efficiency of 4.60%, which is 50.8% higher than that of the Pt reference CE. The as-demonstrated higher catalytic activity of the composite CEs compared to their single components could be ascribed to the combination of the fast electron transport of the MWCNTs and the high catalytic activity of CZTSe NPs.

  1. Synthesis of CdS nanoparticles quantum dots capped by 2,2′-dithiodibenzoic acid and study of its interaction with some transition metal ions

    International Nuclear Information System (INIS)

    Hosseini, Mohammad Saeid; Jahanbani, Hamideh

    2013-01-01

    In this work, CdS quantum dots (QDs) capped by 2,2′-dithiodibenzoic acid (DDBA) were prepared at one step. The size, shape, components and spectral properties of DDBA-capped-CdS QDs were characterized by transmission electron microscopy, infrared spectrometry and spectroflourometry. The results showed that the prepared QDs with an average diameter of 15 nm have a favorable fluorescence, which is highly affected by pH of the environment. Interaction of some heavy metal ions including Ag(I), Hg(II), Cu(II), Fe(II), Ni(II), pb(II), Mn(II), Zn(II) and Co(II) with DDBA-capped-CdS QDs was investigated at different buffering pH media. Based on the fluorescence quenching of the QDs in the presence of metal ion of interest, feasibility of their determinations were examined according to the Stern–Volmer equation. The investigations showed that Ag(I) ions can be determined in the presence of many co-existence metal ions at the buffering pH of 7. This method was then applied for Ag(I) measurement in some environmental samples, satisfactorily. -- Highlights: ► A new CdS quantum dot capped with 2,2′-dithiodibenzoic acid (DDBA) was prepared. ► The prepared QDs benefit from a favorable fluorescence. ► Interaction of some metal ions with the QDs was examined according to the Stern–Volmer equation. ► The determination of Ag(I) is feasible in the presence of many co-existence metal ions. ► The method benefits from high-speed and considerable simplicity for Ag(I) determination

  2. Few-layer black phosphorus nanoparticles.

    Science.gov (United States)

    Sofer, Zdenek; Bouša, Daniel; Luxa, Jan; Mazanek, Vlastimil; Pumera, Martin

    2016-01-28

    Herein, black phosphorus quantum dots and nanoparticles of a few layer thickness were prepared and characterized using STEM, AFM, dynamic light scattering, X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy and photoluminescence. Impact electrochemistry of the induvidual black phosphorus nanoparticles allows their size determination. The centrifugation of colloidal black phosphorus nanoparticles allowed separation of quantum dots with sizes up to 15 nm. These black phosphorus nanoparticles exhibit a large band gap and are expected to find a wide range of applications from semiconductors to biomolecule tags. The use of black phosphorus nanoparticles for vapour sensing was successfully demonstrated.

  3. Biocompatible yogurt carbon dots: evaluation of utilization for medical applications

    Science.gov (United States)

    Dinç, Saliha; Kara, Meryem; Demirel Kars, Meltem; Aykül, Fatmanur; Çiçekci, Hacer; Akkuş, Mehmet

    2017-09-01

    In this study, carbon dots (CDs) were produced from yogurt, a fermented milk product, via microwave-assisted process (800 W) in 30 min without using any additional chemical agents. Yogurt CDs had outstanding nitrogen and oxygen ratios. These dots were monodisperse and about 2 nm sized. The toxicological assessments of yogurt carbon dots in human cancer cells and normal epithelial cells and their fluorescence imaging in living cell system were carried out. Yogurt carbon dots had intense fluorescent signal under confocal microscopy and good fluorescence stability in living cell system. The resulting yogurt carbon dots exhibited high biocompatibility up to 7.1 mg/mL CD concentration which may find utilization in medical applications such as cellular tracking, imaging and drug delivery. Yogurt carbon dots have potential to be good diagnostic agents to visualize cancer cells which may be developed as a therapeutic carrier.

  4. Solid-state thermal decomposition of the [Co(NH{sub 3}){sub 5}CO{sub 3}]NO{sub 3}{center_dot}0.5H{sub 2}O complex: A simple, rapid and low-temperature synthetic route to Co{sub 3}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Farhadi, Saeid, E-mail: sfarhad2001@yahoo.com [Department of Chemistry, Lorestan University, Khorramabad 68135-465 (Iran, Islamic Republic of); Safabakhsh, Jalil [Department of Chemistry, Lorestan University, Khorramabad 68135-465 (Iran, Islamic Republic of)

    2012-02-25

    Highlights: Black-Right-Pointing-Pointer [Co(NH{sub 3}){sub 5}CO{sub 3}]NO{sub 3}{center_dot}0.5H{sub 2}O complex was used for preparing pure Co{sub 3}O{sub 4} nanoparticles. Black-Right-Pointing-Pointer Co{sub 3}O{sub 4} nanoparticles were prepared at low temperature of 175 Degree-Sign C. Black-Right-Pointing-Pointer Co{sub 3}O{sub 4} nanoparticles show a weak ferromagnetic behaviour at room temperature. Black-Right-Pointing-Pointer The method is simple, low-cost and suitable for the production of Co{sub 3}O{sub 4}. - Abstract: Co{sub 3}O{sub 4} nanoparticles were easily prepared via the decomposition of the pentammine(carbonato)cobalt(III) nitrate precursor complex [Co(NH{sub 3}){sub 5}CO{sub 3}]NO{sub 3}{center_dot}0.5H{sub 2}O at low temperature (175 Degree-Sign C). The product was characterized by thermal analysis, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), UV-visible spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, Brunauer-Emmett-Teller (BET) specific surface area measurements and magnetic measurements. The FT-IR, XRD, Raman and EDX results indicated that the synthesized Co{sub 3}O{sub 4} nanoparticles are highly pure and have a single phase. The TEM analysis revealed nearly uniform and quasi-spherical Co{sub 3}O{sub 4} nanoparticles with an average particle size of approximately 10 nm. The optical absorption spectrum of the Co{sub 3}O{sub 4} nanoparticles showed two direct band gaps of 2.18 and 3.52 eV with a red shift in comparison with previous reported values. The prepared Co{sub 3}O{sub 4} nanoparticles showed a weak ferromagnetic behaviour that could be attributed to uncompensated surface spins and/or finite-size effects. Using the present method, Co{sub 3}O{sub 4} nanoparticles can be produced without expensive organic solvents and complicated equipment. This simple, rapid, safe and low-cost synthetic route can be extended to the synthesis of other

  5. Cytotoxicity of cadmium-containing quantum dots based on a study using a microfluidic chip

    International Nuclear Information System (INIS)

    Zheng Xiannuo; Weng Lixing; Tian Jing; Wang Lianhui; Wu Lei; Jin Qinghui; Zhao Jianlong

    2012-01-01

    There is a lack of reliable nanotoxicity assays available for monitoring and quantifying multiple cellular events in cultured cells. In this study, we used a microfluidic chip to systematically investigate the cytotoxicity of three kinds of well-characterized cadmium-containing quantum dots (QDs) with the same core but different shell structures, including CdTe core QDs, CdTe/CdS core–shell QDs, and CdTe/CdS/ZnS core–shell–shell QDs, in HEK293 cells. Using the microfluidic chip combined with fluorescence microscopy, multiple QD-induced cellular events including cell morphology, viability, proliferation, and QD uptake were simultaneously analysed. The three kinds of QDs showed significantly different cytotoxicities. The CdTe QDs, which are highly toxic to HEK293 cells, resulted in remarkable cellular and nuclear morphological changes, a dose-dependent decrease in cell viability, and strong inhibition of cell proliferation; the CdTe/CdS QDs were moderately toxic but did not significantly affect the proliferation of HEK293 cells; while the CdTe/CdS/ZnS QDs had no detectable influence on cytotoxicity with respect to cell morphology, viability, and proliferation. Our data indicated that QD cytotoxicity was closely related to their surface structures and specific physicochemical properties. This study also demonstrated that the microfluidic chip could serve as a powerful tool to systematically evaluate the cytotoxicity of nanoparticles in multiple cellular events. (paper)

  6. Cytotoxicity of cadmium-containing quantum dots based on a study using a microfluidic chip

    Science.gov (United States)

