CD44-engineered mesoporous silica nanoparticles for overcoming multidrug resistance in breast cancer

International Nuclear Information System (INIS)

Wang, Xin; Liu, Ying; Wang, Shouju; Shi, Donghong; Zhou, Xianguang; Wang, Chunyan; Wu, Jiang; Zeng, Zhiyong; Li, Yanjun; Sun, Jing; Wang, Jiandong; Zhang, Longjiang; Teng, Zhaogang; Lu, Guangming

2015-01-01

Graphical abstract: - Highlights: • CD44-engineered mesoporous silica nanoparticles are synthesized. • The mechanism of CD44-engineered mesoporous silica nanoparticles is revealed. • This new delivery system increased the drug accumulation in vitro and in vivo. • This new delivery system offers an effective approach to treat multidrug resistance. - Abstract: Multidrug resistance is a major impediment for the successful chemotherapy in breast cancer. CD44 is over-expressed in multidrug resistant human breast cancer cells. CD44 monoclonal antibody exhibits anticancer potential by inhibiting proliferation and regulating P-glycoprotein-mediated drug efflux activity in multidrug resistant cells. Thereby, CD44 monoclonal antibody in combination with chemotherapeutic drug might be result in enhancing chemosensitivity and overcoming multidrug resistance. The purpose of this study is to investigate the effects of the CD44 monoclonal antibody functionalized mesoporous silica nanoparticles containing doxorubicin on human breast resistant cancer MCF-7 cells. The data showed that CD44-modified mesoporous silica nanoparticles increased cytotoxicity and enhanced the downregulation of P-glycoprotein in comparison to CD44 antibody. Moreover, CD44-engineered mesoporous silica nanoparticles provided active target, which promoted more cellular uptake of DOX in the resistant cells and more retention of DOX in tumor tissues than unengineered counterpart. Animal studies of the resistant breast cancer xenografts demonstrated that CD44-engineered drug delivery system remarkably induced apoptosis and inhibited the tumor growth. Our results indicated that the CD44-engineered mesoporous silica nanoparticle-based drug delivery system offers an effective approach to overcome multidrug resistance in human breast cancer

Silica sacrificial layer-assisted in-plane incorporation of Au nanoparticles into mesoporous titania thin films through different reduction methods.

Science.gov (United States)

Liang, Chih-Peng; Yamauchi, Yusuke; Liu, Chia-Hung; Wu, Kevin C-W

2013-06-28

This study focuses on the incorporation of gold nanoparticles (Au NPs) into our previously synthesized mesoporous titania thin films consisting of titania nanopillars and inverse mesospace (C. W. Wu, T. Ohsuna, M. Kuwabara and K. Kuroda, J. Am. Chem. Soc., 2006, 128, 4544-4545, denoted as MTTFs). Recently, mesoporous titania materials doped with noble metals such as gold have attracted considerable attention because noble metals can enhance the efficiency of mesoporous titania-based devices. In this research, we attempted to use four different reduction methods (i.e., thermal treatment, photo irradiation, liquid immersion, and vapor contacting) to introduce gold nanoparticles (Au NPs) into MTTFs. The synthesized Au@MTTFs were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We further systematically investigated the formation mechanism of gold nanoparticles on the external and internal surfaces of the MTTFs. With the assistance of a silica sacrificial layer, well-dispersed Au NPs with sizes of 4.1 nm were obtained inside the MTTF by photo irradiation. The synthesized Au@MTTF materials show great potential in various photo-electronic and photo-catalytic applications.

Rod-shaped silica particles derivatized with elongated silver nanoparticles immobilized within mesopores

Energy Technology Data Exchange (ETDEWEB)

Mnasri, Najib [Institut Charles Gerhardt de Montpellier, CNRS UMR 5253, Université Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 5 (France); Materials, Environment and Energy Laboratory (UR14ES26), Faculty of Science, University of Gafsa, 2112 Gafsa (Tunisia); Charnay, Clarence; Ménorval, Louis-Charles de [Institut Charles Gerhardt de Montpellier, CNRS UMR 5253, Université Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 5 (France); Elaloui, Elimame [Materials, Environment and Energy Laboratory (UR14ES26), Faculty of Science, University of Gafsa, 2112 Gafsa (Tunisia); Zajac, Jerzy, E-mail: jerzy.zajac@umontpellier.fr [Institut Charles Gerhardt de Montpellier, CNRS UMR 5253, Université Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 5 (France)

2016-11-15

Silver-derivatized silica particles possessing a non-spherical morphology and surface plasmon resonance properties have been achieved. Nanometer-sized silica rods with uniformly sized mesopore channels were prepared first making use of alkyltrimethyl ammonium surfactants as porogens and the 1:0.10 tetraethyl orthosilicate (TEOS) : 3-aminopropyltriethoxysilane (APTES) mixture as a silicon source. Silica rods were subsequently functionalized by introducing elongated silver nanoparticles within the intra-particle mesopores thanks to the AgNO{sub 3} reduction procedure based on the action of hemiaminal groups previously located on the mesopore walls. The textural and structural features of the samples were inferred from the combined characterization studies including SEM and TEM microscopy, nitrogen adsorption-desorption at 77 K, powder XRD in the small- and wide-angle region, as well as UV–visible spectroscopy. {sup 129}Xe NMR spectroscopy appeared particularly useful to obtain a correct information about the porous structure of rod-shaped silica particles and the silver incorporation within their intra-particle mesopores. - Highlights: • Mesoporous monodisperse submicron-sized silica rods were achieved. • Silver nanoparticles were located lengthwise within the intra-particle mesopores. • Textural and plasmonic properties of particles studied by {sup 129}Xe NMR and UV–Vis.

Biological Applications and Transmission Electron Microscopy Investigations of Mesoporous Silica Nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Trewyn, Brian G. [Iowa State Univ., Ames, IA (United States)

2006-01-01

The research presented and discussed within involves the development of novel biological applications of mesoporous silica nanoparticles (MSN) and an investigation of mesoporous material by transmission electron microscopy (TEM). Mesoporous silica nanoparticles organically functionalized shown to undergo endocytosis in cancer cells and drug release from the pores was controlled intracellularly and intercellularly. Transmission electron microscopy investigations demonstrated the variety of morphologies produced in this field of mesoporous silica nanomaterial synthesis. A series of room-temperature ionic liquid (RTIL) containing mesoporous silica nanoparticle (MSN) materials with various particle morphologies, including spheres, ellipsoids, rods, and tubes, were synthesized. By changing the RTIL template, the pore morphology was tuned from the MCM-41 type of hexagonal mesopores to rotational moire type of helical channels, and to wormhole-like porous structures. These materials were used as controlled release delivery nanodevices to deliver antibacterial ionic liquids against Escherichia coli K12. The involvement of a specific organosiloxane function group, covalently attached to the exterior of fluorescein doped mesoporous silica nanoparticles (FITC-MSN), on the degree and kinetics of endocytosis in cancer and plant cells was investigated. The kinetics of endocystosis of TEG coated FITC-MSN is significantly quicker than FITC-MSN as determined by flow cytometry experiments. The fluorescence confocal microscopy investigation showed the endocytosis of TEG coated-FITC MSN triethylene glycol grafted fluorescein doped MSN (TEG coated-FITC MSN) into both KeLa cells and Tobacco root protoplasts. Once the synthesis of a controlled-release delivery system based on MCM-41-type mesoporous silica nanorods capped by disulfide bonds with superparamagnetic iron oxide nanoparticles was completed. The material was characterized by general methods and the dosage and kinetics of the

One-step synthesis of mesoporous silica–graphene composites by ...

Indian Academy of Sciences (India)

Silica–graphene oxide composites were synthesized by hydrothermal method with simultaneous functionalization and reduction of graphene oxide (GO) in the presence of mesoporous silica. Two types of silica were used in the study, mesoporous synthetic silica (MSU-F) synthesized by sol-gel method and mesoporous ...

Ordered mesoporous silica-based inorganic nanocomposites

International Nuclear Information System (INIS)

Wang Qingqing; Shantz, Daniel F.

2008-01-01

This article reviews the synthesis and characterization of nanoparticles and nanowires grown in ordered mesoporous silicas (OMS). Summarizing work performed over the last 4 years, this article highlights the material properties of the final nanocomposite in the context of the synthesis methodology employed. While certain metal-OMS systems (e.g. gold in MCM-41) have been extensively studied this article highlights that there is a rich set of chemistries that have yet to be explored. The article concludes with some thoughts on future developments and challenges in this area. - Graphical abstract: HAADF TEM image of gold nanoparticles in amine-functionalized MCM-41 (from Ref. [22])

Monodisperse metal nanoparticle catalysts on silica mesoporous supports: synthesis, characterizations, and catalytic reactions

Energy Technology Data Exchange (ETDEWEB)

Somorjai, G.A.

2009-09-14

The design of high performance catalyst achieving near 100% product selectivity at maximum activity is one of the most important goals in the modern catalytic science research. To this end, the preparation of model catalysts whose catalytic performances can be predicted in a systematic and rational manner is of significant importance, which thereby allows understanding of the molecular ingredients affecting the catalytic performances. We have designed novel 3-dimensional (3D) high surface area model catalysts by the integration of colloidal metal nanoparticles and mesoporous silica supports. Monodisperse colloidal metal NPs with controllable size and shape were synthesized using dendrimers, polymers, or surfactants as the surface stabilizers. The size of Pt, and Rh nanoparticles can be varied from sub 1 nm to 15 nm, while the shape of Pt can be controlled to cube, cuboctahedron, and octahedron. The 3D model catalysts were generated by the incorporation of metal nanoparticles into the pores of mesoporous silica supports via two methods: capillary inclusion (CI) and nanoparticle encapsulation (NE). The former method relies on the sonication-induced inclusion of metal nanoparticles into the pores of mesoporous silica, whereas the latter is performed by the encapsulation of metal nanoparticles during the hydrothermal synthesis of mesoporous silica. The 3D model catalysts were comprehensively characterized by a variety of physical and chemical methods. These catalysts were found to show structure sensitivity in hydrocarbon conversion reactions. The Pt NPs supported on mesoporous SBA-15 silica (Pt/SBA-15) displayed significant particle size sensitivity in ethane hydrogenolysis over the size range of 1-7 nm. The Pt/SBA-15 catalysts also exhibited particle size dependent product selectivity in cyclohexene hydrogenation, crotonaldehyde hydrogenation, and pyrrole hydrogenation. The Rh loaded SBA-15 silica catalyst showed structure sensitivity in CO oxidation reaction. In

Synthesis and Characterization of Hyaluronic Acid Modified Colloidal Mesoporous Silica Nanoparticles

Science.gov (United States)

Zhang, Wenbiao; Wang, Yu; Li, Zhen; Wang, Wanxia; Sun, Honghao; Liu, Mingxing

2017-12-01

The colloidal mesoporous silica nanoparticles functionalized with hyaluronic acid (CMS-HA) were successfully synthesized by grafting hyaluronic acid onto the external surface of the amino-functionalized mesoporous silica nanoparticles (CMS-NH2). Moreover, the paticle properties of CMS-HA were characterized by fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS) and transmission electron microscopy (TEM). The nanomaterials were negatively charged and had a relatively uniform spherical morphology with about 100 nm in diameter, which could make it more compatible with blood. So the results suggested that the CMS-HA might be a critical nanomaterial for applying in target drug delivery system.

Pseudorotaxane capped mesoporous silica nanoparticles for 3,4-methylenedioxymethamphetamine (MDMA) detection in water

DEFF Research Database (Denmark)

Lozano-Torres, Beatriz; Pascual, Lluís; Bernardos, Andrea

2017-01-01

Mesoporous silica nanoparticles loaded with fluorescein and capped by a pseudorotaxane, formed between a naphthalene derivative and cyclobis(paraquat-p-phenylene) (CBPQT4+), were used for the selective and sensitive fluorogenic detection of 3,4-methylenedioxymethamphetamine (MDMA).......Mesoporous silica nanoparticles loaded with fluorescein and capped by a pseudorotaxane, formed between a naphthalene derivative and cyclobis(paraquat-p-phenylene) (CBPQT4+), were used for the selective and sensitive fluorogenic detection of 3,4-methylenedioxymethamphetamine (MDMA)....

Multifunctional EuYVO4 nanoparticles coated with mesoporous silica

International Nuclear Information System (INIS)

Justino, Larissa G.; Nigoghossian, Karina; Capote, Ticiana S.O.; Scarel-Caminaga, Raquel M.; Ribeiro, Sidney J.L.; Caiut, José Maurício A.

2016-01-01

Mesoporous structures are interesting materials for the incorporation of dyes, drugs, and luminescent systems, leading to materials with important multifunctionalities. In a very unique way, these guest/host materials combine the high stability of inorganic systems, new guest-structuring features, and adsorption mechanisms in their well-defined pores. This work evaluates the luminescent properties of rare earth-doped YVO 4 nanoparticles coated with a mesoporous silica shell. The use of two different synthesis methodologies allowed for particle size control. The crystalline phase emerged without further heat treatment. The mesoporous shell decreased undesirable quenching effects on YVO 4 :Eu 3+ nanoparticles and rendered them biocompatible. The materials prepared herein could have interesting applications as luminescent markers or drug release systems.

Nanocomposites based on graphene oxide and mesoporous silica nanoparticles: Preparation, characterization and nanobiointeractions with red blood cells and human plasma proteins

Science.gov (United States)

Fonseca, Leandro C.; de Araújo, Maciel M.; de Moraes, Ana Carolina M.; da Silva, Douglas S.; Ferreira, Ariane G.; Franqui, Lidiane S.; Martinez, Diego Stéfani T.; Alves, Oswaldo L.

2018-04-01

The current work refers to the development of a novel nanocomposite based on graphene oxide (GO) and mesoporous amino silica nanoparticles (H2N-MSNs) and its biological interaction with red blood cells (RBCs) and human blood plasma toward the investigation of nanobiointeractions. Silica nanoparticles and several graphene oxide-based materials are, separately, known for their high hemolytic potential and strong interaction with human plasma proteins. In this context, the GO-MSN interaction and its influence in minimizing the reported effects were investigated. The materials were synthesized by covalently attaching H2N-MSNs onto the surface of GO through an amidation reaction. GO-MSN nanocomposites were obtained by varying the mass of H2N-MSNs and were characterized by FTIR, NMR, XRD, TGA, zeta potential and TEM. The characterization results confirm that nanocomposites were obtained, suggest covalent bond attachment mostly by amine-epoxy reactions and evidence an unexpected reduction reaction of GO by H2N-MSNs, whose mechanism is proposed. Biological assays showed a decrease of hemolysis (RBC lysis) and a minimization of the interaction with human plasma proteins (protein corona formation). These are important findings toward achieving in vivo biocompatibility and understanding the nanobiointeractions. Finally, this work opens possibilities for new nanomedicine applications of GO-MSN nanocomposites, such as drug delivery system.

Biosynthesis of gold nanoparticles using diatoms-silica-gold and EPS-gold bionanocomposite formation

OpenAIRE

Schröfel, Adam; Kratošová, Gabriela; Bohunická, Markéta; Dobročka, Edmund; Vávra, Ivo

2011-01-01

Novel synthesis of gold nanoparticles, EPS-gold, and silica-gold bionanocomposites by biologically driven processes employing two diatom strains (Navicula atomus, Diadesmis gallica) is described. Transmission electron microscopy (TEM) and electron diffraction analysis (SAED) revealed a presence of gold nanoparticles in the experimental solutions of the diatom culture mixed with tetrachloroaureate. Nature of the gold nanoparticles was confirmed by X-ray diffraction studies. Scanning electron m...

Surface modification of silica particles with gold nanoparticles as an augmentation of gold nanoparticle mediated laser perforation

Science.gov (United States)

Kalies, Stefan; Gentemann, Lara; Schomaker, Markus; Heinemann, Dag; Ripken, Tammo; Meyer, Heiko

2014-01-01

Gold nanoparticle mediated (GNOME) laser transfection/perforation fulfills the demands of a reliable transfection technique. It provides efficient delivery and has a negligible impact on cell viability. Furthermore, it reaches high-throughput applicability. However, currently only large gold particles (> 80 nm) allow successful GNOME laser perforation, probably due to insufficient sedimentation of smaller gold nanoparticles. The objective of this study is to determine whether this aspect can be addressed by a modification of silica particles with gold nanoparticles. Throughout the analysis, we show that after the attachment of gold nanoparticles to silica particles, comparable or better efficiencies to GNOME laser perforation are reached. In combination with 1 µm silica particles, we report laser perforation with gold nanoparticles with sizes down to 4 nm. Therefore, our investigations have great importance for the future research in and the fields of laser transfection combined with plasmonics. PMID:25136494

Synthesis of Pyrimethanil-Loaded Mesoporous Silica Nanoparticles and Its Distribution and Dissipation in Cucumber Plants.

Science.gov (United States)

Zhao, Pengyue; Cao, Lidong; Ma, Dukang; Zhou, Zhaolu; Huang, Qiliang; Pan, Canping

2017-05-16

Mesoporous silica nanoparticles are used as pesticide carries in plants, which has been considered as a novel method to reduce the indiscriminate use of conventional pesticides. In the present work, mesoporous silica nanoparticles with particle diameters of 200-300 nm were synthesized in order to obtain pyrimethanil-loaded nanoparticles. The microstructure of the nanoparticles was observed by scanning electron microscopy. The loading content of pyrimethanil-loaded nanoparticles was investigated. After treatment on cucumber leaves, the concentrations of pyrimethanil were determined in different parts of cucumber over a period of 48 days using high performance liquid chromatography tandem mass spectrometry. It was shown that the pyrimethanil-loaded mesoporous silica nanoparticles might be more conducive to acropetal, rather than basipetal, uptake, and the dosage had almost no effect on the distribution and dissipation rate in cucumber plants. The application of the pesticide-loaded nanoparticles in leaves had a low risk of pyrimethanil accumulating in the edible part of the plant.

Gold Incorporated Mesoporous Silica Thin Film Model Surface as a Robust SERS and Catalytically Active Substrate

Directory of Open Access Journals (Sweden)

Anandakumari Chandrasekharan Sunil Sekhar

2016-05-01

Full Text Available Ultra-small gold nanoparticles incorporated in mesoporous silica thin films with accessible pore channels perpendicular to the substrate are prepared by a modified sol-gel method. The simple and easy spin coating technique is applied here to make homogeneous thin films. The surface characterization using FESEM shows crack-free films with a perpendicular pore arrangement. The applicability of these thin films as catalysts as well as a robust SERS active substrate for model catalysis study is tested. Compared to bare silica film our gold incorporated silica, GSM-23F gave an enhancement factor of 103 for RhB with a laser source 633 nm. The reduction reaction of p-nitrophenol with sodium borohydride from our thin films shows a decrease in peak intensity corresponding to –NO2 group as time proceeds, confirming the catalytic activity. Such model surfaces can potentially bridge the material gap between a real catalytic system and surface science studies.

Plasmonic properties and enhanced fluorescence of gold and dye-doped silica nanoparticle aggregates

Science.gov (United States)

Green, Nathaniel Scott

The development of metal-enhanced fluorescence has prompted a great interest in augmenting the photophysical properties of fluorescent molecules with noble metal nanostructures. Our research efforts, outlined in this dissertation, focus on augmenting properties of fluorophores by conjugation with gold nanostructures. The project goals are split into two separate efforts; the enhancement in brightness of fluorophores and long distance non-radiative energy transfer between fluorophores. We believe that interacting dye-doped silica nanoparticles with gold nanoparticles can facilitate both of these phenomena. Our primary research interest is focused on optimizing brightness, as this goal should open a path to studying the second goal of non-radiative energy transfer. The two major challenges to this are constructing suitable nanomaterials and functionalizing them to promote plasmonically active complexes. The synthesis of dye-doped layered silica nanoparticles allows for control over the discrete location of the dye and a substrate that can be surface functionalized. Controlling the exact location of the dye is important to create a silica spacer, which promotes productive interactions with metal nanostructures. Furthermore, the synthesis of silica nanoparticles allows for various fluorophores to be studied in similar environments (removing solvent and other chemo-sensitive issues). Functionalizing the surface of silica nanoparticles allows control over the degree of silica and gold nanoparticle aggregation in solution. Heteroaggregation in solution is useful for producing well-aggregated clusters of many gold around a single silica nanoparticle. The dye-doped surface functionalized silica nanoparticles can than be mixed efficiently with gold nanomaterials. Aggregating multiple gold nanospheres around a single dye-doped silica nanoparticle can dramatically increase the fluorescent brightness of the sample via metal-enhanced fluorescence due to increase plasmonic

Large third-order optical nonlinearity in vertically oriented mesoporous silica thin films embedded with Ag nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Tan, Min; Liu, Qiming, E-mail: qmliu@whu.edu.cn [Wuhan University, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology (China)

2016-12-15

Taking advantage of the channel confinement of mesoporous films to prevent the agglomeration of Ag nanoparticles to achieve large third-order optical nonlinearity in amorphous materials, Ag-loaded composite mesoporous silica film was prepared by the electrochemical deposition method on ITO substrate. Ag ions were firstly transported into the channels of mesoporous film by the diffusion and binding force of channels, which were reduced to nanoparticles by applying suitable voltage. The existence and uniform distribution of Ag nanoparticles ranging in 1–10 nm in the mesoporous silica thin films were exhibited by UV spectrophotometer, X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) measurements. The third-order optical nonlinearity induced by Ag nanoparticles was studied by the Z-scan technique. Due to the local field surface plasmon resonance, the maximum third-order nonlinear optical susceptibility of Ag-loaded composite mesoporous silica film is 1.53×10{sup −10} esu, which is 1000 times larger than that of the Ag-contained chalcogenide glasses which showed large nonlinearity in amorphous materials.

Mesoporous Silica and Organosilica Nanoparticles: Physical Chemistry, Biosafety, Delivery Strategies, and Biomedical Applications

KAUST Repository

Croissant, Jonas G.

2017-11-30

Predetermining the physico-chemical properties, biosafety, and stimuli-responsiveness of nanomaterials in biological environments is essential for safe and effective biomedical applications. At the forefront of biomedical research, mesoporous silica nanoparticles and mesoporous organosilica nanoparticles are increasingly investigated to predict their biological outcome by materials design. In this review, it is first chronicled that how the nanomaterial design of pure silica, partially hybridized organosilica, and fully hybridized organosilica (periodic mesoporous organosilicas) governs not only the physico-chemical properties but also the biosafety of the nanoparticles. The impact of the hybridization on the biocompatibility, protein corona, biodistribution, biodegradability, and clearance of the silica-based particles is described. Then, the influence of the surface engineering, the framework hybridization, as well as the morphology of the particles, on the ability to load and controllably deliver drugs under internal biological stimuli (e.g., pH, redox, enzymes) and external noninvasive stimuli (e.g., light, magnetic, ultrasound) are presented. To conclude, trends in the biomedical applications of silica and organosilica nanovectors are delineated, such as unconventional bioimaging techniques, large cargo delivery, combination therapy, gaseous molecule delivery, antimicrobial protection, and Alzheimer\\'s disease therapy.

Mesoporous silica nanoparticles for stimuli-responsive controlled drug delivery: advances, challenges, and outlook

Directory of Open Access Journals (Sweden)

Song Y

2016-12-01

Full Text Available Yuanhui Song, Yihong Li, Qien Xu, Zhe Liu Wenzhou Institute of Biomaterials and Engineering (WIBE, Wenzhou Medical University, Wenzhou, Zhejiang, People’s Republic of China Abstract: With the development of nanotechnology, the application of nanomaterials in the field of drug delivery has attracted much attention in the past decades. Mesoporous silica nanoparticles as promising drug nanocarriers have become a new area of interest in recent years due to their unique properties and capabilities to efficiently entrap cargo molecules. This review describes the latest advances on the application of mesoporous silica nanoparticles in drug delivery. In particular, we focus on the stimuli-responsive controlled release systems that are able to respond to intracellular environmental changes, such as pH, ATP, GSH, enzyme, glucose, and H2O2. Moreover, drug delivery induced by exogenous stimuli including temperature, light, magnetic field, ultrasound, and electricity is also summarized. These advanced technologies demonstrate current challenges, and provide a bright future for precision diagnosis and treatment. Keywords: mesoporous silica nanoparticle, drug delivery system, controlled release, stimuli-responsive, chemotherapy

Innovative Route to Prepare of Au/C Catalysts by Replication of Gold-containing Mesoporous Silicas

KAUST Repository

Kerdi, Fatmé ; Caps, Valerie; Tuel, Alain

2011-01-01

precursor and the composite material is heated at 900 °C under vacuum or nitrogen. Silica is then removed by acid leaching, leading to partially encapsulated gold particles in mesoporous carbon. Carbon prevents aggregation of gold particles at high

Multifunctional EuYVO{sub 4} nanoparticles coated with mesoporous silica

Energy Technology Data Exchange (ETDEWEB)

Justino, Larissa G. [Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, 14040-901 Ribeirão Preto, SP (Brazil); Nigoghossian, Karina [Inst. of Chemistry – São Paulo State University- UNESP, 14801-970 Araraquara, SP (Brazil); Capote, Ticiana S.O.; Scarel-Caminaga, Raquel M. [Department of Morphology, Dental School at Araraquara, Univ. Estadual Paulista – UNESP, Araraquara, SP (Brazil); Ribeiro, Sidney J.L. [Inst. of Chemistry – São Paulo State University- UNESP, 14801-970 Araraquara, SP (Brazil); Caiut, José Maurício A., E-mail: caiut@ffclrp.usp.br [Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, 14040-901 Ribeirão Preto, SP (Brazil)

2016-11-15

Mesoporous structures are interesting materials for the incorporation of dyes, drugs, and luminescent systems, leading to materials with important multifunctionalities. In a very unique way, these guest/host materials combine the high stability of inorganic systems, new guest-structuring features, and adsorption mechanisms in their well-defined pores. This work evaluates the luminescent properties of rare earth-doped YVO{sub 4} nanoparticles coated with a mesoporous silica shell. The use of two different synthesis methodologies allowed for particle size control. The crystalline phase emerged without further heat treatment. The mesoporous shell decreased undesirable quenching effects on YVO{sub 4}:Eu{sup 3+} nanoparticles and rendered them biocompatible. The materials prepared herein could have interesting applications as luminescent markers or drug release systems.

Degradability and Clearance of Silicon, Organosilica, Silsesquioxane, Silica Mixed Oxide, and Mesoporous Silica Nanoparticles

KAUST Repository

Croissant, Jonas G.

2017-01-13

The biorelated degradability and clearance of siliceous nanomaterials have been questioned worldwide, since they are crucial prerequisites for the successful translation in clinics. Typically, the degradability and biocompatibility of mesoporous silica nanoparticles (MSNs) have been an ongoing discussion in research circles. The reason for such a concern is that approved pharmaceutical products must not accumulate in the human body, to prevent severe and unpredictable side-effects. Here, the biorelated degradability and clearance of silicon and silica nanoparticles (NPs) are comprehensively summarized. The influence of the size, morphology, surface area, pore size, and surface functional groups, to name a few, on the degradability of silicon and silica NPs is described. The noncovalent organic doping of silica and the covalent incorporation of either hydrolytically stable or redox- and enzymatically cleavable silsesquioxanes is then described for organosilica, bridged silsesquioxane (BS), and periodic mesoporous organosilica (PMO) NPs. Inorganically doped silica particles such as calcium-, iron-, manganese-, and zirconium-doped NPs, also have radically different hydrolytic stabilities. To conclude, the degradability and clearance timelines of various siliceous nanomaterials are compared and it is highlighted that researchers can select a specific nanomaterial in this large family according to the targeted applications and the required clearance kinetics.

A study of mesoporous silica-encapsulated gold nanorods as enhanced light scattering probes for cancer cell imaging

Energy Technology Data Exchange (ETDEWEB)

Zhan Qiuqiang; Qian Jun; Li Xin; He Sailing, E-mail: qianjun@coer.zju.edu.cn [Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310058 (China)

2010-02-05

Mesoporous encapsulation of gold nanorods (GNRs) in a silica shell of controllable thickness (4.5-25.5 nm) was realized through a single-step coating method without any intermediary coating. The dependence of localized surface plasmon resonance (LSPR) extinction spectra of the coated GNRs on the thickness of the silica shell was investigated with both simulation and experiments, which agreed well with each other. It was found that cetyltrimethyl ammonium bromide (CTAB) molecules, which act as surfactants for the GNRs and dissociate in the solution, greatly affect the silica coating. Mesoporous silica-encapsulated GNRs were also shown to be highly biocompatible and stable in bio-environments. Based on LSPR enhanced scattering, mesoporous silica-encapsulated GNRs were utilized for dark field scattering imaging of cancer cells. Biomolecule-conjugated mesoporous silica-encapsulated GNRs were specifically taken up by cancer cells in vitro, justifying their use as effective optical probes for early cancer diagnosis. Mesoporous silica can also be modified with functional groups and conjugated with certain biomolecules for specific labeling on mammalian cells as well as carrying drugs or biomolecules into biological cells.

Functionalized magnetic mesoporous silica nanoparticles for U removal from low and high pH groundwater

Energy Technology Data Exchange (ETDEWEB)

Li, Dien, E-mail: dien.li@srs.gov [Savannah River National Laboratory, Aiken, SC 29808 (United States); Egodawatte, Shani [Department of Chemistry, University of Iowa, Iowa City, IA 52242 (United States); Kaplan, Daniel I. [Savannah River National Laboratory, Aiken, SC 29808 (United States); Larsen, Sarah C. [Department of Chemistry, University of Iowa, Iowa City, IA 52242 (United States); Serkiz, Steven M. [Savannah River National Laboratory, Aiken, SC 29808 (United States); Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States); Seaman, John C. [Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802 (United States)

2016-11-05

Highlights: • Magnetic mesoporous silica nanoparticles were functionalized with organic molecules. • The functionalized nanoparticles had high surface areas and consistent pore sizes. • The functionalized nanoparticles were easily separated due to their magnetism. • They exhibited high capacity for uranium removal from low- or high-pH groundwater. - Abstract: U(VI) species display limited adsorption onto sediment minerals and synthetic sorbents in pH <4 or pH >8 groundwater. In this work, magnetic mesoporous silica nanoparticles (MMSNs) with magnetite nanoparticle cores were functionalized with various organic molecules using post-synthetic methods. The functionalized MMSNs were characterized using N{sub 2} adsorption-desorption isotherms, thermogravimetric analysis (TGA), transmission electron microscopy (TEM), {sup 13}C cross polarization and magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectroscopy, and powder X-ray diffraction (XRD), which indicated that mesoporous silica (MCM-41) particles of 100–200 nm formed around a core of magnetic iron oxide, and the functional groups were primarily grafted into the mesopores of ∼3.0 nm in size. The functionalized MMSNs were effective for U removal from pH 3.5 and 9.6 artificial groundwater (AGW). Functionalized MMSNs removed U from the pH 3.5 AGW by as much as 6 orders of magnitude more than unfunctionalized nanoparticles or silica and had adsorption capacities as high as 38 mg/g. They removed U from the pH 9.6 AGW as much as 4 orders of magnitude greater than silica and 2 orders of magnitude greater than the unfunctionalized nanoparticles with adsorption capacities as high as 133 mg/g. These results provide an applied solution for treating U contamination that occurs at extreme pH environments and a scientific foundation for solving critical industrial issues related to environmental stewardship and nuclear power production.

Controlled epitaxial growth of mesoporous silica/gold nanorod nanolollipops and nanodumb-bells

International Nuclear Information System (INIS)

Huang, Ching-Mao; Chung, Ming-Fang; Lo, Leu-Wei; Souris, Jeffrey S.

2014-01-01

In this work, we describe the controlled synthesis of novel heterogeneous nanostructures comprised of mesoporous silica-coated gold nanorods (MSGNRs) in the form of core–shell nanolollipops and nanodumb-bells, using a seed-mediated sol–gel method. Although MSGNR core–shell (θ-MSGNR) structures have been reported previously by us and others, we herein discuss the first ever fabrication of MSGNR nanolollipops (φ-MSGNR) and nanodumb-bells (β-MSGNR), achieved by simply controlling the aging time of gold nanorods (GNRs), the residual cetyltrimethylammonium bromide (CTAB) coating of GNRs, and the addition of dimethyl formamide during incubation, centrifugation, and sonication, respectively. Transmission electron microscopy revealed two bare GNR isoforms, with aspect ratios of approximately 4 and 6, while scanning electron microscopy was used to further elucidate the morphology of φ-MSGNR and β-MSGNR heterostructures. In agreement with the smaller dielectric constants afforded by incomplete silica encasement, spectroscopic studies of φ-MSGNR and β-MSGNR, surface plasmon resonance (SPR) bands revealed 20-40 nm blue shifts relative to the SPR of θ-MSGNR. On the basis of the attributes and applications of more conventional θ-MSGNRs, φ-MSGNRs and β-MSGNRs are anticipated to provide most of the utility of θ-MSGNRs, but with the additional functionalities that accompany their incorporation of both bare gold and mesoporous silica encased tips; with significant/unique implications for biomedical and catalytic applications

Preparation of fluorescent mesoporous hollow silica-fullerene nanoparticles via selective etching for combined chemotherapy and photodynamic therapy

Science.gov (United States)

Yang, Yannan; Yu, Meihua; Song, Hao; Wang, Yue; Yu, Chengzhong

2015-07-01

Well-dispersed mesoporous hollow silica-fullerene nanoparticles with particle sizes of ~50 nm have been successfully prepared by incorporating fullerene molecules into the silica framework followed by a selective etching method. The fabricated fluorescent silica-fullerene composite with high porosity demonstrates excellent performance in combined chemo/photodynamic therapy.Well-dispersed mesoporous hollow silica-fullerene nanoparticles with particle sizes of ~50 nm have been successfully prepared by incorporating fullerene molecules into the silica framework followed by a selective etching method. The fabricated fluorescent silica-fullerene composite with high porosity demonstrates excellent performance in combined chemo/photodynamic therapy. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02769a

Functionalized mesoporous silica nanoparticles for stimuli-responsive and targeted

Energy Technology Data Exchange (ETDEWEB)

Knezevic, Nikola [Iowa State Univ., Ames, IA (United States)

2009-12-15

Construction of functional supramolecular nanoassemblies has attracted great deal of attention in recent years for their wide spectrum of practical applications. Mesoporous silica nanoparticles (MSN) in particular were shown to be effective scaffolds for the construction of drug carriers, sensors and catalysts. Herein, we describe the synthesis and characterization of stimuli-responsive, controlled release MSN-based assemblies for drug delivery.

One-step synthesis of mesoporous silica–graphene composites by ...

Indian Academy of Sciences (India)

Administrator

reaction of the –COOH group of GO and the silanol (Si–OH) of silica. The Raman spectra of the ... Graphene; graphene oxide; mineral silica; silica; mesoporous silica; hydrothermal reduction. 1. Introduction .... mer's method which uses a combination of potassium ... tional groups both on the basal planes and the edges. The.

A novel method for the synthesis of monodisperse gold-coated silica nanoparticles

International Nuclear Information System (INIS)

English, Michael D.; Waclawik, Eric R.

2012-01-01

Monodisperse silica nanoparticles were synthesised by the well-known Stober protocol, then dispersed in acetonitrile (ACN) and subsequently added to a bisacetonitrile gold(I) coordination complex ([Au(MeCN) 2 ] + ) in ACN. The silica hydroxyl groups were deprotonated in the presence of ACN, generating a formal negative charge on the siloxy groups. This allowed the [Au(MeCN) 2 ] + complex to undergo ligand exchange with the silica nanoparticles and form a surface coordination complex with reduction to metallic gold (Au 0 ) proceeding by an inner sphere mechanism. The residual [Au(MeCN) 2 ] + complex was allowed to react with water, disproportionating into Au 0 and Au(III), respectively, with the Au 0 adding to the reduced gold already bound on the silica surface. The so-formed metallic gold seed surface was found to be suitable for the conventional reduction of Au(III) to Au 0 by ascorbic acid (ASC). This process generated a thin and uniform gold coating on the silica nanoparticles. The silica NPs batches synthesised were in a size range from 45 to 460 nm. Of these silica NP batches, the size range from 400 to 480 nm were used for the gold-coating experiments.

Magnetic solid-phase extraction based on mesoporous silica-coated magnetic nanoparticles for analysis of oral antidiabetic drugs in human plasma

Energy Technology Data Exchange (ETDEWEB)

Souza, Karynne Cristina de; Andrade, Gracielle Ferreira [Centro de Desenvolvimento da Tecnologia Nuclear, CDTN/CNEN, Rua Professor Mário Werneck, s/n. Campus Universitário, Belo Horizonte, MG CEP 30.123-970 (Brazil); Vasconcelos, Ingrid; Oliveira Viana, Iara Maíra de; Fernandes, Christian [Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Martins Barros de Sousa, Edésia, E-mail: sousaem@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear, CDTN/CNEN, Rua Professor Mário Werneck, s/n. Campus Universitário, Belo Horizonte, MG CEP 30.123-970 (Brazil)

2014-07-01

In the present work, magnetic nanoparticles embedded into mesoporous silica were prepared in two steps: first, magnetite was synthesized by oxidation–precipitation method, and next, the magnetic nanoparticles were coated with mesoporous silica by using nonionic block copolymer surfactants as structure-directing agents. The mesoporous SiO{sub 2}-coated Fe{sub 3}O{sub 4} samples were functionalized using octadecyltrimethoxysilane as silanizing agent. The pure and functionalized silica nanoparticles were physicochemically and morphologically characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N{sub 2} adsorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The resultant magnetic silica nanoparticles were applied as sorbents for magnetic solid-phase extraction (MSPE) of oral antidiabetic drugs in human plasma. Our results revealed that the magnetite nanoparticles were completely coated by well-ordered mesoporous silica with free pores and stable pore walls, and that the structural and magnetic properties of the Fe{sub 3}O{sub 4} nanoparticles were preserved in the applied synthesis route. Indeed, the sorbent material was capable of extracting the antidiabetic drugs from human plasma, being useful for the sample preparation in biological matrices. - Highlights: • SBA-15/Fe{sub 3}O{sub 4} was synthesized and functionalized with octadecyltrimethoxysilane. • Magnetite nanoparticles were completely coated by well-ordered mesoporous silica. • The samples were used as sorbent for magnetic solid-phase extraction (MSPE). • The sorbent material was capable of extracting drugs from human plasma. • The extraction ability makes the material a candidate to be employed as MSPE.

Fabrication of mesoporous silica nanoparticles by sol gel method followed various hydrothermal temperature

Science.gov (United States)

Purwaningsih, Hariyati; Pratiwi, Vania Mitha; Purwana, Siti Annisa Bani; Nurdiansyah, Haniffudin; Rahmawati, Yenny; Susanti, Diah

2018-04-01

Rice husk is an agricultural waste that is potentially used as natural silica resources. Natural silica claimed to be safe in handling, cheap and can be generate from cheap resource. In this study mesoporous silica was synthesized using sodium silicate extracted from rice husk ash. This research's aim are to study the optimization of silica extraction from rice husk, characterizing mesoporous silica from sol-gel method and surfactant templating from rice husk and the effect of hydrothermal temperature on mesoporous silica nanoparticle (MSNp) formation. In this research, rice husk was extracted with sol-gel method and was followed by hydrothermal treatment; several of hydrothermal temperatures were 85°C, 100°C, 115°C, 130°C and 145° for 24 hours. X-ray diffraction analysis was identified of α-SiO2 phase and NaCl compound impurities. Scherer's analysis method for crystallite size have resulted 6.27-40.3 nm. FTIR results of silica from extraction and MSNp indicated Si-O-Si bonds on the sample. SEM result showed the morphology of the sample that has spherical shape and smooth surface. TEM result showed particle size ranged between 69,69-84,42 nm. BET showed that the pore size classified as mesoporous with pore diameter size is 19,29 nm.