    Zheng, Xiannuo; Tian, Jing; Weng, Lixing; Wu, Lei; Jin, Qinghui; Zhao, Jianlong; Wang, Lianhui

    2012-02-01

    There is a lack of reliable nanotoxicity assays available for monitoring and quantifying multiple cellular events in cultured cells. In this study, we used a microfluidic chip to systematically investigate the cytotoxicity of three kinds of well-characterized cadmium-containing quantum dots (QDs) with the same core but different shell structures, including CdTe core QDs, CdTe/CdS core-shell QDs, and CdTe/CdS/ZnS core-shell-shell QDs, in HEK293 cells. Using the microfluidic chip combined with fluorescence microscopy, multiple QD-induced cellular events including cell morphology, viability, proliferation, and QD uptake were simultaneously analysed. The three kinds of QDs showed significantly different cytotoxicities. The CdTe QDs, which are highly toxic to HEK293 cells, resulted in remarkable cellular and nuclear morphological changes, a dose-dependent decrease in cell viability, and strong inhibition of cell proliferation; the CdTe/CdS QDs were moderately toxic but did not significantly affect the proliferation of HEK293 cells; while the CdTe/CdS/ZnS QDs had no detectable influence on cytotoxicity with respect to cell morphology, viability, and proliferation. Our data indicated that QD cytotoxicity was closely related to their surface structures and specific physicochemical properties. This study also demonstrated that the microfluidic chip could serve as a powerful tool to systematically evaluate the cytotoxicity of nanoparticles in multiple cellular events.

  7. ABC transporters affect the elimination and toxicity of CdTe quantum dots in liver and kidney cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mingli; Yin, Huancai; Bai, Pengli [CAS Key Lab of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu 215163 (China); Miao, Peng [CAS Key Lab of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu 215163 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Deng, Xudong [Department of Chemical Engineering, McMaster University, Hamilton, Ontario, L8S 4L7 (Canada); Xu, Yingxue [CAS Key Lab of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu 215163 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Hu, Jun [CAS Key Lab of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu 215163 (China); Yin, Jian, E-mail: yinj@sibet.ac.cn [CAS Key Lab of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu 215163 (China)

    2016-07-15

    This paper aimed to investigate the role of adenosine triphosphate-binding cassette (ABC) transporters on the efflux and the toxicity of nanoparticles in liver and kidney cells. In this study, we synthesized CdTe quantum dots (QDs) that were monodispersed and emitted green fluorescence (maximum peak at 530 nm). Such QDs tended to accumulate in human hepatocellular carcinoma cells (HepG2), human kidney cells 2 (HK-2), and Madin-Darby canine kidney (MDCK) cells, and cause significant toxicity in all the three cell lines. Using specific inhibitors and inducers of P-glycoprotein (Pgp) and multidrug resistance associated proteins (Mrps), the cellular accumulation and subsequent toxicity of QDs in HepG2 and HK-2 cells were significantly affected, while only slight changes appeared in MDCK cells, corresponding well with the functional expressions of ABC transporters in cells. Moreover, treatment of QDs caused concentration- and time- dependent induction of ABC transporters in HepG2 and HK-2 cells, but such phenomenon was barely found in MDCK cells. Furthermore, the effects of CdTe QDs on ABC transporters were found to be greater than those of CdCl{sub 2} at equivalent concentrations of cadmium, indicating that the effects of QDs should be a combination of free Cd{sup 2+} and specific properties of QDs. Overall, these results indicated a strong dependence between the functional expressions of ABC transporters and the efflux of QDs, which could be an important reason for the modulation of QDs toxicity by ABC transporters. - Highlights: • ABC transporters contributed actively to the cellular efflux of CdTe quantum dots. • ABC transporters affected the cellular toxicity of CdTe quantum dots. • Treatment of CdTe quantum dots induced the gene expression of ABC transporters. • Free Cd{sup 2+} should be partially involved in the effects of QDs on ABC transporters. • Cellular efflux of quantum dots could be an important modulator for its toxicity.

  8. Facile synthetic method for pristine graphene quantum dots and graphene oxide quantum dots: origin of blue and green luminescence.

    Science.gov (United States)

    Liu, Fei; Jang, Min-Ho; Ha, Hyun Dong; Kim, Je-Hyung; Cho, Yong-Hoon; Seo, Tae Seok

    2013-07-19

    Pristine graphene quantum dots and graphene oxide quantum dots are synthesized by chemical exfoliation from the graphite nanoparticles with high uniformity in terms of shape (circle), size (less than 4 nm), and thickness (monolayer). The origin of the blue and green photoluminescence of GQDs and GOQDs is attributed to intrinsic and extrinsic energy states, respectively. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Preparation and development of FeS2 Quantum Dots on SiO2 nanostructures immobilized in biopolymers and synthetic polymers as nanoparticles and nanofibers catalyst for antibiotic degradation.

    Science.gov (United States)

    Gao, Wei; Razavi, Razieh; Fakhri, Ali

    2018-03-22

    The FeS 2 Quantum Dots (QDs) decorated SiO 2 nanostructure were prepared by hydrothermal synthesis method. Chitosan and polypyrrole as polymers were used for the immobilization process. The characteristic structure of prepared samples was analyzed using several techniques such as X-ray diffraction, scanning and transmittance electron microscopy, photoluminescence and UV-vis spectroscopy. The mean crystallite sizes of FeS 2 QDs/SiO 2 nanocomposites, FeS 2 QDs/SiO 2 -chitosan nanocomposites and FeS 2 QDs/SiO 2 -polypyrrole nanohybrids are 56.12, 76.38, and 83.24nm, respectively. The band gap energy of FeS 2 QDs/SiO 2 nanocomposites, FeS 2 QDs/SiO 2 -chitosan nanocomposites and FeS 2 QDs/SiO 2 -polypyrrole nanohybrids were found out to be 3.0, 2.8, and 2.7eV, respectively. The photocatalysis properties were investigated by degradation of ampicillin under UV light illumination. The effect of experimental variables, such as, pH and time, on photo-degradation efficiency was studied. The results show that the three prepared samples nanopowders under UV light was in pH3 at 60min. As it could be seen that the amount of ampicillin degradation was increased with the loading of FeS 2 QDs on SiO 2 and FeS 2 QDs/SiO 2 on chitosan nanoparticles and polypyrrole nanofiber. The antibacterial experiment was investigated under visible light illumination and the FeS 2 QDs/SiO 2 -chitosan nanocomposites and FeS 2 QDs/SiO 2 -polypyrrole nanohybrids demonstrate good antibacterial compared to FeS 2 QDs/SiO 2 nanocomposites. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Improving conversion efficiency of CdS quantum dots-sensitized TiO{sub 2} nanotube arrays by doping with Zn{sup 2+} and decorating with ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chong, E-mail: chongchen@henu.edu.cn [Henan Key Laboratory of Photovoltaic Materials, Henan University, Kaifeng 475004 (China); School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Wang, Lei; Li, Fumin; Ling, Lanyu [Henan Key Laboratory of Photovoltaic Materials, Henan University, Kaifeng 475004 (China); School of Physics and Electronics, Henan University, Kaifeng 475004 (China)

    2014-08-01

    The Zn-doped TiO{sub 2} nanotube arrays (TNTs) decorated with ZnO nanoparticles have been prepared via electrochemical anodization and immersing method. Furthermore, the CdS quantum dots (QDs) were deposited on the prepared Zn-doped TNTs-ZnO thin films by chemical bath deposition (CBD) method to fabricate the CdS QDs-sensitized Zn-doped TNTs-ZnO photoelectrodes. The nanostructure, morphology, optical properties and electrochemical properties of the CdS/Zn-doped TNTs-ZnO photoelectrode with comparison to those of the CdS/TNTs photoelectrodes were investigated. It has been found that the Zn-doped TNTs-ZnO photoelectrodes significantly increased the UV–vis light absorption of the CdS/Zn-doped TNTs-ZnO photoelectrodes and reduced the charge recombination at the surfaces of the CdS/Zn-doped TNTs-ZnO photoelectrodes. As a consequence, when the Zn-doped TNTs-ZnO film was adopted instead of the plain TNTs film, the light-chemical energy conversion efficiency of the CdS/Zn-doped TNTs-ZnO photoelectrode was much improved compared with the CdS/TNTs photoelectrode. A maximum energy conversion efficiency achieved for the CdS/Zn-doped TNTs-ZnO photoelectrode is 3.86%, which is a 17% improvement compared with the maximum energy conversion efficiency of 3.29% achieved for the CdS/TNTs photoelectrodes. - Highlights: • The CdS/Zn-doped TNTs-ZnO photoelectrodes were synthesized. • The optical properties and photochemical properties were investigated. • The energy conversion efficiency depends on the Zn doping concentration. • The energy conversion efficiency was improved by the Zn doping.

  11. A homogeneous assay for highly sensitive detection of CaMV35S promoter in transgenic soybean by förster resonance energy transfer between nitrogen-doped graphene quantum dots and Ag nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yaqi; Sun, Li [School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013 (China); Qian, Jing [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013 (China); Wang, Chengke [School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013 (China); Liu, Qian [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013 (China); Han, En [School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013 (China); Hao, Nan [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013 (China); Zhang, Liuping [Sinograin Zhenjiang Grains & Oils Quality Testing Center Co., Ltd., Zhenjiang, 212013 (China); Cai, Jianrong, E-mail: jrcai@ujs.edu.cn [School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013 (China); Wang, Kun, E-mail: wangkun@ujs.edu.cn [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013 (China)

    2016-12-15

    In this work, a novel homogeneous assay for DNA quantitative analysis based on förster resonance energy transfer (FRET) was developed for cauliflwer mosaic virus 35s (CaMV35S) promoter of transgenic soybean detection. The homogenous FRET of fluorescence signal was fabricated by DNA hybridization with probe modified nitrogen-doped graphene quantum dots (NGQDs) and silver nanoparticles (AgNPs), which acted the donor-acceptor pairs for the first time. The highly efficient FRET and unique properties of the NGQDs made the proposed FRET system as a functionalized detection platform for labelling of DNA. Upon the recognition of specific target DNA (tDNA), the FRET between NGQDs and AgNPs was triggered to produce fluorescence quenching, which could be used for tDNA detection. The fabricated homogeneous FRET assay displayed a wide linear range of 0.1–500.0 nM and a low limit of detection 0.03 nM for the detection of CaMV35S (S/N = 3). This proposed biosensor revealed high specificity to detect tDNA, with acceptable intra-assay precision and excellent stability. This method was successfully applied to identify the real sample of 0.5% containing transgenic soybean, which achieved the most of national law regulations. This assay was further validated by polymerase chain reaction as the genetically modified organisms, suggesting that the proposed FRET system is a feasible tool for the further daily genetically modified organism detection. - Highlights: • Both NGQDs and AgNPs were selected as the novel FRET donor-acceptor pairs. • The proposed homogeneous FRET assay was developed for CaMV35S detection. • The resulting method could identify 0.5% containing transgenic soybean sample. • This assay was inexpensive, simple and highly sensitive.

  12. A novel "dual-potential" electrochemiluminescence aptasensor array using CdS quantum dots and luminol-gold nanoparticles as labels for simultaneous detection of malachite green and chloramphenicol.

    Science.gov (United States)

    Feng, Xiaobin; Gan, Ning; Zhang, Huairong; Yan, Qing; Li, Tianhua; Cao, Yuting; Hu, Futao; Yu, Hongwei; Jiang, Qianli

    2015-12-15

    A novel type of "dual-potential" electrochemiluminescence (ECL) aptasensor array was fabricated on a homemade screen-printed carbon electrode (SPCE) for simultaneous detection of malachite green (MG) and chloramphenicol (CAP) in one single assay. The SPCE substrate consisted of a common Ag/AgCl reference electrode, carbon counter electrode and two carbon working electrodes (WE1 and WE2). In the system, CdS quantum dots (QDs) were modified on WE1 as cathode ECL emitters and luminol-gold nanoparticles (L-Au NPs) were modified on WE2 as anode ECL emitters. Then the MG aptamer complementary strand (MG cDNA) and CAP aptamer complementary strand (CAP cDNA) were attached on CdS QDs and L-Au NPs, respectively. The cDNA would hybridize with corresponding aptamer that was respectively tagged with cyanine dye (Cy5) (as quenchers of CdS QDs) and chlorogenic acid (CA) (as quenchers of l-Au NPs) using poly(ethylenimine) (PEI) as a bridging agent. PEI could lead to a large number of quenchers on the aptamer, which increased the quenching efficiency. Upon MG and CAP adding, the targets could induce strand release due to the highly affinity of analytes toward aptamers. Meanwhile, it could release the Cy5 and CA, which recovered cathode ECL of CdS QDs and anode ECL of L-Au NPs simultaneously. This "dual-potential" ECL strategy could be used to detect MG and CAP with the linear ranges of 0.1-100 nM and 0.2-150 nM, with detection limits of 0.03 nM and 0.07 nM (at 3sB), respectively. More importantly, this designed method was successfully applied to determine MG and CAP in real fish samples and held great potential in the food analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Fluorescent ligand fishing combination with in-situ imaging and characterizing to screen Hsp 90 inhibitors from Curcuma longa L. based on InP/ZnS quantum dots embedded mesoporous nanoparticles.

    Science.gov (United States)

    Hu, Yue; Fu, Anchen; Miao, Zhaoyi; Zhang, Xiaojing; Wang, Tianlin; Kang, An; Shan, Jinjun; Zhu, Dong; Li, Wei

    2018-02-01

    Although ligand fishing has been shown to be an efficient technique for the identification of bioactive components from complex mixtures such as natural products, it cannot be applied to biomedical image processing. Herein, a specific fluorescent ligand fishing combined with in situ imaging approach is presented for the identification of heat shock protein 90 (Hsp 90) inhibitors from complex matrixes, Curcuma longa L., using N-terminus immobilized Hsp 90α functionalized InP/ZnS quantum dots embedded mesoporous nanoparticles (i.e. Hsp 90α (NT)-FQDNs) as extraction sorbents and fluorescent tracer. The fished ligands were identified by liquid chromatography time-of-flight/mass spectrometry (LC-TOF/MS) and gas chromatography-mass spectrometry (GC-MS). Moreover, in situ imaging by confocal laser scanning microscopy (CLSM) was applied for evaluating the effect of fished-ligands on bioactivity-induced apoptosis morphologically in HeLa cells. MTT assay verified the bioactivity of the ligands and molecular docking results further provided convincing information to verify the feasible binding mode between ligands and protein. Twelve ligands as potential Hsp 90 inhibitors were ultimately fished and identified from Curcuma longa L. crude extracts. The proposed approach based on Hsp 90α functionalized nanocomposites is superior in the combination of highly specific screening efficiency and concurrent visual in situ imaging, which could have great promise for the development of other plant-derived Hsp 90 inhibitors, and providing a rapid and reliable platform for discovering biologically active molecules in natural products. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. A homogeneous assay for highly sensitive detection of CaMV35S promoter in transgenic soybean by förster resonance energy transfer between nitrogen-doped graphene quantum dots and Ag nanoparticles.