Enhancement of Degradation and Dechlorination of Trichloroethylene via Supporting Palladium/Iron Bimetallic Nanoparticles onto Mesoporous Silica

Directory of Open Access Journals (Sweden)

Jianjun Wei

2016-07-01

Full Text Available This study is aimed to prevent the agglomeration of Pd/Fe bimetallic nanoparticles and thus improve the efficiency toward degradation and dechlorination of chlorinated organic contaminants. A mesoporous silica with a primary pore diameter of 8.3 nm and a specific surface area of 688 m2/g was prepared and used as the host of Pd/Fe nanoparticles. The Pd/Fe nanoparticles were deposited onto or into the mesoporous silica by reduction of ferrous ion and hexachloropalladate ion in aqueous phase. Batch degradation and dechlorination reactions of trichloroethylene were conducted with initial trichloroethylene concentration of 23.7 mg/L, iron loading of 203 or 1.91 × 103 mg/L and silica loading of 8.10 g/L at 25 °C. Concentration of trichloroethylene occurs on the supported Pd/Fe nanoparticles, with trichloroethylene degrading to 56% and 59% in 30 min on the supported Pd/Fe nanoparticles with weight percentage of palladium to iron at 0.075% and 0.10% respectively. The supported Pd/Fe nanoparticles exhibit better dechlorination activity. When the supported Pd/Fe nanoparticles with a weight percentage of palladium to iron of 0.10% were loaded much less than the bare counterpart, the yield of ethylene plus ethane in 10 h on them was comparable, i.e., 19% vs. 21%. This study offers a future approach to efficiently combine the reactivity of supported Pd/Fe nanoparticles and the adsorption ability of mesoporous silica.

Synthesis of gold nanoparticles with graphene oxide.

Science.gov (United States)

Wang, Wenshuo; He, Dawei; Zhang, Xiqing; Duan, Jiahua; Wu, Hongpeng; Xu, Haiteng; Wang, Yongsheng

2014-05-01

Single sheets of functionalized graphene oxide are derived through chemical exfoliation of natural flake graphite. We present an effective synthetic method of graphene-gold nanoparticles hybrid nanocomposites. AFM (Atomic Force Microscope) was used to measure the thickness of the individual GO nanosheet. FTIR (Fourier transform infrared) spectroscopy was used to verify the attachment of oxygen functionalities on the surface of graphene oxide. TEM (Transmission Electron Microscope) data revealed the average diameters of the gold colloids and characterized the composite particles situation. Absorption spectroscopy showed that before and after synthesis the gold particle size did not change. Our studies indicate that the hybrid is potential substrates for catalysts and biosensors.

Asymmetric mesoporous silica nanoparticles as potent and safe immunoadjuvants provoke high immune responses.

Science.gov (United States)

Abbaraju, Prasanna Lakshmi; Jambhrunkar, Manasi; Yang, Yannan; Liu, Yang; Lu, Yao; Yu, Chengzhong

2018-02-20

Asymmetric mesoporous silica nanoparticles with a head-tail structure are potent immunoadjuvants for delivering a peptide antigen, generating a higher antibody immune response in mice compared to their symmetric counterparts.

Inorganic Nanocrystals Functionalized Mesoporous Silica Nanoparticles: Fabrication and Enhanced Bio-applications

Directory of Open Access Journals (Sweden)

Tiancong Zhao

2017-12-01

Full Text Available Mesoporous SiO2 nanoparticles (MSNs are one of the most promising materials for bio-related applications due to advantages such as good biocompatibility, tunable mesopores, and large pore volume. However, unlike the inorganic nanocrystals with abundant physical properties, MSNs alone lack functional features. Thus, they are not sufficiently suitable for bio-applications that require special functions. Consequently, MSNs are often functionalized by incorporating inorganic nanocrystals, which provide a wide range of intriguing properties. This review focuses on inorganic nanocrystals functionalized MSNs, both their fabrication and bio-applications. Some of the most utilized methods for coating mesoporous silica (mSiO2 on nanoparticles were summarized. Magnetic, fluorescence and photothermal inorganic nanocrystals functionalized MSNs were taken as examples to demonstrate the bio-applications. Furthermore, asymmetry of MSNs and their effects on functions were also highlighted.

Interconnected mesopores and high accessibility in UVM-7-like silicas

Energy Technology Data Exchange (ETDEWEB)

Perez-Cabero, Monica [Universitat de Valencia, Institut de Ciencia dels Materials (Spain); Hungria, Ana B. [Universidad de Cadiz, Departamento de Ciencia de Materiales, Ingenieria Metalurgica y Quimica Inorganica (Spain); Morales, Jose Manuel [Universitat de Valencia, Institut de Ciencia dels Materials (Spain); Tortajada, Marta; Ramon, Daniel [Biopolis S. L. (Spain); Moragues, Alaina; El Haskouri, Jamal; Beltran, Aurelio; Beltran, Daniel; Amoros, Pedro, E-mail: pedro.amoros@uv.es [Universitat de Valencia, Institut de Ciencia dels Materials (Spain)

2012-08-15

Nanoparticulated bimodal mesoporous silicas (NBS) have proved to constitute adequate supports in a variety of applications requiring enhanced accessibility to the active sites. Mass-transfer kinetics seems to be highly favoured in UVM-7-derived NBS materials. To understand the mass-diffusion phenomena throughout UVM-7-like supports requires well-grounded knowledge about their pore architecture. 3-D reconstructions of the UVM-7 mesostructure carried out by electron tomography reveal the existence of a true hierarchic connectivity involving both inter- and intra-nanoparticle pores. This connectivity makes self-supported nanoparticulated mesoporous bimodal carbon replicas of the supports feasible to obtaining by nanocasting. Both the temperature-induced mobility of gold nanodomains and the fast and efficient enzyme adsorption in UVM-7-like silicas are examples of non-constrained diffusion processes happening inside such an open network.

Interconnected mesopores and high accessibility in UVM-7-like silicas

International Nuclear Information System (INIS)

Pérez-Cabero, Mónica; Hungría, Ana B.; Morales, José Manuel; Tortajada, Marta; Ramón, Daniel; Moragues, Alaina; El Haskouri, Jamal; Beltrán, Aurelio; Beltrán, Daniel; Amorós, Pedro

2012-01-01

Nanoparticulated bimodal mesoporous silicas (NBS) have proved to constitute adequate supports in a variety of applications requiring enhanced accessibility to the active sites. Mass-transfer kinetics seems to be highly favoured in UVM-7-derived NBS materials. To understand the mass-diffusion phenomena throughout UVM-7-like supports requires well-grounded knowledge about their pore architecture. 3-D reconstructions of the UVM-7 mesostructure carried out by electron tomography reveal the existence of a true hierarchic connectivity involving both inter- and intra-nanoparticle pores. This connectivity makes self-supported nanoparticulated mesoporous bimodal carbon replicas of the supports feasible to obtaining by nanocasting. Both the temperature-induced mobility of gold nanodomains and the fast and efficient enzyme adsorption in UVM-7-like silicas are examples of non-constrained diffusion processes happening inside such an open network.

Ag nanoparticles hosted in monolithic mesoporous silica by thermal decomposition method

International Nuclear Information System (INIS)

Chen Wei; Zhang Junying

2003-01-01

Ag nanoparticles were obtained by thermal decomposition of silver nitrate within pores of mesoporous silica. Microstructure of this composite was examined by X-ray diffraction and high-resolution transmission electron microscopy. Optical measurements for the nanocomposite show that Ag particle doping leads to a large red shift of the absorption edge

Amine-functionalized magnetic mesoporous silica nanoparticles for DNA separation

Energy Technology Data Exchange (ETDEWEB)

Sheng, Wei; Wei, Wei; Li, Junjian; Qi, Xiaoliang; Zuo, Gancheng; Chen, Qi; Pan, Xihao; Dong, Wei, E-mail: weidong@njust.edu.cn

2016-11-30

Highlights: • Fe{sub 3}O{sub 4}@SiO{sub 2}@EDPS with uniform size and good dispersity is prepared. • We fabricated MMSN@EDPS with distinct core-shell–shell triple-layer composition. • DNA adsorption capacity of MMSN@EDPS is considerable. - Abstract: We report a modified approach for the functionalized magnetic mesoporous silica nanoparticles (MMSN) using polymer microspheres incorporated with magnetic nanoparticles in the presence of cetyltrimethylammonium bromide (CTAB) and the core-shell magnetic silica nanoparticles (MSN). These particles were functionalized with amino groups via the addition of aminosilane directly to the particle sol. We then evaluate their DNA separation abilities and find the capacity of DNA binding significantly increased (210.22 μg/mg) compared with normal magnetic silica spheres (138.44 μg/mg) by using an ultraviolet and visible spectrophotometer (UV). The morphologies, magnetic properties, particle size, pore size, core-shell structure and Zeta potential are characterized by Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), Transmission electron microscopy (TEM), Powder X-ray diffraction (XRD), and dynamic light scattering (DLS). This work demonstrates that our MMSN own an excellent potential application in bioseparation and drug delivery.

Ordered mesoporous polymer-silica hybrid nanoparticles as vehicles for the intracellular controlled release of macromolecules.

Science.gov (United States)

Kim, Tae-Wan; Slowing, Igor I; Chung, Po-Wen; Lin, Victor Shang-Yi

2011-01-25

A two-dimensional hexagonal ordered mesoporous polymer-silica hybrid nanoparticle (PSN) material was synthesized by polymerization of acrylate monomers on the surface of SBA-15 mesoporous silica nanoparticles. The structure of the PSN material was analyzed using a series of different techniques, including transmission electron microscopy, powder X-ray diffraction, and N(2) sorption analysis. These structurally ordered mesoporous polymer-silica hybrid nanoparticles were used for the controlled release of membrane-impermeable macromolecules inside eukaryotic cells. The cellular uptake efficiency and biocompatibility of PSN with human cervical cancer cells (HeLa) were investigated. Our results show that the inhibitory concentration (IC(50)) of PSN is very high (>100 μg/mL per million cells), while the median effective concentration for the uptake (EC(50)) of PSN is low (EC(50) = 4.4 μg/mL), indicating that PSNs are fairly biocompatible and easily up-taken in vitro. A membrane-impermeable macromolecule, 40 kDa FITC-Dextran, was loaded into the mesopores of PSNs at low pH. We demonstrated that the PSN material could indeed serve as a transmembrane carrier for the controlled release of FITC-Dextran at the pH level inside live HeLa cells. We believe that further developments of this PSN material will lead to a new generation of nanodevices for intracellular controlled delivery applications.

Optical Nonlinear Refractive Index of Laser-Ablated Gold Nanoparticles Graphene Oxide Composite

Directory of Open Access Journals (Sweden)

Amir Reza Sadrolhosseini

2014-01-01

Full Text Available Gold nanoparticles were prepared in graphene oxide using laser ablation technique. The ablation times were varied from 10 to 40 minutes, and the particle size was decreased from 16.55 nm to 5.18 nm in spherical shape. The nanoparticles were capped with carboxyl and the hydroxyl groups were obtained from Fourier transform infrared spectroscopy. Furthermore, the UV-visible peak shifted with decreasing of nanoparticles size, appearing from 528 nm to 510 nm. The Z-scan technique was used to measure the nonlinear refractive indices of graphene oxide with different concentrations and a gold nanoparticle graphene oxide nanocomposite. Consequently, the optical nonlinear refractive indices of graphene oxide and gold nanoparticle graphene oxide nanocomposite were shifted from 1.63×10-9 cm2/W to 4.1×10-9 cm2/W and from 1.85×10-9 cm2/W to 5.8×10-9 cm2/W, respectively.

Electron energy loss spectroscopy of gold nanoparticles on graphene

International Nuclear Information System (INIS)

DeJarnette, Drew; Roper, D. Keith

2014-01-01

Plasmon excitation decay by absorption, scattering, and hot electron transfer has been distinguished from effects induced by incident photons for gold nanoparticles on graphene monolayer using electron energy loss spectroscopy (EELS). Gold nano-ellipses were evaporated onto lithographed graphene, which was transferred onto a silicon nitride transmission electron microscopy grid. Plasmon decay from lithographed nanoparticles measured with EELS was compared in the absence and presence of the graphene monolayer. Measured decay values compared favorably with estimated radiative and non-radiative contributions to decay in the absence of graphene. Graphene significantly enhanced low-energy plasmon decay, increasing mode width 38%, but did not affect higher energy plasmon or dark mode decay. This decay beyond expected radiative and non-radiative mechanisms was attributed to hot electron transfer, and had quantum efficiency of 20%, consistent with previous reports

Concentration quenching and photostability in Eu(dbm)3phen embedded in mesoporous silica nanoparticles

International Nuclear Information System (INIS)

Moretti, Elisa; Talon, Aldo; Storaro, Loretta; Le Donne, Alessia; Binetti, Simona; Benedetti, Alvise; Polizzi, Stefano

2014-01-01

Ordered mesoporous silica nanoparticles (MSNs) were impregnated with different loadings of the luminescent complex tris(dibenzoylmethane) mono(1,10-phenanthroline)europium(III) (Eu(dbm) 3 phen), with the aim of increasing the luminescence by avoiding concentration quenching and having mainly in mind the application as spectral converter for multi-crystalline silicon solar cells. The morphological, structural and luminescence properties of the impregnated silica nanoparticles were characterized by N 2 physisorption, X-ray diffraction, transmission electron microscopy, infrared spectroscopy, UV–visible spectroscopy and photoluminescence excitation and emission measurements. Photostability was tested under 1 sun (1000 W/m 2 ) illumination for 24 h and the related effects were inspected by UV–visible and photoluminescence spectroscopies. Impregnation of the complex into 50–70 nm MSNs with pore size tailored around 2.9 nm depressed concentration quenching and allowed the use of complex loadings as high as 23 wt%. Sunlight irradiation caused a marked increase in the luminescence intensity. -- Highlights: • Mesoporous silica nanoparticles tailored to the size of Eu 3+ (dbm) 3 phen molecules. • Concentration quenching avoided up to 23 wt% of Eu 3+ (dbm) 3 phen/silica. • Sun irradiation increased luminescence intensity by two order of magnitudes

Tetracycline-Containing MCM-41 Mesoporous Silica Nanoparticles for the Treatment of Escherichia coli.

Science.gov (United States)

Koneru, Bhuvaneswari; Shi, Yi; Wang, Yu-Chieh; Chavala, Sai H; Miller, Michael L; Holbert, Brittany; Conson, Maricar; Ni, Aiguo; Di Pasqua, Anthony J

2015-10-30

Tetracycline (TC) is a well-known broad spectrum antibiotic, which is effective against many Gram positive and Gram negative bacteria. Controlled release nanoparticle formulations of TC have been reported, and could be beneficial for application in the treatment of periodontitis and dental bone infections. Furthermore, TC-controlled transcriptional regulation systems (Tet-on and Tet-off) are useful for controlling transgene expression in vitro and in vivo for biomedical research purposes; controlled TC release systems could be useful here, as well. Mesoporous silica nanomaterials (MSNs) are widely studied for drug delivery applications; Mobile crystalline material 41 (MCM-41), a type of MSN, has a mesoporous structure with pores forming channels in a hexagonal fashion. We prepared 41 ± 4 and 406 ± 55 nm MCM-41 mesoporous silica nanoparticles and loaded TC for controlled dug release; TC content in the TC-MCM-41 nanoparticles was 18.7% and 17.7% w/w, respectively. Release of TC from TC-MCM-41 nanoparticles was then measured in phosphate-buffered saline (PBS), pH 7.2, at 37 °C over a period of 5 h. Most antibiotic was released from both over this observation period; however, the majority of TC was released over the first hour. Efficacy of the TC-MCM-41 nanoparticles was then shown to be superior to free TC against Escherichia coli (E. coli) in culture over a 24 h period, while blank nanoparticles had no effect.

Atom Transfer Radical Polymerization of Styrene in Presence of Mesoporous Silica Nanoparticles: Application of Reverse, Simultaneous Reverse and Normal Initiation Techniques

Directory of Open Access Journals (Sweden)

Khezrollah Khezri

2014-04-01

Full Text Available Atom transfer radical polymerization (ATRP of styrene in presence of mesoporous silica nanoparticles was carried out at 110 °C. Reverse atom transfer radical polymerization (RATRP and simultaneous reverse and normal initiation for atom transfer radical polymerization (SR&NI ATRP techniques were used as two appropriate introduced techniques for circumventing oxidation problems. Usage of metal catalyst in its higher oxidation state was the main feature of these initiation techniques in which deficiencies of normal ATRP were circumvented. Structure, surface area and pore diameter of synthesized mesoporous silica nanoparticles were evaluated using X–ray diffraction and nitrogen adsorption/desorption isotherm analysis. Average particle size was estimated around 600 nm by electron microscopy images. In addition, according to these images, nanoparticles revealed an appropriate size distribution. Particles size and their distribution were examined using scanning. Final monomer conversion was determined by using gas chromatography. The number and weight average molecular weights (Mn and Mw and polydispersity indexes (PDI were also evaluated by gel permeation chromatography. According to the results obtained, addition of mesoporous silica nanoparticles in both RATRP and SR&NI ATRP systems revealed similar effects: decrement of conversion and Mn and also increment of PDI values observed by increasing of mesoporous silica nanoparticles content. Improvement in thermal stability of the nanocomposites in comparison with neat polystyrene was demonstrated by thermogravimetric analysis (TGA. Moreover, in case of nanocomposites, thermal stability was obtained by higher loading of nanoparticles. A decrease in glass transition temperature by higher content of mesoporous silica nanoparticles has been demonstrated by differential scanning calorimetry analysis.

Cerium oxide-deposited mesoporous silica nanoparticles for the determination of carcinoembryonic antigen in serum using inductively coupled plasma-mass spectrometry

International Nuclear Information System (INIS)

Choi, H.W.; Lee, K.H.; Hur, N.H.; Lim, H.B.

2014-01-01

Highlights: • Sandwich-type immunoassay using ICP-MS and nanoparticles to determine biomarkers. • CeO 2 -deposited mesoporous silica nanoparticles were synthesized as a probe. • Ratiometric measurement significantly improved the calibration linearity. • Excellent detection limit was achieved by signal amplification. - Abstract: CeO 2 -deposited mesoporous silica nanoparticles were synthesized as a probe to determine carcinoembryonic antigen (CEA) in serum by inductively coupled plasma-mass spectrometry (ICP-MS). The prepared mesoporous nanoparticles were modified and tagged to the target for sandwich-type immunoassay. Fe 3 O 4 magnetic nanoparticles (MNPs) were also synthesized and immobilized with antibody to extract the target biomarker. The calibration curve of the synthesized CeO 2 -deposited silica nanoparticles, which was plotted by the signal ratio of 140 Ce/ 57 Fe measured by ICP-MS vs. the concentration of CEA, showed excellent linearity and sensitivity owing to the signal amplification and low spectral interference. Under optimal conditions, the sandwich-type analytical method was applied to determine CEA in serum spiked in the range of 0.001–5 ng mL −1 and showed a limit of detection of 0.36 ng mL −1 . Since the deposited CeO 2 in the mesoporous silica layer can be substituted by other metal compounds, various kinds of metal-deposited nanoparticles can be prepared as probe materials for multiplex detection in bioanalysis

Advances in Multicompartment Mesoporous Silica Micro/Nanoparticles for Theranostic Applications.

Science.gov (United States)

Liu, Jian; Liu, Tingting; Pan, Jian; Liu, Shaomin; Lu, G Q Max

2018-04-04

Mesoporous silica nanoparticles (MSNs) are promising functional nanomaterials for a variety of biomedical applications, such as bioimaging, drug/gene delivery, and cancer therapy. This is due to their low density, low toxicity, high biocompatibility, large specific surface areas, and excellent thermal and mechanical stability. The past decade has seen rapid advances in the development of MSNs with multiple compartments. These include hierarchical porous structures and core-shell, yolk-shell, and Janus structured particles for efficient diagnosis and therapeutic applications. We review advances in this area, covering the categories of multicompartment MSNs and their synthesis methods, with an emphasis on hierarchical structures and the incorporation of multiple functions. We classify multicompartment mesoporous silica micro/nanostructures, ranging from core-shell and yolk-shell structures to Janus and raspberry-like nanoparticles, and discuss their synthesis methods. We review applications of these multicompartment MSNs, including bioimaging, targeted drug/gene delivery, chemotherapy, phototherapy, and in vitro diagnostics. We also highlight the latest trends and new opportunities. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering Volume 9 is June 7, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Phospholipid-Coated Mesoporous Silica Nanoparticles Acting as Lubricating Drug Nanocarriers

Directory of Open Access Journals (Sweden)

Tao Sun

2018-05-01

Full Text Available Osteoarthritis (OA is a severe disease caused by wear and inflammation of joints. In this study, phospholipid-coated mesoporous silica nanoparticles (MSNs@lip were prepared in order to treat OA at an early stage. The phospholipid layer has excellent lubrication capability in aqueous media due to the hydration lubrication mechanism, while mesoporous silica nanoparticles (MSNs act as effective drug nanocarriers. The MSNs@lip were characterized by scanning electron microscope, transmission electron microscope, Fourier transform infrared spectrum, X-ray photoelectron spectrum, thermogravimetric analysis and dynamic light scattering techniques to confirm that the phospholipid layer was coated onto the surface of MSNs successfully. A series of tribological tests were performed under different experimental conditions, and the results showed that MSNs@lip with multi-layers of phospholipids greatly reduced the friction coefficient in comparison with MSNs. Additionally, MSNs@lip demonstrated sustained drug release behavior and were biocompatible based on CCK-8 assay using MC3T3-E1 cells. The MSNs@lip developed in the present study, acting as effective lubricating drug nanocarriers, may represent a promising strategy to treat early stage OA by lubrication enhancement and drug delivery therapy.

Innovative preparation of Au/C by replication of gold-containing mesoporous silica catalysts

KAUST Repository

Kerdi, Fatmé ; Caps, Valerie; Tuel, Alain

2010-01-01

A new strategy, based on the nanocasting concept, has been used to prepare gold nanoparticles (NPs) highly dispersed in meso-structured carbons. Gold is first introduced in various functionalized mesostructured silicas (MCM-48 and SBA-15

Activators generated by electron transfer for atom transfer radical polymerization of styrene in the presence of mesoporous silica nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Khezri, Khezrollah, E-mail: kh.khezri@ut.ac.ir [School of Chemistry, University College of Science, University of Tehran, PO Box 14155-6455, Tehran (Iran, Islamic Republic of); Roghani-Mamaqani, Hossein [Department of Polymer Engineering, Sahand University of Technology, PO Box 51335-1996, Tabriz (Iran, Islamic Republic of)

2014-11-15

Graphical abstract: Effect of mesoporous silica nanoparticles (MCM-41) on the activator generated by electron transfer for atom transfer radical polymerization (AGET ATRP) is investigated. Decrement of conversion and number average molecular weight and also increment of polydispersity index (PDI) values are three main results of addition of MCM-41 nanoparticles. Incorporation of MCM-41 nanoparticles in the polystyrene matrix can clearly increase thermal stability and decrease glass transition temperature of the nanocomposites. - Highlights: • Spherical morphology, hexagonal structure, and high surface area with regular pore diameters of the synthesized MCM-41 nanoparticles are examined. • AGET ATRP of styrene in the presence of MCM-41 nanoparticles is performed. • Effect of MCM-41 nanoparticles addition on the polymerization rate, conversion and molecular weights of the products are discussed. • Improvement in thermal stability of the nanocomposites and decreasing T{sub g} values was also observed by incorporation of MCM-41 nanoparticles. - Abstract: Activator generated by electron transfer for atom transfer radical polymerization was employed to synthesize well-defined mesoporous silica nanoparticles/polystyrene composites. Inherent features of spherical mesoporous silica nanoparticles were evaluated by nitrogen adsorption/desorption isotherm, X-ray diffraction and scanning electron microscopy analysis techniques. Conversion and molecular weight evaluations were carried out using gas and size exclusion chromatography respectively. By the addition of only 3 wt% mesoporous silica nanoparticles, conversion decreases from 81 to 58%. Similarly, number average molecular weight decreases from 17,116 to 12,798 g mol{sup −1}. However, polydispersity index (PDI) values increases from 1.24 to 1.58. A peak around 4.1–4.2 ppm at proton nuclear magnetic resonance spectroscopy results clearly confirms the living nature of the polymerization. Thermogravimetric

Cerium oxide-deposited mesoporous silica nanoparticles for the determination of carcinoembryonic antigen in serum using inductively coupled plasma-mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Choi, H.W. [Department of Chemistry, NSBI, Dankook University, 126 Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi-do 448-701 (Korea, Republic of); Lee, K.H.; Hur, N.H. [Department of Chemistry, Sogang University, Shinsu-dong, Mapo-gu, Seoul (Korea, Republic of); Lim, H.B., E-mail: plasma@dankook.ac.kr [Department of Chemistry, NSBI, Dankook University, 126 Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi-do 448-701 (Korea, Republic of)

2014-10-17

Highlights: • Sandwich-type immunoassay using ICP-MS and nanoparticles to determine biomarkers. • CeO{sub 2}-deposited mesoporous silica nanoparticles were synthesized as a probe. • Ratiometric measurement significantly improved the calibration linearity. • Excellent detection limit was achieved by signal amplification. - Abstract: CeO{sub 2}-deposited mesoporous silica nanoparticles were synthesized as a probe to determine carcinoembryonic antigen (CEA) in serum by inductively coupled plasma-mass spectrometry (ICP-MS). The prepared mesoporous nanoparticles were modified and tagged to the target for sandwich-type immunoassay. Fe{sub 3}O{sub 4} magnetic nanoparticles (MNPs) were also synthesized and immobilized with antibody to extract the target biomarker. The calibration curve of the synthesized CeO{sub 2}-deposited silica nanoparticles, which was plotted by the signal ratio of {sup 140}Ce/{sup 57}Fe measured by ICP-MS vs. the concentration of CEA, showed excellent linearity and sensitivity owing to the signal amplification and low spectral interference. Under optimal conditions, the sandwich-type analytical method was applied to determine CEA in serum spiked in the range of 0.001–5 ng mL{sup −1} and showed a limit of detection of 0.36 ng mL{sup −1}. Since the deposited CeO{sub 2} in the mesoporous silica layer can be substituted by other metal compounds, various kinds of metal-deposited nanoparticles can be prepared as probe materials for multiplex detection in bioanalysis.

Wrinkling of graphene membranes supported by silica nanoparticles on substrates

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Yamamoto, Mahito; Cullen, William; Fuhrer, Michael; Einstein, Theodore; Department of Physics, University of Maryland Team

2011-03-01

The challenging endeavor of modulating the morphology of graphene via a patterned substrate to produce a controlled deformation has great potential importance for strain engineering the electronic properties of graphene. An essential step in this direction is to understand the response of graphene to substrate features of known geometry. Here we employ silica nanoparticles with a diameter of 10-100 nm to uniformly decorate Si O2 and mica substrates before depositing graphene, to promote nanoscale modulation of graphene geometry. The morphology of graphene on this modified substrate is then characterized by atomic force spectroscopy. We find that graphene on the substrate is locally raised by the supporting nanoparticles, and wrinkling propagates radially from the protrusions to form a ridge network which links the protrusions. We discuss the dependence of the wrinkled morphology on nanoparticle diameter and graphene thickness in terms of graphene elasticity and adhesion energy. Supported by NSF-MRSEC, Grant DMR 05-20471

Dual soft-template system based on colloidal chemistry for the synthesis of hollow mesoporous silica nanoparticles.

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Li, Yunqi; Bastakoti, Bishnu Prasad; Imura, Masataka; Tang, Jing; Aldalbahi, Ali; Torad, Nagy L; Yamauchi, Yusuke

2015-04-20

A new dual soft-template system comprising the asymmetric triblock copolymer poly(styrene-b-2-vinyl pyridine-b-ethylene oxide) (PS-b-P2VP-b-PEO) and the cationic surfactant cetyltrimethylammonium bromide (CTAB) is used to synthesize hollow mesoporous silica (HMS) nanoparticles with a center void of around 17 nm. The stable PS-b-P2VP-b-PEO polymeric micelle serves as a template to form the hollow interior, while the CTAB surfactant serves as a template to form mesopores in the shells. The P2VP blocks on the polymeric micelles can interact with positively charged CTA(+) ions via negatively charged hydrolyzed silica species. Thus, dual soft-templates clearly have different roles for the preparation of the HMS nanoparticles. Interestingly, the thicknesses of the mesoporous shell are tunable by varying the amounts of TEOS and CTAB. This study provides new insight on the preparation of mesoporous materials based on colloidal chemistry. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and Physicochemical Characterization of Mesoporous SiO2 Nanoparticles

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Dharani Das

2014-01-01

Full Text Available There exists a knowledge gap in understanding potential toxicity of mesoporous silica nanoparticles. A critical step in assessing toxicity of these particles is to have a wide size range with different chemistries and physicochemical properties. There are several challenges when synthesizing mesoporous silica nanoparticles over a wide range of sizes including (1 nonuniform synthesis protocols using the same starting materials, (2 the low material yield in a single batch synthesis (especially for particles below 60–70 nm, and (3 morphological instability during surfactant removal process and surface modifications. In this study, we synthesized a library of mesoporous silica nanoparticles with approximate particle sizes of 25, 70, 100, 170, and 600 nm. Surfaces of the silica nanoparticles were modified with hydrophilic-CH2–(CH22–COOH and relatively hydrophobic-CH2–(CH210–COOH functional groups. All silica nanoparticles were analysed for morphology, surface functionality, surface area/pore volume, surface organic content, and dispersion characteristics in liquid media. Our analysis revealed the synthesis of a spectrum of monodisperse bare and surface modified mesoporous silica nanoparticles with a narrow particle size distribution and devoid of cocontaminants critical for toxicity studies. Complete physicochemical characterization of these synthetic mesoporous silica nanoparticles will permit systematic toxicology studies for investigation of structure-activity relationships.

The comparative immunotoxicity of mesoporous silica nanoparticles and colloidal silica nanoparticles in mice

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Lee S

2013-01-01

Full Text Available Soyoung Lee,1,* Mi-Sun Kim,1,* Dakeun Lee,2 Taeg Kyu Kwon,3 Dongwoo Khang,4 Hui-Suk Yun,5 Sang-Hyun Kim11CMRI, Laboratory of Immunotoxicology, Department of Pharmacology,School of Medicine, Kyungpook National University, Daegu, Republic of Korea; 2Department of Pathology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea; 3Department of Immunology, School of Medicine, Keimyung University, Daegu, Republic of Korea; 4School of Nano and Advanced Materials Science and Engineering, Gyeongsang National University, Jinju, Republic of Korea; 5Engineering Ceramics Department, Powder and Ceramics Division, Korea Institute of Materials Science, Changwon, Republic of Korea*These authors contributed equally to this workBackground: Mesoporous silica (MPS nanoparticles (NPs, which have a unique pore structure and extremely large surface area and pore volume, have received much attention because of their biomedical application potential. Using MPS NPs for biomedical devices requires the verification of their biocompatibility because the surface area of NPs is one of the most important determinants of toxicity, including the cellular uptake and immune response. We have previously reported that the cytotoxicity and inflammation potential of MPS NPs have been shown to be lower than those of general amorphous colloidal silica (Col NPs in macrophages, but the low cytotoxicity does not guarantee high biocompatibility in vivo. In this study, we compared the in vivo immunotoxicity of MPS and Col NPs in the mouse model to define the effects of pore structural conditions of silica NPs.Materials and methods: Both MPS and Col NPs (2, 20, and 50 mg/kg/day were intraperitoneally administered in female BALB/c mice for 4 weeks, and clinical toxicity, lymphocyte population, serum IgG/IgM levels, and histological changes were examined.Results: There was no overt sign of clinical toxicity in either MPS- or Col-treated mice. However, MPS NPs led to

Peptide-laden mesoporous silica nanoparticles with promoted bioactivity and osteo-differentiation ability for bone tissue engineering.

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Luo, Zuyuan; Deng, Yi; Zhang, Ranran; Wang, Mengke; Bai, Yanjie; Zhao, Qiang; Lyu, Yalin; Wei, Jie; Wei, Shicheng

2015-07-01

Combination of mesoporous silica materials and bioactive factors is a promising niche-mimetic solution as a hybrid bone substitution for bone tissue engineering. In this work, we have synthesized biocompatible silica-based nanoparticles with abundant mesoporous structure, and incorporated bone-forming peptide (BFP) derived from bone morphogenetic protein-7 (BMP-7) into the mesoporous silica nanoparticles (MSNs) to obtain a slow-release system for osteogenic factor delivery. The chemical characterization demonstrates that the small osteogenic peptide is encapsulated in the mesoporous successfully, and the nitrogen adsorption-desorption isotherms suggest that the peptide encapsulation has no influence on mesoporous structure of MSNs. In the cell experiment, the peptide-laden MSNs (p-MSNs) show higher MG-63 cell proliferation, spreading and alkaline phosphatase (ALP) activity than the bare MSNs, indicating good in vitro cytocompatibility. Simultaneously, the osteogenesis-related proteins expression and calcium mineral deposition disclose enhanced osteo-differentiation of human mesenchymal stem cells (hMSCs) under the stimulation of the p-MSNs, confirming that BFP released from MSNs could significantly promote the osteogenic differentiation of hMSCs, especially at 500μg/mL of p-MSNs concentration. The peptide-modified MSNs with better bioactivity and osteogenic differentiation make it a potential candidate as bioactive material for bone repairing, bone regeneration, and bio-implant coating applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Biocompatibility, endocytosis, and intracellular trafficking of mesoporous silica and polystyrene nanoparticles in ovarian cancer cells: effects of size and surface charge groups

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Ekkapongpisit, Maneerat; Giovia, Antonino; Follo, Carlo; Caputo, Giuseppe; Isidoro, Ciro

2012-01-01

Background and methods Nanoparticles engineered to carry both a chemotherapeutic drug and a sensitive imaging probe are valid tools for early detection of cancer cells and to monitor the cytotoxic effects of anticancer treatment simultaneously. Here we report on the effect of size (10–30 nm versus 50 nm), type of material (mesoporous silica versus polystyrene), and surface charge functionalization (none, amine groups, or carboxyl groups) on biocompatibility, uptake, compartmentalization, and intracellular retention of fluorescently labeled nanoparticles in cultured human ovarian cancer cells. We also investigated the involvement of caveolae in the mechanism of uptake of nanoparticles. Results We found that mesoporous silica nanoparticles entered via caveolae-mediated endocytosis and reached the lysosomes; however, while the 50 nm nanoparticles permanently resided within these organelles, the 10 nm nanoparticles soon relocated in the cytoplasm. Naked 10 nm mesoporous silica nanoparticles showed the highest and 50 nm carboxyl-modified mesoporous silica nanoparticles the lowest uptake rates, respectively. Polystyrene nanoparticle uptake also occurred via a caveolae-independent pathway, and was negatively affected by serum. The 30 nm carboxyl-modified polystyrene nanoparticles did not localize in lysosomes and were not toxic, while the 50 nm amine-modified polystyrene nanoparticles accumulated within lysosomes and eventually caused cell death. Ovarian cancer cells expressing caveolin-1 were more likely to endocytose these nanoparticles. Conclusion These data highlight the importance of considering both the physicochemical characteristics (ie, material, size and surface charge on chemical groups) of nanoparticles and the biochemical composition of the cell membrane when choosing the most suitable nanotheranostics for targeting cancer cells. PMID:22904626

Synthesis, characterization, and biodistribution studies of {sup 99m}Tc-labeled SBA-16 mesoporous silica nanoparticles

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Branco de Barros, André Luís [Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, Minas Gerais (Brazil); Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais (Brazil); Silva de Oliveira Ferraz, Karina; Soares Dantas, Thais Cristina; Ferreira Andrade, Gracielle [Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, Minas Gerais (Brazil); Nascimento Cardoso, Valbert [Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais (Brazil); Barros de Sousa, Edésia Martins, E-mail: sousaem@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, Minas Gerais (Brazil)

2015-11-01

Along with anti-cancer drug delivery researches, many efforts have been done to develop new tracers for diagnostic applications. Based on advances in molecular imaging, nanoparticles can be used to visualize, characterize and measure biological process at molecular and cellular level. Therefore, the purpose of this study was to synthesize, characterize and radiolabeled mesoporous silica nanoparticles (MSNs) for in vivo applications. The nanoparticles were synthesized, functionalized with 3-aminopropyltriethoxysilane (APTES) and then, anchored with diethylenetriaminepentaacetic acid (DTPA). Particles were physicochemical characterized by elemental analysis (CHN), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and zeta potential, and were morphologically characterized by scanning electron microscopy (SEM), low-angle X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. Results indicate that functionalization process was successfully achieved. Next, functionalized silica nanoparticles were radiolabeled with technetium-99m showing high radiochemical yields and high radiolabeled stability. These findings allow the use of the particles for in vivo applications. Biodistribution and scintigraphic images were carried out in healthy mice in order to determine the fate of the particles. Results from in vivo experiments showed high uptake by liver, as expected due to phagocytosis. However, particles also showed a significant uptake in the lungs, indicated by high lung-to-non-target tissue ratio. In summary, taking into account the great potential of these silica mesoporous structures to carry molecules this platform could be a good strategy for theranostic purposes. - Highlights: • Silica mesoporous nanoparticles were successfully prepared. • Functionalization with DTPA was achieved. • High radiolabeled yields and in vitro stability were reached. • Biodistribution and scintigraphic images were performed.

Mesoporous silica wrapped with graphene oxide-conducting PANI nanowires as a novel hybrid electrode for supercapacitor

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Javed, Mohsin; Abbas, Syed Mustansar; Siddiq, Mohammad; Han, Dongxue; Niu, Li

2018-02-01

A high charge-carrier transport is an important aim in the synthesis of nanostructures for an effective supercapacitor. This article describes a methodology to prepare mesoporous silica nanoparticles (MSNs) wrapped with graphene oxide (GO) together with conducting polyaniline (PANI) wires. The morphology and chemical structure of the prepared samples have been tested by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and X-ray diffraction (XRD), whereas the stability and electrostatic interaction of the structures have been verified by thermogravimetric analysis (TGA) and Fourier-transform infrared (FT-IR) spectroscopy, respectively. The supercapacitive behaviour of these nanocomposites has been analysed by cyclic voltammetry (CV), charge-discharge tests, and electrochemical impedance spectroscopy (EIS). Compared with pristine MSNs and PANI, the 20%-GO@MSNs/PANI nanocomposite had the highest specific capacitance, reaching 412 F g-1. The nanocomposite structure maximizes the synergy between mesoporous metal oxide, conducting PANI, and GO, yielding a significantly enhanced specific capacitance, rapid charge-discharge rates, and good cycling stability of the resulting device. The wrapping with GO prevents the structural breakdown and acts as a highly conductive pathway by bridging the individual particles, whereas the MSNs nanoparticles greatly enlarge the specific surface area to facilitate ion transport and charge transfer throughout the cycling performance of supercapacitor. The approach adopted in this article can be applied for preparing similar novel functional materials in future for electrochemical applications.

Mesoporous silica nanoparticles functionalized with folic acid/methionine for active targeted delivery of docetaxel

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Khosravian P

2016-12-01

Full Text Available Pegah Khosravian,1 Mehdi Shafiee Ardestani,2 Mehdi Khoobi,3 Seyed Naser Ostad,4 Farid Abedin Dorkoosh,1 Hamid Akbari Javar,1,* Massoud Amanlou5,6,* 1Department of Pharmaceutics, 2Department of Radiopharmacy, 3Department of Pharmaceutical Biomaterials, 4Department of Pharmacology and Toxicology, 5Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, 6Drug Design and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran *These authors contributed equally to this work Abstract: Mesoporous silica nanoparticles (MSNs are known as carriers with high loading capacity and large functionalizable surface area for target-directed delivery. In this study, a series of docetaxel-loaded folic acid- or methionine-functionalized mesoporous silica nanoparticles (DTX/MSN-FA or DTX/MSN-Met with large pores and amine groups at inner pore surface properties were prepared. The results showed that the MSNs were successfully synthesized, having good pay load and pH-sensitive drug release kinetics. The cellular investigation on MCF-7 cells showed better performance of cytotoxicity and cell apoptosis and an increase in cellular uptake of targeted nanoparticles. In vivo fluorescent imaging on healthy BALB/c mice proved that bare MSN-NH2 are mostly accumulated in the liver but MSN-FA or MSN-Met are more concentrated in the kidney. Importantly, ex vivo fluorescent images of tumor-induced BALB/c mice organs revealed the ability of MSN-FA to reach the tumor tissues. In conclusion, DTX/MSNs exhibited a good anticancer activity and enhanced the possibility of targeted drug delivery for breast cancer. Keywords: targeted delivery, mesoporous silica nanoparticle, folic acid, methionine, docetaxel

Amine functionalized cubic mesoporous silica nanoparticles as an oral delivery system for curcumin bioavailability enhancement

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Budi Hartono, Sandy; Hadisoewignyo, Lannie; Yang, Yanan; Meka, Anand Kumar; Antaresti; Yu, Chengzhong

2016-12-01

In the present work, a simple method was used to develop composite curcumin-amine functionalized mesoporous silica nanoparticles (MSN). The nanoparticles were used to improve the bioavailability of curcumin in mice through oral administration. We investigated the effect of particle size on the release profile, solubility and oral bioavailability of curcumin in mice, including amine functionalized mesoporous silica micron-sized-particles (MSM) and MSN (100-200 nm). Curcumin loaded within amine functionalized MSN (MSN-A-Cur) had a better release profile and a higher solubility compared to amine MSM (MSM-A-Cur). The bioavailability of MSN-A-Cur and MSM-A-Cur was considerably higher than that of ‘free curcumin’. These results indicate promising features of amine functionalized MSN as a carrier to deliver low solubility drugs with improved bioavailability via the oral route.

Mesoporous Silica Supported Au Nanoparticles with Controlled Size as Efficient Heterogeneous Catalyst for Aerobic Oxidation of Alcohols

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Xuefeng Chu

2015-01-01

Full Text Available A series of Au catalysts with different sizes were synthesized and employed on amine group functionalized ordered mesoporous silica solid supports as catalyst for the aerobic oxidation of various alcohols. The mesoporous silica of MCM-41 supported Au nanoparticles (Au-1 exhibited the smallest particle size at ~1.8 nm with superior catalytic activities owing to the confinement effect of the mesoporous channels. Au-1 catalyst is also very stable and reusable under aerobic condition. Therefore, this presented work would obviously provide us a platform for synthesizing more size-controlled metal catalysts to improve the catalytic performances.

Protein-gold clusters-capped mesoporous silica nanoparticles for high drug loading, autonomous gemcitabine/doxorubicin co-delivery, and in-vivo tumor imaging

KAUST Repository

Croissant, Jonas G.; Zhang, Dingyuan; Alsaiari, Shahad K.; Lu, Jie; Deng, Lin; Tamanoi, Fuyuhiko; Zink, Jeffrey I.; Khashab, Niveen M.

2016-01-01

Functional nanocarriers capable of transporting high drug contents without premature leakage and to controllably deliver several drugs are needed for better cancer treatments. To address this clinical need, gold cluster bovine serum albumin (AuNC@BSA) nanogates were engineered on mesoporous silica nanoparticles (MSN) for high drug loadings and co-delivery of two different anticancer drugs. The first drug, gemcitabine (GEM, 40 wt%), was loaded in positively-charged ammonium-functionalized MSN (MSN-NH3+). The second drug, doxorubicin (DOX, 32 wt%), was bound with negatively-charged AuNC@BSA electrostatically-attached onto MSN-NH3+, affording highly loaded pH-responsive MSN-AuNC@BSA nanocarriers. The co-delivery of DOX and GEM was achieved for the first time via an inorganic nanocarrier, possessing a zero-premature leakage behavior as well as drug loading capacities seven times higher than polymersome NPs. Besides, unlike the majority of strategies used to cap the pores of MSN, AuNC@BSA nanogates are biotools and were applied for targeted red nuclear staining and in-vivo tumor imaging. The straightforward non-covalent combination of MSN and gold-protein cluster bioconjugates thus leads to a simple, yet multifunctional nanotheranostic for the next generation of cancer treatments.

Protein-gold clusters-capped mesoporous silica nanoparticles for high drug loading, autonomous gemcitabine/doxorubicin co-delivery, and in-vivo tumor imaging

KAUST Repository

Croissant, Jonas G.

2016-03-23

Functional nanocarriers capable of transporting high drug contents without premature leakage and to controllably deliver several drugs are needed for better cancer treatments. To address this clinical need, gold cluster bovine serum albumin (AuNC@BSA) nanogates were engineered on mesoporous silica nanoparticles (MSN) for high drug loadings and co-delivery of two different anticancer drugs. The first drug, gemcitabine (GEM, 40 wt%), was loaded in positively-charged ammonium-functionalized MSN (MSN-NH3+). The second drug, doxorubicin (DOX, 32 wt%), was bound with negatively-charged AuNC@BSA electrostatically-attached onto MSN-NH3+, affording highly loaded pH-responsive MSN-AuNC@BSA nanocarriers. The co-delivery of DOX and GEM was achieved for the first time via an inorganic nanocarrier, possessing a zero-premature leakage behavior as well as drug loading capacities seven times higher than polymersome NPs. Besides, unlike the majority of strategies used to cap the pores of MSN, AuNC@BSA nanogates are biotools and were applied for targeted red nuclear staining and in-vivo tumor imaging. The straightforward non-covalent combination of MSN and gold-protein cluster bioconjugates thus leads to a simple, yet multifunctional nanotheranostic for the next generation of cancer treatments.

Multifunctional PEG modified DOX loaded mesoporous silica nanoparticle@CuS nanohybrids as photo-thermal agent and thermal-triggered drug release vehicle for hepatocellular carcinoma treatment

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Wu, Lingjie; Wu, Ming; Zeng, Yongyi; Zhang, Da; Zheng, Aixian; Liu, Xiaolong; Liu, Jingfeng

2015-01-01

The combination of a multi-therapeutic mode with a controlled fashion is a key improvement in nanomedicine. Here, we synthesized polyethylene glycol (PEG)-modified doxorubicin (DOX)-loaded mesoporous silica nanoparticle (MSN) @CuS nanohybrids as efficient drug delivery carriers, combined with photothermal therapy and chemotherapy to enhance the therapeutic efficacy on hepatocellular carcinoma (HCC). The physical properties of the nanohybrids were characterized by transmission electron microscopy (TEM), N2 adsorption and desorption experiments and by the Vis-NIR absorption spectra. The results showed that the doxorubicin could be stored in the inner pores of mesoporous silica nanoparticles; the CuS nanoparticles, which are coated on the surface of a mesoporous silica nanoparticle, could serve as efficient photothermal therapy (PTT) agents; the loaded drug release could be easily triggered by NIR irradiation. The combination of the PTT treatment with controlled chemotherapy could further enhance the cancer ablation ability compared to any of the single approaches alone. Hence, the reported PEG-modified DOX-loaded mesoporous silica nanoparticle@CuS nanohybrids might be very promising therapeutic agents for HCC treatment.

Inkjet Printing of Drug-Loaded Mesoporous Silica Nanoparticles-A Platform for Drug Development.

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Wickström, Henrika; Hilgert, Ellen; Nyman, Johan O; Desai, Diti; Şen Karaman, Didem; de Beer, Thomas; Sandler, Niklas; Rosenholm, Jessica M

2017-11-21

Mesoporous silica nanoparticles (MSNs) have shown great potential in improving drug delivery of poorly water soluble (BCS class II, IV) and poorly permeable (BCS class III, IV) drugs, as well as facilitating successful delivery of unstable compounds. The nanoparticle technology would allow improved treatment by reducing adverse reactions of currently approved drugs and possibly reintroducing previously discarded compounds from the drug development pipeline. This study aims to highlight important aspects in mesoporous silica nanoparticle (MSN) ink formulation development for digital inkjet printing technology and to advice on choosing a method (2D/3D) for nanoparticle print deposit characterization. The results show that both unfunctionalized and polyethyeleneimine (PEI) surface functionalized MSNs, as well as drug-free and drug-loaded MSN-PEI suspensions, can be successfully inkjet-printed. Furthermore, the model BCS class IV drug remained incorporated in the MSNs and the suspension remained physically stable during the processing time and steps. This proof-of-concept study suggests that inkjet printing technology would be a flexible deposition method of pharmaceutical MSN suspensions to generate patterns according to predefined designs. The concept could be utilized as a versatile drug screening platform in the future due to the possibility of accurately depositing controlled volumes of MSN suspensions on various materials.

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.

Hierarchical Mesoporous Organosilica-Silica Core-Shell Nanoparticles Capable of Controlled Fungicide Release.

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Luo, Leilei; Liang, Yucang; Erichsen, Egil Severin; Anwander, Reiner

2018-05-17

A new class of hierarchically structured mesoporous silica core-shell nanoparticles (HSMSCSNs) with a periodic mesoporous organosilica (PMO) core and a mesoporous silica (MS) shell is reported. The applied one-pot, two-step strategy allows rational control over the core/shell chemical composition, topology, and pore/particle size, simply by adjusting the reaction conditions in the presence of cetyltrimethylammonium bromide (CTAB) as structure-directing agent under basic conditions. The spherical, ethylene- or methylene-bridged PMO cores feature hexagonal (p6mm) or cage-like cubic symmetry (Pm3‾ n) depending on the organosilica precursor. The hexagonal MS shell was obtained by n-hexane-induced controlled hydrolysis of TEOS followed by directional co-assembly/condensation of silicate/CTAB composites at the PMO cores. The HSMSCSNs feature a hierarchical pore structure with pore diameters of about 2.7 and 5.6 nm in the core and shell domains, respectively. The core sizes and shell thicknesses are adjustable in the ranges of 90-275 and 15-50 nm, respectively, and the surface areas (max. 1300 m 2  g -1 ) and pore volumes (max. 1.83 cm 3  g -1 ) are among the highest reported for core-shell nanoparticles. The adsorption and controlled release of the fungicide propiconazole by the HSMSCSNs showed a three-stage release profile. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of Novel Mesoporous Silica Materials with Hierarchical Pore Structures

Energy Technology Data Exchange (ETDEWEB)

Yoon, Suk Bon; Choi, Wang Kyu; Choi, Byung Seon; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-05-15

Porous materials with various pore sizes in the range of micropore (< 2 nm), mesopore (2-50 nm), and macropore (> 50 nm) are attractive due to their many emerging applications such as catalysts, separation systems, and low dielectric constant materials. The discovery of new M41S mesoporous silica families with pore sizes larger than 2 nm in diameter in 1992 extended the applications into much wider pore ranges, bringing in a new prosperous era in porous material research. The synthesis of these silica materials has been mainly accomplished through a self-assembly between surfactant molecules and inorganic species under various pH conditions. Recently, core-shell nanoparticles with a silica core and mesoporous shell under basic conditions were synthesized using the silica nanoparticles as a core, and a silica precursor (TEOS) and cationic surfactant (CTABr) as a material for the formation of the mesoporous shell. The resultant materials were very monodispersive in size and showed a narrow pore size distribution in the range of ca 2-3 nm in diameter, depending on the alkyl-chain length of the surfactants used. In this work, the mesoporous shell coated-fumed silicas (denoted as MS M-5s) were synthesized by using fumed silica instead of the silica nanoparticle as a core based on previous reports. Also, the structural properties of the MS M-5s such as the specific surface area and pore volume were easily controlled by varying the amount of the silica precursor and surfactant. The resultant materials exhibited a BET surface area of ca 279-446 m{sup 2}/g and total pore volume of ca 0.64-0.74 cm{sup 3}/g and showed a narrow pore size distribution (PSD) due to the removal of the organic surfactant molecules

Functional mesoporous silica nanoparticles for bio-imaging applications.

Science.gov (United States)

Cha, Bong Geun; Kim, Jaeyun

2018-03-22

Biomedical investigations using mesoporous silica nanoparticles (MSNs) have received significant attention because of their unique properties including controllable mesoporous structure, high specific surface area, large pore volume, and tunable particle size. These unique features make MSNs suitable for simultaneous diagnosis and therapy with unique advantages to encapsulate and load a variety of therapeutic agents, deliver these agents to the desired location, and release the drugs in a controlled manner. Among various clinical areas, nanomaterials-based bio-imaging techniques have advanced rapidly with the development of diverse functional nanoparticles. Due to the unique features of MSNs, an imaging agent supported by MSNs can be a promising system for developing targeted bio-imaging contrast agents with high structural stability and enhanced functionality that enable imaging of various modalities. Here, we review the recent achievements on the development of functional MSNs for bio-imaging applications, including optical imaging, magnetic resonance imaging (MRI), positron emission tomography (PET), computed tomography (CT), ultrasound imaging, and multimodal imaging for early diagnosis. With further improvement in noninvasive bio-imaging techniques, the MSN-supported imaging agent systems are expected to contribute to clinical applications in the future. This article is categorized under: Diagnostic Tools > In vivo Nanodiagnostics and Imaging Nanotechnology Approaches to Biology > Nanoscale Systems in Biology. © 2018 Wiley Periodicals, Inc.

Electrodeposition of gold nanoparticles on mesoporous TiO{sub 2} photoelectrode to enhance visible region photocurrent

Energy Technology Data Exchange (ETDEWEB)

Supriyono,; Krisnandi, Yuni Krisyuningsih; Gunlazuardi, Jarnuzi, E-mail: jarnuzi@ui.ac.id [Department of Chemistry, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia)

2016-04-19

Electrodeposition of gold nanoparticles (Au NPs) on the mesoporous TiO{sub 2} photoelectrode to enchance visible region photocurrent have been investigated. Mesoporous TiO{sub 2} was prepared by a sol gel method and immobilized to the fluorine doped tin oxide (FTO) substrate by dip coating technique. Gold nanoparticles were electrodeposited on the TiO{sub 2} surface and the result FTO/TiO{sub 2}/Au was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), UV-Vis diffuse reflectance spectroscopy (DRS), and X-ray diffraction (XRD). The generated photocurrent was evaluated with an electrochemical workstation (e-DAQ/e-recorder 401) using 60 W wolfram lamp as visible light source. The photoelectrochemical evaluation indicated that the presence of gold nanoparticles on TiO{sub 2} photoelectrode shall enhance the photocurrent up to 50%.

Fabrication and optical characterization of silica optical fibers containing gold nanoparticles.

Science.gov (United States)

de Oliveira, Rafael E P; Sjödin, Niclas; Fokine, Michael; Margulis, Walter; de Matos, Christiano J S; Norin, Lars

2015-01-14

Gold nanoparticles have been used since antiquity for the production of red-colored glasses. More recently, it was determined that this color is caused by plasmon resonance, which additionally increases the material's nonlinear optical response, allowing for the improvement of numerous optical devices. Interest in silica fibers containing gold nanoparticles has increased recently, aiming at the integration of nonlinear devices with conventional optical fibers. However, fabrication is challenging due to the high temperatures required for silica processing and fibers with gold nanoparticles were solely demonstrated using sol-gel techniques. We show a new fabrication technique based on standard preform/fiber fabrication methods, where nanoparticles are nucleated by heat in a furnace or by laser exposure with unprecedented control over particle size, concentration, and distribution. Plasmon absorption peaks exceeding 800 dB m(-1) at 514-536 nm wavelengths were observed, indicating higher achievable nanoparticle concentrations than previously reported. The measured resonant nonlinear refractive index, (6.75 ± 0.55) × 10(-15) m(2) W(-1), represents an improvement of >50×.

Reduced graphene oxide supported gold nanoparticles for electrocatalytic reduction of carbon dioxide

Science.gov (United States)

Saquib, Mohammad; Halder, Aditi

2018-02-01

Electrochemical reduction of carbon dioxide is one of the methods which have the capability to recycle CO2 into valuable products for energy and industrial applications. This research article describes about a new electrocatalyst "reduced graphene oxide supported gold nanoparticles" for selective electrochemical conversion of carbon dioxide to carbon monoxide. The main aim for conversion of CO2 to CO lies in the fact that the latter is an important component of syn gas (a mixture of hydrogen and carbon monoxide), which is then converted into liquid fuel via well-known industrial process called Fischer-Tropsch process. In this work, we have synthesized different composites of the gold nanoparticles supported on defective reduced graphene oxide to evaluate the catalytic activity of reduced graphene oxide (RGO)-supported gold nanoparticles and the role of defective RGO support towards the electrochemical reduction of CO2. Electrochemical and impedance measurements demonstrate that higher concentration of gold nanoparticles on the graphene support led to remarkable decrease in the onset potential of 240 mV and increase in the current density for CO2 reduction. Lower impedance and Tafel slope values also clearly support our findings for the better performance of RGOAu than bare Au for CO2 reduction.

Green approach for preparation of reduced graphene oxide decorated with gold nanoparticles and its optical and catalytic properties

International Nuclear Information System (INIS)

Šimšíková, M.; Bartoš, M.; Keša, P.; Šikola, T.

2016-01-01

Graphene oxide (GO) was reduced and modified by gold nanoparticles using aqueous leaf extract of green tea. Successful formation of gold nanoparticles (AuNPs) on graphene oxide surface was determined by scanning electron microscopy (SEM). Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared analyses (FT-IR) have been used to demonstrate the behavior of complex of reduced graphene oxide with gold nanoparticles (rGO-AuNPs), the removal of oxygen-containing groups from the graphene, and subsequent formation of reduced graphene oxide (rGO). We also demonstrated the change of optical properties of GO after the reduction and formation of gold nanoparticles on its surface by UV–vis spectroscopy and fluorescence spectroscopy. The positive impact of rGO-AuNPs composite on safranin T reduction in the presence of NaBH_4 without light irradiation was examined, as well. The dye decolorization was observed within 60 min which highlights the exceptional catalytic potential of the rGO-AuNPs. - Highlights: • Reduction of GO was performed by an environmentally friendly approach. • Gold nanoparticles were prepared by self-assembly on the graphene oxide surface. • Surface properties were enhanced after the formation of gold nanoparticles. • Optical properties have been changed after the graphene reduction and formation of gold nanoparticles. • The decolorization of safranin T was observed within 60 min.

Green approach for preparation of reduced graphene oxide decorated with gold nanoparticles and its optical and catalytic properties

Energy Technology Data Exchange (ETDEWEB)

Šimšíková, M., E-mail: michaela.simsikova@ceitec.vutbr.cz [CEITEC BUT, Brno University of Technology, Technická 10, 616 69 Brno (Czech Republic); Bartoš, M. [CEITEC BUT, Brno University of Technology, Technická 10, 616 69 Brno (Czech Republic); Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno (Czech Republic); Keša, P. [Department of Biochemistry, Faculty of Science, P.J. Šafárik University, Šrobárova 2, 041 54 Košice (Slovakia); Department of Biophysics, Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Košice (Slovakia); Šikola, T. [CEITEC BUT, Brno University of Technology, Technická 10, 616 69 Brno (Czech Republic); Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno (Czech Republic)

2016-07-01

Graphene oxide (GO) was reduced and modified by gold nanoparticles using aqueous leaf extract of green tea. Successful formation of gold nanoparticles (AuNPs) on graphene oxide surface was determined by scanning electron microscopy (SEM). Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared analyses (FT-IR) have been used to demonstrate the behavior of complex of reduced graphene oxide with gold nanoparticles (rGO-AuNPs), the removal of oxygen-containing groups from the graphene, and subsequent formation of reduced graphene oxide (rGO). We also demonstrated the change of optical properties of GO after the reduction and formation of gold nanoparticles on its surface by UV–vis spectroscopy and fluorescence spectroscopy. The positive impact of rGO-AuNPs composite on safranin T reduction in the presence of NaBH{sub 4} without light irradiation was examined, as well. The dye decolorization was observed within 60 min which highlights the exceptional catalytic potential of the rGO-AuNPs. - Highlights: • Reduction of GO was performed by an environmentally friendly approach. • Gold nanoparticles were prepared by self-assembly on the graphene oxide surface. • Surface properties were enhanced after the formation of gold nanoparticles. • Optical properties have been changed after the graphene reduction and formation of gold nanoparticles. • The decolorization of safranin T was observed within 60 min.

Fabrication of high specificity hollow mesoporous silica nanoparticles assisted by Eudragit for targeted drug delivery.

Science.gov (United States)

She, Xiaodong; Chen, Lijue; Velleman, Leonora; Li, Chengpeng; Zhu, Haijin; He, Canzhong; Wang, Tao; Shigdar, Sarah; Duan, Wei; Kong, Lingxue

2015-05-01

Hollow mesoporous silica nanoparticles (HMSNs) are one of the most promising carriers for effective drug delivery due to their large surface area, high volume for drug loading and excellent biocompatibility. However, the non-ionic surfactant templated HMSNs often have a broad size distribution and a defective mesoporous structure because of the difficulties involved in controlling the formation and organization of micelles for the growth of silica framework. In this paper, a novel "Eudragit assisted" strategy has been developed to fabricate HMSNs by utilising the Eudragit nanoparticles as cores and to assist in the self-assembly of micelle organisation. Highly dispersed mesoporous silica spheres with intact hollow interiors and through pores on the shell were fabricated. The HMSNs have a high surface area (670 m(2)/g), small diameter (120 nm) and uniform pore size (2.5 nm) that facilitated the effective encapsulation of 5-fluorouracil within HMSNs, achieving a high loading capacity of 194.5 mg(5-FU)/g(HMSNs). The HMSNs were non-cytotoxic to colorectal cancer cells SW480 and can be bioconjugated with Epidermal Growth Factor (EGF) for efficient and specific cell internalization. The high specificity and excellent targeting performance of EGF grafted HMSNs have demonstrated that they can become potential intracellular drug delivery vehicles for colorectal cancers via EGF-EGFR interaction. Copyright © 2014 Elsevier Inc. All rights reserved.

A fluorescent and chemiluminescent difunctional mesoporous silica nanoparticle as a label for the ultrasensitive detection of cancer cells

Energy Technology Data Exchange (ETDEWEB)

Tao Liang [Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi' an 710062 (China); Song Chaojun; Sun Yuanjie [Department of Immunology, The Fourth Military Medical University, Xi' an 710032 (China); Li Xiaohua; Li Yunyun [Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi' an 710062 (China); Jin Boquan [Department of Immunology, The Fourth Military Medical University, Xi' an 710032 (China); Zhang Zhujun, E-mail: zhangzj@snnu.edu.cn [Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi' an 710062 (China); Yang Kun, E-mail: yangkunkun@fmmu.edu.cn [Department of Immunology, The Fourth Military Medical University, Xi' an 710032 (China)

2013-01-25

Highlights: Black-Right-Pointing-Pointer Difunctional amino mesoporous silica nanoparticles (FCMSN) were synthesized. Black-Right-Pointing-Pointer The fluorescence and chemiluminescence properties of the FCMSN were studied. Black-Right-Pointing-Pointer The NaIO{sub 4} oxidation method was used for modification of the FCMSN. Black-Right-Pointing-Pointer Liver cancer 7721 cell was detected. Black-Right-Pointing-Pointer The specificity affected by FCMSN's amino groups was studied. - Abstract: A new kind of ultrabright fluorescent and chemiluminescent difunctional mesoporous silica nanoparticle (FCMSN) is reported. A luminescent dye, Rhodamine 6G or tris(2,2 Prime -bipyridyl)dichlororuthenium(II) hexahydrate (Rubpy), is doped inside nanochannels of a silica matrix. The hydrophobic groups in the silica matrix avoid the leakage of dye from open channels. The amines groups on the surface of the FCMSN improve the modification performance of the nanoparticle. Because the nanochannels are isolated by a network skeleton of silica, fluorescence quenching based on the inner filter effect of the fluorescent dyes immobilized in nanochannels is weakened effectively. The Quantum Yield of obtained 90 nm silica particles was about 61%. Compared with the fluorescent core-shell nanoparticle, the chemiluminescence reagents can freely enter the nanoparticles to react with fluorescent dyes to create chemiluminescence. The results show that the FCMSN are both fluorescent labels and chemiluminescent labels. In biological applications, the NaIO{sub 4} oxidation method was proven to be superior to the glutaraldehyde method. The amount of amino could affect the specificity of the FCMSN. The fluorescence microscopy imaging demonstrated that the FCMSN is viable for biological applications.

Mesoporous silica nanoparticles supported copper(II) and nickel(II) Schiff base complexes: Synthesis, characterization, antibacterial activity and enzyme immobilization

Science.gov (United States)

Tahmasbi, Leila; Sedaghat, Tahereh; Motamedi, Hossein; Kooti, Mohammad

2018-02-01

Mesoporous silica nanoparticles (MSNs) were prepared by sol-gel method and functionalized with 3-aminopropyltriethoxysilane. Schiff base grafted mesoporous silica nanoparticle was synthesized by the condensation of 2-hydroxy-3-methoxybenzaldehyde and amine-functionalized MSNs. The latter material was then treated with Cu(II) and Ni(II) salts separately to obtain copper and nickel complexes anchored mesoporous composites. The newly prepared hybrid organic-inorganic nanocomposites have been characterized by several techniques such as FT-IR, LA-XRD, FE-SEM, TEM, EDS, BET and TGA. The results showed all samples have MCM-41 type ordered mesoporous structure and functionalization occurs mainly inside the mesopore channel. The presence of all elements in synthesized nanocomposites and the coordination of Schiff base via imine nitrogen and phenolate oxygen were confirmed. MSNs and all functionalized MSNs have uniform spherical nanoparticles with a mean diameter less than 100 nm. The as-synthesized mesoporous nanocomposites were investigated for antibacterial activity against Gram-positive (B. subtilis and S. aureus) and Gram-negative (E. coli and P. aeruginosa) bacteria, as carrier for gentamicin and also for immobilization of DNase, coagulase and amylase enzymes. MSN-SB-Ni indicated bacteriocidal effect against S.aureus and all compounds were found to be good carrier for gentamicin. Results of enzyme immobilization for DNase and coagulase and α-amylase revealed that supported metal complexes efficiently immobilized enzymes.

Cholera toxin subunit B-mediated intracellular trafficking of mesoporous silica nanoparticles toward the endoplasmic reticulum

Science.gov (United States)

Walker, William Andrew

In recent decades, pharmaceutical research has led to the development of numerous treatments for human disease. Nanoscale delivery systems have the potential to maximize therapeutic outcomes by enabling target specific delivery of these therapeutics. The intracellular localization of many of these materials however, is poorly controlled, leading to sequestration in degradative cellular pathways and limiting the efficacy of their payloads. Numerous proteins, particularly bacterial toxins, have evolved mechanisms to subvert the degradative mechanisms of the cell. Here, we have investigated a possible strategy for shunting intracellular delivery of encapsulated cargoes from these pathways by modifying mesoporous silica nanoparticles (MSNs) with the well-characterized bacterial toxin Cholera toxin subunit B (CTxB). Using established optical imaging methods we investigated the internalization, trafficking, and subcellular localization of our modified MSNs in an in vitro animal cell model. We then attempted to demonstrate the practical utility of this approach by using CTxB-modified mesoporous silica nanoparticles to deliver propidium iodide, a membrane-impermeant fluorophore.

Biocompatibility, endocytosis, and intracellular trafficking of mesoporous silica and polystyrene nanoparticles in ovarian cancer cells: effects of size and surface charge groups

Directory of Open Access Journals (Sweden)

Ekkapongpisit M

2012-07-01

Full Text Available Maneerat Ekkapongpisit,1 Antonino Giovia,1 Carlo Follo,1 Giuseppe Caputo,2,3 Ciro Isidoro11Laboratory of Molecular Pathology and Nanobioimaging, Department of Health Sciences, Università del Piemonte Orientale “A Avogadro”, Novara, 2Dipartimento di Chimica dell’Università di Torino, Torino, 3Cyanine Technology SpA, Torino, ItalyBackground and methods: Nanoparticles engineered to carry both a chemotherapeutic drug and a sensitive imaging probe are valid tools for early detection of cancer cells and to monitor the cytotoxic effects of anticancer treatment simultaneously. Here we report on the effect of size (10–30 nm versus 50 nm, type of material (mesoporous silica versus polystyrene, and surface charge functionalization (none, amine groups, or carboxyl groups on biocompatibility, uptake, compartmentalization, and intracellular retention of fluorescently labeled nanoparticles in cultured human ovarian cancer cells. We also investigated the involvement of caveolae in the mechanism of uptake of nanoparticles.Results: We found that mesoporous silica nanoparticles entered via caveolae-mediated endocytosis and reached the lysosomes; however, while the 50 nm nanoparticles permanently resided within these organelles, the 10 nm nanoparticles soon relocated in the cytoplasm. Naked 10 nm mesoporous silica nanoparticles showed the highest and 50 nm carboxyl-modified mesoporous silica nanoparticles the lowest uptake rates, respectively. Polystyrene nanoparticle uptake also occurred via a caveolae-independent pathway, and was negatively affected by serum. The 30 nm carboxyl-modified polystyrene nanoparticles did not localize in lysosomes and were not toxic, while the 50 nm amine-modified polystyrene nanoparticles accumulated within lysosomes and eventually caused cell death. Ovarian cancer cells expressing caveolin-1 were more likely to endocytose these nanoparticles.Conclusion: These data highlight the importance of considering both the

Capped Mesoporous Silica Nanoparticles for the Selective and Sensitive Detection of Cyanide.

Science.gov (United States)

Sayed, Sameh El; Licchelli, Maurizio; Martínez-Máñez, Ramón; Sancenón, Félix

2017-10-18

The development of easy and affordable methods for the detection of cyanide is of great significance due to the high toxicity of this anion and the potential risks associated with its pollution. Herein, optical detection of cyanide in water has been achieved by using a hybrid organic-inorganic nanomaterial. Mesoporous silica nanoparticles were loaded with [Ru(bipy) 3 ] 2+ , functionalized with macrocyclic nickel(II) complex subunits, and capped with a sterically hindering anion (hexametaphosphate). Cyanide selectively induces demetallation of nickel(II) complexes and the removal of capping anions from the silica surface, allowing the release of the dye and the consequent increase in fluorescence intensity. The response of the capped nanoparticles in aqueous solution is highly selective and sensitive towards cyanide with a limit of detection of 2 μm. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mesoporous Silica Thin Membranes with Large Vertical Mesochannels for Nanosize-Based Separation.

Science.gov (United States)

Liu, Yupu; Shen, Dengke; Chen, Gang; Elzatahry, Ahmed A; Pal, Manas; Zhu, Hongwei; Wu, Longlong; Lin, Jianjian; Al-Dahyan, Daifallah; Li, Wei; Zhao, Dongyuan

2017-09-01

Membrane separation technologies are of great interest in industrial processes such as water purification, gas separation, and materials synthesis. However, commercial filtration membranes have broad pore size distributions, leading to poor size cutoff properties. In this work, mesoporous silica thin membranes with uniform and large vertical mesochannels are synthesized via a simple biphase stratification growth method, which possess an intact structure over centimeter size, ultrathin thickness (≤50 nm), high surface areas (up to 1420 m 2 g -1 ), and tunable pore sizes from ≈2.8 to 11.8 nm by adjusting the micelle parameters. The nanofilter devices based on the free-standing mesoporous silica thin membranes show excellent performances in separating differently sized gold nanoparticles (>91.8%) and proteins (>93.1%) due to the uniform pore channels. This work paves a promising way to develop new membranes with well-defined pore diameters for highly efficient nanosize-based separation at the macroscale. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of Mesoporous Silica Nanoparticles' (MSNs) intracellular trafficking and their application as drug delivery vehicles

Science.gov (United States)

Yanes, Rolando Eduardo

Mesoporous silica nanoparticles (MSNs) are attractive drug delivery vehicle candidates due to their biocompatibility, stability, high surface area and efficient cellular uptake. In this dissertation, I discuss three aspects of MSNs' cellular behavior. First, MSNs are targeted to primary and metastatic cancer cell lines, then their exocytosis from cancer cells is studied, and finally they are used to recover intracellular proteins. Targeting of MSNs to primary cancer cells is achieved by conjugating transferrin on the surface of the mesoporous framework, which resulted in enhancement of nanoparticle uptake and drug delivery efficacy in cells that overexpress the transferrin receptor. Similarly, RGD peptides are used to target metastatic cancer cell lines that over-express integrin alphanubeta3. A circular RGD peptide is bound to the surface of MSNs and the endocytosis and cell killing efficacy of camptothecin loaded nanoparticles is significantly improved in cells that express the target receptor. Besides targeting, I studied the ultimate fate of phosphonate coated mesoporous silica nanoparticles inside cells. I discovered that the nanoparticles are exocytosed from cells through lysosomal exocytosis. The nanoparticles are exocytosed in intact form and the time that they remain inside the cells is affected by the surface properties of the nanoparticles and the type of cells. Cells that have a high rate of lysosomal exocytosis excrete the nanoparticles rapidly, which makes them more resistant to drug loaded nanoparticles because the amount of drug that is released inside the cell is limited. When the exocytosis of MSNs is inhibited, the cell killing efficacy of nanoparticles loaded with camptothecin is enhanced. The discovery that MSNs are exocytosed by cells led to a study to determine if proteins could be recovered from the exocytosed nanoparticles. The procedure to isolate exocytosed zinc-doped iron core MSNs and identify the proteins bound to them was developed

Novel strategy for the preparation of graphene-encapsulated mesoporous metal oxides with enhanced lithium storage

International Nuclear Information System (INIS)

Lin, Rong; Yue, Wenbo; Niu, Fangzhou; Ma, Jie

2016-01-01

As potential anode materials for lithium-ion batteries, mesoporous metal oxides show high reversible capacities but relatively poor cycle stability due to the structural collapse during cycles. Graphene-encapsulated mesoporous metal oxides may increase the electronic conductivity of the composite as well as stabilize the mesostructure of metal oxides, thereby enhancing the electrochemical performance of mesoporous metal oxides. Herein we describe a novel strategy for the preparation of graphene-encapsulated mesoporous metal oxides (SnO_2, Mn_3O_4), which exhibit superior electrochemical performance compared to pure mesoporous metal oxides. Moreover, some mesoporous metal oxides may be further reduced to low-valence metal oxides when calcined in presence of graphene. Mesoporous metal oxides with high isoelectric points are not essential for this synthesis method since metal oxides are connected with graphene through mesoporous silica template, thus expanding the types of graphene-encapsulated mesoporous metal oxides.

Magnetic properties of GdMnO3 nanoparticles embedded in mesoporous silica

Science.gov (United States)

Tajiri, Takayuki; Mito, Masaki; Deguchi, Hiroyuki; Kohno, Atsushi

2018-05-01

Perovskite manganite GdMnO3 nanoparticles were synthesized using mesoporous silica as a template, and their magnetic properties and crystal structure were investigated. Powder X-ray diffraction data indicated successful synthesis of the GdMnO3 nanoparticles, with mean particle sizes of 13.9 and 20.9 nm. The lattice constants for the nanoparticles were slightly different from those for the bulk material and varied with the particle size. The magnetic transition temperatures for the nanoparticles were higher than those of the bulk crystal. The synthesized GdMnO3 nanoparticles exhibited superparamagnetic behaviors: The blocking temperature, coercive field, and transition temperature depended on the particle size. Magnetic measurements and crystal structure analysis suggest that the changes in the magnetic properties for GdMnO3 nanoparticles can be attributed to the modulation of the crystallographic structure.

Nanosilver-penetrated polyion graphene complex membrane for mediator-free amperometric immunoassay of alpha-fetoprotein using nanosilver-coated silica nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Tang Juan [Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108 (China); Tang Dianping, E-mail: dianping.tang@fzu.edu.c [Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108 (China); Su Biling; Li Qunfang; Qiu Bin [Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108 (China); Chen Guonan, E-mail: gnchen@fzu.edu.c [Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108 (China)

2011-04-15

Research highlights: {yields} We fabricate a polyion graphene complex membrane-based immunosensing platform for sensitive electrochemical immunoassay of alpha-fetoprotein. {yields} Nanosilver-coated silica nanocomposites as bionanolabels. {yields} Graphene nanosheets, single-stranded DNA and silver nanoparticles as matrices. {yields} Direct electron transfer without electron mediator. {yields} Analysis of real samples and method comparison. - Abstract: A facile and sensitive mediator-free electrochemical immunosensor for detection of alpha-fetoprotein (AFP) was designed by using nanosilver-coated silica nanoparticles (Ag-SiO{sub 2}) as bionanolabels. To construct such an electrochemical immunosensor, silver ions/single-stranded DNA/graphene nanosheets were initially immobilized on a gold electrode in turn, then silver ions were in situ reduced to silver nanoparticles with the aid of NaBH{sub 4}, and anti-AFP antibodies conjugated to silver nanoparticles were used. In the presence of AFP analyte, the sandwiched immunocomplex was formed on the electrode surface by using horseradish peroxidase-anti-AFP conjugate-labeled Ag-SiO{sub 2} (HRP-anti-AFP-Ag-SiO{sub 2}) as secondary antibodies. Compared with pure silver nanoparticles, Ag-SiO{sub 2} nanocomposites could provide a large room for the immobilization of HRP-anti-AFP, and improve the electrochemical responses of the immunosensor. Meanwhile, the presence of highly conductive graphene nanosheets and silver nanoparticles provided a good pathway for electron transfer. Under optimal conditions, the immunosensor exhibited good electrochemical responses toward AFP ranging from 0.3 to 200 ng/mL with a detection limit (LOD) of 0.05 ng/mL (at 3{sigma}) in pH 6.0 PBS-H{sub 2}O{sub 2} system. Intra- and inter-assay displayed good precisions with coefficient of variation below 9.5%. In addition, the method was evaluated with 23 clinical serum samples, receiving good correlation with results from commercially available

Nanosilver-penetrated polyion graphene complex membrane for mediator-free amperometric immunoassay of alpha-fetoprotein using nanosilver-coated silica nanoparticles

International Nuclear Information System (INIS)

Tang Juan; Tang Dianping; Su Biling; Li Qunfang; Qiu Bin; Chen Guonan

2011-01-01

Research highlights: → We fabricate a polyion graphene complex membrane-based immunosensing platform for sensitive electrochemical immunoassay of alpha-fetoprotein. → Nanosilver-coated silica nanocomposites as bionanolabels. → Graphene nanosheets, single-stranded DNA and silver nanoparticles as matrices. → Direct electron transfer without electron mediator. → Analysis of real samples and method comparison. - Abstract: A facile and sensitive mediator-free electrochemical immunosensor for detection of alpha-fetoprotein (AFP) was designed by using nanosilver-coated silica nanoparticles (Ag-SiO 2 ) as bionanolabels. To construct such an electrochemical immunosensor, silver ions/single-stranded DNA/graphene nanosheets were initially immobilized on a gold electrode in turn, then silver ions were in situ reduced to silver nanoparticles with the aid of NaBH 4 , and anti-AFP antibodies conjugated to silver nanoparticles were used. In the presence of AFP analyte, the sandwiched immunocomplex was formed on the electrode surface by using horseradish peroxidase-anti-AFP conjugate-labeled Ag-SiO 2 (HRP-anti-AFP-Ag-SiO 2 ) as secondary antibodies. Compared with pure silver nanoparticles, Ag-SiO 2 nanocomposites could provide a large room for the immobilization of HRP-anti-AFP, and improve the electrochemical responses of the immunosensor. Meanwhile, the presence of highly conductive graphene nanosheets and silver nanoparticles provided a good pathway for electron transfer. Under optimal conditions, the immunosensor exhibited good electrochemical responses toward AFP ranging from 0.3 to 200 ng/mL with a detection limit (LOD) of 0.05 ng/mL (at 3σ) in pH 6.0 PBS-H 2 O 2 system. Intra- and inter-assay displayed good precisions with coefficient of variation below 9.5%. In addition, the method was evaluated with 23 clinical serum samples, receiving good correlation with results from commercially available electrochemiluminescent analyzer.

Synthesis of mesoporous silica nanoparticles by sol–gel as nanocontainer for future drug delivery applications

Energy Technology Data Exchange (ETDEWEB)

Vazquez, N.I.; Gonzalez, Z.; Ferrari, B.; Castro, Y.