    Science.gov (United States)

    Li, Yaqi; Sun, Li; Qian, Jing; Wang, Chengke; Liu, Qian; Han, En; Hao, Nan; Zhang, Liuping; Cai, Jianrong; Wang, Kun

    2016-12-15

    In this work, a novel homogeneous assay for DNA quantitative analysis based on förster resonance energy transfer (FRET) was developed for cauliflwer mosaic virus 35s (CaMV35S) promoter of transgenic soybean detection. The homogenous FRET of fluorescence signal was fabricated by DNA hybridization with probe modified nitrogen-doped graphene quantum dots (NGQDs) and silver nanoparticles (AgNPs), which acted the donor-acceptor pairs for the first time. The highly efficient FRET and unique properties of the NGQDs made the proposed FRET system as a functionalized detection platform for labelling of DNA. Upon the recognition of specific target DNA (tDNA), the FRET between NGQDs and AgNPs was triggered to produce fluorescence quenching, which could be used for tDNA detection. The fabricated homogeneous FRET assay displayed a wide linear range of 0.1-500.0 nM and a low limit of detection 0.03 nM for the detection of CaMV35S (S/N = 3). This proposed biosensor revealed high specificity to detect tDNA, with acceptable intra-assay precision and excellent stability. This method was successfully applied to identify the real sample of 0.5% containing transgenic soybean, which achieved the most of national law regulations. This assay was further validated by polymerase chain reaction as the genetically modified organisms, suggesting that the proposed FRET system is a feasible tool for the further daily genetically modified organism detection. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. A homogeneous assay for highly sensitive detection of CaMV35S promoter in transgenic soybean by förster resonance energy transfer between nitrogen-doped graphene quantum dots and Ag nanoparticles

    International Nuclear Information System (INIS)

    Li, Yaqi; Sun, Li; Qian, Jing; Wang, Chengke; Liu, Qian; Han, En; Hao, Nan; Zhang, Liuping; Cai, Jianrong; Wang, Kun

    2016-01-01

    In this work, a novel homogeneous assay for DNA quantitative analysis based on förster resonance energy transfer (FRET) was developed for cauliflwer mosaic virus 35s (CaMV35S) promoter of transgenic soybean detection. The homogenous FRET of fluorescence signal was fabricated by DNA hybridization with probe modified nitrogen-doped graphene quantum dots (NGQDs) and silver nanoparticles (AgNPs), which acted the donor-acceptor pairs for the first time. The highly efficient FRET and unique properties of the NGQDs made the proposed FRET system as a functionalized detection platform for labelling of DNA. Upon the recognition of specific target DNA (tDNA), the FRET between NGQDs and AgNPs was triggered to produce fluorescence quenching, which could be used for tDNA detection. The fabricated homogeneous FRET assay displayed a wide linear range of 0.1–500.0 nM and a low limit of detection 0.03 nM for the detection of CaMV35S (S/N = 3). This proposed biosensor revealed high specificity to detect tDNA, with acceptable intra-assay precision and excellent stability. This method was successfully applied to identify the real sample of 0.5% containing transgenic soybean, which achieved the most of national law regulations. This assay was further validated by polymerase chain reaction as the genetically modified organisms, suggesting that the proposed FRET system is a feasible tool for the further daily genetically modified organism detection. - Highlights: • Both NGQDs and AgNPs were selected as the novel FRET donor-acceptor pairs. • The proposed homogeneous FRET assay was developed for CaMV35S detection. • The resulting method could identify 0.5% containing transgenic soybean sample. • This assay was inexpensive, simple and highly sensitive.

  16. Interaction of porphyrins with CdTe quantum dots

    International Nuclear Information System (INIS)

    Zhang Xing; Liu Zhongxin; Ma Lun; Hossu, Marius; Chen Wei

    2011-01-01

    Porphyrins may be used as photosensitizers for photodynamic therapy, photocatalysts for organic pollutant dissociation, agents for medical imaging and diagnostics, applications in luminescence and electronics. The detection of porphyrins is significantly important and here the interaction of protoporphyrin-IX (PPIX) with CdTe quantum dots was studied. It was observed that the luminescence of CdTe quantum dots was quenched dramatically in the presence of PPIX. When CdTe quantum dots were embedded into silica layers, almost no quenching by PPIX was observed. This indicates that PPIX may interact and alter CdTe quantum dots and thus quench their luminescence. The oxidation of the stabilizers such as thioglycolic acid (TGA) as well as the nanoparticles by the singlet oxygen generated from PPIX is most likely responsible for the luminescence quenching. The quenching of quantum dot luminescence by porphyrins may provide a new method for photosensitizer detection.

  17. Multifunctional nanoparticles: Analytical prospects

    International Nuclear Information System (INIS)

    Dios, Alejandro Simon de; Diaz-Garcia, Marta Elena

    2010-01-01

    Multifunctional nanoparticles are among the most exciting nanomaterials with promising applications in analytical chemistry. These applications include (bio)sensing, (bio)assays, catalysis and separations. Although most of these applications are based on the magnetic, optical and electrochemical properties of multifunctional nanoparticles, other aspects such as the synergistic effect of the functional groups and the amplification effect associated with the nanoscale dimension have also been observed. Considering not only the nature of the raw material but also the shape, there is a huge variety of nanoparticles. In this review only magnetic, quantum dots, gold nanoparticles, carbon and inorganic nanotubes as well as silica, titania and gadolinium oxide nanoparticles are addressed. This review presents a narrative summary on the use of multifuncional nanoparticles for analytical applications, along with a discussion on some critical challenges existing in the field and possible solutions that have been or are being developed to overcome these challenges.

  18. Study on the fluorescence characteristics of carbon dots

    Science.gov (United States)

    Mao, Xiao-Jiao; Zheng, Hu-Zhi; Long, Yi-Juan; Du, Juan; Hao, Jian-Yu; Wang, Ling-Ling; Zhou, Dong-Bo

    2010-02-01

    Herein, we prepared water-soluble fluorescent carbon dots with diameter about 1.5 nm from cheap commercial lampblack. These fluorescent carbon nanoparticles are stable toward photobleaching and stable in water for more than half a year without fluorescence decrease. In order to improve its fluorescence properties, we passivated these nanoparticles with bisamino-terminated polyethylene glycol (PEG 1500N). Therefore, both fluorescence quantum yield and lifetime increased after this progress. In addition, the passivated carbon dots were more inert to solvent than the bare one and showed different responses to pH change.

  19. Green wet chemical route to synthesize capped CdSe quantum dots

    Indian Academy of Sciences (India)

    In the present work, we report green synthesis of tartaric acid (TA) and triethanolamine (TEA) capped ... CdSe quantum dots; chemical bath deposition; capping; green chemistry; nanomaterials. 1. .... at high concentration of nanoparticles.

  20. Quantum dots. From multimodal imaging diagnostics to radiation-induced photodynamic therapy of cancer

    International Nuclear Information System (INIS)

    Bakalova, R.; Aoki, Ichio; Zhelev, Z.; Kanno, Iwao

    2008-01-01

    Nanotechnology-based tools and techniques are rapidly emerging in the field of molecular imaging, biosensing and targeted drug delivery. Employing constructs such as quantum dots (QDs), fullerenes, dendrimers, liposomes, nanotubes and emulsion, these advances lead toward the concept of personalized medicine and the potential for very early, even pre-symptomatic, diagnoses coupled with highly effective targeted therapy. The new term nanomedicine has been used recently. Why nanoparticles are so attractive for molecular imaging diagnostics? Nanoparticles allow a concentration of a large amount of contrast molecules in a very small area/volume (∼20-100 nm in diameter). Thus, after conjugation with target-specific ligands, even single cells or molecules could be detected in the blood stream or tissues, using different techniques. The nanoparticles have also a potential for therapeutic purposes (e.g., drug and gene delivery), which is expected to generate innovations and play a crucial role in medicine. For example, the diagnosis and treatment of cancer at the cellular level could be greatly improved with the development of techniques that enable a highly selective interaction and delivery of analyte probes into the cancer cells and subcellular compartments. Target-specific drug/gene delivery and early diagnosis of cancer is one of the priority research areas in which nanomedicine will play a vital role. Nanomedicine attracts also other clinical fields as surgery, cardiology, respiratory diseases, etc. (author)

  1. Nonlinear Dot Plots.

    Science.gov (United States)

    Rodrigues, Nils; Weiskopf, Daniel

    2018-01-01

    Conventional dot plots use a constant dot size and are typically applied to show the frequency distribution of small data sets. Unfortunately, they are not designed for a high dynamic range of frequencies. We address this problem by introducing nonlinear dot plots. Adopting the idea of nonlinear scaling from logarithmic bar charts, our plots allow for dots of varying size so that columns with a large number of samples are reduced in height. For the construction of these diagrams, we introduce an efficient two-way sweep algorithm that leads to a dense and symmetrical layout. We compensate aliasing artifacts at high dot densities by a specifically designed low-pass filtering method. Examples of nonlinear dot plots are compared to conventional dot plots as well as linear and logarithmic histograms. Finally, we include feedback from an expert review.

  2. Formation and photoluminescence of "Cauliflower" silicon nanoparticles

    NARCIS (Netherlands)

    Tang, W.; Eilers, J.J.; Huis, van M.A.; Wang, D.; Schropp, R.E.I.; Vece, Di M.