2017-07-01

Development of mesoporous silica nanoparticles as carriers for drug delivery systems has increased exponentially during the last decade. The present work is focused on the synthesis of silica carriers by sol–gel from tetraethyl orthosilicate (TEOS) as precursor of silica and cetyltrimethylammonium bromide (CTAB) as pore generating agent. The synthesis conditions were modified varying the molar ratio of water/TEOS, NH3/TEOS and amount of CTAB. The silica particles were characterized by scan electron microscopy techniques (FESEM), high resolution transmission electron microscopy (HR-TEM), N2 adsorption–desorption isotherms, Zeta-potential and Dynamic Light Scattering (DLS). The results show that the specific surface area and the porosity of silica particles were strongly affected by the addition of CTAB and the amount of H2O. The dispersion and stability of silica mesoporous particles is achieved in spite of the high surface reactivity. The synthesis formulation affects considerably to the particle morphology, which changes from spheres to rods when the molar ratio of H2O increases. A maximum specific surface area of 1480m2/g was obtained with pore sizes ranging 2.5–2.8nm. (Author)

Synthesis, characterization, and application of surface-functionalized ordered mesoporous nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Chung, Po-Wen [Iowa State Univ., Ames, IA (United States)

2009-01-01

The dissertation begins with Chapter 1, which is a general introduction of the fundamental synthesis of mesoporous silica materials, the selective functionlization of mesoporous silica materials, and the synthesis of nanostructured porous materials via nanocasting. In Chapter 2, the thermo-responsive polymer coated mesoporous silica nanoparticles (MSN) was synthesized via surface-initated polymerization and exhibited unique partition activities in a biphasic solution with the thermally induced change. In Chapter 3, the monodispersed spherical MSN with different mesoporous structure (MCM-48) was developed and employed as a template for the synthesis of mesoporous carbon nanoparticles (MCN) via nanocasting. MCN was demonstrated for the delivery of membrane impermeable chemical agents inside the cells. The cellular uptake efficiency and biocompabtibility of MCN with human cervical cancer cells were also investigated. In addition to the biocompabtibility of MCN, MCN was demonstrated to support Rh-Mn nanoparticles for catalytic reaction in Chapter 4. Owing to the unique mesoporosity, Rh-Mn nanoparticles can be well distributed inside the mesoporous structure and exhibited interesting catalytic performance on CO hydrogenation. In Chapter 5, the synthesis route of the aforementioned MCM-48 MSN was discussed and investigated in details and other metal oxide nanoparticles were also developed via nanocasting by using MCM-48 MSN as a template. At last, there is a general conclusion summarized in Chapter 6.

Esterase- and pH-responsive poly(β-amino ester)-capped mesoporous silica nanoparticles for drug delivery

Science.gov (United States)

Fernando, Isurika R.; Ferris, Daniel P.; Frasconi, Marco; Malin, Dmitry; Strekalova, Elena; Yilmaz, M. Deniz; Ambrogio, Michael W.; Algaradah, Mohammed M.; Hong, Michael P.; Chen, Xinqi; Nassar, Majed S.; Botros, Youssry Y.; Cryns, Vincent L.; Stoddart, J. Fraser

2015-04-01

Gating of mesoporous silica nanoparticles (MSNs) with the stimuli-responsive poly(β-amino ester) has been achieved. This hybrid nanocarrier releases doxorubicin (DOX) under acidic conditions or in the presence of porcine liver esterase. The DOX loaded poly(β-amino ester)-capped MSNs reduce cell viability when tested on MDA-MB-231 human breast cancer cells.Gating of mesoporous silica nanoparticles (MSNs) with the stimuli-responsive poly(β-amino ester) has been achieved. This hybrid nanocarrier releases doxorubicin (DOX) under acidic conditions or in the presence of porcine liver esterase. The DOX loaded poly(β-amino ester)-capped MSNs reduce cell viability when tested on MDA-MB-231 human breast cancer cells. Electronic supplementary information (ESI) available: Experimental details relating to (i) the synthesis and characterisation of the surface-functionalised MSN and POL (ii) cargo-loading and release studies in solution, (iii) cellular internalisation of nanomaterials, and (iv) cell viability tests. See DOI: 10.1039/c4nr07443b

Gold nanoflowers with mesoporous silica as "nanocarriers" for drug release and photothermal therapy in the treatment of oral cancer using near-infrared (NIR) laser light

Science.gov (United States)

Song, Wenzhi; Gong, Junxia; Wang, Yuqian; Zhang, Yan; Zhang, Hongmei; Zhang, Weihang; Zhang, Hu; Liu, Xin; Zhang, Tianfu; Yin, Wanzhong; Yang, Wensheng

2016-04-01

In this experiment, we successfully developed nanocarriers in the form of gold nanoflowers coated with two layers of silica for the purposes of drug loading and NIR (near-infrared) photothermal therapy for the treatment of oral cancer. The gold nanoflowers converted NIR laser energy into heat energy. The cores were coated with a thin silica layer (AuNFs@SiO2) to protect the gold nanoflowers from intraparticle ripening. The second layer was mesoporous silica (AuNFs@SiO2@mSiO2), which acted as a nanocarrier for anticancer drug (DOX) loads. The mean effective diameter of the nanoparticles was approximately 150-200 nm, whereas the peak absorption of the AuNFs was 684 nm. After the AuNFs were encapsulated by the silica shells, the plasmonic absorption peak of AuNFs@SiO2 and AuNFs@SiO2@mSiO2 exhibited a red shift to 718 nm. When exposed to an 808 nm NIR laser, these crystals showed an obvious photothermal conversion in the NIR region and a highly efficient release of DOX. Biocompatibility was assessed in vitro using Cell Counting Kit-8 assays, and the results showed that the nanocarriers induced no obvious cytotoxicity. This nanomaterial could be considered a new type of material that shows promising potential for photothermal-chemotherapy against malignant tumours, including those of oral cancers.

Novel methodology for labelling mesoporous silica nanoparticles using the 18F isotope and their in vivo biodistribution by positron emission tomography

International Nuclear Information System (INIS)

Rojas, Santiago; Gispert, Juan Domingo; Menchón, Cristina; Baldoví, Herme G.; Buaki-Sogo, Mireia; Rocha, Milagros; Abad, Sergio; Victor, Victor Manuel; García, Hermenegildo; Herance, José Raúl

2015-01-01

Nanoparticles have been proposed for several biomedical applications due to their potential as drug carriers, diagnostic and therapeutic agents. However, only a few of them have been approved for their use in humans. In order to gauge the potential applicability of a specific type of nanoparticle, in vivo biodistribution studies to characterize their pharmacokinetic properties are essential. In this regard, mesoporous silica nanoparticles (30–130 nm) have been functionalized with amino groups in order to react with N-succinimidyl 4-[ 18 F]fluorobenzoate and thus anchor the 18 F positron emission isotope by using a novel and easy labelling strategy. In vivo biodistribution was characterized in mice after intravenous administration of radiolabelled nanoparticles by positron emission tomography. Our results indicated that radiolabelled mesoporous silica nanoparticles were excreted into bile and urine and accumulated mainly in the organs of the reticuloendothelial system and lungs

Gold Core Mesoporous Organosilica Shell Degradable Nanoparticles for Two-Photon Imaging and Gemcitabine Monophosphate Delivery

KAUST Repository

Rhamani, Saher

2017-09-12

The synthesis of gold core degradable mesoporous organosilica shell nanoparticles is described. The nanopaticles were very efficient for two-photon luminescence imaging of cancer cells and for in vitro gemcitabine monophosphate delivery, allowing promising theranostic applications in the nanomedicine field.

Gold Core Mesoporous Organosilica Shell Degradable Nanoparticles for Two-Photon Imaging and Gemcitabine Monophosphate Delivery

KAUST Repository

Rhamani, Saher; Chaix, Arnaud; Aggad, Dina; Hoang, Phuong Mai; Moosa, Basem; Garcia, Marcel; Gary-Bobo, Magali; Charnay, Clarence; Almalik, Abdulaziz; Durand, Jean-Olivier; Khashab, Niveen M.

2017-01-01

The synthesis of gold core degradable mesoporous organosilica shell nanoparticles is described. The nanopaticles were very efficient for two-photon luminescence imaging of cancer cells and for in vitro gemcitabine monophosphate delivery, allowing promising theranostic applications in the nanomedicine field.

Electro-catalytic properties of graphene composites containing gold or silver nanoparticles

International Nuclear Information System (INIS)

Pruneanu, Stela; Pogacean, Florina; Biris, Alexandru R.; Coros, Maria; Watanabe, Fumiya; Dervishi, Enkeleda; Biris, Alexandru S.

2013-01-01

Highlights: ► Graphene sheets with embedded gold or silver nanoparticles were prepared by RF-cCVD method. ► The crystallinity of the composite samples is less influenced by the type of metallic nanoparticles (silver or gold). ► The composite nanostructures exhibit excellent electro-catalytic properties toward carbamazepine oxidation. -- Abstract: Composite nanostructures based on few-layers graphene with encased gold or silver nanoparticles (denoted as Gr-Au and Gr-Ag, respectively) were separately prepared in a single-step synthesis by radio frequency catalytic chemical vapor deposition (RF-cCVD) over Au x /MgO and Ag x /MgO catalytic system (where x = 3 wt.%), respectively. Their morphological properties were investigated by electron microscopy techniques (TEM/HRTEM), which demonstrated that the number of graphitic layers within the sheet varied between 2 and 7. Thorough TEM analysis also indicated that gold nanoparticles had a mean size of 22 nm, while silver nanoparticles were found to be larger with a mean size of 35 nm. X-ray powder diffraction proved that the crystallinity of the Gr-Au or Gr-Ag samples is less influenced by the type of metallic nanoparticles (silver or gold) encased between the graphitic layers. The mean value of the crystalline domain perpendicular to graphene (0 0 2) crystallographic plane was determined to be approximately 2.25 nm (for Gr-Au sample) and 2.14 nm (for Gr-Ag sample), both corresponding to 6 graphitic layers. Gr-Ag and Gr-Au nanostructures were used to modify platinum substrates and subsequently employed for the electrochemical analysis of carbamazepine. A significant decrease in the electrochemical oxidation potential of carbamazepine (150 mV) was obtained with both modified electrodes. The detection limit (DL) was found to be 2.75 × 10 −5 M and 2.92 × 10 −5 M for the Pt/Gr-Ag and Pt/Gr-Au electrode, respectively

Mesoporous silica nanoparticles as a biomolecule delivery vehicle in plants

Energy Technology Data Exchange (ETDEWEB)

Hussain, Hashmath I., E-mail: hashmath.i@deakin.edu.au [Deakin University, Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences (Australia); Yi, Zhifeng [Deakin University, Institute for Frontier Materials (Australia); Rookes, James E. [Deakin University, Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences (Australia); Kong, Lingxue X. [Deakin University, Institute for Frontier Materials (Australia); Cahill, David M. [Deakin University, Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences (Australia)

2013-06-15

We report the uptake by wheat, lupin and Arabidopsis of mesoporous silica nanoparticles functionalised with amine cross-linked fluorescein isothiocyanate (MSN-APTES-FITC). The preparation of these particles at room temperature enabled the synthesis of 20 nm particles that contained a network of interconnected pores around 2 nm in diameter. The uptake and distribution of these nanoparticles were examined during seed germination, in roots of plants grown in a hydroponic system and in whole leaves and roots of plants via vacuum infiltration. The nanoparticles did not affect seed germination in lupin and there was no phytotoxicity. Following germination of wheat and lupin grown in a nutrient solution containing nanoparticles, they were found within cells and cell walls of the emerging root and in the vascular transport elements, the xylem, and in other associated cells. In leaves and roots of Arabidopsis the nanoparticles were found, following vacuum infiltration of whole seedlings, to be taken up by the entire leaf and they were principally found in the intercellular spaces of the mesophyll but also throughout much of the root system. We propose that MSNs could be used as a novel delivery system for small molecules in plants.

Manganese oxide-based multifunctionalized mesoporous silica nanoparticles for pH-responsive MRI, ultrasonography and circumvention of MDR in cancer cells.

Science.gov (United States)

Chen, Yu; Yin, Qi; Ji, Xiufeng; Zhang, Shengjian; Chen, Hangrong; Zheng, Yuanyi; Sun, Yang; Qu, Haiyun; Wang, Zheng; Li, Yaping; Wang, Xia; Zhang, Kun; Zhang, Linlin; Shi, Jianlin

2012-10-01

Nano-biotechnology has been introduced into cancer theranostics by engineering a new generation of highly versatile hybrid mesoporous composite nanocapsules (HMCNs) for manganese-based pH-responsive dynamic T(1)-weighted magnetic resonance imaging (MRI) to efficiently respond and detect the tumor acidic microenvironment, which was further integrated with ultrasonographic function based on the intrinsic unique hollow nanostructures of HMCNs for potentially in vitro and in vivo dual-modality cancer imaging. The manganese oxide-based multifunctionalization of hollow mesoporous silica nanoparticles was achieved by an in situ redox reaction using mesopores as the nanoreactors. Due to the dissolution nature of manganese oxide nanoparticles under weak acidic conditions, the relaxation rate r(1) of manganese-based mesoporous MRI-T(1) contrast agents (CAs) could reach 8.81 mM(-1)s(-1), which is a 11-fold magnitude increase compared to the neutral condition, and is almost two times higher than commercial Gd(III)-based complex agents. This is also the highest r(1) value ever reported for manganese oxide nanoparticles-based MRI-T(1) CAs. In addition, the hollow interiors and thin mesoporous silica shells endow HMCNs with the functions of CAs for efficient in vitro and in vivo ultrasonography under both harmonic- and B-modes. Importantly, the well-defined mesopores and large hollow interiors of HMCNs could encapsulate and deliver anticancer agents (doxorubicin) intracellularly to circumvent the multidrug resistance (MDR) of cancer cells and restore the anti-proliferative effect of drugs by nanoparticle-mediated endocytosis process, intracellular drug release and P-gp inhibition/ATP depletion in cancer cells. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhanced electrical conductivity of poly(methyl methacrylate) filled with graphene and in situ synthesized gold nanoparticles

Science.gov (United States)

Feng, Jie; Athanassiou, Athanassia; Bonaccorso, Francesco; Fragouli, Despina

2018-06-01

The improvement of the electrical conductivity of polymers by incorporating graphene has been intensively studied in recent years. To further boost the electrical conductivity, blending third-party additives into the polymer/graphene systems has been demonstrated as a viable strategy. Herein, we propose a simple route to increase the electrical conductivity of poly(methyl methacrylate) (PMMA)/graphene nanoplatelet (GnP) composites, by the in situ synthesis of gold nanoparticles directly into the solid film. In particular, PMMA, GnPs and a gold precursor are solution blended to form the composite films. The subsequent heat-induced formation of gold nanoparticles directly in the solid state film, cause the significant decrease of the percolation threshold of GnPs loading, from 3% to 1% by weight in the composite. This is attributed to the preferential formation of the gold nanoparticles onto the GnPs, with synergistic effects beneficial for the improvement of the electrical conductivity. The formation procedure of the gold nanoparticles, and their arrangement into the composite matrix are studied. We demonstrate that following this straightforward process it is possible to form nanocomposites able to conduct efficiently electric current even at low graphene loadings preserving at the same time the mechanical properties of the polymer matrix.

Novel methodology for labelling mesoporous silica nanoparticles using the {sup 18}F isotope and their in vivo biodistribution by positron emission tomography

Energy Technology Data Exchange (ETDEWEB)

Rojas, Santiago; Gispert, Juan Domingo; Menchón, Cristina [PRBB, Institut d’Alta Tecnologia PRBB Fundació Privada (IAT) (Spain); Baldoví, Herme G.; Buaki-Sogo, Mireia [Polytechnic University of Valencia, University Institute of Chemical Technology (Spain); Rocha, Milagros [Foundation for the Promotion of Healthcare and Biomedical Research in the Valencian Community (FISABIO) (Spain); Abad, Sergio [PRBB, Institut d’Alta Tecnologia PRBB Fundació Privada (IAT) (Spain); Victor, Victor Manuel [Foundation for the Promotion of Healthcare and Biomedical Research in the Valencian Community (FISABIO) (Spain); García, Hermenegildo, E-mail: hgarcia@qim.upv.es [Polytechnic University of Valencia, University Institute of Chemical Technology (Spain); Herance, José Raúl, E-mail: jrherance@yahoo.es [PRBB, Institut d’Alta Tecnologia PRBB Fundació Privada (IAT) (Spain)

2015-03-15

Nanoparticles have been proposed for several biomedical applications due to their potential as drug carriers, diagnostic and therapeutic agents. However, only a few of them have been approved for their use in humans. In order to gauge the potential applicability of a specific type of nanoparticle, in vivo biodistribution studies to characterize their pharmacokinetic properties are essential. In this regard, mesoporous silica nanoparticles (30–130 nm) have been functionalized with amino groups in order to react with N-succinimidyl 4-[{sup 18}F]fluorobenzoate and thus anchor the {sup 18}F positron emission isotope by using a novel and easy labelling strategy. In vivo biodistribution was characterized in mice after intravenous administration of radiolabelled nanoparticles by positron emission tomography. Our results indicated that radiolabelled mesoporous silica nanoparticles were excreted into bile and urine and accumulated mainly in the organs of the reticuloendothelial system and lungs.

Continuous laser irradiation under ambient conditions: A simple way for the space-selective growth of gold nanoparticles inside a silica monolith

International Nuclear Information System (INIS)

El Hamzaoui, Hicham; Bernard, Remy; Chahadih, Abdallah; Chassagneux, Fernand; Bois, Laurence; Capoen, Bruno; Bouazaoui, Mohamed

2011-01-01

Highlights: → Visible continuous laser direct-write gold nanoparticles inside a silica monolith. → The presence of the additive (Na 2 CO 3 ) is not necessary to the growth of gold nanoparticles. → A simple heat treatment leads to precipitation of gold nanoparticles inside the silica matrices with, or without, the additive. → The local precipitation of gold nanoparticles by continuous photo-irradiation occurs following a photo-thermal activated mechanism. -- Abstract: Thanks to the potential and various applications of metal-dielectric nanocomposites, their syntheses constitute an interesting subject in material research. In this work, we demonstrate the achievement of gold nanocrystals growth through a visible and continuous laser irradiation. The in situ and direct space-selective generation of metallic nanoparticles is localized under the surface within transparent silica monoliths. For that purpose, the porous silica monoliths are prepared using a sol-gel route and post-doped with gold precursors before the irradiation. The presence of Au nanoparticles inside the irradiated areas was evidenced using absorption spectroscopy, X-ray diffraction analysis and transmission electron microscopy. The comparison between the results obtained after a laser irradiation and by a simple heat-treatment reveals that the local precipitation of gold nanoparticles by continuous photo-irradiation occurs following a photo-thermal activated mechanism.

Self-assembly of supramolecular triarylamine nanowires in mesoporous silica and biocompatible electrodes thereof

Science.gov (United States)

Licsandru, Erol-Dan; Schneider, Susanne; Tingry, Sophie; Ellis, Thomas; Moulin, Emilie; Maaloum, Mounir; Lehn, Jean-Marie; Barboiu, Mihail; Giuseppone, Nicolas

2016-03-01

Biocompatible silica-based mesoporous materials, which present high surface areas combined with uniform distribution of nanopores, can be organized in functional nanopatterns for a number of applications. However, silica is by essence an electrically insulating material which precludes applications for electro-chemical devices. The formation of hybrid electroactive silica nanostructures is thus expected to be of great interest for the design of biocompatible conducting materials such as bioelectrodes. Here we show that we can grow supramolecular stacks of triarylamine molecules in the confined space of oriented mesopores of a silica nanolayer covering a gold electrode. This addressable bottom-up construction is triggered from solution simply by light irradiation. The resulting self-assembled nanowires act as highly conducting electronic pathways crossing the silica layer. They allow very efficient charge transfer from the redox species in solution to the gold surface. We demonstrate the potential of these hybrid constitutional materials by implementing them as biocathodes and by measuring laccase activity that reduces dioxygen to produce water.Biocompatible silica-based mesoporous materials, which present high surface areas combined with uniform distribution of nanopores, can be organized in functional nanopatterns for a number of applications. However, silica is by essence an electrically insulating material which precludes applications for electro-chemical devices. The formation of hybrid electroactive silica nanostructures is thus expected to be of great interest for the design of biocompatible conducting materials such as bioelectrodes. Here we show that we can grow supramolecular stacks of triarylamine molecules in the confined space of oriented mesopores of a silica nanolayer covering a gold electrode. This addressable bottom-up construction is triggered from solution simply by light irradiation. The resulting self-assembled nanowires act as highly conducting

Fabrication and characterization of an inorganic gold and silica nanoparticle mediated drug delivery system for nitric oxide

Energy Technology Data Exchange (ETDEWEB)

Das, Amitava; Singla, Sumit K; Shah, Vijay H [Gastroenterology Research Unit, Department of Internal Medicine, Mayo Clinic College of Medicine, 200 First Street S.W., Rochester, MN 55905 (United States); Mukherjee, Priyabrata; Mukhopadhyay, Debabrata; Patra, Chitta Ranjan [Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, 200 First Street S.W., Rochester, MN 55905 (United States); Guturu, Praveen [Department of Internal Medicine, UTMB, Galveston, TX 77555 (United States); Frost, Megan C, E-mail: patra.chittaranjan@mayo.edu, E-mail: patra.chitta@gmail.com [Department of Biomedical Engineering, Michigan Technological University, Houghton, MI 49931 (United States)

2010-07-30

Nitric oxide (NO) plays an important role in inhibiting the development of hepatic fibrosis and its ensuing complication of portal hypertension by inhibiting human hepatic stellate cell (HSC) activation. Here we have developed a gold nanoparticle and silica nanoparticle mediated drug delivery system containing NO donors, which could be used for potential therapeutic application in chronic liver disease. The gold nanoconjugates were characterized using several physico-chemical techniques such as UV-visible spectroscopy and transmission electron microscopy. Silica nanoconjugates were synthesized and characterized as reported previously. NO released from gold and silica nanoconjugates was quantified under physiological conditions (pH = 7.4 at 37 deg. C) for a substantial period of time. HSC proliferation and the vascular tube formation ability, manifestations of their activation, were significantly attenuated by the NO released from these nanoconjugates. This study indicates that gold and silica nanoparticle mediated drug delivery systems for introducing NO could be used as a strategy for the treatment of hepatic fibrosis or chronic liver diseases, by limiting HSC activation.

Fabrication and characterization of an inorganic gold and silica nanoparticle mediated drug delivery system for nitric oxide

International Nuclear Information System (INIS)

Das, Amitava; Singla, Sumit K; Shah, Vijay H; Mukherjee, Priyabrata; Mukhopadhyay, Debabrata; Patra, Chitta Ranjan; Guturu, Praveen; Frost, Megan C

2010-01-01

Nitric oxide (NO) plays an important role in inhibiting the development of hepatic fibrosis and its ensuing complication of portal hypertension by inhibiting human hepatic stellate cell (HSC) activation. Here we have developed a gold nanoparticle and silica nanoparticle mediated drug delivery system containing NO donors, which could be used for potential therapeutic application in chronic liver disease. The gold nanoconjugates were characterized using several physico-chemical techniques such as UV-visible spectroscopy and transmission electron microscopy. Silica nanoconjugates were synthesized and characterized as reported previously. NO released from gold and silica nanoconjugates was quantified under physiological conditions (pH = 7.4 at 37 deg. C) for a substantial period of time. HSC proliferation and the vascular tube formation ability, manifestations of their activation, were significantly attenuated by the NO released from these nanoconjugates. This study indicates that gold and silica nanoparticle mediated drug delivery systems for introducing NO could be used as a strategy for the treatment of hepatic fibrosis or chronic liver diseases, by limiting HSC activation.

Natural material-decorated mesoporous silica nanoparticle container for multifunctional membrane-controlled targeted drug delivery

Directory of Open Access Journals (Sweden)

Hu Y

2017-11-01

Full Text Available Yan Hu,1 Lei Ke,2 Hao Chen,1 Ma Zhuo,1 Xinzhou Yang,1 Dan Zhao,1 Suying Zeng,1 Xincai Xiao1 1Department of Pharmaceutics, School of Pharmaceutical Science, South-Central University for Nationalities, 2Department of Medicinal Chemistry, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China Abstract: To avoid the side effects caused by nonspecific targeting, premature release, weak selectivity, and poor therapeutic efficacy of current nanoparticle-based systems used for drug delivery, we fabricated natural material-decorated nanoparticles as a multifunctional, membrane-controlled targeted drug delivery system. The nanocomposite material coated with a membrane was biocompatible and integrated both specific tumor targeting and responsiveness to stimulation, which improved transmission efficacy and controlled drug release. Mesoporous silica nanoparticles (MSNs, which are known for their biocompatibility and high drug-loading capacity, were selected as a model drug container and carrier. The membrane was established by the polyelectrolyte composite method from chitosan (CS which was sensitive to the acidic tumor microenvironment, folic acid-modified CS which recognizes the folate receptor expressed on the tumor cell surface, and a CD44 receptor-targeted polysaccharide hyaluronic acid. We characterized the structure of the nanocomposite as well as the drug release behavior under the control of the pH-sensitive membrane switch and evaluated the antitumor efficacy of the system in vitro. Our results provide a basis for the design and fabrication of novel membrane-controlled nanoparticles with improved tumor-targeting therapy. Keywords: multifunctional, membrane-controlled, natural materials, mesoporous silica nanoparticles, targeted drug delivery

Evaluation of superparamagnetic and biocompatible properties of mesoporous silica coated cobalt ferrite nanoparticles synthesized via microwave modified Pechini method

Energy Technology Data Exchange (ETDEWEB)

Gharibshahian, M. [Faculty of New Sciences and Technologies, Semnan University, Semnan (Iran, Islamic Republic of); Mirzaee, O., E-mail: O_mirzaee@semnan.ac.ir [Faculty of Materials and Metallurgical Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Nourbakhsh, M.S. [Faculty of New Sciences and Technologies, Semnan University, Semnan (Iran, Islamic Republic of)

2017-03-01

Cobalt ferrite nano particles were synthesized by Pechini sol-gel method and calcined at 700 °C in electrical and microwave furnace. The microwave calcined sample was coated with mesoporous silica by hydrothermal method. Characterization was performed by XRD, FESEM, TEM, VSM, BET and FTIR analysis. The cytotoxicity was evaluated by MTT assay with 3T3 fibroblast cells. The XRD and FTIR results confirmed spinal formation in both cases and verified the formation of silica coating on the nanoparticles. For microwave calcination, The XRD and SEM results demonstrated smaller and flat adhesion forms of nanoparticles with the average size of 15 nm. The VSM results demonstrated nearly superparamagnetic nanoparticles with significant saturation magnetization equal to 64 emu/g. By coating, saturation magnetization was decreased to 36 emu/g. Moreover, the BET results confirmed the formation of mesoporous coating with the average pore diameters of 2.8 nm and average pore volume of 0.82 cm{sup 3} g{sup −1}. Microwave calcined nanoparticles had the best structural and magnetic properties. - Highlights: • CoFe{sub 2}O{sub 4} nanoparticles were synthesized using the microwave modified Pechini method. • The Effect of calcination route and silica coating on NPs properties was studied. • The nearly superparamagnetic nanoparticles were achieved by microwave calcination. • MFC NPs had the best magnetic properties and MTT assay showed no toxicity for MFC-MSC NPs. • A useful scheme was designed to achieve biological superparamagnetic core/shell NPs.

Recent applications of the combination of mesoporous silica nanoparticles with nucleic acids: development of bioresponsive devices, carriers and sensors.

Science.gov (United States)

Castillo, Rafael R; Baeza, Alejandro; Vallet-Regí, María

2017-02-28

The discovery and control of the biological roles mediated by nucleic acids have turned them into a powerful tool for the development of advanced biotechnological materials. Such is the importance of these gene-keeping biomacromolecules that even nanomaterials have succumbed to the claimed benefits of DNA and RNA. Currently, there could be found in the literature a practically intractable number of examples reporting the use of combination of nanoparticles with nucleic acids, so boundaries are demanded. Following this premise, this review will only cover the most recent and powerful strategies developed to exploit the possibilities of nucleic acids as biotechnological materials when in combination with mesoporous silica nanoparticles. The extensive research done on nucleic acids has significantly incremented the technological possibilities for those biomacromolecules, which could be employed in many different applications, where substrate or sequence recognition or modulation of biological pathways due to its coding role in living cells are the most promising. In the present review, the chosen counterpart, mesoporous silica nanoparticles, also with unique properties, became a reference material for drug delivery and biomedical applications due to their high biocompatibility and porous structure suitable for hosting and delivering small molecules. Although most of the reviews dealt with significant advances in the use of nucleic acid and mesoporous silica nanoparticles in biotechnological applications, a rational classification of these new generation hybrid materials is still uncovered. In this review, there will be covered promising strategies for the development of living cell and biological sensors, DNA-based molecular gates with targeting, transfection or silencing properties, which could provide a significant advance in current nanomedicine.

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

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

Stable graphene oxide-gold nanoparticle platforms for biosensing applications.

Science.gov (United States)

Hernández-Sánchez, Dania; Villabona-Leal, Giovanny; Saucedo-Orozco, Izcoatl; Bracamonte, Victoria; Pérez, Elías; Bittencourt, Carla; Quintana, Mildred

2018-01-17

Graphene oxide-gold nanoparticle (AuNPs@GO) hybrids were fabricated in water dispersions of graphene oxide (GO) and Au precursor completely free of stabilizing agents by UV-light irradiation. Gold nanoparticle (AuNP) nucleation, growth, and stabilization mechanisms at the surface of GO are discussed on the basis of UV-Vis, Raman, IR, and X-Ray photo-spectroscopy studies. The analyses of AuNPs@GO hybrids by transmission electron microscopy (TEM), thermogravimetric (TGA) and electrochemical tests show that they exhibit outstanding chemical, thermal and electrochemical stabilities. Thus, AuNPs@GO biosensing platforms were fabricated for surface enhanced Raman spectroscopy (SERS) detection of crystal violet (CV), a SERS standard molecule, and in a different set of experiments, for flavin adenine dinucleotide (FAD), a flavoprotein coenzyme that plays an important role in many oxidoreductase and reversible redox conversions in biochemical reactions. AuNPs@GO hybrids synthesized by using UV light irradiation show exceptional stability and high intensification of the Raman signals showing that they have high potential for use as biomedical probes for the detection, monitoring, and diagnosis of medical diseases.

Gold nanoflowers with mesoporous silica as “nanocarriers” for drug release and photothermal therapy in the treatment of oral cancer using near-infrared (NIR) laser light

International Nuclear Information System (INIS)

Song, Wenzhi; Gong, Junxia; Wang, Yuqian; Zhang, Yan; Zhang, Hongmei; Zhang, Weihang; Zhang, Hu; Liu, Xin; Zhang, Tianfu; Yin, Wanzhong; Yang, Wensheng

2016-01-01

In this experiment, we successfully developed nanocarriers in the form of gold nanoflowers coated with two layers of silica for the purposes of drug loading and NIR (near-infrared) photothermal therapy for the treatment of oral cancer. The gold nanoflowers converted NIR laser energy into heat energy. The cores were coated with a thin silica layer (AuNFs@SiO_2) to protect the gold nanoflowers from intraparticle ripening. The second layer was mesoporous silica (AuNFs@SiO_2@mSiO_2), which acted as a nanocarrier for anticancer drug (DOX) loads. The mean effective diameter of the nanoparticles was approximately 150–200 nm, whereas the peak absorption of the AuNFs was 684 nm. After the AuNFs were encapsulated by the silica shells, the plasmonic absorption peak of AuNFs@SiO_2 and AuNFs@SiO_2@mSiO_2 exhibited a red shift to 718 nm. When exposed to an 808 nm NIR laser, these crystals showed an obvious photothermal conversion in the NIR region and a highly efficient release of DOX. Biocompatibility was assessed in vitro using Cell Counting Kit-8 assays, and the results showed that the nanocarriers induced no obvious cytotoxicity. This nanomaterial could be considered a new type of material that shows promising potential for photothermal-chemotherapy against malignant tumours, including those of oral cancers.

Gold nanoflowers with mesoporous silica as “nanocarriers” for drug release and photothermal therapy in the treatment of oral cancer using near-infrared (NIR) laser light

Energy Technology Data Exchange (ETDEWEB)

Song, Wenzhi; Gong, Junxia [Jilin University, Department of Stomatology, China-Japan Union Hospital (China); Wang, Yuqian [Jilin University, China-Japan Union Hospital, Scientific Research Center (China); Zhang, Yan [Jilin University, Department of Stomatology, China-Japan Union Hospital (China); Zhang, Hongmei [Jilin University, China-Japan Union Hospital, Scientific Research Center (China); Zhang, Weihang; Zhang, Hu; Liu, Xin; Zhang, Tianfu [Jilin University, Department of Stomatology, China-Japan Union Hospital (China); Yin, Wanzhong, E-mail: yinwanzhong88@hotmail.com [First Clinical Hospital of Jilin University, Department of Otorhinolaryngology (China); Yang, Wensheng, E-mail: wsyang@mail.jlu.edu.cn [College of Chemistry, The Key Laboratory of Surface and Interface Chemistry of Jilin Province (China)

2016-04-15

In this experiment, we successfully developed nanocarriers in the form of gold nanoflowers coated with two layers of silica for the purposes of drug loading and NIR (near-infrared) photothermal therapy for the treatment of oral cancer. The gold nanoflowers converted NIR laser energy into heat energy. The cores were coated with a thin silica layer (AuNFs@SiO{sub 2}) to protect the gold nanoflowers from intraparticle ripening. The second layer was mesoporous silica (AuNFs@SiO{sub 2}@mSiO{sub 2}), which acted as a nanocarrier for anticancer drug (DOX) loads. The mean effective diameter of the nanoparticles was approximately 150–200 nm, whereas the peak absorption of the AuNFs was 684 nm. After the AuNFs were encapsulated by the silica shells, the plasmonic absorption peak of AuNFs@SiO{sub 2} and AuNFs@SiO{sub 2}@mSiO{sub 2} exhibited a red shift to 718 nm. When exposed to an 808 nm NIR laser, these crystals showed an obvious photothermal conversion in the NIR region and a highly efficient release of DOX. Biocompatibility was assessed in vitro using Cell Counting Kit-8 assays, and the results showed that the nanocarriers induced no obvious cytotoxicity. This nanomaterial could be considered a new type of material that shows promising potential for photothermal-chemotherapy against malignant tumours, including those of oral cancers.

In situ synthesis of copper nanoparticles on SBA-16 silica spheres

Directory of Open Access Journals (Sweden)

Asma Tufail Shah

2016-07-01

Full Text Available A chemical method for in situ synthesis of copper nanoparticles on SBA-16 silica spheres under ambient conditions has been reported. The silica support has been introduced into copper precursor solution before chemical reduction. Metal ions diffuse into mesopores (pore diameter 5–7 nm of silica where in situ reduction by hydrazine leads to formation of nanoparticles. These mesopores act as nanoreactor and their walls prevent metal particle’s agglomeration by providing a physical barrier. The obtained copper nanoparticles have been investigated by electron microscopy, X-ray diffraction, UV–Visible spectroscopy, Fourier transform Infra-red spectroscopy and thermogravimetric analyzer. SEM, TEM and UV–Visible spectroscopic images revealed that nanosized particles have been successfully synthesized by this method. Thermogravimetric investigations revealed that copper nanoparticles impregnated on silica were thermally more stable compared to unsupported nanoparticles. Silica not only helps in maintaining the particle size but also makes nanoparticles stable at high temperatures due to its thick pore walls. Macro sized silica support also makes separation/handling of nanoparticles easy and simple.

Stability and Antimicrobial Activity of Nisin-Loaded Mesoporous Silica Nanoparticles: A Game-Changer in the War against Maleficent Microbes

DEFF Research Database (Denmark)

Behzadi, Faezeh; Darouie, Sheyda; Alavi, S. Mehdi

2018-01-01

Antimicrobial agents, such as nisin, are used extensively in the food industry. Here, we investigated various approaches to load nisin onto mesoporous silica nanoparticles (MSNs, 92 ± 10 nm in diameter), to enhance its stability and sustained release. The morphology, size, and surface charge...

In Vivo Integrity and Biological Fate of Chelator-Free Zirconium-89-Labeled Mesoporous Silica Nanoparticles.

Science.gov (United States)

Chen, Feng; Goel, Shreya; Valdovinos, Hector F; Luo, Haiming; Hernandez, Reinier; Barnhart, Todd E; Cai, Weibo

2015-08-25

Traditional chelator-based radio-labeled nanoparticles and positron emission tomography (PET) imaging are playing vital roles in the field of nano-oncology. However, their long-term in vivo integrity and potential mismatch of the biodistribution patterns between nanoparticles and radio-isotopes are two major concerns for this approach. Here, we present a chelator-free zirconium-89 ((89)Zr, t1/2 = 78.4 h) labeling of mesoporous silica nanoparticle (MSN) with significantly enhanced in vivo long-term (>20 days) stability. Successful radio-labeling and in vivo stability are demonstrated to be highly dependent on both the concentration and location of deprotonated silanol groups (-Si-O(-)) from two types of silica nanoparticles investigated. This work reports (89)Zr-labeled MSN with a detailed labeling mechanism investigation and long-term stability study. With its attractive radio-stability and the simplicity of chelator-free radio-labeling, (89)Zr-MSN offers a novel, simple, and accurate way for studying the in vivo long-term fate and PET image-guided drug delivery of MSN in the near future.

Large pore mesoporous silica nanomaterials for application in delivery of biomolecules

Science.gov (United States)

Knežević, Nikola Ž.; Durand, Jean-Olivier

2015-01-01

Various approaches for the synthesis of mesoporous silicate nanoparticles (MSN) with large pore (LP) diameters (in the range of 3-50 nm) are reviewed in this article. The work also covers the construction of magnetic analogues of large pore-mesoporous silica nanoparticles (LPMMSN) and their biomedical applications. The constructed materials exhibit vast potential for application in the loading and delivery of large drug molecules and biomolecules. Literature reports on the application of LPMSN and LPMMSN materials for the adsorption and delivery of proteins, enzymes, antibodies, and nucleic acids are covered in depth, which exemplify their highly potent characteristics for use in drug and biomolecule delivery to diseased tissues.Various approaches for the synthesis of mesoporous silicate nanoparticles (MSN) with large pore (LP) diameters (in the range of 3-50 nm) are reviewed in this article. The work also covers the construction of magnetic analogues of large pore-mesoporous silica nanoparticles (LPMMSN) and their biomedical applications. The constructed materials exhibit vast potential for application in the loading and delivery of large drug molecules and biomolecules. Literature reports on the application of LPMSN and LPMMSN materials for the adsorption and delivery of proteins, enzymes, antibodies, and nucleic acids are covered in depth, which exemplify their highly potent characteristics for use in drug and biomolecule delivery to diseased tissues. Dedicated to Professor Jeffrey I. Zink on the occasion of his 70th birthday.

Gradual growth of gold nanoseeds on silica for SiO2-gold homogeneous nano core/shell applications by the chemical reduction method

International Nuclear Information System (INIS)

Rezvani Nikabadi, H; Shahtahmasebi, N; Rezaee Rokn-Abadi, M; Bagheri Mohagheghi, M M; Goharshadi, E K

2013-01-01

In this paper, a facile method for the synthesis of gold nanoseeds on the functionalized surface of silica nanoparticles has been investigated. Mono-dispersed silica particles and gold nanoparticles were prepared by the chemical reduction method. The thickness of the Au shell was well controlled by repeating the reduction time of HAuCl 4 on silica/3-aminopropyltriethoxysilane (APTES)/initial gold nanoparticles. The prepared SiO 2 -gold core/shell nanoparticles were studied using x-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy and ultraviolet visible (UV-Vis) spectroscopy. The TEM images indicated that the silica nanoparticles were spherical in shape with 100 nm diameters and functionalizing silica nanoparticles with a layer of bi-functional APTES molecules and tetrakis hydroxy methyl phosphonium chloride. The gold nanoparticles show a narrow size of up to 5 nm and by growing gold nanoseeds over the silica cores a red shift in the maximum absorbance of UV-Vis spectroscopy from 524 to 637 nm was observed.

Porous silica nanoparticles as carrier for curcumin delivery

Science.gov (United States)

Hartono, Sandy Budi; Hadisoewignyo, Lannie; Irawaty, Wenny; Trisna, Luciana; Wijaya, Robby

2018-04-01

Mesoporous silica nanoparticles (MSN) with large surface areas and pore volumes show great potential as drug and gene carriers. However, there are still some challenging issues hinders their clinical application. Many types of research in the use of mesoporous silica material for drug and gene delivery involving complex and rigorous procedures. A facile and reproducible procedure to prepare combined drug carrier is required. We investigated the effect of physiochemical parameters of mesoporous silica, including structural symmetry (cubic and hexagonal), particles size (micro size: 1-2 µm and nano size: 100 -300 nm), on the solubility and release profile of curcumin. Transmission Electron Microscopy, X-Ray Powder Diffraction, and Nitrogen sorption were used to confirm the synthesis of the mesoporous silica materials. Mesoporous silica materials with different mesostructures and size have been synthesized successfully. Curcumin has anti-oxidant, anti-inflammation and anti-virus properties which are beneficial to fight various diseases such as diabetic, cancer, allergic, arthritis and Alzheimer. Curcumin has low solubility which minimizes its therapeutic effect. The use of nanoporous material to carry and release the loaded molecules is expected to enhance curcumin solubility. Mesoporous silica materials with a cubic mesostructure had a higher release profile and curcumin solubility, while mesoporous silica materials with a particle size in the range of nano meter (100-300) nm also show better release profile and solubility.

Evaluating the potential of gold, silver, and silica nanoparticles to saturate mononuclear phagocytic system tissues under repeat dosing conditions.

Science.gov (United States)

Weaver, James L; Tobin, Grainne A; Ingle, Taylor; Bancos, Simona; Stevens, David; Rouse, Rodney; Howard, Kristina E; Goodwin, David; Knapton, Alan; Li, Xiaohong; Shea, Katherine; Stewart, Sharron; Xu, Lin; Goering, Peter L; Zhang, Qin; Howard, Paul C; Collins, Jessie; Khan, Saeed; Sung, Kidon; Tyner, Katherine M

2017-07-17

As nanoparticles (NPs) become more prevalent in the pharmaceutical industry, questions have arisen from both industry and regulatory stakeholders about the long term effects of these materials. This study was designed to evaluate whether gold (10 nm), silver (50 nm), or silica (10 nm) nanoparticles administered intravenously to mice for up to 8 weeks at doses known to be sub-toxic (non-toxic at single acute or repeat dosing levels) and clinically relevant could produce significant bioaccumulation in liver and spleen macrophages. Repeated dosing with gold, silver, and silica nanoparticles did not saturate bioaccumulation in liver or spleen macrophages. While no toxicity was observed with gold and silver nanoparticles throughout the 8 week experiment, some effects including histopathological and serum chemistry changes were observed with silica nanoparticles starting at week 3. No major changes in the splenocyte population were observed during the study for any of the nanoparticles tested. The clinical impact of these changes is unclear but suggests that the mononuclear phagocytic system is able to handle repeated doses of nanoparticles.

A study of some fundamental physicochemical variables on the morphology of mesoporous silica nanoparticles MCM-41 type

Science.gov (United States)

Beltrán-Osuna, Ángela A.; Gómez Ribelles, José L.; Perilla, Jairo E.

2017-12-01

All variables affecting the morphology of mesoporous silica nanoparticles (MSN) should be carefully analyzed in order to truly tailored design their mesoporous structure according to their final use. Although complete control on MCM-41 synthesis has been already claimed, reproducibility and repeatability of results remain a big issue due to the lack of information reported in literature. Stirring rate, reaction volume, and system configuration (i.e., opened or closed reactor) are three variables that are usually omitted, making the comparison of product characteristics difficult. Specifically, the rate of solvent evaporation is seldom disclosed, and its influence has not been previously analyzed. These variables were systematically studied in this work, and they were proven to have a fundamental impact on final particle morphology. Hence, a high degree of circularity ( C = 0.97) and monodispersed particle size distributions were only achieved when a stirring speed of 500 rpm and a reaction scale of 500 mL were used in a partially opened system, for a 2 h reaction at 80 °C. Well-shaped spherical mesoporous silica nanoparticles with a diameter of 95 nm, a pore size of 2.8 nm, and a total surface area of 954 m2 g-1 were obtained. Final characteristics made this product suitable to be used in biomedicine and nanopharmaceutics, especially for the design of drug delivery systems.

Dewetting dynamics of a gold film on graphene: implications for nanoparticle formation.

Science.gov (United States)

Namsani, Sadanandam; Singh, Jayant K

2016-01-01

The dynamics of dewetting of gold films on graphene surfaces is investigated using molecular dynamics simulation. The effect of temperature (973-1533 K), film diameter (30-40 nm) and film thickness (0.5-3 nm) on the dewetting mechanism, leading to the formation of nanoparticles, is reported. The dewetting behavior for films ≤5 Å is in contrast to the behavior seen for thicker films. The retraction velocity, in the order of ∼300 m s(-1) for a 1 nm film, decreases with an increase in film thickness, whereas it increases with temperature. However at no point do nanoparticles detach from the surface within the temperature range considered in this work. We further investigated the self-assembly behavior of nanoparticles on graphene at different temperatures (673-1073 K). The process of self-assembly of gold nanoparticles is favorable at lower temperatures than at higher temperatures, based on the free-energy landscape analysis. Furthermore, the shape of an assembled structure is found to change from spherical to hexagonal, with a marked propensity towards an icosahedral structure based on the bond-orientational order parameters.

On the role of the colloidal stability of mesoporous silica nanoparticles as gene delivery vectors

Energy Technology Data Exchange (ETDEWEB)

Cebrian, Virginia [Hospital Universitario La Paz-IdiPAZ (Spain); Yaguee, Clara; Arruebo, Manuel, E-mail: arruebom@unizar.es [University of Zaragoza, Aragon Nanoscience Institute (INA), C/Mariano Esquillor, Edif. I-D (Spain); Martin-Saavedra, Francisco M. [Hospital Universitario La Paz-IdiPAZ (Spain); Santamaria, Jesus [CIBER de Bioingenieria, Biomateriales y Nanomedicina, CIBER-BBN (Spain); Vilaboa, Nuria [Hospital Universitario La Paz-IdiPAZ (Spain)

2011-09-15

Mesoporous silica nanoparticles have been synthesized and functionalized with four different types of molecules containing amino groups, i.e., with primary amines only, with quaternary amines, with quaternized cyclic amines, or with polyethylenimine (PEI), which is formed by primary, secondary, and tertiary amines. These nanoparticles were then incubated with reporter plasmids and the ability of the resulting complexes to transfect human cells was studied. Only nanoparticles functionalized with PEI were efficient for transfection. The agglomeration behavior and the electrokinetic potential of the nanoparticle-plasmid complexes have been studied, as well as their cell internalization behavior using a fluorescent-labeled plasmid that allows its monitorization by confocal microscopy. The results indicate that the efficiency of PEI-functionalized nanoparticles for transfection resides to some extent in the different characteristics imparted to the nanoparticles regarding agglomeration and surface charge behavior.

Enhanced antibacterial activity of silver-decorated sandwich-like mesoporous silica/reduced graphene oxide nanosheets through photothermal effect

Science.gov (United States)

Liu, Rong; Wang, Xuandong; Ye, Jun; Xue, Ximei; Zhang, Fangrong; Zhang, Huicong; Hou, Xuemei; Liu, Xiaolong; Zhang, Yun

2018-03-01

Drug resistance of bacteria has become a global health problem, as it makes conventional antibiotics less efficient. It is urgently needed to explore novel antibacterial materials and develop effective treatment strategies to overcome the drug resistance of antibiotics. Herein, we successfully synthesized silver decorated sandwich-like mesoporous silica/reduced graphene oxide nanosheets (rGO/MSN/Ag) as a novel antibacterial material through facile method. The rGO and Ag nanoparticles can be reduced in the reaction system without adding any other reductants. In addition, the rGO/MSN/Ag showed higher photothermal conversion capacity due to the modification of silver nanoparticles and exhibited excellent antibacterial activities against Pseudomonas putida, Escherichia coli and Rhodococcus at relatively low dosages, which was confirmed by the minimum inhibitory concentration (MIC) test. Meanwhile, the E. coli with a high concentration was selected for exposure using an 808 nm laser, and the antibacterial effect was obviously enhanced by the near-infrared irradiation induced photothermal effect. Moreover, the hepatocyte LO2 were used for the cytotoxicity evaluation, and the rGO/MSN/Ag showed low toxicity and were without detectable cytotoxicity at the antimicrobial dose. As the prepared rGO/MSN/Ag nanosheets have the advantages of low-cost and high antibacterial activity, they might be of promising and useful antibacterial agents for different applications.

Preparation of Mesoporous Carbons from Acrylonitrile-methyl Methacrylate Copolymer/Silica Nanocomposites Synthesized by in-situ Emulsion Polymerization

Institute of Scientific and Technical Information of China (English)

BAO Yongzhong; ZHAO Wenting; HUANG Zhiming

2013-01-01

Acrylonitrile-methyl methacrylate (AN-MMA) copolymer/silica nanocomposites were synthesized by in-situ emulsion polymerization initiated by 2,2′-azobis(2-amidinopropane) dihydrochloride absorbed onto colloidal silica particles,and the mesoporous carbon materials were prepared through carbonization of the obtained AN-MMA copolymer/silica nanocomposites,followed by HF etching.Thermogravimetric analysis of AN-MMA copolymer/silica nanocomposites showed that the carbon yield of copolymer was slightly decreased as silica particle incorporated.N2 adsorption-desorption,scan electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and morphology of the mesoporous carbon materials.Both SEM and TEM results showed that disordered mesopores were formed in the obtained carbon material mainly through templating effect of silica nanoparticles.The diameter of mesopores was mainly distributed in the range from 5 nm to 15 nm.The mean pore diameter and total pore volume of the material increased as the mass fraction of silica in the nanocomposites increased from 0 to 24.93％.The significant increase of the mean pore diameter and the decrease of surface area for the carbon material prepared from the nanocomposite with 24.93％ silica were caused by partial aggregation of silica nanoparticles in the polymer matrix.

Polyelectrolyte functionalized gold nanoparticles-reduced graphene oxide nanohybrid for electrochemical determination of aminophenol isomers

International Nuclear Information System (INIS)

Li, Xinchun; Zhong, Anni; Wei, Shanshan; Luo, Xiaoli; Liang, Yanjin; Zhu, Qiao

2015-01-01

A green chemical method for preparation of gold nanoparticles-reduced graphene oxide nanocomposite is described. This can be readily accomplished through a two-step chemical reduction scheme by using poly(diallyldimethylammonium chloride), a cationic polyelectrolyte as a common reducer. Polyelectrolyte here also serves to stabilize gold nanoparticles and is beneficial to electrical communication, leading to the formation of well-characteristic nanohybrid. The prepared nanomaterial showed remarkable electrocatalytic ability as a result of the rational conjunction of graphene and gold nanoparticles, which was demonstrated by direct electrochemical determination of three aminophenol isomers on a modified glassy carbon electrode. Effective peak separation of three isomers was achieved due to the favorable electron-transfer network perfectly assembled on the electrode surface, thus enabling the simultaneous assay of multiple components featuring analogous chemical structure without chromatographic separation. The modified electrode was further used to detect para-aminophenol in paracetamol tablets. The present method is simple, eco-friendly and holds potential for electroanalytical and biosensing applications

Liposome-coated mesoporous silica nanoparticles loaded with L-cysteine for photoelectrochemical immunoassay of aflatoxin B1.

Science.gov (United States)

Lin, Youxiu; Zhou, Qian; Zeng, Yongyi; Tang, Dianping

2018-06-02

The authors describe a photoelectrochemical (PEC) immunoassay for determination of aflatoxin B 1 (AFB 1 ) in foodstuff. The competitive immunoreaction is carried out on a microplate coated with a capture antibody against AFB 1 using AFB 1 -bovine serum albumin (BSA)-liposome-coated mesoporous silica nanoparticles (MSN) loaded with L-cysteine as a support. The photocurrent is produced by a photoactive material consisting of cerium-doped Bi 2 MoO 6 . Initially, L-cysteine acting as the electron donor is gated in the pores by interaction between mesoporous silica and liposome. Thereafter, AFB 1 -BSA conjugates are covalently bound to the liposomes. Upon introduction of the analyte (AFB 1 ), the labeled AFB 1 -BSA complex competes with the analyte for the antibody deposited on the microplate. Accompanying with the immunocomplex, the liposomes on the MSNs are lysed upon addition of Triton X-100. This results in the opening of the pores and in a release of L-cysteine. Free cysteine then induces the electron-hole scavenger of the photoactive nanosheets to increase the photocurrent. The photocurrent (relative to background signal) increases with increasing AFB 1 concentration. Under optimum conditions, the photoactive nanosheets display good photoelectrochemical responses, and allow the detection of AFB 1 at a concentration as low as 0.1 pg·mL -1 within a linear response in the 0.3 pg·mL -1 to 10 ng·mL -1 concentration range. Accuracy was evaluated by analyzing naturally contaminated and spiked peanut samples by using a commercial AFB 1 ELISA kit as the reference, and well-matching results were obtained. Graphical abstract Schematic presentation of a photoelectrochemical immunoassay for AFB 1 . It is based on the use of Ce-doped Bi 2 MoO 6 nanosheets and of liposome-coated mesoporous silica nanoparticles loaded with L-cysteine.

pH and ion strength modulated ionic species loading in mesoporous silica nanoparticles

International Nuclear Information System (INIS)

Liu, Wei; Liu, Jianbo; Yang, Xiaohai; Wang, Kemin; Wang, Qing; Yang, Meng; Li, Li; Xu, Jianguo

2013-01-01

Mesoporous silica nanoparticles (MSN) have emerged as appealing host materials to accommodate guest molecules for biomedical applications, and recently various methods have been developed to modulate the loading of guest molecules in the silica matrix. Herein, it was demonstrated that pH and ion strength showed great influence on the loading of charged species into the nanoparticles, taking MCM-41 as a host MSN model and methylviologen (MV 2+ ) and 1,5-naphthalene disulfonate (NDS 2− ) as typical charged ionic guest molecules. As the pH increased from 3.0 to 8.0, the loading amount of MV 2+ increased gradually, while on the contrary, it decreased gradually for NDS 2− , for the solution pH changed the electrostatic interaction between the silica matrix and the ionic guest molecules. Additionally, the adding of NaCl reduced the electrostatic interaction, which resulted in a decreasing of the electrostatic rejection and electrostatic accumulation for the molecules carrying the same and the opposite charge to the particle respectively. Thus, pH and ion strength can be employed as simple approaches to modulate the loading of charged molecules and permselectivity in MSN. This work has a definite guidance function for molecule loading, transport modulation, controlled release as well as sensors based on MSN. (paper)

Layer by layer assembly of gold nanoparticles and graphene via Langmuir Blodgett method for efficient light-harvesting in photocatalytic applications

International Nuclear Information System (INIS)

Shakir, Imran; Ali, Zahid; Kang, Dae Joon

2014-01-01

Highlights: • Layer by layer assembly of gold nanoparticles and graphene. • Efficient visible light photocatalysis. • Plasmonic resonances by nanoparticles are utilized for visible light scattering. • Electron scavenging reaction. • Easy handling and recycling. - Abstract: The synthesis of a photocatalyst that is highly active under visible light is one of the most challenging tasks for solar-energy utilization. Here we report a multilayer assembly of gold nanoparticles and graphene that offers dual functionality to efficiently harness visible photons. Firstly, plasmonic resonances by gold nanoparticles are utilized for visible light scattering; secondly the electron scavenging reaction is enhanced by the gold nanoparticles trapping the electrons that are injected from the dye into the graphene. Moreover, the structure is in the form of a thin film, which demonstrates the potential for easy handling and recycling. Precise control over light harvesting and the photocatalytic response is achieved by controlling the number of layers

Layer by layer assembly of gold nanoparticles and graphene via Langmuir Blodgett method for efficient light-harvesting in photocatalytic applications

Energy Technology Data Exchange (ETDEWEB)

Shakir, Imran, E-mail: shakir@skku.edu [Deanship of scientific research, College of Engineering, King Saud University, PO-BOX 800, Riyadh 11421 (Saudi Arabia); Ali, Zahid [BK 21 Physics Research Division, Department of Energy Science, Institute of Basic Sciences, SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); National Institute of Lasers and Optronics, Islamabad (Pakistan); Kang, Dae Joon [BK 21 Physics Research Division, Department of Energy Science, Institute of Basic Sciences, SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2014-12-25

Highlights: • Layer by layer assembly of gold nanoparticles and graphene. • Efficient visible light photocatalysis. • Plasmonic resonances by nanoparticles are utilized for visible light scattering. • Electron scavenging reaction. • Easy handling and recycling. - Abstract: The synthesis of a photocatalyst that is highly active under visible light is one of the most challenging tasks for solar-energy utilization. Here we report a multilayer assembly of gold nanoparticles and graphene that offers dual functionality to efficiently harness visible photons. Firstly, plasmonic resonances by gold nanoparticles are utilized for visible light scattering; secondly the electron scavenging reaction is enhanced by the gold nanoparticles trapping the electrons that are injected from the dye into the graphene. Moreover, the structure is in the form of a thin film, which demonstrates the potential for easy handling and recycling. Precise control over light harvesting and the photocatalytic response is achieved by controlling the number of layers.

On the role of the colloidal stability of mesoporous silica nanoparticles as gene delivery vectors

International Nuclear Information System (INIS)

Cebrián, Virginia; Yagüe, Clara; Arruebo, Manuel; Martín-Saavedra, Francisco M.; Santamaría, Jesus; Vilaboa, Nuria

2011-01-01

Mesoporous silica nanoparticles have been synthesized and functionalized with four different types of molecules containing amino groups, i.e., with primary amines only, with quaternary amines, with quaternized cyclic amines, or with polyethylenimine (PEI), which is formed by primary, secondary, and tertiary amines. These nanoparticles were then incubated with reporter plasmids and the ability of the resulting complexes to transfect human cells was studied. Only nanoparticles functionalized with PEI were efficient for transfection. The agglomeration behavior and the electrokinetic potential of the nanoparticle–plasmid complexes have been studied, as well as their cell internalization behavior using a fluorescent-labeled plasmid that allows its monitorization by confocal microscopy. The results indicate that the efficiency of PEI-functionalized nanoparticles for transfection resides to some extent in the different characteristics imparted to the nanoparticles regarding agglomeration and surface charge behavior.

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

Investigating the Interaction of Water Vapour with Aminopropyl Groups on the Surface of Mesoporous Silica Nanoparticles.

Science.gov (United States)

Paul, Geo; Musso, Giorgia Elena; Bottinelli, Emanuela; Cossi, Maurizio; Marchese, Leonardo; Berlier, Gloria

2017-04-05

The interaction of water molecules with the surface of hybrid silica-based mesoporous materials is studied by 29 Si, 1 H and 13 C solid-state NMR and IR spectroscopy, with the support of ab initio calculations. The surface of aminopropyl-grafted mesoporous silica nanoparticles is studied in the dehydrated state and upon interaction with controlled doses of water vapour. Former investigations described the interactions between aminopropyl and residual SiOH groups; the present study shows the presence of hydrogen-bonded species (SiOH to NH 2 ) and weakly interacting "free" aminopropyl chains with restricted mobility, together with a small amount of protonated NH 3 + groups. The concentration of the last-named species increased upon interaction with water, and this indicates reversible and fast proton exchange from water molecules to a fraction of the amino groups. Herein, this is discussed and explained for the first time, by a combination of experimental and theoretical approaches. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Iodinated oil-loaded, fluorescent mesoporous silica-coated iron oxide nanoparticles for magnetic resonance imaging/computed tomography/fluorescence trimodal imaging

Directory of Open Access Journals (Sweden)

Xue S

2014-05-01

Full Text Available Sihan Xue,1 Yao Wang,1 Mengxing Wang,2 Lu Zhang,1 Xiaoxia Du,2 Hongchen Gu,1 Chunfu Zhang1,31School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong University, 2Shanghai Key Laboratory of Magnetic Resonance, Department of Physics, East China Normal University, 3State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, People’s Republic of ChinaAbstract: In this study, a novel magnetic resonance imaging (MRI/computed tomography (CT/fluorescence trifunctional probe was prepared by loading iodinated oil into fluorescent mesoporous silica-coated superparamagnetic iron oxide nanoparticles (i-fmSiO4@SPIONs. Fluorescent mesoporous silica-coated superparamagnetic iron oxide nanoparticles (fmSiO4@SPIONs were prepared by growing fluorescent dye-doped silica onto superparamagnetic iron oxide nanoparticles (SPIONs directed by a cetyltrimethylammonium bromide template. As prepared, fmSiO4@SPIONs had a uniform size, a large surface area, and a large pore volume, which demonstrated high efficiency for iodinated oil loading. Iodinated oil loading did not change the sizes of fmSiO4@SPIONs, but they reduced the MRI T2 relaxivity (r2 markedly. I-fmSiO4@SPIONs were stable in their physical condition and did not demonstrate cytotoxic effects under the conditions investigated. In vitro studies indicated that the contrast enhancement of MRI and CT, and the fluorescence signal intensity of i-fmSiO4@SPION aqueous suspensions and macrophages, were intensified with increased i-fmSiO4@SPION concentrations in suspension and cell culture media. Moreover, for the in vivo study, the accumulation of i-fmSiO4@SPIONs in the liver could also be detected by MRI, CT, and fluorescence imaging. Our study demonstrated that i-fmSiO4@SPIONs had great potential for MRI/C/fluorescence trimodal imaging.Keywords: multifunctional probe, SPIONs, mesoporous silica

Gold Nanoparticle-Graphene Oxide Nanocomposites That Enhance the Device Performance of Polymer Solar Cells

Directory of Open Access Journals (Sweden)

Ming-Kai Chuang

2014-01-01

Full Text Available Metal nanoparticle-decorated graphene oxides are promising materials for use in various optoelectronic applications because of their unique plasmonic properties. In this paper, a simple, environmentally friendly method for the synthesis of gold nanoparticle-decorated graphene oxide that can be used to improve the efficiency of organic photovoltaic devices (OPVs is reported. Here, the amino acid glycine is employed as an environmentally friendly reducing reagent for the reduction of gold ions in the graphene oxide solutions. Transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, UV-Vis spectroscopy, and Raman spectroscopy are used to characterize the material properties of the resulting nanomaterials. Furthermore, these nanocomposites are employed as the anode buffer layer in OPVs to trigger surface plasmonic resonance, which improved the efficiency of the OPVs. The results indicate that such nanomaterials appear to have great potential for application in OPVs.

Functionalized Mesoporous Silica Membranes for CO2 Separation Applications

Directory of Open Access Journals (Sweden)

Hyung-Ju Kim

2015-01-01

Full Text Available Mesoporous silica molecular sieves are emerging candidates for a number of potential applications involving adsorption and molecular transport due to their large surface areas, high pore volumes, and tunable pore sizes. Recently, several research groups have investigated the potential of functionalized mesoporous silica molecular sieves as advanced materials in separation devices, such as membranes. In particular, mesoporous silica with a two- or three-dimensional pore structure is one of the most promising types of molecular sieve materials for gas separation membranes. However, several important challenges must first be addressed regarding the successful fabrication of mesoporous silica membranes. First, a novel, high throughput process for the fabrication of continuous and defect-free mesoporous silica membranes is required. Second, functionalization of mesopores on membranes is desirable in order to impart selective properties. Finally, the separation characteristics and performance of functionalized mesoporous silica membranes must be further investigated. Herein, the synthesis, characterization, and applications of mesoporous silica membranes and functionalized mesoporous silica membranes are reviewed with a focus on CO2 separation.

pH-responsive mesoporous silica nanoparticles employed in controlled drug delivery systems for cancer treatment

International Nuclear Information System (INIS)

Yang, Ke-Ni; Zhang, Chun-Qiu; Wang, Wei; Wang, Paul C.; Zhou, Jian-Ping; Liang, Xing-Jie

2014-01-01

In the fight against cancer, controlled drug delivery systems have emerged to enhance the therapeutic efficacy and safety of anti-cancer drugs. Among these systems, mesoporous silica nanoparticles (MSNs) with a functional surface possess obvious advantages and were thus rapidly developed for cancer treatment. Many stimuli-responsive materials, such as nanoparticles, polymers, and inorganic materials, have been applied as caps and gatekeepers to control drug release from MSNs. This review presents an overview of the recent progress in the production of pH-responsive MSNs based on the pH gradient between normal tissues and the tumor microenvironment. Four main categories of gatekeepers can respond to acidic conditions. These categories will be described in detail

Synthesis and nonlinear optical properties of zirconia-protected gold nanoparticles embedded in sol-gel derived silica glass

Science.gov (United States)

Le Rouge, A.; El Hamzaoui, H.; Capoen, B.; Bernard, R.; Cristini-Robbe, O.; Martinelli, G.; Cassagne, C.; Boudebs, G.; Bouazaoui, M.; Bigot, L.

2015-05-01

A new approach to dope a silica glass with gold nanoparticles (GNPs) is presented. It consisted in embedding zirconia-coated GNPs in a silica sol to form a doped silica gel. Then, the sol-doped nanoporous silica xerogel is densified leading to the formation of a glass monolith. The spectral position and shape of the surface plasmon resonance (SPR) reported around 520 nm remain compatible with small spherical GNPs in a silica matrix. The saturable absorption behavior of this gold/zirconia-doped silica glass has been evidenced by Z-scan technique. A second-order nonlinear absorption coefficient β of about -13.7 cm GW-1 has been obtained at a wavelength near the SPR of the GNPs.

Computer modeling of the optical properties and heating of spherical gold and silica-gold nanoparticles for laser combined imaging and photothermal treatment

International Nuclear Information System (INIS)

Pustovalov, V; Astafyeva, L; Jean, B

2009-01-01

Recently, several groups of investigators (Anderson, Halas, Zharov, El-Sayed and their co-workers (Pitsillides et al 2003 Biophys. J. 84 4023-31, Zharov et al 2003 Appl. Phys. Lett. 83 4897-9, Zharov et al 2004 Proc. SPIE 5319 291-9, Loo et al 2005 Nano Lett. 5 709-11, Gobin et al 2007 Nano Lett. 7 1929-34, Fu et al 2008 Nanotechnology 19 045103, Huang et al 2006 J. Am. Chem. Soc. 128 2115-20, Jain et al 2006 J. Phys. Chem. B 110 7238-48, Jain et al 2007 Nano Today 2 18-29)) demonstrated, through pioneering results, the great potential of laser thermal therapy of cells and tissues conjugated with gold nanoparticles. It was also proposed to use combined diagnostics and therapy on the basis of nanoparticle selection for achievement of efficient contrast for laser imaging applications, as well as for photothermal therapy. However, the current understanding of the relationship between optical properties (absorption, backscattering) of nanoparticles, the efficiency of nanoparticle heating and the possibility to use them for combined imaging and therapy is limited. Here, we report the results of computer modeling of optical absorption and backscattering properties and laser heating of gold and silica-gold spherical nanoparticles for laser combined imaging and photothermal treatment of cells and tissues conjugated with nanoparticles. The efficiencies of nanoparticle heating and backscattering by nanoparticles, depending upon their radii, structure and optical properties of the metal, were investigated. This paper focuses on the analysis and determination of appropriate ranges of nanoparticle sizes for the purposes of laser combined imaging and photothermal treatment. The possibility to use spherical gold and silica-gold nanoparticles in determined ranges of radii for these purposes for laser wavelengths 532 and 800 nm is investigated.

Enhanced lifetime characteristics in flexible polymer light-emitting devices by encapsulation of epoxy/silica-coated gold nanoparticles resin (ESGR)

International Nuclear Information System (INIS)

Chiu, Pin-Hsiang; Huang, Chien-Jung; Yang, Cheng-Fu; Meen, Teen-Hang; Wang, Yeong-Her

2010-01-01

This paper reports the effects of a new multilayer encapsulation for the lifetime of flexible PLEDs on plastic substrate. The multilayer encapsulation consisted of a novel epoxy/silica-coated gold nanoparticles resin (ESGR) as the pre-encapsulation layer and a SiO 2 layer as the encapsulation cap. The ESGR was prepared by mixing UV-curable epoxy resin and powders of silica-coated gold nanoparticles. The silica-coated gold nanoparticles is a necessity because the epoxy resin is not a good moisture barrier. The flexible PLEDs with multilayer encapsulation exhibited no dark spots after being stored for over 300 h at 25 deg. C and 60% relative humidity. Also, the operational half-luminance decay time of device was 1360 h, seven times longer than that of a device without encapsulation. These results confirmed that the multilayer encapsulation, which restricted the moisture that penetrated into the devices, could be applied to the encapsulation of flexible PLEDs.

A flexible, bolaamphiphilic template for mesoporous silicas.

Science.gov (United States)

Yuen, Alexander K L; Heinroth, Falk; Ward, Antony J; Masters, Anthony F; Maschmeyer, Thomas

2013-08-28

A novel symmetrical bolaamphiphile, containing two N-methylimidazolium head-groups bridged by a 32-methylene linker, was synthesized and characterized. A variety of mesoporous silicas was prepared using the bolaamphiphile as a "soft template". The effects of absolute surfactant concentration and synthesis conditions upon the morphologies of these silicas were investigated. For a given surfactant concentration, particle morphology; pore size; and pore ordering were modified through control of the template to silica-precursor ratio and synthesis conditions. Observed morphologies included: lenticular core-shell nanoparticles and decorticated globules, truncated hexagonal plates, and sheets. In all cases the mesopores are aligned along the shortest axis of the nanomaterial. Decorticated materials displayed surface areas of up to 1200 m(2) g(-1) and pore diameters (D(BJH)) of 24-28 Å. Small-angle X-ray diffraction and transmission electron microscopy measurements revealed that the majority of the materials has elliptical pores arranged in rectangular lattices (c2mm). Adoption of this symmetry group is a result of the template aggregate deformation from a regular hexagonal phase of cylindrical rods to a ribbon phase under the synthetic conditions.

Ultrahigh capacity anode material for lithium ion battery based on rod gold nanoparticles decorated reduced graphene oxide

Energy Technology Data Exchange (ETDEWEB)

Atar, Necip, E-mail: necipatar@gmail.com [Department of Chemical Engineering, Pamukkale University, Denizli (Turkey); Eren, Tanju [Department of Chemical Engineering, Pamukkale University, Denizli (Turkey); Yola, Mehmet Lütfi [Department of Metallurgical and Materials Engineering, Sinop University, Sinop (Turkey)

2015-09-01

In this study, we report the synthesis of rod shaped gold nanoparticles/2-aminoethanethiol functionalized reduced graphene oxide composite (rdAuNPs/AETrGO) and its application as an anode material for lithium-ion batteries. The structure of the rdAuNPs/AETrGO composite was characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The electrochemical performance was investigated at different current rates by using a coin-type cell. It was found that the rod shaped gold nanoparticles were highly dispersed on the reduced graphene oxide sheets. Moreover, the rdAuNPs/AETrGO composite showed a high specific gravimetric capacity of about 1320 mAh g{sup −1} and a long-term cycle stability. - Highlights: • We prepared rod shaped gold nanoparticles functionalized reduced graphene oxide. • The nanocomposite was used as an anode material for lithium-ion batteries. • The nanocomposite showed a high specific gravimetric capacity of about 1320 mAh g{sup −1}. • The nanocomposite exhibited a long-term cycle stability.

Ultrahigh capacity anode material for lithium ion battery based on rod gold nanoparticles decorated reduced graphene oxide

International Nuclear Information System (INIS)

Atar, Necip; Eren, Tanju; Yola, Mehmet Lütfi

2015-01-01

In this study, we report the synthesis of rod shaped gold nanoparticles/2-aminoethanethiol functionalized reduced graphene oxide composite (rdAuNPs/AETrGO) and its application as an anode material for lithium-ion batteries. The structure of the rdAuNPs/AETrGO composite was characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The electrochemical performance was investigated at different current rates by using a coin-type cell. It was found that the rod shaped gold nanoparticles were highly dispersed on the reduced graphene oxide sheets. Moreover, the rdAuNPs/AETrGO composite showed a high specific gravimetric capacity of about 1320 mAh g −1 and a long-term cycle stability. - Highlights: • We prepared rod shaped gold nanoparticles functionalized reduced graphene oxide. • The nanocomposite was used as an anode material for lithium-ion batteries. • The nanocomposite showed a high specific gravimetric capacity of about 1320 mAh g −1 . • The nanocomposite exhibited a long-term cycle stability

Delivery of Gemcitabine Prodrugs Employing Mesoporous Silica Nanoparticles

Directory of Open Access Journals (Sweden)

Alessio Malfanti

2016-04-01

Full Text Available In this paper, mesoporous silica nanoparticles (MSNs were studied as vehicles for the delivery of the antitumoral drug gemcitabine (GEM and of its 4-(N-acyl derivatives, (4-(N-valeroyl-(C5GEM, 4-(N-lauroyl-(C12GEM and 4-(N-stearoyl-gemcitabine (C18GEM. The loading of the GEM lipophilic prodrugs on MSNs was explored with the aim to obtain both a physical and a chemical protection of GEM from rapid plasmatic metabolization. For this purpose, MSNs as such or with grafted aminopropyl and carboxyethyl groups were prepared and characterized. Then, their different drug loading capacity in relation to the nature of the functional group was evaluated. In our experimental conditions, GEM was not loaded in any MSNs, while C12GEM was the most efficiently encapsulated and employed for further evaluation. The results showed that loading capacity increased with the presence of functional groups on the nanoparticles; similarly, the presence of functional groups on MSNs’ surface influenced the drug release profile. Finally, the cytotoxicity of the different preparations was evaluated and data showed that C12GEM loaded MSNs are less cytotoxic than the free drug with an activity that increased with the incubating time, indicating that all these systems are able to release the drug in a controlled manner. Altogether, the results demonstrate that these MSNs could be an interesting system for the delivery of anticancer drugs.

Adsorption and Recovery of Polyphenolic Flavonoids Using TiO_2-Functionalized Mesoporous Silica Nanoparticles

International Nuclear Information System (INIS)

Khan, M. Arif; Wallace, William T.; Islam, Syed Z.; Nagpure, Suraj; Strzalka, Joseph

2017-01-01

Exploiting specific interactions with titania (TiO_2) has been proposed for the separation and recovery of a broad range of biomolecules and natural products, including therapeutic polyphenolic flavonoids which are susceptible to degradation, such as quercetin. Functionalizing mesoporous silica with TiO_2 has many potential advantages over bulk and mesoporous TiO_2 as an adsorbent for natural products, including robust synthetic approaches leading to high surface area, stable separation platforms. Here, TiO_2 surface functionalized mesoporous silica nanoparticles (MSNPs) are synthesized and characterized as a function of TiO_2 content (up to 636 mg TiO2/g). The adsorption isotherms of two polyphenolic flavonoids, quercetin and rutin, were determined (0.05-10 mg/ml in ethanol), and a 100-fold increase in the adsorption capacity was observed relative to functionalized nonporous particles with similar TiO_2 surface coverage. An optimum extent of functionalization (approximately 440 mg TiO_2/g particles) is interpreted from characterization techniques including grazing incidence x-ray scattering (GIXS), high resolution transmission electron microscopy (HRTEM) and nitrogen adsorption, which examined the interplay between the extent of TiO_2 functionalization and the accessibility of the porous structures. The recovery of flavonoids is demonstrated using ligand displacement in ethanolic citric acid solution (20% w/v), in which greater than 90% recovery can be achieved in a multistep extraction process. The radical scavenging activity (RSA) of the recovered and particle-bound quercetin as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay demonstrates greater than 80% retention of antioxidant activity by both particle-bound and recovered quercetin. In conclusion, these mesoporous titanosilicate materials can serve as a synthetic platform to isolate, recover, and potentially deliver degradation-sensitive natural products to biological systems.

Effect of Multimodal Pore Channels on Cargo Release from Mesoporous Silica Nanoparticles

Directory of Open Access Journals (Sweden)

Sushilkumar A. Jadhav

2016-01-01

Full Text Available Mesoporous silica nanoparticles (MSNs with multimodal pore channels were fully characterized by TEM, nitrogen adsorption-desorption, and DLS analyses. MSNs with average diameter of 200 nm with dual pore channel zones with pore diameters of 1.3–2.6 and 4 nm were tested for their use in drug delivery application. Important role of the multimodal pore systems present on MSNs on the quantitative release of model drug ibuprofen was investigated. The results obtained revealed that the release profile for ibuprofen clearly shows distinct zones which can be attributed to the respective porous channel zones present on the particles. The fluctuations in the concentration of ibuprofen during the prolonged release from MSNs were caused by the multimodal pore channel systems.

Mesoporous polyaniline film on ultra-thin graphene sheets for high performance supercapacitors

Science.gov (United States)

Wang, Qian; Yan, Jun; Fan, Zhuangjun; Wei, Tong; Zhang, Milin; Jing, Xiaoyan

2014-02-01

A facile approach has been developed to fabricate mesoporous PANI film on ultra-thin graphene nanosheet (G-mPANI) hybrid by in situ polymerization using graphene-mesoporous silica composite as template. Due to its mesoporous structure, over-all conductive network, G-mPANI electrode displays a specific capacitance of 749 F g-1 at 0.5 A g-1 with excellent rate capability (remains 73% even at 5.0 A g-1), much higher than that of pristine PANI electrode (315 F g-1 at 0.5 A g-1, 39% retention at 5.0 A g-1) in 1 mol L-1 H2SO4 aqueous solution. More interestingly, the G-mPANI hybrid can maintain 88% of its initial capacitance compared to 45% for pristine PANI after 1000 cycles, suggesting a superior electrochemical cyclic stability.

Nanoengineered mesoporous silica nanoparticles for smart delivery of doxorubicin

Science.gov (United States)

Mishra, Akhilesh Kumar; Pandey, Himanshu; Agarwal, Vishnu; Ramteke, Pramod W.; Pandey, Avinash C.

2014-08-01

The motive of the at hand exploration was to contrive a proficient innovative pH-responsive nanocarrier designed for an anti-neoplastic agent that not only owns competent loading capacity but also talented to liberate the drug at the specific site. pH sensitive hollow mesoporous silica nanoparticles ( MSN) have been synthesized by sequence of chemical reconstruction with an average particle size of 120 nm. MSN reveal noteworthy biocompatibility and efficient drug loading magnitude. Active molecules such as Doxorubicin (DOX) can be stocked and set free from the pore vacuities of MSN by tuning the pH of the medium. The loading extent of MSN was found up to 81.4 wt% at pH 7.8. At mild acidic pH, DOX is steadily released from the pores of MSN. Both, the nitrogen adsorption-desorption isotherms and X-ray diffraction patterns reflects that this system holds remarkable stable mesostructure. Additionally, the outcomes of cytotoxicity assessment further establish the potential of MSN as a relevant drug transporter which can be thought over an appealing choice to a polymeric delivery system.

Mesoporous Silica: A Suitable Adsorbent for Amines

Directory of Open Access Journals (Sweden)

Abdollahzadeh-Ghom Sara

2009-01-01

Full Text Available Abstract Mesoporous silica with KIT-6 structure was investigated as a preconcentrating material in chromatographic systems for ammonia and trimethylamine. Its adsorption capacity was compared to that of existing commercial materials, showing its increased adsorption power. In addition, KIT-6 mesoporous silica efficiently adsorbs both gases, while none of the employed commercial adsorbents did. This means that KIT-6 Mesoporous silica may be a good choice for integrated chromatography/gas sensing micro-devices.

Quaternized Chitosan-Capped Mesoporous Silica Nanoparticles as Nanocarriers for Controlled Pesticide Release.