    2015-01-01

    The technological advantages of silicon make silicon nanoparticles, which can be used as quantum dots in a tandem configuration, highly relevant for photovoltaics. However, producing a silicon quantum dot solar cell structure remains a challenge. Here we use a gas aggregation cluster source to

  3. Cellular gravity

    NARCIS (Netherlands)

    F.C. Gruau; J.T. Tromp (John)

    1999-01-01

    textabstractWe consider the problem of establishing gravity in cellular automata. In particular, when cellular automata states can be partitioned into empty, particle, and wall types, with the latter enclosing rectangular areas, we desire rules that will make the particles fall down and pile up on

  4. The cellular uptake of antisense oligonucleotid of E6 mRNA into cervical cancer cells by DOPE-modified hydroxyapatite nanoparticles

    OpenAIRE

    Negin Saffarzadeh; Seyed Mehdi Kalantar; Ali Jebali; Seyed Hossein Hekmatimoghaddam; Mohammad Hassan Sheikhha; Ehsan Farashahi

    2014-01-01

    Objective(s): Although several chemical and physical methods for gene delivery have been introduced, their cytotoxicity, non-specific immune responses and the lack of biodegradability remain the main issues. In this study, hydroxyapatite nanoparticles (NPs) and 1,2-dioleoyl-sn-glycero-3-phosphoethanol​amine (DOPE)-modified hydroxyapatite NPs was coated with antisense oligonucleotide of E6 mRNA, and their uptakes into the cervical cancer cell line were evaluated. Materials and Methods: Calcium...

  5. Interaction of Water-Soluble CdTe Quantum Dots with Bovine Serum Albumin

    Science.gov (United States)

    2011-01-01

    Semiconductor nanoparticles (quantum dots) are promising fluorescent markers, but it is very little known about interaction of quantum dots with biological molecules. In this study, interaction of CdTe quantum dots coated with thioglycolic acid (TGA) with bovine serum albumin was investigated. Steady state spectroscopy, atomic force microscopy, electron microscopy and dynamic light scattering methods were used. It was explored how bovine serum albumin affects stability and spectral properties of quantum dots in aqueous media. CdTe–TGA quantum dots in aqueous solution appeared to be not stable and precipitated. Interaction with bovine serum albumin significantly enhanced stability and photoluminescence quantum yield of quantum dots and prevented quantum dots from aggregating. PMID:27502633

  6. Photoluminescence study of carbon dots from ginger and galangal herbs using microwave technique

    Science.gov (United States)

    Isnaeni; Rahmawati, I.; Intan, R.; Zakaria, M.

    2018-03-01

    Carbon dots are new type of fluorescent nanoparticle that can be synthesis easily from natural sources. We have synthesized carbon dots from ginger and galangal herbs using microwave technique and studied their optical properties. We synthesized colloidal carbon dots in water solvent by varying microwave processing time. UV-Vis absorbance, photoluminescence, time-resolved photoluminescence, and transmission electron microscope were utilized to study properties of carbon dots. We found that microwave processing time significantly affect optical properties of synthesized carbon dots. UV-Vis absorbance spectra and time-resolved photoluminescence results show that luminescent of carbon dots is dominated by recombination process from n-π* surface energy level. With further development, these carbon dots are potential for several applications.

  7. Biopolymeric nanoparticles

    International Nuclear Information System (INIS)

    Sundar, Sushmitha; Kundu, Joydip; Kundu, Subhas C

    2010-01-01

    This review on nanoparticles highlights the various biopolymers (proteins and polysaccharides) which have recently revolutionized the world of biocompatible and degradable natural biological materials. The methods of their fabrication, including emulsification, desolvation, coacervation and electrospray drying are described. The characterization of different parameters for a given nanoparticle, such as particle size, surface charge, morphology, stability, structure, cellular uptake, cytotoxicity, drug loading and drug release, is outlined together with the relevant measurement techniques. Applications in the fields of medicine and biotechnology are discussed along with a promising future scope. (topical review)

  8. In vivo quantification of quantum dot systemic transport in C57BL/6 hairless mice following skin application post-ultraviolet radiation.

    Science.gov (United States)

    Jatana, Samreen; Palmer, Brian C; Phelan, Sarah J; Gelein, Robert; DeLouise, Lisa A

    2017-04-14

    Previous work has demonstrated size, surface charge and skin barrier dependent penetration of nanoparticles into the viable layers of mouse skin. The goal of this work was to characterize the tissue distribution and mechanism of transport of nanoparticles beyond skin, with and without Ultraviolet Radiation (UVR) induced skin barrier disruption. Atomic absorption spectroscopy (AAS), flow cytometry and confocal microscopy were used to examine the effect of UVR dose (180 and 360 mJ/cm 2 UVB) on the skin penetration and systemic distribution of quantum dot (QD) nanoparticles topically applied at different time-points post UVR using a hairless C57BL/6 mouse model. Results indicate that QDs can penetrate mouse skin, regardless of UVR exposure, as evidenced by the increased cadmium in the local lymph nodes of all QD treated mice. The average % recovery for all treatment groups was 69.68% with ~66.84% of the applied dose recovered from the skin (both epicutaneous and intracutaneous). An average of 0.024% of the applied dose was recovered from the lymph nodes across various treatment groups. When QDs are applied 4 days post UV irradiation, at the peak of the skin barrier defect and LC migration to the local lymph node, there is an increased cellular presence of QD in the lymph node; however, AAS analysis of local lymph nodes display no difference in cadmium levels due to UVR treatment. Our data suggests that Langerhans cells (LCs) can engulf QDs in skin, but transport to the lymph node may occur by both cellular (dendritic and macrophage) and non-cellular mechanisms. It is interesting that these specific nanoparticles were retained in skin similarly regardless of UVR barrier disruption, but the observed skin immune cell interaction with nanoparticles suggest a potential for immunomodulation, which we are currently examining in a murine model of skin allergy.

  9. Photoexcited quantum dots for killing multidrug-resistant bacteria

    Science.gov (United States)

    Courtney, Colleen M.; Goodman, Samuel M.; McDaniel, Jessica A.; Madinger, Nancy E.; Chatterjee, Anushree; Nagpal, Prashant

    2016-05-01

    Multidrug-resistant bacterial infections are an ever-growing threat because of the shrinking arsenal of efficacious antibiotics. Metal nanoparticles can induce cell death, yet the toxicity effect is typically nonspecific. Here, we show that photoexcited quantum dots (QDs) can kill a wide range of multidrug-resistant bacterial clinical isolates, including methicillin-resistant Staphylococcus aureus, carbapenem-resistant Escherichia coli, and extended-spectrum β-lactamase-producing Klebsiella pneumoniae and Salmonella typhimurium. The killing effect is independent of material and controlled by the redox potentials of the photogenerated charge carriers, which selectively alter the cellular redox state. We also show that the QDs can be tailored to kill 92% of bacterial cells in a monoculture, and in a co-culture of E. coli and HEK 293T cells, while leaving the mammalian cells intact, or to increase bacterial proliferation. Photoexcited QDs could be used in the study of the effect of redox states on living systems, and lead to clinical phototherapy for the treatment of infections.

  10. From DOT to Dotty

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    - Module types are interfaces, which can be abstracted. In this talk Martin will present DOT, a particularly simple calculus that can express systems following these principles. DOT has been developed as the foundation of the next version of Scala. He will also report on dotty, a new Scala compiler that implements the constructs of DOT in its core data structures and that uses the lessons learned to drive Scala’s evolution.