Science.gov (United States)

Cao, Lidong; Zhang, Huirong; Cao, Chong; Zhang, Jiakun; Li, Fengmin; Huang, Qiliang

2016-06-28

Nanotechnology-based pesticide formulations would ensure effective utilization of agricultural inputs. In the present work, mesoporous silica nanoparticles (MSNs) with particle diameters of ~110 nm and pore sizes of ~3.7 nm were synthesized via a liquid crystal templating mechanism. A water-soluble chitosan (CS) derivative ( N -(2-hydroxyl)propyl-3-trimethyl ammonium CS chloride, HTCC) was successfully capped on the surface of pyraclostrobin-loaded MSNs. The physicochemical and structural analyses showed that the electrostatic interactions and hydrogen bonding were the major forces responsible for the formation of HTCC-capped MSNs. HTCC coating greatly improved the loading efficiency (LC) (to 40.3%) compared to using bare MSNs as a single encapsulant (26.7%). The microstructure of the nanoparticles was revealed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The pyraclostrobin-loaded nanoparticles showed an initial burst and subsequent sustained release behavior. HTCC-capped MSNs released faster than bare MSNs in the initial stage. Pyraclostrobin-loaded HTCC-capped MSNs with half doses of pyraclostrobin technical demonstrated almost the same fungicidal activity against Phomopsis asparagi (Sacc.), which obviously reduced the applied pesticide and enhanced the utilization efficiency. Therefore, HTCC-decorated MSNs demonstrated great potential as nanocarriers in agrochemical applications.

Sustained release of fungicide metalaxyl by mesoporous silica nanospheres

Energy Technology Data Exchange (ETDEWEB)

Wanyika, Harrison, E-mail: hwanyika@gmail.com [Jomo Kenyatta University of Agriculture and Technology, Department of Chemistry (Kenya)

2013-08-15

The use of nanomaterials for the controlled delivery of pesticides is nascent technology that has the potential to increase the efficiency of food production and decrease pollution. In this work, the prospect of mesoporous silica nanoparticles (MSN) for storage and controlled release of metalaxyl fungicide has been investigated. Mesoporous silica nanospheres with average particle diameters of 162 nm and average pore sizes of 3.2 nm were prepared by a sol-gel process. Metalaxyl molecules were loaded into MSN pores from an aqueous solution by a rotary evaporation method. The loaded amount of metalaxyl as evaluated by thermogravimetric analysis was about 14 wt%. Release of the fungicide entrapped in the MSN matrix revealed sustained release behavior. About 76 % of the free metalaxyl was released in soil within a period of 30 days while only 11.5 and 47 % of the metalaxyl contained in the MSN carrier was released in soil and water, respectively, within the same period. The study showed that MSN can be used to successfully store metalaxyl molecules in its mesoporous framework and significantly delay their release in soil.

Sustained release of fungicide metalaxyl by mesoporous silica nanospheres

International Nuclear Information System (INIS)

Wanyika, Harrison

2013-01-01

The use of nanomaterials for the controlled delivery of pesticides is nascent technology that has the potential to increase the efficiency of food production and decrease pollution. In this work, the prospect of mesoporous silica nanoparticles (MSN) for storage and controlled release of metalaxyl fungicide has been investigated. Mesoporous silica nanospheres with average particle diameters of 162 nm and average pore sizes of 3.2 nm were prepared by a sol–gel process. Metalaxyl molecules were loaded into MSN pores from an aqueous solution by a rotary evaporation method. The loaded amount of metalaxyl as evaluated by thermogravimetric analysis was about 14 wt%. Release of the fungicide entrapped in the MSN matrix revealed sustained release behavior. About 76 % of the free metalaxyl was released in soil within a period of 30 days while only 11.5 and 47 % of the metalaxyl contained in the MSN carrier was released in soil and water, respectively, within the same period. The study showed that MSN can be used to successfully store metalaxyl molecules in its mesoporous framework and significantly delay their release in soil

Gold nano-particles fixed on glass

International Nuclear Information System (INIS)

Worsch, Christian; Wisniewski, Wolfgang; Kracker, Michael; Rüssel, Christian

2012-01-01

Highlights: ► We produced wear resistant gold–ruby coatings on amorphous substrates. ► Thin sputtered gold layers were covered by or embedded in silica coatings. ► Annealing above T g of the substrate glass led to the formation of gold nano particles. ► A 1 1 1-texture of the gold particles is observed via XRD and EBSD. ► EBSD-patterns can be acquired from crystals covered by a thin layer of glass. - Abstract: A simple process for producing wear resistant gold nano-particle coatings on transparent substrates is proposed. Soda-lime-silica glasses were sputtered with gold and subsequently coated with SiO 2 using a combustion chemical vapor deposition technique. Some samples were first coated with silica, sputtered with gold and then coated with a second layer of silica. The samples were annealed for 20 min at either 550 or 600 °C. This resulted in the formation of round, well separated gold nano-particles with sizes from 15 to 200 nm. The color of the coated glass was equivalent to that of gold–ruby glasses. Silica/gold/silica coatings annealed at 600 °C for 20 min were strongly adherent and scratch resistant. X-ray diffraction and electron backscatter diffraction (EBSD) were used to describe the crystal orientations of the embedded particles. The gold particles are preferably oriented with their (1 1 1) planes perpendicular to the surface.

Immobilization of Thiadiazole Derivatives on Magnetite Mesoporous Silica Shell Nanoparticles in Application to Heavy Metal Removal from Biological Samples

International Nuclear Information System (INIS)

Emadi, Masoomeh; Shams, Esmaeil

2010-01-01

In this report magnetite was synthesized by a coprecipitation method, then coated with a layer of silica. Another layer of mesoporous silica was added by a sol-gel method, then 5-amino-1,3,4-thiadiazole-thiol (ATT) was immobilized onto the synthesized nanoparticles with a simple procedure. This was followed by a series of characterizations, including transmission electron microscopy (TEM), FT-IR spectrum, elemental analysis and XRD. Heavy metal uptake of the modified nanoparticles was examined by atomic absorption spectroscopy. For further investigation we chose Cu 2+ as the preferred heavy metal to evaluate the amount of adsorption, as well as the kinetics and mechanism of adsorption. Finally, the capacity of our nanoparticles for the heavy metal removal from blood was shown. We found that the kinetic rate of Cu 2+ adsorption was 0.05 g/mg/min, and the best binding model was the Freundlich isotherm.

Investigation on the effect of Tb(dbm)3phen on the luminescent properties of Eu(dbm)3phen-containing mesoporous silica nanoparticles

International Nuclear Information System (INIS)

Moretti, E.; Bellotto, L.; Basile, M.; Malba, C.; Enrichi, F.; Benedetti, A.; Polizzi, S.

2013-01-01

Eu(dbm) 3 phen and Tb(dbm) 3 phen complexes (tris(dibenzoylmethane) mono(1,10-phenantroline) Ln(III)) were impregnated in ordered mesoporous silica nanoparticles (MSNs) with an average size of 50–70 nm and a pore diameter centred at 2.8 nm, with the aim of increasing the luminescence by avoiding concentration quenching and having mainly in mind the application as down-shifter for multi-crystalline solar cells. The morphological, structural, textural and luminescent properties of the synthesized samples were characterized by N 2 adsorption–desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–visible spectroscopy and photoluminescence measurements. It is demonstrated that inclusion in the MSNs allows one to use much higher loadings (23 wt%) of the Eu-complex than in other matrices, and that co-doping with Tb(dbm) 3 phen improves luminescence for samples with Eu(dbm) 3 phen content lower than about 10 wt%. Results are interpreted by using a simple sphere of action model adapted to the case of a pore-limited system. - Graphical abstract: Sensitization of the antenna effect (down-conversion of UV radiation to red light) by the presence of Tb(dbm) 3 phen in the cavities of mesoporous silica nanoparticles containing Eu(dbm) 3 phen. - Highlights: • Detailed study of Eu(dbm) 3 phen-doped mesoporous silica nanoparticles luminescence. • Inclusion of up to 23 wt% of Eu(dbm) 3 phen without concentration quenching. • Detailed study of the role of the Tb(dbm) 3 phen co-dopant. • Co-doping effective for Eu 3+ (dbm) 3 phen loadings lower than about 10 wt%

Effect of surface hydroxyl groups on heat capacity of mesoporous silica

Science.gov (United States)

Marszewski, Michal; Butts, Danielle; Lan, Esther; Yan, Yan; King, Sophia C.; McNeil, Patricia E.; Galy, Tiphaine; Dunn, Bruce; Tolbert, Sarah H.; Hu, Yongjie; Pilon, Laurent

2018-05-01

This paper quantifies the effect of surface hydroxyl groups on the effective specific and volumetric heat capacities of mesoporous silica. To achieve a wide range of structural diversity, mesoporous silica samples were synthesized by various methods, including (i) polymer-templated nanoparticle-based powders, (ii) polymer-templated sol-gel powders, and (iii) ambigel silica samples dried by solvent exchange at room temperature. Their effective specific heat capacity, specific surface area, and porosity were measured using differential scanning calorimetry and low-temperature nitrogen adsorption-desorption measurements. The experimentally measured specific heat capacity was larger than the conventional weight-fraction-weighted specific heat capacity of the air and silica constituents. The difference was attributed to the presence of OH groups in the large internal surface area. A thermodynamic model was developed based on surface energy considerations to account for the effect of surface OH groups on the specific and volumetric heat capacity. The model predictions fell within the experimental uncertainty.

Decomposition of formic acid over silica encapsulated and amine functionalised gold nanoparticles

DEFF Research Database (Denmark)

Mielby, Jerrik Jørgen; Kunov-Kruse, Andreas Jonas; Kegnæs, Søren

2017-01-01

Formic acid has recently attracted considerable attention as a safe and convenient source of hydrogen for sustainable chemical synthesis and renewable energy storage. Here, we show that silica encapsulated and amine functionalised gold nanoparticles are highly active catalysts for the production...... of hydrogen by vapour phase decomposition of formic acid. The core-shell catalysts are prepared in a reverse micelle system that makes it possible to control the size of the Au nanoparticles and the thickness of the SiO2 shells, which has a large impact on the catalytic activity. The smallest gold...... nanoparticles are 2.2 ± 0.3 nm in diameter and have a turnover frequency (TOF) of up to 958 h−1 at a temperature of 130 °C. Based on detailed in situ ATR-FTIR studies and results from kinetic isotope labelling experiments we propose that the active site is a low-coordinated and amine functionalised Au atom...

Mesoporous Carbon Produced from Tri-constituent Mesoporous Carbon-silica Composite for Water Purification

KAUST Repository

Yu, Yanjie

2012-01-01

Highly ordered mesoporous carbon-silica nanocomposites with interpenetrating carbon and silica networks were synthesized by the evaporation-induced tri-constituent co- assembly approach. The removal of silica by concentrated NaOH solution produced mesoporous carbons, which contained not only the primary large pores, but also the secondary mesopores in the carbon walls. The thus synthesized mesoporous carbon was further activated by using ZnCl2. The activated mesoporous carbon showed an improved surface area and pore volume. The synthesized mesoporous carbon was tested for diuron removal from water and the results showed that the carbon gave a fast diuron adsorption kinetics and a high diuron removal capacity, which was attributable to the primary mesopore channels being the highway for mass transfer, which led to short diffusion path length and easy accessibility of the interpenetrated secondary mesopores. The optimal adsorption capacity of the porous carbon was determined to be 390 mg/g, the highest values ever reported for diuron adsorption on carbon-based materials.

Mesoporous Carbon Produced from Tri-constituent Mesoporous Carbon-silica Composite for Water Purification

KAUST Repository

Yu, Yanjie

2012-05-01

Highly ordered mesoporous carbon-silica nanocomposites with interpenetrating carbon and silica networks were synthesized by the evaporation-induced tri-constituent co- assembly approach. The removal of silica by concentrated NaOH solution produced mesoporous carbons, which contained not only the primary large pores, but also the secondary mesopores in the carbon walls. The thus synthesized mesoporous carbon was further activated by using ZnCl2. The activated mesoporous carbon showed an improved surface area and pore volume. The synthesized mesoporous carbon was tested for diuron removal from water and the results showed that the carbon gave a fast diuron adsorption kinetics and a high diuron removal capacity, which was attributable to the primary mesopore channels being the highway for mass transfer, which led to short diffusion path length and easy accessibility of the interpenetrated secondary mesopores. The optimal adsorption capacity of the porous carbon was determined to be 390 mg/g, the highest values ever reported for diuron adsorption on carbon-based materials.

Biodegradable Oxamide-Phenylene-Based Mesoporous Organosilica Nanoparticles with Unprecedented Drug Payloads for Delivery in Cells

KAUST Repository

Croissant, Jonas; Fatieiev, Yevhen; Julfakyan, Khachatur; Lu, Jie; Emwas, Abdelhamid; Anjum, Dalaver; Omar, Haneen; Tamanoi, Fuyuhiko; Zink, Jeffrey; Khashab, Niveen M.

2016-01-01

We describe biodegradable mesoporous hybrid NPs in the presence of proteins, and its application for drug delivery. We synthesized oxamide-phenylene-based mesoporous organosilica nanoparticles (MON) in the absence of silica source which had a

Syntheses and applications of periodic mesoporous organosilica nanoparticles

KAUST Repository

Croissant, Jonas G.

2015-11-06

Periodic Mesoporous Organosilica (PMO) nanomaterials are envisioned to be one of the most prolific subjects of research in the next decade. Similar to mesoporous silica nanoparticles (MSN), PMO nanoparticles (NPs) prepared from organo-bridged alkoxysilanes have tunable mesopores that could be utilized for many applications such as gas and molecule adsorption, catalysis, drug and gene delivery, electronics, and sensing; but unlike MSN, the diversity in chemical nature of the pore walls of such nanomaterials is theoretically unlimited. Thus, we expect that PMO NPs will attract considerable interest over the next decade. In this review, we will present a comprehensive overview of the synthetic strategies for the preparation of nanoscaled PMO materials, and then describe their applications in catalysis and nanomedicine. The remarkable assets of the PMO structure are also detailed, and insights are provided for the preparation of more complex PMO nanoplatforms.

Acid-base equilibria inside amine-functionalized mesoporous silica.

Science.gov (United States)

Yamaguchi, Akira; Namekawa, Manato; Kamijo, Toshio; Itoh, Tetsuji; Teramae, Norio

2011-04-15

Acid-base equilibria and effective proton concentration inside a silica mesopore modified with a trimethyl ammonium (TMAP) layer were studied by steady-state fluorescence experiments. The mesoporous silica with a dense TMAP layer (1.4 molecules/nm(2)) was prepared by a post grafting of N-trimethoxysilylpropyl-N,N,N-trimethylammonium at surfactant-templated mesoporous silica (diameter of silica framework =3.1 nm). The resulting TMAP-modified mesoporous silica strongly adsorbed of anionic fluorescence indicator dyes (8-hydroxypyrene-1,3,6-trisulfonate (pyranine), 8-aminopyrene-1,3,6-trisulfonate (APTS), 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid disulfuric acid (TPPS), 2-naphthol-3,6-disulfonate (2NT)) and fluorescence excitation spectra of these dyes within TMAP-modified mesoporous silica were measured by varying the solution pH. The fluorescence experiments revealed that the acid-base equilibrium reactions of all pH indicator dyes within the TMAP-modified silica mesopore were quite different from those in bulk water. From the analysis of the acid-base equilibrium of pyranine, the following relationships between solution pH (pH(bulk)) and the effective proton concentration inside the pore (pH(pore)) were obtained: (1) shift of pH(pore) was 1.8 (ΔpH(pore)=1.8) for the pH(bulk) change from 2.1 to 9.1 (ΔpH(bulk)=7.0); (2) pH(pore) was not simply proportional to pH(bulk); (3) the inside of the TMAP-modified silica mesopore was suggested to be in a weak acidic or neutral condition when pH(bulk) was changed from 2.0 to 9.1. Since these relationships between pH(bulk) and pH(pore) could explain the acid-base equilibria of other pH indicator dyes (APTS, TPPS, 2NT), these relationships were inferred to describe the effective proton concentration inside the TMAP-modified silica mesopore. © 2011 American Chemical Society

Effect of Mesoporous Silica and Hydroxyapatite Nanoparticles on the Tensile and Dynamic Mechanical Thermal Properties of Polypropylene and Polypropylene Foam

Directory of Open Access Journals (Sweden)

Alireza Albooyeh

2014-12-01

Full Text Available The main purpose of this paper is the experimental study on the tensile and dynamic - mechanical thermal properties of polypropylene (PP and polypropylene foam reinforced with mesoporous silica (MCM-41, hydroxyapatite (HA and the composite of mesoporous silica and hydroxyapatite (MCM41-HA nanoparticles. Nanocomposites and nanocomposite foams containing PP, maleic anhydride grafted polypropylene, different nanoparticles and chemical blowing agent (for foam samples are mixed using the melt-compounding technique in a twin-screw extruder. The results of the tests show that at the same nanoparticles content, all the nanofillers cause better mechanical properties than neat PP and PP foam. Also, due to the porous structure of the foam samples, these samples have the higher damping characteristics and lower tensile properties than the solid samples. Because of higher rigidity and higher strength of HA nanoparticles, the greatest increase in modulus and tensile strength occurs by adding these nanoparticles to neat PP and PP foam. The highest damping factor is obtained by adding MCM-41-HA nanoparticles to PP and PP foam, because of the porous nature of the MCM-41 particles which were reinforced by HA particles. The results of differential scanning calorimetry show that the addition of different nanoparticles does not have any significant effect on crystallinity and melting behavior of PP. Scanning electron microscopy images show that the nanomaterials were fine and uniformly dispersed within the polymer matrix. Furthermore, the addition of different nanoparticles to PP foam causes to increase the cell density, to reduce the cell sizes and to improve the cell sizes distribution. In this respect, the lowest cell sizes and the highest cell density are created by adding HA and MCM41-HA  nanopaticles to PP foams.

Quaternized Chitosan-Capped Mesoporous Silica Nanoparticles as Nanocarriers for Controlled Pesticide Release

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Lidong Cao

2016-06-01

Full Text Available Nanotechnology-based pesticide formulations would ensure effective utilization of agricultural inputs. In the present work, mesoporous silica nanoparticles (MSNs with particle diameters of ~110 nm and pore sizes of ~3.7 nm were synthesized via a liquid crystal templating mechanism. A water-soluble chitosan (CS derivative (N-(2-hydroxylpropyl-3-trimethyl ammonium CS chloride, HTCC was successfully capped on the surface of pyraclostrobin-loaded MSNs. The physicochemical and structural analyses showed that the electrostatic interactions and hydrogen bonding were the major forces responsible for the formation of HTCC-capped MSNs. HTCC coating greatly improved the loading efficiency (LC (to 40.3% compared to using bare MSNs as a single encapsulant (26.7%. The microstructure of the nanoparticles was revealed by scanning electron microscopy (SEM and transmission electron microscopy (TEM. The pyraclostrobin-loaded nanoparticles showed an initial burst and subsequent sustained release behavior. HTCC-capped MSNs released faster than bare MSNs in the initial stage. Pyraclostrobin-loaded HTCC-capped MSNs with half doses of pyraclostrobin technical demonstrated almost the same fungicidal activity against Phomopsis asparagi (Sacc., which obviously reduced the applied pesticide and enhanced the utilization efficiency. Therefore, HTCC-decorated MSNs demonstrated great potential as nanocarriers in agrochemical applications.

Progammed synthesis of magnetic mesoporous silica coated carbon nanotubes for organic pollutant adsorption

Energy Technology Data Exchange (ETDEWEB)

Tong, Yue; Zhang, Min, E-mail: congmingyang123@163.com; Xia, Peixiong; Wang, Linlin; Zheng, Jing; Li, Weizhen; Xu, Jingli, E-mail: xujingli@sues.edu.cn

2016-05-15

Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis method and were characterized by TEM, XRD, FTIR, TGA, N{sub 2} adsorption–desorption and VSM. The well-designed mesoporous magnetic nanotubes had a large specific area, a highly open mesoporous structure and high magnetization. Firstly, SiO{sub 2}-coated maghemite/CNTs nanoparticles (CNTs/Fe{sub 3}O{sub 4}@SiO{sub 2} composites) were synthesized by the combination of high temperature decomposition process and an sol–gel method, in which the iron acetylacetonate as well as TEOS acted as the precursor for maghemite and SiO{sub 2}, respectively. The CNTs/Fe{sub 3}O{sub 4}@SiO{sub 2} composites revealed a core–shell structure, Then, CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} was obtained by extracting cetyltrimethylammonium bromide (CTAB) via an ion-exchange procedure. The resulting composites show not only a magnetic response to an externally applied magnetic field, but also can be a good adsorbent for the organic pollutant in the ambient temperature. - Graphical abstract: Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis, which can be a good adsorbent for the organic pollutant in the ambient temperature. - Highlights: • The surface of CNTs/Fe{sub 3}O{sub 4} is hydrophilic, which facilitates the silica coating. • The CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} was synthesized by a facile method. • The CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} can be a good adsorbent for the organic pollutant.

Mesoporous silica formulation strategies for drug dissolution enhancement: a review.

Science.gov (United States)

McCarthy, Carol A; Ahern, Robert J; Dontireddy, Rakesh; Ryan, Katie B; Crean, Abina M

2016-01-01

Silica materials, in particular mesoporous silicas, have demonstrated excellent properties to enhance the oral bioavailability of poorly water-soluble drugs. Current research in this area is focused on investigating the kinetic profile of drug release from these carriers and manufacturing approaches to scale-up production for commercial manufacture. This review provides an overview of different methods utilized to load drugs onto mesoporous silica carriers. The influence of silica properties and silica pore architecture on drug loading and release are discussed. The kinetics of drug release from mesoporous silica systems is examined and the manufacturability and stability of these formulations are reviewed. Finally, the future prospects of mesoporous silica drug delivery systems are considered. Substantial progress has been made in the characterization and development of mesoporous drug delivery systems for drug dissolution enhancement. However, more research is required to fully understand the drug release kinetic profile from mesoporous silica materials. Incomplete drug release from the carrier and the possibility of drug re-adsorption onto the silica surface need to be investigated. Issues to be addressed include the manufacturability and regulation status of formulation approaches employing mesoporous silica to enhance drug dissolution. While more research is needed to support the move of this technology from the bench to a commercial medicinal product, it is a realistic prospect for the near future.

Mesoporous Silica Nanoparticle-Coated Microneedle Arrays for Intradermal Antigen Delivery.

Science.gov (United States)

Tu, Jing; Du, Guangsheng; Reza Nejadnik, M; Mönkäre, Juha; van der Maaden, Koen; Bomans, Paul H H; Sommerdijk, Nico A J M; Slütter, Bram; Jiskoot, Wim; Bouwstra, Joke A; Kros, Alexander

2017-08-01

To develop a new intradermal antigen delivery system by coating microneedle arrays with lipid bilayer-coated, antigen-loaded mesoporous silica nanoparticles (LB-MSN-OVA). Synthesis of MSNs with 10-nm pores was performed and the nanoparticles were loaded with the model antigen ovalbumin (OVA), and coated with a lipid bilayer (LB-MSN-OVA). The uptake of LB-MSN-OVA by bone marrow-derived dendritic cells (BDMCs) was studied by flow cytometry. The designed LB-MSN-OVA were coated onto pH-sensitive pyridine-modified microneedle arrays and the delivery of LB-MSN-OVA into ex vivo human skin was studied. The synthesized MSNs demonstrated efficient loading of OVA with a maximum loading capacity of about 34% and the lipid bilayer enhanced the colloidal stability of the MSNs. Uptake of OVA loaded in LB-MSN-OVA by BMDCs was higher than that of free OVA, suggesting effective targeting of LB-MSN-OVA to antigen-presenting cells. Microneedles were readily coated with LB-MSN-OVA at pH 5.8, yielding 1.5 μg of encapsulated OVA per microneedle array. Finally, as a result of the pyridine modification, LB-MSN-OVA were effectively released from the microneedles upon piercing the skin. Microneedle arrays coated with LB-MSN-OVA were successfully developed and shown to be suitable for intradermal delivery of the encapsulated protein antigen.

Iron oxide nanoparticle layer templated by polydopamine spheres: a novel scaffold toward hollow-mesoporous magnetic nanoreactors.

Science.gov (United States)

Huang, Liang; Ao, Lijiao; Xie, Xiaobin; Gao, Guanhui; Foda, Mohamed F; Su, Wu

2015-01-14

Superparamagnetic iron oxide nanoparticle layers with high packing density and controlled thickness were in situ deposited on metal-affinity organic templates (polydopamine spheres), via one-pot thermal decomposition. The as synthesized hybrid structure served as a facile nano-scaffold toward hollow-mesoporous magnetic carriers, through surfactant-assisted silica encapsulation and its subsequent calcination. Confined but accessible gold nanoparticles were successfully incorporated into these carriers to form a recyclable catalyst, showing quick magnetic response and a large surface area (642.5 m(2) g(-1)). Current nano-reactors exhibit excellent catalytic performance and high stability in reduction of 4-nitrophenol, together with convenient magnetic separability and good reusability. The integration of compact iron oxide nanoparticle layers with programmable polydopamine templates paves the way to fabricate magnetic-response hollow structures, with high permeability and multi-functionality.

Preparation of Mesoporous Silica-Supported Palladium Catalysts for Biofuel Upgrade

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Ling Fei

2012-01-01

Full Text Available We report the preparation of two hydrocracking catalysts Pd/CoMoO4/silica and Pd/CNTs/CoMoO4/silica (CNTs, carbon nanotubes. The structure, morphologies, composition, and thermal stability of catalysts were studied by X-ray diffraction (XRD, scanning electron microscopy (SEM, Raman spectroscopy, transmission electron microscopy (TEM, energy-dispersive X-ray (EDX, and thermogravimetric analysis (TGA. The catalyst activity was measured in a Parr reactor with camelina fatty acid methyl esters (FAMEs as the feed. The analysis shows that the palladium nanoparticles have been incorporated onto mesoporous silica in Pd/CoMoO4/silica or on the CNTs surface in Pd/CNTs/CoMoO4/silica catalysts. The different combinations of metals and supports have selective control cracking on heavy hydrocarbons.

Ordered mesoporous silica materials with complicated structures

KAUST Repository

Han, Yu

2012-05-01

Periodically ordered mesoporous silicas constitute one of the most important branches of porous materials that are extensively employed in various chemical engineering applications including adsorption, separation and catalysis. This short review gives an introduction to recently developed mesoporous silicas with emphasis on their complicated structures and synthesis mechanisms. In addition, two powerful techniques for solving complex mesoporous structures, electron crystallography and electron tomography, are compared to elucidate their respective strength and limitations. Some critical issues and challenges regarding the development of novel mesoporous structures as well as their applications are also discussed. © 2011 Elsevier Ltd.

Core/shell magnetic mesoporous silica nanoparticles with radially oriented wide mesopores

Directory of Open Access Journals (Sweden)

Nikola Ž. Knežević

2014-06-01

Full Text Available Core/shell nanoparticles, containing magnetic iron-oxide (maghemite core and mesoporous shell with radial porous structure, were prepared by dispersing magnetite nanoparticles and adding tetraethylorthosilicate to a basic aqueous solution containing structure-templating cetyltrimethylammonium bromide and a pore-swelling mesithylene. The material is characterized by SEM and TEM imaging, nitrogen sorption and powder X-ray diffraction. Distinctive features of the prepared material are its high surface area (959 m2/g, wide average pore diameter (12.4 nm and large pore volume (2.3 cm3/g. The material exhibits radial pore structure and the high angle XRD pattern characteristic for maghemite nanoparticles, which are obtained upon calcination of the magnetite-containing material. The observed properties of the prepared material may render the material applicable in separation, drug delivery, sensing and heterogeneous catalysis.

Mesoporous silica nanoparticle supported PdIr bimetal catalyst for selective hydrogenation, and the significant promotional effect of Ir

Energy Technology Data Exchange (ETDEWEB)

Yang, Hui; Huang, Chao; Yang, Fan [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Yang, Xu [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China); Du, Li [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China); Liao, Shijun, E-mail: chsjliao@scut.edu.cn [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China)

2015-12-01

Graphical abstract: A mesoporous silica nanoparticle (MSN) supported bimetal catalyst, PdIr/MSN, was prepared by a facile impregnation and hydrogen reduction method. The strong promotional effect of Ir was observed and thoroughly investigated. At the optimal molar ratio of Ir to Pd (N{sub Ir}/N{sub Pd} = 0.1), the activity of PdIr{sub 0.1}/MSN was up to eight times and 28 times higher than that of monometallic Pd/MSN and Ir/MSN, respectively. The catalysts were characterized comprehensively by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and hydrogen temperature programmed reduction, which revealed that the promotional effect of Ir may be due to the enhanced dispersion of active components on the MSN, and to the intensified Pd–Ir electronic interaction caused by the addition of Ir. - Highlights: • Mesoporous nanoparticles were synthesized and used as support for metal catalyst. • PdIr bimetallic catalyst exhibited significantly improved hydrogenation activity. • The strong promotion of Ir was recognized firstly and investigated intensively. • PdIr exhibits 18 times higher activity than Pd to the hydrogenation of nitrobenzene. - Abstract: A mesoporous silica nanoparticle (MSN) supported bimetal catalyst, PdIr/MSN, was prepared by a facile impregnation and hydrogen reduction method. The strong promotional effect of Ir was observed and thoroughly investigated. At the optimal molar ratio of Ir to Pd (N{sub Ir}/N{sub Pd} = 0.1), the activity of PdIr{sub 0.1}/MSN was up to eight times and 28 times higher than that of monometallic Pd/MSN and Ir/MSN, respectively. The catalysts were characterized comprehensively by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and hydrogen temperature programmed reduction, which revealed that the promotional effect of Ir may be due to the enhanced dispersion of active components on the MSN, and to the intensified Pd–Ir electronic interaction

Separation of pharmacologically active nitrogen-containing compounds on silica gels modified with 6,10-ionene, dextran sulfate, and gold nanoparticles

Science.gov (United States)

Ioutsi, A. N.; Shapovalova, E. N.; Ioutsi, V. A.; Mazhuga, A. G.; Shpigun, O. A.

2017-12-01

New stationary phases for HPLC are obtained via layer-by-layer deposition of polyelectrolytes and studied: (1) silica gel modified layer-by-layer with 6,10-ionene and dextran sulfate (Sorbent 1); (2) silica gel twice subjected to the above modification (Sorbent 2); and (3) silica gel modified with 6,10-ionene, gold nanoparticles, and dextran sulfate (Sorbent 3). The effect the content of the organic solvent in the mobile phase and the concentration and pH of the buffer solution have on the chromatographic behavior of several pharmacologically active nitrogen-containing compounds is studied. The sorbents are stable during the process and allow the effective separation of beta-blockers, calcium channel blockers, alpha-agonists, and antihistamines. A mixture of caffeine, nadolol, tetrahydrozoline, pindolol, orphenadrine, doxylamine, carbinoxamine, and chlorphenamine is separated in 6.5 min on the silica gel modified with 6,10-ionene, gold nanoparticles, and dextran sulfate.

Mesoporous silica nanoparticles for treating spinal cord injury

Science.gov (United States)

White-Schenk, Désirée.; Shi, Riyi; Leary, James F.

2013-02-01

An estimated 12,000 new cases of spinal cord injury (SCI) occur every year in the United States. A small oxidative molecule responsible for secondary injury, acrolein, is an important target in SCI. Acrolein attacks essential proteins and lipids, creating a feed-forward loop of oxidative stress in both the primary injury area and the surrounding areas. A small molecule used and FDA-approved for hypertension, hydralazine, has been found to "scavenge" acrolein after injury, but its delivery and short half-life, as well as its hypertension effects, hinder its application for SCI. Nanomedical systems broaden the range of therapeutic availability and efficacy over conventional medicine. They allow for targeted delivery of therapeutic molecules to tissues of interest, reducing side effects of untargeted therapies in unwanted areas. Nanoparticles made from silica form porous networks that can carry therapeutic molecules throughout the body. To attenuate the acrolein cascade and improve therapeutic availability, we have used a one-step, modified Stober method to synthesize two types of silica nanoparticles. Both particles are "stealth-coated" with poly(ethylene) glycol (PEG) (to minimize interactions with the immune system and to increase circulation time), which is also a therapeutic agent for SCI by facilitating membrane repair. One nanoparticle type contains an amine-terminal PEG (SiNP-mPEG-Am) and the other possesses a terminal hydrazide group (SiNP-mPEG-Hz). The former allows for exploration of hydralazine delivery, loading, and controlled release. The latter group has the ability to react with acrolein, allowing the nanoparticle to scavenge directly. The nanoparticles have been characterized and are being explored using neuronal PC-12 cells in vitro, demonstrating the potential of novel silica nanoparticles for use in attenuating secondary injury after SCI.

Incorporation of Znq2 complexes into mesoporous silica and their transparent polymer luminescent nanocomposites

International Nuclear Information System (INIS)

Du Yaying; Fu Yuqin; Shi Yongli; Lue Xiaodan; Lue Changli; Su Zhongmin

2009-01-01

Znq 2 -functionalized colloidal mesoporous silicas (Znq 2 -CMS)/polymer transparent nanocomposites were prepared by in situ bulk polymerization. CMS nanoparticles or nanorods with hydroxyl-, mercapto- and sulfonic-functionalized interiors were obtained by different synthetic routes in the nanosize dimensions between 50 and 500 nm. The luminescent Znq 2 complex was successfully introduced in the pores of different mesoporous silicas by chemical adsorption as the driving force. The different internal circumstances of mesoporous silicas had an obvious effect on the luminescence and lifetime of Znq 2 complex. The transparent fluorescent nanocomposites were fabricated from different Znq 2 -CMS and suitable monomers. The Znq 2 -CMS were uniformly dispersed in the polymer matrix without evident aggregation. The photoluminescence properties of Znq 2 -CMS in the transparent matrix exhibited a dependence on the inner surrounding of CMS due to the interaction between Znq 2 -CMS and polymers. The maximum emission peak of the nanocomposites had a red-shift of 28 nm as compared to pure Znq 2 -CMS. - Graphical abstract: Znq 2 -functionalized colloidal mesoporous silicas (Znq 2 -CMS)/polymer transparent fluorescent nanocomposites were prepared by in situ bulk polymerization. The figure shows the synthetic scheme for the Znq 2 -CMS and their transparent bulk nanocomposites.

Photochemical oxygen reduction by zinc phthalocyanine and silver/gold nanoparticle incorporated silica thin films

Energy Technology Data Exchange (ETDEWEB)

Pal, Manas; Ganesan, Vellaichamy, E-mail: velganesh@yahoo.com; Azad, Uday Pratap

2012-12-15

Silver or gold nanoparticles are synthesized using a borohydride reduction method and are anchored simultaneously into/onto the mercaptopropyl functionalized silica. Later, zinc phthalocyanine is adsorbed onto the above materials. Thin films of these materials are prepared by coating an aqueous colloidal suspension of the respective material onto glass plates. Visible light irradiation of these films in oxygen saturated, stirred aqueous solutions effectively reduces oxygen to hydrogen peroxide. The photocatalytic reduction of oxygen is explained on the basis of the semiconducting properties of the silica films. The back electron transfer reaction is largely prevented by means of a sacrificial electron donor, triethanolamine. - Highlights: Black-Right-Pointing-Pointer Zinc phthalocyanine adsorbed silica materials were prepared. Black-Right-Pointing-Pointer Thin films of these materials photocatalytically reduce oxygen. Black-Right-Pointing-Pointer The photocatalysis is explained based on semiconductor properties of the materials. Black-Right-Pointing-Pointer Metal nanoparticles increase the photocatalytic efficiency of the materials.

Detection of glutathione based on MnO2 nanosheet-gated mesoporous silica nanoparticles and target induced release of glucose measured with a portable glucose meter.

Science.gov (United States)

Tan, Qingqing; Zhang, Ruirui; Kong, Rongmei; Kong, Weisu; Zhao, Wenzhi; Qu, Fengli

2017-12-08

The authors describe a novel method for the determination of glutathione (GSH). Detection is based on target induced release of glucose from MnO 2 nanosheet-gated aminated mesoporous silica nanoparticles (MSNs). In detail, glucose is loaded into the pores of MSNs. Negatively charged MnO 2 nanosheets are assembled on the MSNs through electrostatic interactions. The nanosheets are reduced by GSH, and this results in the release of glucose which is quantified by using a commercial electrochemical glucose meter. GSH can be quantified by this method in the 100 nM to 10 μM concentration range, with a 34 nM limit of detection. Graphical abstract Glucose is loaded into the pores of mesoporous silica nanoparticles (MSNs). MnO 2 nanosheets are assembled on MSNs through electrostatic interactions. Glutathione (GSH) can reduce the nanosheets, and this results in the release of glucose which is quantified by using a commercial glucose meter.

Incorporation of mesoporous silica nanoparticles into random electrospun PLGA and PLGA/gelatin nanofibrous scaffolds enhances mechanical and cell proliferation properties

International Nuclear Information System (INIS)

Mehrasa, Mohammad; Asadollahi, Mohammad Ali; Nasri-Nasrabadi, Bijan; Ghaedi, Kamran; Salehi, Hossein; Dolatshahi-Pirouz, Alireza; Arpanaei, Ayyoob

2016-01-01

Poly(lactic-co-glycolic acid) (PLGA) and PLGA/gelatin random nanofibrous scaffolds embedded with different amounts of mesoporous silica nanoparticles (MSNPs) were fabricated using electrospinning method. To evaluate the effects of nanoparticles on the scaffolds, physical, chemical, and mechanical properties as well as in vitro degradation behavior of scaffolds were investigated. The mean diameters of nanofibers were 974 ± 68 nm for the pure PLGA scaffolds vs 832 ± 70, 764 ± 80, and 486 ± 64 for the PLGA/gelatin, PLGA/10 wt% MSNPs, and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively. The results suggested that the incorporation of gelatin and MSNPs into PLGA-based scaffolds enhances the hydrophilicity of scaffolds due to an increase of hydrophilic functional groups on the surface of nanofibers. With porosity examination, it was concluded that the incorporation of MSNPs and gelatin decrease the porosity of scaffolds. Nanoparticles also improved the tensile mechanical properties of scaffolds. Using in vitro degradation analysis, it was shown that the addition of nanoparticles to the nanofibers matrix increases the weight loss percentage of PLGA-based samples, whereas it decreases the weight loss percentage in the PLGA/gelatin composites. Cultivation of rat pheochromocytoma cell line (PC12), as precursor cells of dopaminergic neural cells, on the scaffolds demonstrated that the introduction of MSNPs into PLGA and PLGA/gelatin matrix leads to improved cell attachment and proliferation and enhances cellular processes. - Highlights: • PLGA-based random nanofibers embedded with mesoporous silica nanoparticles were fabricated using electrospinning method • Incorporation of gelatin and MSNPs into PLGA-based scaffolds increased the hydrophilicity of scaffold • Addition of nanoparticles also improved the tensile mechanical properties of scaffolds • Introduction of MSNPs led to improved cell attachment and proliferation

Incorporation of mesoporous silica nanoparticles into random electrospun PLGA and PLGA/gelatin nanofibrous scaffolds enhances mechanical and cell proliferation properties

Energy Technology Data Exchange (ETDEWEB)

Mehrasa, Mohammad [Department of Biotechnology, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran (Iran, Islamic Republic of); Asadollahi, Mohammad Ali, E-mail: ma.asadollahi@ast.ui.ac.ir [Department of Biotechnology, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Nasri-Nasrabadi, Bijan [Department of Chemical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Ghaedi, Kamran [Department of Biology, Faculty of Science, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Salehi, Hossein [Department of Anatomical Sciences, School of Medicine, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Dolatshahi-Pirouz, Alireza [DTU Nanotech, Center for Nanomedicine and Theranostics, Technical University of Denmark (DTU), DK-2800 Kgs. Lyngby (Denmark); Arpanaei, Ayyoob, E-mail: arpanaei@yahoo.com [Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran (Iran, Islamic Republic of)

2016-09-01

Poly(lactic-co-glycolic acid) (PLGA) and PLGA/gelatin random nanofibrous scaffolds embedded with different amounts of mesoporous silica nanoparticles (MSNPs) were fabricated using electrospinning method. To evaluate the effects of nanoparticles on the scaffolds, physical, chemical, and mechanical properties as well as in vitro degradation behavior of scaffolds were investigated. The mean diameters of nanofibers were 974 ± 68 nm for the pure PLGA scaffolds vs 832 ± 70, 764 ± 80, and 486 ± 64 for the PLGA/gelatin, PLGA/10 wt% MSNPs, and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively. The results suggested that the incorporation of gelatin and MSNPs into PLGA-based scaffolds enhances the hydrophilicity of scaffolds due to an increase of hydrophilic functional groups on the surface of nanofibers. With porosity examination, it was concluded that the incorporation of MSNPs and gelatin decrease the porosity of scaffolds. Nanoparticles also improved the tensile mechanical properties of scaffolds. Using in vitro degradation analysis, it was shown that the addition of nanoparticles to the nanofibers matrix increases the weight loss percentage of PLGA-based samples, whereas it decreases the weight loss percentage in the PLGA/gelatin composites. Cultivation of rat pheochromocytoma cell line (PC12), as precursor cells of dopaminergic neural cells, on the scaffolds demonstrated that the introduction of MSNPs into PLGA and PLGA/gelatin matrix leads to improved cell attachment and proliferation and enhances cellular processes. - Highlights: • PLGA-based random nanofibers embedded with mesoporous silica nanoparticles were fabricated using electrospinning method • Incorporation of gelatin and MSNPs into PLGA-based scaffolds increased the hydrophilicity of scaffold • Addition of nanoparticles also improved the tensile mechanical properties of scaffolds • Introduction of MSNPs led to improved cell attachment and proliferation.