  11. Transport in quantum dots

    International Nuclear Information System (INIS)

    Deus, Fernanda; Continetino, Mucio

    2011-01-01

    Full text. In this work we study the time dependent transport in interacting quantum dot. This is a zero-dimensional nano structure system which has quantized electronic states. In our purpose, we are interested in studying such system in a Coulomb blockade regime where a mean-field treatment of the electronic correlations are appropriate. The quantum dot is described by an Anderson type of Hamiltonian where the hybridization term arises from the contact with the leads. We consider a time dependence of both the energy of the localized state in the quantum dot and of the hybridization-like term. These time dependent parameters, under certain conditions, induce a current in the quantum dot even in the absence of difference on the chemical potential of the leads. The approach to this non-equilibrium problem requires the use of a Keldysh formalism. We calculate the non- equilibrium Green's functions and obtain results for the average (equilibrium term) and the non-equilibrium values of the electronic occupation number in the dot. we consider the possibility of a magnetic solution, with different values for the average up and down spins in the quantum dot. Our results allow to obtain, for instance, the tunneling current through the dot. The magnetic nature of the dot, for a certain range of parameters should give rise also to an induced spin current through the dot

  12. Colloidal quantum dot photovoltaics: The effect of polydispersity

    KAUST Repository

    Zhitomirsky, David

    2012-02-08

    The size-effect tunability of colloidal quantum dots enables facile engineering of the bandgap at the time of nanoparticle synthesis. The dependence of effective bandgap on nanoparticle size also presents a challenge if the size dispersion, hence bandgap variability, is not well-controlled within a given quantum dot solid. The impact of this polydispersity is well-studied in luminescent devices as well as in unipolar electronic transport; however, the requirements on monodispersity have yet to be quantified in photovoltaics. Here we carry out a series of combined experimental and model-based studies aimed at clarifying, and quantifying, the importance of quantum dot monodispersity in photovoltaics. We successfully predict, using a simple model, the dependence of both open-circuit voltage and photoluminescence behavior on the density of small-bandgap (large-diameter) quantum dot inclusions. The model requires inclusion of trap states to explain the experimental data quantitatively. We then explore using this same experimentally tested model the implications of a broadened quantum dot population on device performance. We report that present-day colloidal quantum dot photovoltaic devices with typical inhomogeneous linewidths of 100-150 meV are dominated by surface traps, and it is for this reason that they see marginal benefit from reduction in polydispersity. Upon eliminating surface traps, achieving inhomogeneous broadening of 50 meV or less will lead to device performance that sees very little deleterious impact from polydispersity. © 2012 American Chemical Society.

  13. Inhibition of autophagy overcomes the nanotoxicity elicited by cadmium-based quantum dots.

    Science.gov (United States)

    Fan, Jiajun; Sun, Yun; Wang, Shaofei; Li, Yubin; Zeng, Xian; Cao, Zhonglian; Yang, Ping; Song, Ping; Wang, Ziyu; Xian, Zongshu; Gao, Hongjian; Chen, Qicheng; Cui, Daxiang; Ju, Dianwen

    2016-02-01

    Cadmium-based quantum dots (QDs) have shown their values in disease diagnosis, cellular and molecular tracking, small-animal imaging, and therapeutic drug delivery. However, the potential safety problems of QDs, mainly due to their nanotoxicities by unclear mechanisms, have greatly limited its applications. To reverse this situation, we investigated the underlying biological mechanisms of the toxicity of Quantum Dots CdTe/CdS 655 (QDs 655) in this work. QDs 655 was found to elicit nanotoxicity in vitro and in vivo. During the process, autophagy was activated, which was characterized by three main stages of autophagic flux including formation of autophagosomes, lysosomes fused with autophagosomes, and degradation of autophagosomes by lysosomes. Furthermore, the autophagic cell death was demonstrated in vitro under QDs 655 treatment while inhibition of autophagy by pharmacological inhibitors or genetic approaches could attenuate the toxicity induced by QDs 655 in vitro and in vivo. These results indicated that autophagic flux and autophagic cell death were triggered by QDs 655, which elucidated the critical role of autophagy in QDs 655 induced toxicity. Our data may suggest the approach to overcome the toxicity of QDs and other nanoparticles by autophagy inhibition. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. TiO2, SiO2 and ZrO2 Nanoparticles Synergistically Provoke Cellular Oxidative Damage in Freshwater Microalgae

    Directory of Open Access Journals (Sweden)

    Yinghan Liu

    2018-02-01

    Full Text Available Metal-based nanoparticles (NPs are the most widely used engineered nanomaterials. The individual toxicities of metal-based NPs have been plentifully studied. However, the mixture toxicity of multiple NP systems (n ≥ 3 remains much less understood. Herein, the toxicity of titanium dioxide (TiO2 nanoparticles (NPs, silicon dioxide (SiO2 NPs and zirconium dioxide (ZrO2 NPs to unicellular freshwater algae Scenedesmus obliquus was investigated individually and in binary and ternary combination. Results show that the ternary combination systems of TiO2, SiO2 and ZrO2 NPs at a mixture concentration of 1 mg/L significantly enhanced mitochondrial membrane potential and intracellular reactive oxygen species level in the algae. Moreover, the ternary NP systems remarkably increased the activity of the antioxidant defense enzymes superoxide dismutase and catalase, together with an increase in lipid peroxidation products and small molecule metabolites. Furthermore, the observation of superficial structures of S. obliquus revealed obvious oxidative damage induced by the ternary mixtures. Taken together, the ternary NP systems exerted more severe oxidative stress in the algae than the individual and the binary NP systems. Thus, our findings highlight the importance of the assessment of the synergistic toxicity of multi-nanomaterial systems.

  15. The cellular uptake of antisense oligonucleotid of E6 mRNA into cervical cancer cells by DOPE-modified hydroxyapatite nanoparticles

    Directory of Open Access Journals (Sweden)

    Negin Saffarzadeh

    2014-10-01

    Full Text Available Objective(s: Although several chemical and physical methods for gene delivery have been introduced, their cytotoxicity, non-specific immune responses and the lack of biodegradability remain the main issues. In this study, hydroxyapatite nanoparticles (NPs and 1,2-dioleoyl-sn-glycero-3-phosphoethanol​amine (DOPE-modified hydroxyapatite NPs was coated with antisense oligonucleotide of E6 mRNA, and their uptakes into the cervical cancer cell line were evaluated. Materials and Methods: Calcium nitrate and diammonium phosphate were used for the synthesis of the hydroxyapatite nanoparticle. Thus, they were coated with polyethylene glycol (PEG, DOPE and antisense oligonucleotide of E6 mRNA using a cross-linker. Then, hydroxyapatite NPs and DOPE-modified hydroxyapatite NPs were incubated 48 hours with cervical cancer cells and their uptakes were evaluated by fluorescent microscopy. Results: The hydroxyapatite NPs had different shapes and some agglomeration with average size of 100 nm. The results showed DOPE-modified hydroxyapatite NPs had higher uptake than hydroxyapatite NPs (P

  16. Multifunctional nanoparticle-EpCAM aptamer bioconjugates: a paradigm for targeted drug delivery and imaging in cancer therapy.

    Science.gov (United States)

    Das, Manasi; Duan, Wei; Sahoo, Sanjeeb K

    2015-02-01

    The promising proposition of multifunctional nanoparticles for cancer diagnostics and therapeutics has inspired the development of theranostic approach for improved cancer therapy. Moreover, active targeting of drug carrier to specific target site is crucial for providing efficient delivery of therapeutics and imaging agents. In this regard, the present study investigates the theranostic capabilities of nutlin-3a loaded poly (lactide-co-glycolide) nanoparticles, functionalized with a targeting ligand (EpCAM aptamer) and an imaging agent (quantum dots) for cancer therapy and bioimaging. A wide spectrum of in vitro analysis (cellular uptake study, cytotoxicity assay, cell cycle and apoptosis analysis, apoptosis associated proteins study) revealed superior therapeutic potentiality of targeted NPs over other formulations in EpCAM expressing cells. Moreover, our nanotheranostic system served as a superlative bio-imaging modality both in 2D monolayer culture and tumor spheroid model. Our result suggests that, these aptamer-guided multifunctional NPs may act as indispensable nanotheranostic approach toward cancer therapy. This study investigated the theranostic capabilities of nutlin-3a loaded poly (lactide-co-glycolide) nanoparticles functionalized with a targeting ligand (EpCAM aptamer) and an imaging agent (quantum dots) for cancer therapy and bioimaging. It was concluded that the studied multifunctional targeted nanoparticle may become a viable and efficient approach in cancer therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Application of zinc oxide quantum dots in food safety

    Science.gov (United States)

    Zinc oxide quantum dots (ZnO QDs) are nanoparticles of purified powdered ZnO. The ZnO QDs were directly added into liquid foods or coated on the surface of glass jars using polylactic acid (PLA) as a carrier. The antimicrobial activities of ZnO QDs against Listeria monocytogenes, Salmonella Enteriti...

  18. Smith-Purcell radiation from concave dotted gratings

    Science.gov (United States)

    Sergeeva, D. Yu.; Tishchenko, A. A.; Aryshev, A. S.; Strikhanov, M. N.

    2018-02-01

    We present the first-principles theory of Smith-Purcell effect from the concave dotted grating consisting of bent chains of separated micro- or nanoparticles. The numerical analysis demonstrates that the obtained spectral-angular distributions change significantly depending on the structure of the grating.

  19. Study of Streptavidin-Modified Quantum Dots by Capillary Electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Stanisavljevic, M.; Janů, L.; Šmerková, K.; Křížková, S.; Pizúrová, Naděžda; Ryvolová, M.; Adam, V.; Hubálek, J.; Kizek, R.

    2013-01-01

    Roč. 76, 7-8 (2013), s. 335-343 ISSN 0009-5893 Institutional support: RVO:68081723 Keywords : Capillary electrophoresis * Gel electrophoresis * Avidin-biotin technology * Oligonucleotide * Nanoparticle * quantum dots Subject RIV: CE - Biochemistry Impact factor: 1.370, year: 2013

  20. Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications

    Science.gov (United States)

    Ellis, Matthew A.; Grandinetti, Giovanna; Fichter, Katye M.

    2016-01-01

    Fluorescent nanocrystals, specifically quantum dots, have been a useful tool for many biomedical applications. For successful use in biological systems, quantum dots should be highly fluorescent and small/monodisperse in size. While commonly used cadmium-based quantum dots possess these qualities, they are potentially toxic due to the possible release of Cd2+ ions through nanoparticle degradation. Indium-based quantum dots, specifically InP/ZnS, have recently been explored as a viable alternative to cadmium-based quantum dots due to their relatively similar fluorescence characteristics and size. The synthesis presented here uses standard hot-injection techniques for effective nanoparticle growth; however, nanoparticle properties such as size, emission wavelength, and emission intensity can drastically change due to small changes in the reaction conditions. Therefore, reaction conditions such temperature, reaction duration, and precursor concentration should be maintained precisely to yield reproducible products. Because quantum dots are not inherently soluble in aqueous solutions, they must also undergo surface modification to impart solubility in water. In this protocol, an amphiphilic polymer is used to interact with both hydrophobic ligands on the quantum dot surface and bulk solvent water molecules. Here, a detailed protocol is provided for the synthesis of highly fluorescent InP/ZnS quantum dots that are suitable for use in biomedical applications. PMID:26891282

  1. Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications.

    Science.gov (United States)

    Ellis, Matthew A; Grandinetti, Giovanna; Fichter, Katye M; Fichter, Kathryn M

    2016-02-06

    Fluorescent nanocrystals, specifically quantum dots, have been a useful tool for many biomedical applications. For successful use in biological systems, quantum dots should be highly fluorescent and small/monodisperse in size. While commonly used cadmium-based quantum dots possess these qualities, they are potentially toxic due to the possible release of Cd(2+) ions through nanoparticle degradation. Indium-based quantum dots, specifically InP/ZnS, have recently been explored as a viable alternative to cadmium-based quantum dots due to their relatively similar fluorescence characteristics and size. The synthesis presented here uses standard hot-injection techniques for effective nanoparticle growth; however, nanoparticle properties such as size, emission wavelength, and emission intensity can drastically change due to small changes in the reaction conditions. Therefore, reaction conditions such temperature, reaction duration, and precursor concentration should be maintained precisely to yield reproducible products. Because quantum dots are not inherently soluble in aqueous solutions, they must also undergo surface modification to impart solubility in water. In this protocol, an amphiphilic polymer is used to interact with both hydrophobic ligands on the quantum dot surface and bulk solvent water molecules. Here, a detailed protocol is provided for the synthesis of highly fluorescent InP/ZnS quantum dots that are suitable for use in biomedical applications.

  2. Co-sensitization of quantum dot sensitized solar cells composed of TiO2 nanocrystalline photoanode with CdS and PbS nanoparticles and effect of PbS on the performance of solar cell

    Directory of Open Access Journals (Sweden)

    Maziar Marandi

    2017-09-01

    Full Text Available In this research, CdS and PbS quantum dots were applied as the light sensitizers in TiO2 based nanostructured solar cells. The PbS quantum dots could absorb a wide range of the sunlight spectrum on earth due to their low bandgap energy. As a result, the cell sensitization is more effective by application of both CdS and PbS quantum dots sensitizers. The TiO2 nanocrystals were synthesized through a hydrothermal process and deposited on FTO glass substrates as the photoanode scaffold. Then PbS quantum dots were grown on the surface of this nanocrystalline layer by a successive ionic layer adsorption and reaction (SILAR method. The CdS quantum dots were over-grown in the next step through a similar deposition method. Finally this sensitized layer was applied as the photoelectrode of the corresponding quantum dot sensitized solar cells. The results demonstrated that the maximum efficiency was achieved for the cell with a photoanode made of co-sensitization through 2 and 6 cycles of PbS and CdS deposition, respectively. The photovoltaic parameters of this cell were measured as Jsc of 10.81 mA/cm2, Voc of 590 mv and energy conversion efficiency of 2.7+0.2%.

  3. Folic acid-targeted magnetic Tb-doped CeF3 fluorescent nanoparticles as bimodal probes for cellular fluorescence and magnetic resonance imaging.

    Science.gov (United States)

    Ma, Zhi-Ya; Liu, Yu-Ping; Bai, Ling-Yu; An, Jie; Zhang, Lin; Xuan, Yang; Zhang, Xiao-Shuai; Zhao, Yuan-Di

    2015-10-07

    Magnetic fluorescent nanoparticles (NPs) have great potential applications for diagnostics, imaging and therapy. We developed a facile polyol method to synthesize multifunctional Fe3O4@CeF3:Tb@CeF3 NPs with small size (CA) to obtain carboxyl-functionalized NPs (Fe3O4@CeF3:Tb@CeF3-COOH). Folic acid (FA) as an affinity ligand was then covalently conjugated onto NPs to yield Fe3O4@CeF3:Tb@CeF3-FA NPs. They were then applied as multimodal imaging agents for simultaneous in vitro targeted fluorescence imaging and magnetic resonance imaging (MRI) of HeLa cells with overexpressed folate receptors (FR). The results indicated that these NPs had strong luminescence and enhanced T2-weighted MR contrast and would be promising candidates as multimodal probes for both fluorescence and MRI imaging.

  4. Quantum Dots: Theory

    Energy Technology Data Exchange (ETDEWEB)

    Vukmirovic, Nenad; Wang, Lin-Wang

    2009-11-10

    This review covers the description of the methodologies typically used for the calculation of the electronic structure of self-assembled and colloidal quantum dots. These are illustrated by the results of their application to a selected set of physical effects in quantum dots.

  5. Quantum dot spectroscopy

    DEFF Research Database (Denmark)

    Leosson, Kristjan

    1999-01-01

    Semiconductor quantum dots ("solid state atoms") are promising candidates for quantum computers and future electronic and optoelectronic devices. Quantum dots are zero-dimensional electronic systems and therefore have discrete energy levels, similar to atoms or molecules. The size distribution of...

  6. Quantum dot spectroscopy

    DEFF Research Database (Denmark)

    Leosson, Kristjan

    Semiconductor quantum dots ("solid-state atoms") are promising candidates for quantum computers and future electronic and optoelectronic devices. Quantum dots are zero-dimensional electronic systems and therefore have discrete energy levels, similar to atoms or molecules. The size distribution of...

  7. Small airway epithelial cells exposure to printer-emitted engineered nanoparticles induces cellular effects on human microvascular endothelial cells in an alveolar-capillary co-culture model.