Biodegradable Oxamide-Phenylene-Based Mesoporous Organosilica Nanoparticles with Unprecedented Drug Payloads for Delivery in Cells

KAUST Repository

Croissant, Jonas

2016-06-03

We describe biodegradable mesoporous hybrid NPs in the presence of proteins, and its application for drug delivery. We synthesized oxamide-phenylene-based mesoporous organosilica nanoparticles (MON) in the absence of silica source which had a remarkably high organic content with a high surface area. Oxamide functions provided biodegradability in the presence of trypsin model proteins. MON displayed exceptionally high payloads of hydrophilic and hydrophobic drugs (up to 84 wt%), and a unique zero premature leakage without the pore capping, unlike mesoporous silica. MON were biocompatible and internalized into cancer cells for drug delivery.

A simple approach for immobilization of gold nanoparticles on graphene oxide sheets by covalent bonding

NARCIS (Netherlands)

Pham, Tuan Anh; Choi, Byung Choon; Lim, Kwon Taek; Jeong, Yeon Tae

2011-01-01

Amino - functionalized gold nanoparticles with a diameter of around 5 nm were immobilized onto the surface of graphene oxide sheets (GOS) by covalent bonding through a simple amidation reaction. Pristine graphite was firstly oxidized and exfoliated to obtain GOS, which further were acylated with

Mesoporous Silica from Rice Husk Ash

Directory of Open Access Journals (Sweden)

S.A. Mandavgane

2010-12-01

Full Text Available Mesoporous silica is used as a raw material in several areas: in preparation of catalysts, in inks, as aconcrete hardening accelerator, as a component of detergents and soaps, as a refractory constituent etc.Sodium silicate is produced by reacting rice hull ash (RHA with aqueous NaOH and silica is precipitatedfrom the sodium silicate by acidification. In the present work, conversion of about 90% of silica containedin RHA into sodium silicate was achieved in an open system at temperatures of about 100 °C. The resultsshowed that silica obtained from RHA is mesoporous, has a large surface area and small particle size.Rice Husk is usually mixed with coal and this mixture is used for firing boilers. The RHA therefore, usuallycontains carbon particles. Activated carbon embedded on silica has been prepared using the carbon alreadypresent in RHA. This carbon shows good adsorption capacity. ©2010 BCREC UNDIP. All rights reserved(Received: 25th April 2010, Revised: 17th June 2010, Accepted: 24th June 2010[How to Cite: V.R. Shelke, S.S. Bhagade, S.A. Mandavgane. (2010. Mesoporous Silica from Rice Husk Ash. Bulletin of Chemical Reaction Engineering and Catalysis, 5 (2: 63-67. doi:10.9767/bcrec.5.2.793.63-67

Palladium nanoparticles encapsulated in core-shell silica: A structured hydrogenation catalyst with enhanced activity for reduction of oxyanion water pollutants

KAUST Repository

Wang, Yin; Liu, Jinyong; Wang, Peng; Werth, Charles; Strathmann, Timothy J.

2014-01-01

Noble metal nanoparticles have been applied to mediate catalytic removal of toxic oxyanions and halogenated hydrocarbons in contaminated water using H2 as a clean and sustainable reductant. However, activity loss by nanoparticle aggregation and difficulty of nanoparticle recovery are two major challenges to widespread technology adoption. Herein, we report the synthesis of a core-shell-structured catalyst with encapsulated Pd nanoparticles and its enhanced catalytic activity in reduction of bromate (BrO3-), a regulated carcinogenic oxyanion produced during drinking water disinfection process, using 1 atm H2 at room temperature. The catalyst material consists of a nonporous silica core decorated with preformed octahedral Pd nanoparticles that were further encapsulated within an ordered mesoporous silica shell (i.e., SiO2@Pd@mSiO2). Well-defined mesopores (2.3 nm) provide a physical barrier to prevent Pd nanoparticle (6 nm) movement, aggregation, and detachment from the support into water. Compared to freely suspended Pd nanoparticles and SiO2@Pd, encapsulation in the mesoporous silica shell significantly enhanced Pd catalytic activity (by a factor of 10) under circumneutral pH conditions that are most relevant to water purification applications. Mechanistic investigation of material surface properties combined with Langmuir-Hinshelwood modeling of kinetic data suggest that mesoporous silica shell enhances activity by promoting BrO3- adsorption near the Pd active sites. The dual function of the mesoporous shell, enhancing Pd catalyst activity and preventing aggregation of active nanoparticles, suggests a promising general strategy of using metal nanoparticle catalysts for water purification and related aqueous-phase applications.

Palladium nanoparticles encapsulated in core-shell silica: A structured hydrogenation catalyst with enhanced activity for reduction of oxyanion water pollutants

KAUST Repository

Wang, Yin

2014-10-03

Noble metal nanoparticles have been applied to mediate catalytic removal of toxic oxyanions and halogenated hydrocarbons in contaminated water using H2 as a clean and sustainable reductant. However, activity loss by nanoparticle aggregation and difficulty of nanoparticle recovery are two major challenges to widespread technology adoption. Herein, we report the synthesis of a core-shell-structured catalyst with encapsulated Pd nanoparticles and its enhanced catalytic activity in reduction of bromate (BrO3-), a regulated carcinogenic oxyanion produced during drinking water disinfection process, using 1 atm H2 at room temperature. The catalyst material consists of a nonporous silica core decorated with preformed octahedral Pd nanoparticles that were further encapsulated within an ordered mesoporous silica shell (i.e., SiO2@Pd@mSiO2). Well-defined mesopores (2.3 nm) provide a physical barrier to prevent Pd nanoparticle (6 nm) movement, aggregation, and detachment from the support into water. Compared to freely suspended Pd nanoparticles and SiO2@Pd, encapsulation in the mesoporous silica shell significantly enhanced Pd catalytic activity (by a factor of 10) under circumneutral pH conditions that are most relevant to water purification applications. Mechanistic investigation of material surface properties combined with Langmuir-Hinshelwood modeling of kinetic data suggest that mesoporous silica shell enhances activity by promoting BrO3- adsorption near the Pd active sites. The dual function of the mesoporous shell, enhancing Pd catalyst activity and preventing aggregation of active nanoparticles, suggests a promising general strategy of using metal nanoparticle catalysts for water purification and related aqueous-phase applications.

PEGylated Lipid bilayer coated mesoporous silica nanoparticles for co-delivery of paclitaxel and curcumin: Design, characterization and its cytotoxic effect.

Science.gov (United States)

Lin, Jiahao; Cai, Qiang; Tang, Yinian; Xu, Yanjun; Wang, Qian; Li, Tingting; Xu, Huihao; Wang, Shuaiyu; Fan, Kai; Liu, Zhongjie; Jin, Yipeng; Lin, Degui

2018-01-30

Highly ordered mesoporous silica nanoparticles (MSNs) with pore diameter of 2.754nm and particle size of 115±15nm were prepared with etching method. Homogeneous PEGylated lipid bilayer with 10-15nm thickness was coated around the surface of MSNs using film hydration method. Systematic optimization and characterization of co-encapsulation process of paclitaxel (Tax) and curcumin (Cur) into PEGylated lipid bilayer coated mesoporous silica nanoparticles (PLMSNs) were performed carrying out single factor test, associated with Box-Behnken Design. The concentration of encapsulated drugs was measured by reversed phase high performance liquid chromatography (RP-HPLC) method. Optimal factor settings were as follows: 50mg MSNs, ratio of MSNs to lipid (w/w)=1:1.11, and ratio of lipid to CHO (w/w)=3.93:1. The average experimental EE Tax , EE Cur and stability score value were (77.48±2.73) %, (30.70±3.56) % and 4 point respectively based on the conditions mentioned above. Morphology determination of Tax-Cur-PLMSNs revealed that the composite nanoparticles were spherical particals with uniform dispersion. In vitro release experiment indicated that PLMSNs improved dissolution of Tax compared to Tax powder suspension and exhibited sustained release property. Tax-Cur-PLMSNs manifested definite and persistently promoted cytotoxic effect against canine breast cancer cells. This prolonged and enhanced activity of Tax-Cur-PLMSNs might contribute to its sustained release effect. Copyright © 2017. Published by Elsevier B.V.

Thiol-modified gold nanoparticles deposited on silica support using dip coating

International Nuclear Information System (INIS)

Magura, Jozef; Zeleňáková, Adriana; Zeleňák, Vladimír; Kaňuchová, Maria

2014-01-01

Graphical abstract: - Highlights: • Thin layers of gold were deposited on glass substrate. • Layers were modified by two different ligands, 1,4-dithiothreitol and L-glutathione. • Red shift of SPR band was observed in spectra after modification of Au by thiols. • Charge transfer between Au and S atoms leads to ferromagnetic behaviour of samples. - Abstract: In our work, we have prepared thin layers of gold nanoparticles deposited via dip coating technique on silica glass substrate. The prepared thin layers were modified by two different ligands, namely 1,4-dithiothreitol (sample Au-DTT NPs) and L-glutathione (sample Au-GSH NPs). The spectral, structural and magnetic properties of the prepared samples were investigated. The modification of Au nanoparticles with thiol ligands leads to change of their plasmon resonance fields, as indicated by UV–vis spectra. The magnetic measurements showed that the magnetization of the samples is composed from two magnetic contributions: diamagnetic contribution and low field ferromagnetic contribution. Our experimental results show that the charge transfer between Au and S atoms gives rise to the ferromagnetic behaviour of prepared thin layers

Nanostructured Mesoporous Silicas for Bone Tissue Regeneration

Directory of Open Access Journals (Sweden)

Isabel Izquierdo-Barba

2008-01-01

Full Text Available The research on the development of new biomaterials that promote bone tissue regeneration is receiving great interest by the biomedical scientific community. Recent advances in nanotechnology have allowed the design of materials with nanostructure similar to that of natural bone. These materials can promote new bone formation by inducing the formation of nanocrystalline apatites analogous to the mineral phase of natural bone onto their surfaces, i.e. they are bioactive. They also stimulate osteoblast proliferation and differentiation and, therefore, accelerate the healing processes. Silica-based ordered mesoporous materials are excellent candidates to be used as third generation bioceramics that enable the adsorption and local control release of biological active agents that promote bone regeneration. This local delivery capability together with the bioactive behavior of mesoporous silicas opens up promising expectations in the bioclinical field. In this review, the last advances in nanochemistry aimed at designing and tailoring the chemical and textural properties of mesoporous silicas for biomedical applications are described. The recent developed strategies to synthesize bioactive glasses with ordered mesopore arrangements are also summarized. Finally, a deep discussion about the influence of the textural parameters and organic modification of mesoporous silicas on molecules adsorption and controlled release is performed.

Synthesis of internally functionalized silica nanoparticles for theranostic applications

Science.gov (United States)

Walton, Nathan Isaac

This thesis addresses the synthesis and characterization of novel inorganic silica nanoparticle hybrids. It focuses in large part on their potential applications in the medical field. Silica acts as a useful carrier for a variety of compounds and this thesis silica will demonstrate its use as a carrier for boron or gadolinium. Boron-10 and gadolinium-157 have been suggested for the radiological treatment of tumor cells through the process called neutron capture therapy (NCT). Gadolinium is also commonly used as a Magnetic Resonance Imaging (MRI) contrast agent. Particles that carry it have potential theranostic applications of both imaging and treating tumors. Chapter 1 presents a background on synthetic strategies and usages of silica nanoparticles, and NCT theory. Chapter 2 describes a procedure to create mesoporous metal chelating silica nanoparticles, mDTTA. This is achieved via a co-condensation of tetraethoxysilane (TEOS) and 3-trimethoxysilyl-propyl diethylenetriamine (SiDETA) followed by a post-synthesis modification step with bromoacetic acid (BrAA). These particles have a large surface area and well-defined pores of ~2 nm. The mDTTA nanoparticles were used to chelate the copper(II), cobalt(II) and gadolinium(III). The chelating of gadolinium is the most interesting since it can be used as a MRI contrast agent and a neutron capture therapeutic. The synthetic procedure developed also allows for the attachment of a fluorophore that gives the gadolinium chelating mDTTA nanoparticles a dual imaging modality. Chapter 3 presents the synthetic method used to produce two classes of large surface area organically modified silica (ORMOSIL) nanoparticles. Condensating the organosilane vinyltrimethoxysilane in a micellar solution results in nanoparticles that are either surface rough (raspberry-like) or mesoporous nanoparticles, which prior to this thesis has not been demonstrated in ORMOSIL chemistry. Furthermore, the vinyl functionalities are modified, using

The absorption, distribution, excretion and toxicity of mesoporous silica nanoparticles in mice following different exposure routes.

Science.gov (United States)

Fu, Changhui; Liu, Tianlong; Li, Linlin; Liu, Huiyu; Chen, Dong; Tang, Fangqiong

2013-03-01

Mesoporous silica nanoparticles (MSNs) are emerging as one of the promising nanomaterials for biomedical applications, but the nanomaterials-body interaction exposed by different administration routes remained poorly understood. In the present study, a systematic investigation of the absorption, distribution, excretion and toxicity of silica nanoparticles (SNs) with the average size of 110 nm after four different exposure routes including intravenous, hypodermic, intramuscular injection and oral administration to mice were achieved. The results showed that a fraction of the SNs administrated by the intramuscular and hypodermic injection could cross different biological barriers into the liver but with a low absorption rate. Exposing by oral administration, SNs were absorbed into the intestinal tract and persisted in the liver. And SNs administrated by intravenous injection were mainly present in the liver and spleen. In addition, SNs could cause inflammatory response around the injection sites after intramuscular and hypodermic injection. It was also found that SNs were mainly excreted through urine and feces after different exposure routes. This study will be helpful for selecting the appropriate exposed routes for the development of nanomaterials-based drug delivery system for biomedical applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

Targeting of porous hybrid silica nanoparticles to cancer cells

NARCIS (Netherlands)

Rosenholm, J.M.; Meinander, A.; Peuhu, E.; Niemi, R.; Eriksson, J.E.; Sahlgren, C.; Lindén, M.

2009-01-01

Mesoporous silica nanoparticles functionalized by surface hyperbranching polymerization of polyethylene imine), PEI, were further modified by introducing both fluorescent and targeting moieties, with the aim of specifically targeting cancer cells. Owing to the high abundance of folate receptors in

Hybrid Mesoporous Silica-Based Drug Carrier Nanostructures with Improved Degradability by Hydroxyapatite.

Science.gov (United States)

Hao, Xiaohong; Hu, Xixue; Zhang, Cuimiao; Chen, Shizhu; Li, Zhenhua; Yang, Xinjian; Liu, Huifang; Jia, Guang; Liu, Dandan; Ge, Kun; Liang, Xing-Jie; Zhang, Jinchao

2015-10-27

Potential bioaccumulation is one of the biggest limitations for silica nanodrug delivery systems in cancer therapy. In this study, a mesoporous silica nanoparticles/hydroxyapatite (MSNs/HAP) hybrid drug carrier, which enhanced the biodegradability of silica, was developed by a one-step method. The morphology and structure of the nanoparticles were characterized by TEM, DLS, FT-IR, XRD, N2 adsorption-desorption isotherms, and XPS, and the drug loading and release behaviors were tested. TEM and ICP-OES results indicate that the degradability of the nanoparticles has been significantly improved by Ca(2+) escape from the skeleton in an acid environment. The MSNs/HAP sample exhibits a higher drug loading content of about 5 times that of MSNs. The biological experiment results show that the MSNs/HAP not only exhibits good biocompatibility and antitumor effect but also greatly reduces the side effects of free DOX. The as-synthesized hybrid nanoparticles may act as a promising drug delivery system due to their good biocompatibility, high drug loading efficiency, pH sensitivity, and excellent biodegradability.

Inkjet Printing of Drug-Loaded Mesoporous Silica Nanoparticles—A Platform for Drug Development

Directory of Open Access Journals (Sweden)

Henrika Wickström

2017-11-01

Full Text Available Mesoporous silica nanoparticles (MSNs have shown great potential in improving drug delivery of poorly water soluble (BCS class II, IV and poorly permeable (BCS class III, IV drugs, as well as facilitating successful delivery of unstable compounds. The nanoparticle technology would allow improved treatment by reducing adverse reactions of currently approved drugs and possibly reintroducing previously discarded compounds from the drug development pipeline. This study aims to highlight important aspects in mesoporous silica nanoparticle (MSN ink formulation development for digital inkjet printing technology and to advice on choosing a method (2D/3D for nanoparticle print deposit characterization. The results show that both unfunctionalized and polyethyeleneimine (PEI surface functionalized MSNs, as well as drug-free and drug-loaded MSN–PEI suspensions, can be successfully inkjet-printed. Furthermore, the model BCS class IV drug remained incorporated in the MSNs and the suspension remained physically stable during the processing time and steps. This proof-of-concept study suggests that inkjet printing technology would be a flexible deposition method of pharmaceutical MSN suspensions to generate patterns according to predefined designs. The concept could be utilized as a versatile drug screening platform in the future due to the possibility of accurately depositing controlled volumes of MSN suspensions on various materials.

Mesoporous Silica from Rice Husk Ash

Directory of Open Access Journals (Sweden)

V.R. Shelke

2011-01-01

Full Text Available Mesoporous silica is used as a raw material in several areas: in preparation of catalysts, in inks, as a concrete hardening accelerator, as a component of detergents and soaps, as a refractory constituent etc. Sodium silicate is produced by reacting rice hull ash (RHA with aqueous NaOH and silica is precipitated from the sodium silicate by acidification. In the present work, conversion of about 90% of silica contained in RHA into sodium silicate was achieved in an open system at temperatures of about 100 °C. The results showed that silica obtained from RHA is mesoporous, has a large surface area and small particle size. Rice Husk is usually mixed with coal and this mixture is used for firing boilers. The RHA therefore, usually contains carbon particles. Activated carbon embedded on silica has been prepared using the carbon already present in RHA. This carbon shows good adsorption capacity. ©2010 BCREC UNDIP. All rights reserved(Received: 25th April 2010, Revised: 17th June 2010, Accepted: 24th June 2010[How to Cite: V.R. Shelke, S.S. Bhagade, S.A. Mandavgane. (2010. Mesoporous Silica from Rice Husk Ash. Bulletin of Chemical Reaction Engineering and Catalysis, 5 (2: 63-67. doi:10.9767/bcrec.5.2.793.63-67][DOI: http://dx.doi.org/10.9767/bcrec.5.2.793.63-67

Oxidation of Bioethanol using Zeolite-Encapsulated Gold Nanoparticles

DEFF Research Database (Denmark)

Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Wang, Feng

2014-01-01

With the ongoing developments in biomass conversion, the oxidation of bioethanol to acetaldehyde may become a favorable and green alternative to the preparation from ethylene. Here, a simple and effective method to encapsulate gold nanoparticles in zeolite silicalite-1 is reported and their high...... zeolite crystals comprise a broad range of mesopores and contain up to several hundred gold nanoparticles with a diameter of 2-3nm that are distributed inside the zeolites rather than on the outer surface. The encapsulated nanoparticles have good stability and result in 50% conversion of ethanol with 98...

Oxidation of Bioethanol using Zeolite-Encapsulated Gold Nanoparticles

DEFF Research Database (Denmark)

Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Wang, Feng

2014-01-01

With the ongoing developments in biomass conversion, the oxidation of bioethanol to acetaldehyde may become a favorable and green alternative to the preparation from ethylene. Here, a simple and effective method to encapsulate gold nanoparticles in zeolite silicalite‐1 is reported and their high...... zeolite crystals comprise a broad range of mesopores and contain up to several hundred gold nanoparticles with a diameter of 2–3 nm that are distributed inside the zeolites rather than on the outer surface. The encapsulated nanoparticles have good stability and result in 50 % conversion of ethanol with 98...

Synthesis and characterization of plasmon resonant gold nanoparticles and graphene for photovoltaics

Energy Technology Data Exchange (ETDEWEB)

Giangregorio, M.M., E-mail: michelaria.giangregorio@ba.imip.cnr.it [Institute of Methodology and of Plasmas, IMIP-CNR, Department of Chemistry, University of Bari, via Orabona, 4 70126 Bari (Italy); Losurdo, M.; Bianco, G.V.; Dilonardo, E.; Capezzuto, P.; Bruno, G. [Institute of Methodology and of Plasmas, IMIP-CNR, Department of Chemistry, University of Bari, via Orabona, 4 70126 Bari (Italy)

2013-05-15

Here we discuss the use in solar cells of graphene grown by chemical vapor deposition (CVD) and of plasmonic gold nanoparticles (Au NPs) deposited by sputtering. The Au NPs have been coupled with a-Si heterojunction solar cells, with an organic active layer used in organic photovoltaics, and with graphene. Extensive characterization of those three systems by the optical technique of spectroscopic ellipsometry, which is suitable to monitor and analyze the plasmon resonance of the Au NPs, by the microstructural technique of Raman spectroscopy, which is suitable to analyze graphene properties and doping, and by atomic force microscopy has been carried out. Those techniques highlighted interactions between Au NPs and silicon, polymer and graphene, which lead to variation in the plasmon resonance of Au NPs and consequently in the characteristics of the Au NPs/Si, Au NPs/polymer and Au NPs/graphene hybrids. Specifically, we found that an optimal size and density of Au NPs are able to enhance the efficiency of c-Si/a-Si heterojunction solar cells and that exceeding with Au NPs size and density causes device shortcut because of interface interdiffusion between silicon and gold. To discuss organic photovoltaics, Au NPs have been combined with an electro-donating conjugated polymer, the poly[1,4bis(2-thienyl)-2,5-bis-(2-ethyl-hexyloxyphenylenes)]. We found that there is a strong correlation between the thickness and morphology of the organic active layer, which affects the energy and amplitude of the Au NPs plasmon resonance. Finally, Au NPs have been deposited on graphene. We found that Au NPs show the plasmon resonance in the region where graphene is transparent and also yield p-type doping of graphene decreasing its sheet resistance.

Mesoporous Silica Nanoparticles Loaded with Surfactant: Low Temperature Magic Angle Spinning 13C and 29Si NMR Enhanced by Dynamic Nuclear Polarization

Energy Technology Data Exchange (ETDEWEB)

Lafon, Olivier [Universite de Lille Nord de France; Thankamony, Aany S. Lilly [Universite de Lille Nord de France; Kokayashi, Takeshi [Ames Laboratory; Carnevale, Diego [Ecole Polytechnique Federale de Lausanne; Vitzthum, Veronika [Ecole Polytechnique Federale de Lausanne; Slowing, Igor I. [Ames Laboratory; Kandel, Kapil [Ames Laboratory; Vezin, Herve [Universite de Lille Nord de France; Amoureux, Jean-Paul [Universite de Lille Nord de France; Bodenhausen, Geoffrey [Ecole Polytechnique Federale de Lausanne; Pruski, Marek [Ames Laboratory

2012-12-21

We show that dynamic nuclear polarization (DNP) can be used to enhance NMR signals of 13C and 29Si nuclei located in mesoporous organic/inorganic hybrid materials, at several hundreds of nanometers from stable radicals (TOTAPOL) trapped in the surrounding frozen disordered water. The approach is demonstrated using mesoporous silica nanoparticles (MSN), functionalized with 3-(N-phenylureido)propyl (PUP) groups, filled with the surfactant cetyltrimethylammonium bromide (CTAB). The DNP-enhanced proton magnetization is transported into the mesopores via 1H–1H spin diffusion and transferred to rare spins by cross-polarization, yielding signal enhancements εon/off of around 8. When the CTAB molecules are extracted, so that the radicals can enter the mesopores, the enhancements increase to εon/off ≈ 30 for both nuclei. A quantitative analysis of the signal enhancements in MSN with and without surfactant is based on a one-dimensional proton spin diffusion model. The effect of solvent deuteration is also investigated.

Development of gold nanoparticle radiotracers for investigating multiphase system in process industries

International Nuclear Information System (INIS)

Mohd Amirul Syafiq Mohd Yunos; Jaafar Abdullah; Engku Fahmi Engku Chik; Noraishah Othman

2010-01-01

This paper describes the development of colloidal 197 Au-SiO 2 with core-shell structure nanoparticle radiotracers. Using conventional citrate-reduction method, gold nanoparticles were prepared from its corresponding metal salts in aqueous solution then coated with uniform shells of amorphous silica via a sol-gel reaction. This target material of radiotracer application used to investigate multiphase system in process industries without disturbing the system operation. The citrate-reduction-based method provides gold nanoparticles with higher concentration and narrow size distribution. By using transmission electron microscopy (TEM), the resultant of particle size and silica coatings could be varied from tens to several hundred of nanometers by controlling the catalyzer and precipitation time. 197 Au-SiO 2 core-shell nano structure is good to prevent the particles from getting conglomerate resulting in a big mass. In addition, silica surface offer very good chances that make the hydrophobicity behavior on the gold nanoparticles. EDXRF spectrum has proven that 197 Au-SiO 2 core-shell nanoparticles sample consists purely of a gold and silica particles. (author)

Conductometric sensor for ammonia and ethanol using gold nanoparticle-doped mesoporous TiO2

International Nuclear Information System (INIS)

Xiong, Wei; Liu, Huanhuan; Liu, Shantang

2015-01-01

We describe uniform and high-temperature-stable mesoporous TiO 2 beads functionalized with gold nanoparticles (AuNPs-TiO 2 ) for use in conductometric sensing of gases and organic vapors. The size of the interconnected main mesopores of the TiO 2 beads ranges from 8 to 15 nm, and the AuNPs have diameters between 8 and 10 nm. The mesoporous TiO 2 beads are formed during calcination while the structure-directing template agent is removed. Monodispersed AuNPs are formed by reduction in-situ and are placed inside the mesoporous TiO 2 framework. This prevents aggregation of the AuNPs even at 500 °C. The materials were characterized by UV–vis spectroscopy, scanning and transmission electron microscopy, nitrogen adsorption-desorption, and X-ray diffraction. Comb-type gold electrodes were then fabricated on an alumina substrate and are shown to display excellent properties in terms of sensing ammonia, ethanol, methanol or acetone. The sensitivity (defined as the ratio of resistivities under vapor and air) of a typical AuNPs(0.5 %)-TiO 2 gas sensor for ethanol reached up to 5.65 at above 600 ppm at 75 °C. Response time and recovery times (t 90  ≤ 20 s) are faster than (or comparable to) other metal-doped TiO 2 sensors, and working temperatures are much lower. An interesting observation was made in that the changes in the conductivity of the sensor change with temperature. The sensor prepared with AuNPs(0.5 %)-TiO 2 is of the p-type (in its response to ammonia gas) at 45 °C, but becomes n-type at 20 °C. Obviously, rather slight changes in temperature lead to a complete change in the direction of the conductometric signal change. This may provide a new aspect in terms of selective and highly sensitive detection of ammonia at ambient and slightly elevated temperatures. (author)

Inclusion of gold nanoparticles in meso-porous silicon for the SERS analysis of cell adhesion on nano-structured surfaces

KAUST Repository

Coluccio, M.L.

2016-03-25

The study and the comprehension of the mechanism of cell adhesion and cell interaction with a substrate is a key point when biology and medicine meet engineering. This is the case of several biomedical applications, from regenerative medicine and tissue engineering to lab on chip and many others, in which the realization of the appropriate artificial surface allows the control of cell adhesion and proliferation. In this context, we aimed to design and develop a fabrication method of mesoporous (MeP) silicon substrates, doped with gold nanoparticles, in which we combine the capability of porous surfaces to support cell adhesion with the SERS capabilities of gold nanoparticles, to understand the chemical mechanisms of cell/surface interaction. MeP Si surfaces were realized by anodization of a Si wafer, creating the device for cell adhesion and growth. Gold nanoparticles were deposited on porous silicon by an electroless technique. We thus obtained devices with superior SERS capabilities, whereby cell activity may be controlled using Raman spectroscopy. MCF-7 breast cancer cells were cultured on the described substrates and SERS maps revealing the different expression and distribution of adhesion molecules were obtained by Raman spectroscopic analyses.

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

Functionalized mesoporous silica materials for molsidomine adsorption: Thermodynamic study

International Nuclear Information System (INIS)

Alyoshina, Nonna A.; Parfenyuk, Elena V.

2013-01-01

A series of unmodified and organically modified mesoporous silica materials was prepared. The unmodified mesoporous silica was synthesized via sol–gel synthesis in the presence of D-glucose as pore-forming agent. The functionalized by phenyl, aminopropyl and mercaptopropyl groups silica materials were prepared via grafting. The fabricated adsorbent materials were characterized by Fourier transform infrared spectroscopy (FTIR) analysis, N 2 adsorption/desorption and elemental analysis methods. Then their adsorption properties for mesoionic dug molsidomine were investigated at 290–313 K and physiological pH value. Thermodynamic parameters of molsidomine adsorption on the synthesized materials have been calculated. The obtained results showed that the adsorption process of molsidomine on the phenyl modified silica is the most quantitatively and energetically favorable. The unmodified and mercaptopropyl modified silica materials exhibit significantly higher adsorption capacities and energies for molsidomine than the aminopropyl modified sample. The effects are discussed from the viewpoint of nature of specific interactions responsible for the adsorption. - Graphical abstract: Comparative analysis of the thermodynamic characteristics of molsidomine adsorption showed that the adsorption process on mesoporous silica materials is controlled by chemical nature of surface functional groups. Molsidomine adsorption on the phenyl modified silica is the most quantitatively and energetically favorable. Taking into account ambiguous nature of mesoionic compounds, it was found that molsidomine is rather aromatic than dipolar. Display Omitted - Highlights: • Unmodified and organically modified mesoporous silica materials were prepared. • Molsidomine adsorption on the silica materials was studied. • Phenyl modified silica shows the highest adsorption capacity and favorable energy. • Molsidomine exhibits the lowest affinity to aminopropyl modified silica

Stability and Antimicrobial Activity of Nisin-Loaded Mesoporous Silica Nanoparticles: A Game-Changer in the War against Maleficent Microbes.

Science.gov (United States)

Behzadi, Faezeh; Darouie, Sheyda; Alavi, S Mehdi; Shariati, Parvin; Singh, Gurvinder; Dolatshahi-Pirouz, Alireza; Arpanaei, Ayyoob

2018-04-25

Antimicrobial agents, such as nisin, are used extensively in the food industry. Here, we investigated various approaches to load nisin onto mesoporous silica nanoparticles (MSNs, 92 ± 10 nm in diameter), to enhance its stability and sustained release. The morphology, size, and surface charge of the as-prepared nanoparticles were analyzed using scanning transmission electron microscopy, dynamic light scattering, and ζ potential measurement. Nisin was either physically adsorbed or covalently attached to the variously functionalized MSNs, with high loading capacities (>600 mg of nisin g -1 of nanoparticles). The results of antibacterial activity analysis of nisin against Staphylococcus aureus showed that, despite the very low antibacterial activity of nisin covalently conjugated onto MSNs, the physical adsorption of nisin onto the unfunctionalized nanoparticles enhances its antimicrobial activities under various conditions, with no significant cytotoxicity effects on mouse fibroblast L929 cells. In conclusion, MSNs can be recommended as suitable carriers for nisin under various conditions.

Electrochemical synthesis of mesoporous gold films toward mesospace-stimulated optical properties

Science.gov (United States)

Li, Cuiling; Dag, Ömer; Dao, Thang Duy; Nagao, Tadaaki; Sakamoto, Yasuhiro; Kimura, Tatsuo; Terasaki, Osamu; Yamauchi, Yusuke

2015-03-01

Mesoporous gold (Au) films with tunable pores are expected to provide fascinating optical properties stimulated by the mesospaces, but they have not been realized yet because of the difficulty of controlling the Au crystal growth. Here, we report a reliable soft-templating method to fabricate mesoporous Au films using stable micelles of diblock copolymers, with electrochemical deposition advantageous for precise control of Au crystal growth. Strong field enhancement takes place around the center of the uniform mesopores as well as on the walls between the pores, leading to the enhanced light scattering as well as surface-enhanced Raman scattering (SERS), which is understandable, for example, from Babinet principles applied for the reverse system of nanoparticle ensembles.

Incorporation of mesoporous silica nanoparticles into random electrospun PLGA and PLGA/gelatin nanofibrous scaffolds enhances mechanical and cell proliferation properties

DEFF Research Database (Denmark)

Mehrasa, Mohammad; Asadollahi, Mohammad Ali; Nasri-Nasrabadi, Bijan

2016-01-01

Poly(lactic-co-glycolic.acid) (PLGA) and PLGA/gelatin random nanofibrous scaffolds embedded with different amounts of mesoporous silica nanoparticles (MSNPs) were fabricated using electrospinning method. To evaluate the effects of nanoparticles on the scaffolds, physical, chemical, and mechanical...... the porosity of scaffolds. Nanoparticles also improved the tensile mechanical properties of scaffolds. Using in vitro degradation analysis, it was shown that the addition of nanoparticles to the nano fibers matrix increases the weight loss percentage of PLGA-based samples, whereas it decreases the weight loss...... properties as well as in vitro degradation behavior of scaffolds were investigated. The mean diameters of nanofibers were 974 ± 68 nm for the pure PLGA scaffolds vs 832 ± 70, 764 ± 80, and 486 ± 64 for the PLGA/gelatin, PLGA/10 wt% MSNPs, and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively. The results...

A facile FeBr3 based photoATRP for surface modification of mesoporous silica nanoparticles for controlled delivery cisplatin

Science.gov (United States)

Huang, Long; Liu, Meiying; Mao, Liucheng; Huang, Qiang; Huang, Hongye; Zeng, Guangjian; Tian, Jianwen; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

2018-03-01

Mesoporous silica nanoparticles (MSNs) should be one of the most important materials for biomedical application owing to their high specific surface area, regular porous structure, adjustable pore size and chemical inert. However, the biomedical applications of unmodified MSNs are largely impeded for their poor hydrophilicity and lack of functional groups. In this work, a novel photo-initiated atom transfer radical polymerization (ATRP) strategy has been reported for modified mesoporous silica nanoparticles (MSNs) with hydrophilicility copolymers using FeBr3 as the novel photocatalyst and itaconic acid (IA) and 2-methacryloyloxyethyl phosphorylcholine (MPC) as monomers. Because of the hydrophilicity and anticancer agent cis-dichlorodiamineplatinum(II) (CDDP) loading capacity of poly(MPC-co-IA), the controlled drug delivery applications MSNs-NH2-poly(MPC-co-IA) composites toward CDDP were further investigated. A series of characterization results demonstrated that MSNs-NH2-poly(MPC-co-IA) composites can be successfully fabricated through the novel photo-initiated ATRP. MSNs-NH2-poly(MPC-co-IA) composites showed obvious enhancement of water dispersibility, desirable biocompatibility, high drug loading capability, making them great potential for controlled drug delivery of CDDP. Moreover, as compared with the traditional ATRP, that using the transition metal ions and organic ligands as the catalysis systems in elevated temperature, our method provides a more facile, benign and cost-effective route for fabrication of multifunctional MSNs with great potential for biomedical applications. Finally, this FeBr3 based photoATRP strategy should be further extended for the fabrication of many other polymeric composites owing to its good monomer adoptability.

Influence of nanoparticle–graphene separation on the localized surface plasmon resonances of metal nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Masoudian Saadabad, Reza, E-mail: masoudian-reza@yahoo.com, E-mail: rms@mail.usb.ac.ir; Aporvari, Ahmad Shafiei [University of Sistan and Baluchestan, Department of Physics (Iran, Islamic Republic of); Shirdel-Havar, Amir Hushang [Golestan University, Department of Physics (Iran, Islamic Republic of); Havar, Majid Shirdel [University of Kashan, Department of Physics (Iran, Islamic Republic of)

2016-01-15

We develop a theory to model the interaction of graphene substrate with localized plasmon resonances in metallic nanoparticles. The influence of a graphene substrate on the surface plasmon resonances is described using an effective background permittivity that is derived from a pseudoparticle concept using the electrostatic method. For this purpose, the interaction of metal nanoparticle with graphene sheet is studied to obtain the optical spectrum of gold nanoparticles deposited on a graphene substrate. Then, we introduce a factor based on dipole approximation to predict the influence of the separation of nanoparticles and graphene on the spectral position of the localized plasmon resonance of the nanoparticles. We applied the theory for a 4-nm-radius gold nanosphere placed near 1.5 nm graphene layer. It is shown that a blue shift is emerged in the position of plasmon resonance when the nanoparticle moves away from graphene.

Functionalized mesoporous silica materials for molsidomine adsorption: Thermodynamic study

Energy Technology Data Exchange (ETDEWEB)

Alyoshina, Nonna A.; Parfenyuk, Elena V., E-mail: evp@iscras.ru

2013-09-15

A series of unmodified and organically modified mesoporous silica materials was prepared. The unmodified mesoporous silica was synthesized via sol–gel synthesis in the presence of D-glucose as pore-forming agent. The functionalized by phenyl, aminopropyl and mercaptopropyl groups silica materials were prepared via grafting. The fabricated adsorbent materials were characterized by Fourier transform infrared spectroscopy (FTIR) analysis, N{sub 2} adsorption/desorption and elemental analysis methods. Then their adsorption properties for mesoionic dug molsidomine were investigated at 290–313 K and physiological pH value. Thermodynamic parameters of molsidomine adsorption on the synthesized materials have been calculated. The obtained results showed that the adsorption process of molsidomine on the phenyl modified silica is the most quantitatively and energetically favorable. The unmodified and mercaptopropyl modified silica materials exhibit significantly higher adsorption capacities and energies for molsidomine than the aminopropyl modified sample. The effects are discussed from the viewpoint of nature of specific interactions responsible for the adsorption. - Graphical abstract: Comparative analysis of the thermodynamic characteristics of molsidomine adsorption showed that the adsorption process on mesoporous silica materials is controlled by chemical nature of surface functional groups. Molsidomine adsorption on the phenyl modified silica is the most quantitatively and energetically favorable. Taking into account ambiguous nature of mesoionic compounds, it was found that molsidomine is rather aromatic than dipolar. Display Omitted - Highlights: • Unmodified and organically modified mesoporous silica materials were prepared. • Molsidomine adsorption on the silica materials was studied. • Phenyl modified silica shows the highest adsorption capacity and favorable energy. • Molsidomine exhibits the lowest affinity to aminopropyl modified silica.