    Science.gov (United States)

    Sisler, Jennifer D; Pirela, Sandra V; Friend, Sherri; Farcas, Mariana; Schwegler-Berry, Diane; Shvedova, Anna; Castranova, Vincent; Demokritou, Philip; Qian, Yong

    2015-01-01

    The printer is one of the most common office equipment. Recently, it was reported that toner formulations for printing equipment constitute nano-enabled products (NEPs) and contain engineered nanomaterials (ENMs) that become airborne during printing. To date, insufficient research has been performed to understand the potential toxicological properties of printer-emitted particles (PEPs) with several studies using bulk toner particles as test particles. These studies demonstrated the ability of toner particles to cause chronic inflammation and fibrosis in animal models. However, the toxicological implications of inhalation exposures to ENMs emitted from laser printing equipment remain largely unknown. The present study investigates the toxicological effects of PEPs using an in vitro alveolar-capillary co-culture model with Human Small Airway Epithelial Cells (SAEC) and Human Microvascular Endothelial Cells (HMVEC). Our data demonstrate that direct exposure of SAEC to low concentrations of PEPs (0.5 and 1.0 µg/mL) caused morphological changes of actin remodeling and gap formations within the endothelial monolayer. Furthermore, increased production of reactive oxygen species (ROS) and angiogenesis were observed in the HMVEC. Analysis of cytokine and chemokine levels demonstrates that interleukin (IL)-6 and MCP-1 may play a major role in the cellular communication observed between SAEC and HMVEC and the resultant responses in HMVEC. These data indicate that PEPs at low, non-cytotoxic exposure levels are bioactive and affect cellular responses in an alveolar-capillary co-culture model, which raises concerns for potential adverse health effects.

  8. Compact quantum dots for single-molecule imaging.

    Science.gov (United States)

    Smith, Andrew M; Nie, Shuming

    2012-10-09

    Single-molecule imaging is an important tool for understanding the mechanisms of biomolecular function and for visualizing the spatial and temporal heterogeneity of molecular behaviors that underlie cellular biology (1-4). To image an individual molecule of interest, it is typically conjugated to a fluorescent tag (dye, protein, bead, or quantum dot) and observed with epifluorescence or total internal reflection fluorescence (TIRF) microscopy. While dyes and fluorescent proteins have been the mainstay of fluorescence imaging for decades, their fluorescence is unstable under high photon fluxes necessary to observe individual molecules, yielding only a few seconds of observation before complete loss of signal. Latex beads and dye-labeled beads provide improved signal stability but at the expense of drastically larger hydrodynamic size, which can deleteriously alter the diffusion and behavior of the molecule under study. Quantum dots (QDs) offer a balance between these two problematic regimes. These nanoparticles are composed of semiconductor materials and can be engineered with a hydrodynamically compact size with exceptional resistance to photodegradation (5). Thus in recent years QDs have been instrumental in enabling long-term observation of complex macromolecular behavior on the single molecule level. However these particles have still been found to exhibit impaired diffusion in crowded molecular environments such as the cellular cytoplasm and the neuronal synaptic cleft, where their sizes are still too large (4,6,7). Recently we have engineered the cores and surface coatings of QDs for minimized hydrodynamic size, while balancing offsets to colloidal stability, photostability, brightness, and nonspecific binding that have hindered the utility of compact QDs in the past (8,9). The goal of this article is to demonstrate the synthesis, modification, and characterization of these optimized nanocrystals, composed of an alloyed HgxCd1-xSe core coated with an

  9. Synthesis of quantum dots

    Science.gov (United States)

    McDaniel, Hunter

    2017-10-17

    Common approaches to synthesizing alloyed quantum dots employ high-cost, air-sensitive phosphine complexes as the selenium precursor. Disclosed quantum dot synthesis embodiments avoid these hazardous and air-sensitive selenium precursors. Certain embodiments utilize a combination comprising a thiol and an amine that together reduce and complex the elemental selenium to form a highly reactive selenium precursor at room temperature. The same combination of thiol and amine acts as the reaction solvent, stabilizing ligand, and sulfur source in the synthesis of quantum dot cores. A non-injection approach may also be used. The optical properties of the quantum dots synthesized by this new approach can be finely tuned for a variety of applications by controlling size and/or composition of size and composition. Further, using the same approach, a shell can be grown around a quantum dot core that improves stability, luminescence efficiency, and may reduce toxicity.

  10. Uptake, localization and clearance of quantum dots in ciliated protozoa Tetrahymena thermophila

    International Nuclear Information System (INIS)

    Mortimer, Monika; Kahru, Anne; Slaveykova, Vera I.

    2014-01-01

    Protozoa as phagocytizing cells have been shown to integrate engineered nanoparticles (NPs), while the mechanism, dynamics and extent of such uptake are unclear. Here our fluorescence microscopy data showed that CdSe/ZnS quantum dots (QDs) with primary size of 12 nm were readily phagocytized into the food vacuoles of Tetrahymena thermophila in a time- and dose-dependent manner. Twenty hours after the exposure to QDs in sublethal concentration the clearance of the QDs from the cells was incomplete suggesting that phagocytosis of QDs into food vacuoles was not the only pathway of uptake by T. thermophila. This was further proven by the results that the inhibition of phagocytosis did not block the internalization of QDs into protozoans. This study provides a new insight into uptake and cellular trafficking of subtoxic concentrations of nanoparticles that may, due to prolonged retention times in the cells, pose risks by potentially becoming available to higher trophic levels. - Highlights: • Tetrahymena thermophila internalized QDs in a dose- and time-dependent manner. • The egested QDs were not significantly biodegraded in the food vacuoles. • In addition to phagocytosis QDs entered protozoa by alternative uptake pathways. • The clearance of the QDs from the cells was incomplete after 20 h in fresh medium. • The prolonged retention time of nontoxic NPs in protozoa could increase their transfer in food chain. - In addition to phagocytosis, quantum dots (QDs) entered protozoans by alternative pathways which did not lead to complete clearance of the QDs from the cells

  11. Bistable optical response of a nanoparticle heterodimer : Mechanism, phase diagram, and switching time

    NARCIS (Netherlands)

    Nugroho, Bintoro; Iskandar, Alexander; Malyshev, V.A.; Knoester, Jasper

    2013-01-01

    We conduct a theoretical study of the bistable optical response of a nanoparticle heterodimer comprised of a closely spaced semiconductor quantum dot and a metal nanoparticle. The bistable nature of the response results from the interplay between the quantum dot's optical nonlinearity and its

  12. Plant viral nanoparticles-based HER2 vaccine: Immune response influenced by differential transport, localization and cellular interactions of particulate carriers.

    Science.gov (United States)

    Shukla, Sourabh; Myers, Jay T; Woods, Sarah E; Gong, Xingjian; Czapar, Anna E; Commandeur, Ulrich; Huang, Alex Y; Levine, Alan D; Steinmetz, Nicole F

    2017-03-01

    Cancer vaccines are designed to elicit an endogenous adaptive immune response that can successfully recognize and eliminate residual or recurring tumors. Such approaches can potentially overcome shortcomings of passive immunotherapies by generating long-lived therapeutic effects and immune memory while limiting systemic toxicities. A critical determinant of vaccine efficacy is efficient transport and delivery of tumor-associated antigens to professional antigen presenting cells (APCs). Plant viral nanoparticles (VNPs) with natural tropism for APCs and a high payload carrying capacity may be particularly effective vaccine carriers. The applicability of VNP platform technologies is governed by stringent structure-function relationships. We compare two distinct VNP platforms: icosahedral cowpea mosaic virus (CPMV) and filamentous potato virus X (PVX). Specifically, we evaluate in vivo capabilities of engineered VNPs delivering human epidermal growth factor receptor 2 (HER2) epitopes for therapy and prophylaxis of HER2 + malignancies. Our results corroborate the structure-function relationship where icosahedral CPMV particles showed significantly enhanced lymph node transport and retention, and greater uptake by/activation of APCs compared to filamentous PVX particles. These enhanced immune cell interactions and transport properties resulted in elevated HER2-specific antibody titers raised by CPMV- vs. PVX-based peptide vaccine. The 'synthetic virology' field is rapidly expanding with numerous platforms undergoing development and preclinical testing; our studies highlight the need for systematic studies to define rules guiding the design and rational choice of platform, in the context of peptide-vaccine display technologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Microwave-assisted synthesis of BSA-modified silver nanoparticles as a selective fluorescent probe for detection and cellular imaging of cadmium(II)