Chemiluminescence immunoassay based on dual signal amplification strategy of Au/mesoporous silica and multienzyme functionalized mesoporous silica

Energy Technology Data Exchange (ETDEWEB)

Lin Jiehua, E-mail: linjiehua@qust.edu.cn [Key Laboratory of Eco-chemical Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Zhao Yue; Wei Zhijing; Wang Wei [Key Laboratory of Eco-chemical Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China)

2011-11-15

Highlights: > The increased amount of monoclonal antibody in Au/SiO{sub 2} led to a wider linear range. > Due to the increased HRP tags in HRP-Ab{sub 2}/SiO{sub 2}, signal amplification achieved. > A simple dual amplification immunoassay achieved with flow injection analysis. - Abstract: A chemiluminescent dual signal amplification strategy for the determination of {alpha}-fetoprotein (AFP) was proposed based on a sandwich immunoassay format. Monoclonal antibody of AFP immobilized on the gold nanoparticles doped mesoporous SiO{sub 2} (Au/SiO{sub 2}) were prepared and used as a primary antibody. Horseradish peroxidase (HRP) and HRP-labeled secondary antibody (Ab{sub 2}) co-immobilized into the mesoporous SiO{sub 2} nanoparticles (HRP-Ab{sub 2}/SiO{sub 2}) were used as the labeled immunological probe. Due to the high ratio surface areas and pore volumes of the mesoporous SiO{sub 2}, not only the amount of AFP monoclonal antibody but also the amount of the modified HRP and Ab{sub 2} in HRP-Ab{sub 2}/SiO{sub 2} were largely increased. Thus the chemiluminescent signal was amplified by using the system of luminol and H{sub 2}O{sub 2} under the catalysis of HRP. Under the optimal conditions, two linear ranges for AFP were obtained from 0.01 to 0.5 ng mL{sup -1} and 0.5 to 100 ng mL{sup -1} with a detection limit of 0.005 ng mL{sup -1} (3{sigma}). The fabricated signal amplification strategy showed an excellent promise for sensitive detection of AFP and other tumor markers.

Genotyping of single nucleotide polymorphism by probe-gated silica nanoparticles.

Science.gov (United States)

Ercan, Meltem; Ozalp, Veli C; Tuna, Bilge G

2017-11-15

The development of simple, reliable, and rapid approaches for molecular detection of common mutations is important for prevention and early diagnosis of genetic diseases, including Thalessemia. Oligonucleotide-gated mesoporous nanoparticles-based analysis is a new platform for mutation detection that has the advantages of sensitivity, rapidity, accuracy, and convenience. A specific mutation in β-thalassemia, one of the most prevalent inherited diseases in several countries, was used as model disease in this study. An assay for detection of IVS110 point mutation (A > G reversion) was developed by designing probe-gated mesoporous silica nanoparticles (MCM-41) loaded with reporter fluorescein molecules. The silica nanoparticles were characterized by AFM, TEM and BET analysis for having 180 nm diameter and 2.83 nm pore size regular hexagonal shape. Amine group functionalized nanoparticles were analysed with FTIR technique. Mutated and normal sequence probe oligonucleotides)about 12.7 nmol per mg nanoparticles) were used to entrap reporter fluorescein molecules inside the pores and hybridization with single stranded DNA targets amplified by PCR gave different fluorescent signals for mutated targets. Samples from IVS110 mutated and normal patients resulted in statistically significant differences when the assay procedure were applied. Copyright © 2017 Elsevier Inc. All rights reserved.

Coupling gold nanoparticles to silica nanoparticles through disulfide bonds for glutathione detection

International Nuclear Information System (INIS)

Shi Yupeng; Zhang Heng; Zhang Zhaomin; Yi Changqing; Yue Zhenfeng; Teng, Kar-Seng; Li Meijin; Yang Mengsu

2013-01-01

Advances in the controlled assembly of nanoscale building blocks have resulted in functional devices which can find applications in electronics, biomedical imaging, drug delivery etc. In this study, novel covalent nanohybrid materials based upon [Ru(bpy) 3 ] 2+ -doped silica nanoparticles (SiNPs) and gold nanoparticles (AuNPs), which could be conditioned as OFF–ON probes for glutathione (GSH) detection, were designed and assembled in sequence, with the disulfide bonds as the bridging elements. The structural and optical properties of the nanohybrid architectures were characterized using transmission electron microscopy, UV–vis spectroscopy and fluorescence spectroscopy, respectively. Zeta potential measurements, x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were employed to monitor the reaction processes of the SiNPs–S–S–COOH and SiNPs–S–S–AuNPs synthesis. It was found that the covalent nanohybrid architectures were fluorescently dark (OFF state), indicating that SiNPs were effectively quenched by AuNPs. The fluorescence of the OFF–ON probe was resumed (ON state) when the bridge of the disulfide bond was cleaved by reducing reagents such as GSH. This work provides a new platform and strategy for GSH detection using covalent nanohybrid materials. (paper)

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

Formation of monodisperse mesoporous silica microparticles via spray-drying.

Science.gov (United States)

Waldron, Kathryn; Wu, Winston Duo; Wu, Zhangxiong; Liu, Wenjie; Selomulya, Cordelia; Zhao, Dongyuan; Chen, Xiao Dong

2014-03-15

In this work, a protocol to synthesize monodisperse mesoporous silica microparticles via a unique microfluidic jet spray-drying route is reported for the first time. The microparticles demonstrated highly ordered hexagonal mesostructures with surface areas ranging from ~900 up to 1500 m(2)/g and pore volumes from ~0.6 to 0.8 cm(3)/g. The particle size could be easily controlled from ~50 to 100 μm from the same diameter nozzle via changing the initial solute content, or changing the drying temperature. The ratio of the surfactant (CTAB) and silica (TEOS), and the amount of water in the precursor were found to affect the degree of ordering of mesopores by promoting either the self-assembly of the surfactant-silica micelles or the condensation of the silica as two competing processes in evaporation induced self-assembly. The drying rate and the curvature of particles also affected the self-assembly of the mesostructure. The particle mesostructure is not influenced by the inlet drying temperature in the range of 92-160 °C, with even a relatively low temperature of 92 °C producing highly ordered mesoporous microparticles. The spray-drying derived mesoporous silica microparticles, while of larger sizes and more rapidly synthesized, showed a comparable performance with the conventional mesoporous silica MCM-41 in controlled release of a dye, Rhodamine B, indicating that these spray dried microparticles could be used for the immobilisation and controlled release of small molecules. Copyright © 2013 Elsevier Inc. All rights reserved.

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.

Organized mesoporous silica films as templates for the elaboration of organized nanoparticle networks

International Nuclear Information System (INIS)

Gacoin, T; Besson, S; Boilot, J P

2006-01-01

Tremendous work achieved in the last 20 years on nanoparticle synthesis has allowed us to study many new physical properties that are found in the nanometre size range. New developments are now expected when considering assemblies of nanoparticles such as 2D or 3D organized arrays. These systems are indeed expected to exhibit original physical properties resulting from particle-particle interactions. Studies in this field are clearly dependent on the elaboration of materials with controlled particle size, organization and interparticle distance. This paper presents a strategy of elaboration that is based on the use of organized mesoporous silica films as templates. These films are made by sol-gel polymerization around surfactant assemblies and further elimination of the surfactant. This provides porous matrices with a pore organization that is the almost perfect replica of the initial micellar structure. The use of such films for the elaboration of organized arrays of nanoparticles is detailed in the case of CdS and Ag particles. The formation of particles inside the pores is achieved through impregnation with precursors that are allowed to diffuse inside the pores. This leads to particles with a size and a spatial arrangement that is directly related to the initial pore structure of the films. This process opens a wide range of investigations due to the relative ease of fabrication over large surfaces and the numerous possibilities offered by the elaboration of porous films with different pore sizes and organizations

Voltammetric Determination of Lead (II) and Cadmium (II) Using a Bismuth Film Electrode Modified with Mesoporous Silica Nanoparticles

International Nuclear Information System (INIS)

Yang, Die; Wang, Liang; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravi

2014-01-01

A new chemically modified glassy carbon electrode based on bismuth film coated mesoporous silica nanoparticles was developed and evaluated for reliable quantification of trace Pb 2+ and Cd 2+ by anodic stripping square wave voltammetry in natural water samples. Compared with conventional bismuth film electrodes or bismuth nanoparticles modified electrodes, this electrode exhibited significantly improved sensitivity and stability for Pb 2+ and Cd 2+ detection. The key experimental parameters related to the fabrication of the electrode and the voltammetric measurements were optimized on the basis of the stripping signals, where the peak currents increased linearly with the metal concentrations in a range of 2-150 μg L −1 with a detect limit of 0.2 μg L −1 for Pb 2+ , and 0.6 μg L −1 for Cd 2+ for 120s deposition. Good reproducibility was achieved on both single and equally prepared electrodes. In addition, scanning electron microscopy reveals that fibril-like bismuth structures were formed on silica nanoparticles, which could be responsible for the improved voltammetric performance due to the enhanced surface area. Finally, the developed electrode was applied to determine Pb 2+ and Cd 2+ in water samples, indicating that this electrode was sensitive, reliable and effective for the simultaneous determination of Pb 2+ and Cd 2+

Synthesis of a colloid solution of silica-coated gold nanoparticles for X-ray imaging applications

Science.gov (United States)

Kobayashi, Yoshio; Nagasu, Ryoko; Shibuya, Kyosuke; Nakagawa, Tomohiko; Kubota, Yohsuke; Gonda, Kohsuke; Ohuchi, Noriaki

2014-08-01

This work proposes a method for fabricating silica-coated gold (Au) nanoparticles, surface modified with poly(ethylene glycol) (PEG) (Au/SiO2/PEG), with a particle size of 54.8 nm. X-ray imaging of a mouse is performed with the colloid solution. A colloid solution of 17.9 nm Au nanoparticles was prepared by reducing Au ions (III) with sodium citrate in water at 80 °C. The method used for silica-coating the Au nanoparticles was composed of surface-modification of the Au nanoparticles with (3-aminopropyl)-trimethoxysilane (APMS) and a sol-gel process. The sol-gel process was performed in the presence of the surface-modified Au nanoparticles using tetraethylorthosilicate, APMS, water, and sodium hydroxide, in which the formation of silica shells and the introduction of amino groups to the silica-coated particles took place simultaneously (Au/SiO2-NH2). Surface modification of the Au/SiO2-NH2 particles with PEG, or PEGylation of the particle surface, was performed by adding PEG with a functional group that reacted with an amino group in the Au/SiO2-NH2 particle colloid solution. A computed tomography (CT) value of the aqueous colloid solution of Au/SiO2/PEG particles with an actual Au concentration of 0.112 M was as high as 922 ± 12 Hounsfield units, which was higher than that of a commercial X-ray contrast agent with the same iodine concentration. Injecting the aqueous colloid solution of Au/SiO2/PEG particles into a mouse increased the light contrast of tissues. A CT value of the heart rose immediately after the injection, and this rise was confirmed for up to 6 h.

``The Princess and the Pea'' at the Nanoscale: Wrinkling and Delamination of Graphene on Nanoparticles

Science.gov (United States)

Yamamoto, Mahito; Pierre-Louis, Olivier; Huang, Jia; Fuhrer, Michael S.; Einstein, Theodore L.; Cullen, William G.

2012-10-01

Thin membranes exhibit complex responses to external forces or geometrical constraints. A familiar example is the wrinkling, exhibited by human skin, plant leaves, and fabrics, that results from the relative ease of bending versus stretching. Here, we study the wrinkling of graphene, the thinnest and stiffest known membrane, deposited on a silica substrate decorated with silica nanoparticles. At small nanoparticle density, monolayer graphene adheres to the substrate, detached only in small regions around the nanoparticles. With increasing nanoparticle density, we observe the formation of wrinkles which connect nanoparticles. Above a critical nanoparticle density, the wrinkles form a percolating network through the sample. As the graphene membrane is made thicker, global delamination from the substrate is observed. The observations can be well understood within a continuum-elastic model and have important implications for strain-engineering the electronic properties of graphene.

Enhanced electrochemiluminescence based on Ru(bpy)₃²⁺-doped silica nanoparticles and graphene composite for analysis of melamine in milk

Energy Technology Data Exchange (ETDEWEB)

Zhou, Limin [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 (China); University of the Chinese Academy of Sciences (China); Huang, Jianshe [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 (China); Yang, Lu; Li, Libo [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 (China); University of the Chinese Academy of Sciences (China); You, Tianyan, E-mail: youty@ciac.jl.cn [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 (China)

2014-05-01

Highlights: • A sensitive ECL sensor was developed by combining Ru(bpy)₃²⁺-doped silica (Ru(bpy)₃²⁺@SiO₂) nanoparticles with graphene. • The proposed sensor exhibited high sensitivity (~10⁻¹³ M) and wide linear range for melamine. • This method was successfully applied to the detection of melamine in milk. Abstract: A sensitive electrochemiluminescence (ECL) sensor for melamine analysis was fabricated based on Ru(bpy)₃²⁺-doped silica (Ru(bpy)₃²⁺@SiO₂) nanoparticles and graphene composite. Spherical Ru(bpy)₃²⁺@SiO₂ nanoparticles with uniform size about 55 nm were prepared by the reverse microemulsion method. Since per Ru(bpy)₃²⁺@SiO₂ nanoparticle encapsulated a great deal of Ru(bpy)₃²⁺, the ECL intensity has been greatly enhanced, which resulted in high sensitivity. Due to its extraordinary electric conductivity, graphene improved the conductivity and accelerated the electron transfer rate. In addition, graphene could work as electronic channel improving the efficient luminophor amount participating in the ECL reaction, which further enhanced the ECL signal. This proposed sensor was used to melamine analysis and the ECL intensity was proportional to logarithmic melamine concentration range from 1 × 10⁻¹³ M to 1 × 10⁻⁸ M with the detect limit as low as 1 × 10⁻¹³ M. In application to detect melamine in milk, satisfactory recoveries could be obtained, which indicated this sensor having potential application in melamine analysis in real samples.

Characterization and Comparison of Mesoporous Silica Particles for Optimized Drug Delivery

Directory of Open Access Journals (Sweden)

Xinyue Huang

2014-01-01

Full Text Available In this study we have investigated the suitability of a number of different mesoporous silica nanoparticle structures for carrying a drug cargo. We have fully characterized the nanoparticles in terms of their physical parameters; size, surface area, internal pore size and structure. These data are all required if we are to make an informed judgement on the suitability of the structure for drug delivery in vivo. With these parameters in mind, we investigated the loading/ unloading profile of a model therapeutic into the pore structure of the nanoparticles. We demonstrate that the release can be controlled by capping the pores on the nanoparticles to achieve temporal control of the unloading. We have also examined the rate and mechanism of the degradation of the nanoparticles over an extended period of time. The eventual dissolution of the nanoparticles after cargo release is a desirable property for a drug delivery system.

Mesoporous silica nanoparticles loading doxorubicin reverse multidrug resistance: performance and mechanism

Science.gov (United States)

Shen, Jianan; He, Qianjun; Gao, Yu; Shi, Jianlin; Li, Yaping

2011-10-01

Multidrug resistance (MDR) is one of the major obstacles for successful chemotherapy in cancer. One of the effective approaches to overcome MDR is to use nanoparticle-mediated drug delivery to increase drug accumulation in drug resistant cancer cells. In this work, we first report that the performance and mechanism of an inorganic engineered delivery system based on mesoporous silica nanoparticles (MSNs) loading doxorubicin (DMNs) to overcome the MDR of MCF-7/ADR (a DOX-resistant and P-glycoprotein (P-gp) over-expression cancer cell line). The experimental results showed that DMNs could enhance the cellular uptake of doxorubicin (DOX) and increase the cell proliferation suppression effect of DOX against MCF-7/ADR cells. The IC50 of DMNs against MCF-7/ADR cells was 8-fold lower than that of free DOX. However, an improved effect of DOX in DMNs against MCF-7 cells (a DOX-sensitive cancer cell line) was not found. The increased cellular uptake and nuclear accumulation of DOX delivered by DMNs in MCF-7/ADR cells was confirmed by confocal laser scanning microscopy, and could result from the down-regulation of P-gp and bypassing the efflux action by MSNs themselves. The cellular uptake mechanism of DMNs indicated that the macropinocytosis was one of the pathways for the uptake of DMNs by MCF-7/ADR cells. The in vivo biodistribution showed that DMNs induced a higher accumulation of DOX in drug resistant tumors than free DOX. These results suggested that MSNs could be an effective delivery system to overcome multidrug resistance.

Controlled release and intracellular protein delivery from mesoporous silica nanoparticles.

Science.gov (United States)

Deodhar, Gauri V; Adams, Marisa L; Trewyn, Brian G

2017-01-01

Protein therapeutics are promising candidates for disease treatment due to their high specificity and minimal adverse side effects; however, targeted protein delivery to specific sites has proven challenging. Mesoporous silica nanoparticles (MSN) have demonstrated to be ideal candidates for this application, given their high loading capacity, biocompatibility, and ability to protect host molecules from degradation. These materials exhibit tunable pore sizes, shapes and volumes, and surfaces which can be easily functionalized. This serves to control the movement of molecules in and out of the pores, thus entrapping guest molecules until a specific stimulus triggers release. In this review, we will cover the benefits of using MSN as protein therapeutic carriers, demonstrating that there is great diversity in the ways MSN can be used to service proteins. Methods for controlling the physical dimensions of pores via synthetic conditions, applications of therapeutic protein loaded MSN materials in cancer therapies, delivering protein loaded MSN materials to plant cells using biolistic methods, and common stimuli-responsive functionalities will be discussed. New and exciting strategies for controlled release and manipulation of proteins are also covered in this review. While research in this area has advanced substantially, we conclude this review with future challenges to be tackled by the scientific community. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In Situ Growth of Mesoporous Silica with Drugs on Titanium Surface and Its Biomedical Applications.

Science.gov (United States)

Wan, Mimi; Zhang, Jin; Wang, Qi; Zhan, Shuyue; Chen, Xudong; Mao, Chun; Liu, Yuhong; Shen, Jian

2017-06-07

Mesoporous silica has been developed for the modification of titanium surfaces that are used as implant materials. Yet, the traditional modification methods failed to effectively construct mesoporous silica on the titanium surface evenly and firmly, in which the interaction between mesoporous silica and titanium was mainly physical. Here, in situ growth of mesoporous silica on a titanium surface was performed using a simple evaporation-induced self-assembly strategy. Meantime, in situ introduction of drugs (heparin and vancomycin) to mesoporous silica was also adopted to improve the drug-loading amount. Both the above-mentioned processes were completed at the same time. Transmission electron microscopy, N 2 adsorption-desorption isotherms, Fourier transform infrared spectroscopy, scanning electron microscopy, and water contact angle measurements were used to characterize the structure of the mesoporous silica film. Results indicated that the mesoporous silica film that in situ grew on the titanium surface was smooth, thin, transparent, and stable. Cytotoxicity, proliferation performance of osteoblast cells, and in vitro and in vivo studies of the antibacterial activity of the coating were tested. This is the first study to modify the titanium surface by the in situ growth of a mesoporous silica coating with two kinds of drugs. The stability of the mesoporous silica coating can be attributed to the chemical bonding between dopamine and silicon hydroxyl of the mesoporous silica coating, and the smooth surface of mesoporous silica is a result of the method of in situ growth. The large amount of drug-loading also could be ascribed to the in situ introduction of drugs during the synthetic process. The strategy proposed in this work will bring more possibilities for the preparation of advanced functional materials based on the combination of mesoporous structure and metallic materials.

Facile synthesis of mesoporous silica sublayer with hierarchical pore structure on ceramic membrane using anionic polyelectrolyte.

Science.gov (United States)

Kang, Taewook; Oh, Seogil; Kim, Honggon; Yi, Jongheop

2005-06-21

A facile method for introducing mesoporous silica sublayer onto the surface of a ceramic membrane for use in liquid-phase separation is described. To reduce the electrostatic repulsion between the mesoporous silica sol and the ceramic membrane in highly acidic conditions (pH ceramic membrane, as confirmed by experimental titration data. Consistent with the titration results, the amount of mesoporous silica particles on the surface of the ceramic membrane was low, in the absence of PSS- treatment, whereas mesoporous silica sublayer with hierarchical pore structure was produced, when 1 wt % PSS- was used. The results show that mesoporous silica grows in the confined surface, eventually forming a multistacked surface architecture. The mesoporous silica sublayer contained uniform, ordered (P6 mm) mesopores of ca. 7.5 nm from mesoporous silica as well as macropores ( approximately mum) from interparticle voids, as evidenced by transmission electron microscopy and scanning electron microscopy analyses. The morphologies of the supported mesoporous silica could be manipulated, thus permitting the generation of uniform needlelike forms or uniform spheroid particles by varying the concentration of PSS-.

Polymeric carbon nitride/mesoporous silica composites as catalyst support for Au and Pt nanoparticles.

Science.gov (United States)

Xiao, Ping; Zhao, Yanxi; Wang, Tao; Zhan, Yingying; Wang, Huihu; Li, Jinlin; Thomas, Arne; Zhu, Junjiang

2014-03-03

Small and homogeneously dispersed Au and Pt nanoparticles (NPs) were prepared on polymeric carbon nitride (CNx )/mesoporous silica (SBA-15) composites, which were synthesized by thermal polycondensation of dicyandiamide-impregnated preformed SBA-15. By changing the condensation temperature, the degree of condensation and the loading of CNx can be controlled to give adjustable particle sizes of the Pt and Au NPs subsequently formed on the composites. In contrast to the pure SBA-15 support, coating of SBA-15 with polymeric CNx resulted in much smaller and better-dispersed metal NPs. Furthermore, under catalytic conditions the CNx coating helps to stabilize the metal NPs. However, metal NPs on CNx /SBA-15 can show very different catalytic behaviors in, for example, the CO oxidation reaction. Whereas the Pt NPs already show full CO conversion at 160 °C, the catalytic activity of Au NPs seems to be inhibited by the CNx support. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

“The Princess and the Pea” at the Nanoscale: Wrinkling and Delamination of Graphene on Nanoparticles

Directory of Open Access Journals (Sweden)

Mahito Yamamoto

2012-12-01

Full Text Available Thin membranes exhibit complex responses to external forces or geometrical constraints. A familiar example is the wrinkling, exhibited by human skin, plant leaves, and fabrics, that results from the relative ease of bending versus stretching. Here, we study the wrinkling of graphene, the thinnest and stiffest known membrane, deposited on a silica substrate decorated with silica nanoparticles. At small nanoparticle density, monolayer graphene adheres to the substrate, detached only in small regions around the nanoparticles. With increasing nanoparticle density, we observe the formation of wrinkles which connect nanoparticles. Above a critical nanoparticle density, the wrinkles form a percolating network through the sample. As the graphene membrane is made thicker, global delamination from the substrate is observed. The observations can be well understood within a continuum-elastic model and have important implications for strain-engineering the electronic properties of graphene.

A controlled release of ibuprofen by systematically tailoring the morphology of mesoporous silica materials

International Nuclear Information System (INIS)

Qu Fengyu; Zhu Guangshan; Lin Huiming; Zhang Weiwei; Sun Jinyu; Li Shougui; Qiu Shilun

2006-01-01

A series of mesoporous silica materials with similar pore sizes, different morphologies and variable pore geometries were prepared systematically. In order to control drug release, ibuprofen was employed as a model drug and the influence of morphology and pore geometry of mesoporous silica on drug release profiles was extensively studied. The mesoporous silica and drug-loaded samples were characterized by X-ray diffraction, Fourier transform IR spectroscopy, N 2 adsorption and desorption, scanning electron microscopy, and transmission electron microscopy. It was found that the drug-loading amount was directly correlated to the Brunauer-Emmett-Teller surface area, pore geometry, and pore volume; while the drug release profiles could be controlled by tailoring the morphologies of mesoporous silica carriers. - Graphical abstract: The release of ibuprofen is controlled by tailoring the morphologies of mesoporous silica. The mesoporous silica and drug-loaded samples are characterized by powder X-ray diffraction, Fourier transform IR spectroscopy, N 2 adsorption and desorption, scanning electron microscopy, and transmission electron microscopy. The drug-loading amount is directly correlated to the Brunauer-Emmett-Teller surface area, pore geometry, and pore volume; while the drug release profiles can be controlled by tailoring the morphologies of mesoporous silica carriers

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.

Incorporation of polyoxotungstate complexes in silica spheres and in situ formation of tungsten trioxide nanoparticles.

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Zhao, Yuanyuan; Fan, Haimei; Li, Wen; Bi, Lihua; Wang, Dejun; Wu, Lixin

2010-09-21

In this paper, we demonstrated a new convenient route for in situ fabrication of well separated small sized WO(3) nanoparticles in silica spheres, through a predeposition of surfactant encapsulated polyoxotungates as tungsten source, and followed by a calcination process. In a typical procedure, selected polyoxotungates with different charges were enwrapped with dioctadecyldimethylammonium cations through electrostatic interaction. Elemental analysis, thermogravimetric analysis, and spectral characterization confirmed the formation of prepared complexes with the anticipated chemical structure. The complexes were then phase-transferred into aqueous solution that predissolved surfactant cetyltrimethylammonium bromide, and finally incorporated into silica spheres through a joint sol-gel reaction with tetraethyl orthosilicate in a well dispersed state under the protection of organic layer for polyoxotungates from the alkaline reaction condition. Transmission electron microscopic images illustrated the well dispersed WO(3) nanoparticles in the size range of ca. 2.2 nm in the silica spheres after the calcination at 465 °C. The sizes of both the silica spheres and WO(3) nanoparticles could be adjusted independently through changing the doping content to a large extent. Meanwhile, the doped polyoxotungate complexes acted as the template for the mesoporous structure in silica spheres after the calcination. Along with the increase of doping content and surfactant, the mesopore size changed little (2.0-2.9 nm), but the specific surface areas increased quite a lot. Importantly, the WO(3)-nanoparticle-doped silica spheres displayed an interesting photovoltaic property, which is favorable for the funtionalization of these nanomaterials.

Labeling and exocytosis of secretory compartments in RBL mastocytes by polystyrene and mesoporous silica nanoparticles

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Ekkapongpisit M

2012-04-01

Full Text Available Maneerat Ekkapongpisit1,*, Antonino Giovia1,*, Giuseppina Nicotra1, Matteo Ozzano1, Giuseppe Caputo2,3, Ciro Isidoro1 1Laboratory of Molecular Pathology and Nanobioimaging, Department of Health Sciences, Università del Piemonte Orientale "A. Avogadro", Novara, Italy; 2Department of Chemistry, University of Turin, Turin, 3Cyanine Technology SpA, Torino, Italy *These authors contributed equally to this workBackground: For a safe ‘in vivo’ biomedical utilization of nanoparticles, it is essential to assess not only biocompatibility, but also the potential to trigger unwanted side effects at both cellular and tissue levels. Mastocytes (cells having secretory granules containing cytokines, vasoactive amine, and proteases play a pivotal role in the immune and inflammatory responses against exogenous toxins. Mastocytes are also recruited in the tumor stroma and are involved in tumor vascularization and growth.Aim and methods: In this work, mastocyte-like rat basophilic leukemia (RBL cells were used to investigate whether carboxyl-modified 30 nm polystyrene (PS nanoparticles (NPs and naked mesoporous silica (MPS 10 nm NPs are able to label the secretory inflammatory granules, and possibly induce exocytosis of these granules. Uptake, cellular retention and localization of fluorescent NPs were analyzed by cytofluorometry and microscope imaging.Results: Our findings were that: (1 secretory granules of mastocytes are accessible by NPs via endocytosis; (2 PS and MPS silica NPs label two distinct subpopulations of inflammatory granules in RBL mastocytes; and (3 PS NPs induce calcium-dependent exocytosis of inflammatory granules.Conclusion: These findings highlight the value of NPs for live imaging of inflammatory processes, and also have important implications for the clinical use of PS-based NPs, due to their potential to trigger the unwanted activation of mastocytes.Keywords: secretory lysosomes, inflammation, nanoparticles, vesicular traffic

Wrinkling instability in nanoparticle-supported graphene: implications for strain engineering

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Cullen, William; Yamamoto, Mahito; Pierre-Louis, Olivier; Huang, Jia; Fuhrer, Michael; Einstein, Theodore

2013-03-01

We have carried out a systematic study of the wrinkling instability of graphene membranes supported on SiO2 substrates with randomly placed silica nanoparticles. At small nanoparticle density, monolayer graphene adheres to the substrate and is highly conformal over the nanoparticles. With increasing nanoparticle density, and decreasing nanoparticle separation to ~100 nm, graphene's elastic response dominates substrate adhesion, and elastic stretching energy is reduced by the formation of wrinkles which connect protrusions. Above a critical nanoparticle density, the wrinkles form a percolating network through the sample. As the graphene membrane is made thicker, delamination from the substrate is observed. Since the wrinkling instability acts to remove inhomogeneous in-plane elastic strains through out-of-plane buckling, our results can be used to place limits on the possible in-plane strain magnitudes that may be created in graphene to realized strain-engineered electronic structures.[2] Supported by the UMD NSF-MRSEC under Grant No. DMR 05-20471, the US ONR MURI and UMD CNAM.

New mesostructured organosilica with chiral sugar derived structures: nice host for gold nanoparticles stabilisation.

Science.gov (United States)

Hérault, Damien; Cerveau, Geneviève; Corriu, Robert J P; Mehdi, Ahmad

2011-01-14

In this paper we describe the synthesis of functionalised mesoporous organosilicas containing a mannitol derivative in the framework. For this purpose, a bis-silylated precursor 3,4-Di-O-[3-(triethoxysilylpropyl)carbamate]-1,2:5,6-di-O-isopropylidene-D-mannitol was prepared by coupling of 1,2:5,6-di-O-isopropylidene-D-mannitol with 3-(triethoxysilylpropyl)isocyanate. The framework-functionalised materials were obtained in one step by the "direct synthesis" method which consists of a co-hydrolysis and polycondensation of a bis-silylated mannitol precursor with tetraethylorthosilicate (TEOS) in the presence of a non-ionic triblock co-polymer (P123) as structure-directing agent. Interestingly, deprotection of the 1,2,5,6 OH functional groups occurred during the material synthesis. The obtained solids were characterized by (13)C and (29)Si CP-MAS NMR, N(2) adsorption-desorption, powder X-ray diffraction, TEM and elemental analysis. We have shown that, the OH functional groups, which are released during the synthesis of the mesoporous silica, can be used for chelation of ions and stabilisation of nanoparticles. The subsequent growth of gold (0) nanoparticles in the wall has been investigated and evidenced.

Efficient fluorescence energy transfer system between CdTe-doped silica nanoparticles and gold nanoparticles for turn-on fluorescence detection of melamine.

Science.gov (United States)

Gao, Feng; Ye, Qingqing; Cui, Peng; Zhang, Lu

2012-05-09

We here report an efficient and enhanced fluorescence energy transfer system between confined quantum dots (QDs) by entrapping CdTe into the mesoporous silica shell (CdTe@SiO₂) as donors and gold nanoparticles (AuNPs) as acceptors. At pH 6.50, the CdTe@SiO₂-AuNPs assemblies coalesce to form larger clusters due to charge neutralization, leading to the fluorescence quenching of CdTe@SiO₂ as a result of energy transfer. As compared with the energy transfer system between unconfined CdTe and AuNPs, the maximum fluorescence quenching efficiency of the proposed system is improved by about 27.0%, and the quenching constant, K(sv), is increased by about 2.4-fold. The enhanced quenching effect largely turns off the fluorescence of CdTe@SiO₂ and provides an optimal "off-state" for sensitive "turn-on" assay. In the present study, upon addition of melamine, the weak fluorescence system of CdTe@SiO₂-AuNPs is enhanced due to the strong interactions between the amino group of melamine and the gold nanoparticles via covalent bond, leading to the release of AuNPs from the surfaces of CdTe@SiO₂; thus, its fluorescence is restored. A "turn-on" fluorimetric method for the detection of melamine is proposed based on the restored fluorescence of the system. Under the optimal conditions, the fluorescence enhanced efficiency shows a linear function against the melamine concentrations ranging from 7.5 × 10⁻⁹ to 3.5 × 10⁻⁷ M (i.e., 1.0-44 ppb). The analytical sensitivity is improved by about 50%, and the detection limit is decreased by 5.0-fold, as compared with the analytical results using the CdTe-AuNPs system. Moreover, the proposed method was successfully applied to the determination of melamine in real samples with excellent recoveries in the range from 97.4 to 104.1%. Such a fluorescence energy transfer system between confined QDs and AuNPs may pave a new way for designing chemo/biosensing.

Reduced bacteria adhesion on octenidine loaded mesoporous silica nanoparticles coating on titanium substrates.

Science.gov (United States)

Xu, Gaoqiang; Shen, Xinkun; Dai, Liangliang; Ran, Qichun; Ma, Pingping; Cai, Kaiyong

2017-01-01

Bacterial infection is one of the most severe postoperative complications leading to implantation failure. The early bacterial stage (4-6h) was proved to be the "decisive period" for long-term bacteria-related infection. Thus, to endow potential early antibacterial capacity for a titanium (Ti) based implant, an effective antiseptic agent of octenidine dihydrochloride (OCT) was effectively loaded on the mesoporous silica nanoparticles (MSNs)-incorporated titania coating which was fabricated by an electrophoretic-enhanced micro-arc oxidation technique. The surface characteristic of the coatings were characterized by various methods (SEM, AFM, XPS, XRD, etc.), and its corrosion resistance was also examined by the potentiodynamic polarization curves. The composite coating without OCT loading not only displayed good cytocompatibility but also exhibited certain anti-bacterial property. After loading with OCT, its antibacterial efficiency of the titanium substrates with composite coating was greatly enhanced without compromising their cytocompatibility. The study provides an approach for the fabrication of anti-bacterial Ti implant for potential orthopedic application. Copyright © 2016 Elsevier B.V. All rights reserved.

Amine-Functionalized Mesoporous Silica Nanoparticles: A New Nanoantibiotic for Bone Infection Treatment

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Pedraza Daniel

2018-01-01

Full Text Available This manuscript reports an effective new alternative for the management of bone infection by the development of an antibiotic nanocarrier able to penetrate bacterial biofilm, thus enhancing antimicrobial effectiveness. This nanosystem, also denoted as “nanoantibiotic”, consists in mesoporous silica nanoparticles (MSNs loaded with an antimicrobial agent (levofloxacin, LEVO and externally functionalized with N-(2-aminoethyl-3- aminopropyltrimethoxysilane (DAMO as targeting agent. This amine functionalization provides MSNs of positive charges, which improves the affinity towards the negatively charged bacteria wall and biofilm. Physical and chemical properties of the nanoantibiotic were studied using different characterization techniques, including Xray diffraction (XRD, transmission electron microscopy (TEM, N2 adsorption porosimetry, elemental chemical analysis, dynamic light scattering (DLS, zeta (ζ-potential and solid-state nuclear magnetic resonance (NMR. “In vial” LEVO release profiles and the in vitro antimicrobial effectiveness of the different released doses were investigated. The efficacy of the nanoantibiotic against a S. aureus biofilm was also determined, showing the practically total destruction of the biofilm due to the high penetration ability of the developed nanosystem. These findings open up promising expectations in the field of bone infection treatment.

Amine-Functionalized Mesoporous Silica Nanoparticles: A New Nanoantibiotic for Bone Infection Treatment

Directory of Open Access Journals (Sweden)

Pedraza Daniel

2017-12-01

Full Text Available This manuscript reports an effective new alternative for the management of bone infection by the development of an antibiotic nanocarrier able to penetrate bacterial biofilm, thus enhancing antimicrobial effectiveness. This nanosystem, also denoted as “nanoantibiotic”, consists in mesoporous silica nanoparticles (MSNs loaded with an antimicrobial agent (levofloxacin, LEVO and externally functionalized with N-(2-aminoethyl-3-aminopropyltrimethoxysilane (DAMO as targeting agent. This amine functionalization provides MSNs of positive charges, which improves the affinity towards the negatively charged bacteria wall and biofilm. Physical and chemical properties of the nanoantibiotic were studied using different characterization techniques, including Xray diffraction (XRD, transmission electron microscopy (TEM, N2 adsorption porosimetry, elemental chemical analysis, dynamic light scattering (DLS, zeta (ζ -potential and solid-state nuclear magnetic resonance (NMR. “In vial” LEVO release profiles and the in vitro antimicrobial effectiveness of the different released doses were investigated. The efficacy of the nanoantibiotic against a S. aureus biofilm was also determined, showing the practically total destruction of the biofilm due to the high penetration ability of the developed nanosystem. These findings open up promising expectations in the field of bone infection treatment.

Simple Synthesis and Enhanced Performance of Graphene Oxide-Gold Composites

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Min Song

2012-01-01

Full Text Available Graphene oxide-gold composites were prepared by one-step reaction in aqueous solution, where the gold nanoparticles were deposited on the graphene oxide during their synthesis process. Transmission electron morphology, X-ray diffraction, Roman spectra, and UV-Vis absorption spectra were used to characterize the obtained composites. Furthermore, based on the BET analysis results, it was found that the surface area of the composite film was obviously enhanced compared with the synthesized graphene oxide. Electrochemical measurements indicated that the modification of the composites on electrode could efficiently enhance the voltammetric response, suggesting the potential application for making electrochemical sensors.

Synthesis of pH-sensitive poly(β-amino ester)-coated mesoporous silica nanoparticles for the controlled release of drugs

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Talavera-Pech, William A.; Esparza-Ruiz, Adriana; Quintana-Owen, Patricia; Vilchis-Nestor, Alfredo R.; Barrón-Zambrano, Jesus A.; Ávila-Ortega, Alejandro

2018-03-01

This report describes the synthesis of a controlled drug delivery system that was obtained by coating mesoporous silica nanoparticles (MSNs) with poly(β-amino ester) (PbAE), which is a solid and stable material at physiological pH, but is dissolved at acidic pH values, such as those in tumor tissues (from 5.0 to 6.5). To synthesize the system, PbAE chains were grafted onto amino-functionalized MSNs through a reaction between the surface amino groups of MSNs and the ends of acrylate chains of a PbAE. The system was physicochemically characterized by dynamic light scattering (DLS), Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, X-ray photoelectron spectrometry, and X-ray diffraction analyses. In addition, the in vitro release of doxorubicin (DOX) and doxycycline (DXY) in acidic and physiological media was evaluated. It was observed that the PbAE modification did not affect the mesoporous structure of MSNs. When the amount of 3-aminopropyltriethoxysilane was increased during functionalization, the amount of PbAE binding to MSNs increased as well. With respect to drug release, the sample with the highest amount of PbAE showed better control in the delivery of DXY and DOX in acidic media, because at pH 5.5, the release of both drugs was 40% higher than that at pH 7.4. These results reveal two aspects about the presence of PbAE in MSNs: PbAE does not affect the mesoporous structure of the nanoparticles, and PbAE is the main factor controlling the delivery of drugs in acidic media.

o-Vanillin functionalized mesoporous silica - coated magnetite nanoparticles for efficient removal of Pb(II) from water

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Culita, Daniela C.; Simonescu, Claudia Maria; Patescu, Rodica-Elena; Dragne, Mioara; Stanica, Nicolae; Oprea, Ovidiu

2016-06-01

o-Vanillin functionalized mesoporous silica - coated magnetite (Fe3O4@MCM-41-N-oVan) was synthesized and fully characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, N2 adsorption-desorption technique and magnetic measurements. The capacity of Fe3O4@MCM-41-N-oVan to adsorb Pb(II) from aqueous solutions was evaluated in comparison with raw mesoporous silica - coated magnetite (Fe3O4@MCM-41) and amino - modified mesoporous silica coated magnetite (Fe3O4@MCM-41-NH2). The effect of adsorption process parameters such us pH, contact time, initial Pb(II) concentration was also investigated. The adsorption data were successfully fitted with the Langmuir model, exhibiting a maximum adsorption capacity of 155.71 mg/g at pH=4.4 and T=298 K. The results revealed that the adsorption rate was very high at the beginning of the adsorption process, 80-90% of the total amount of Pb(II) being removed within the first 60 min, depending on the initial concentration. The results of the present work suggest that Fe3O4@MCM-41-N-oVan is a suitable candidate for the separation of Pb(II) from contaminated water.

Catalytic Activity and Photophysical Properties of Biomolecules Immobilized on Mesoporous Silica

DEFF Research Database (Denmark)

Ikemoto, Hideki

Mesoporous silicas, based on Santa Barbara Amorphous-15 (SBA-15), with different morphology, structure, pore size and functional groups have been synthesized. Two metalloenzymes and a photosynthetic membrane protein were immobilized on or confined in the pores of the mesoporous silicas to prepare...

Mesoporous Silica and Organosilica Nanoparticles: Physical Chemistry, Biosafety, Delivery Strategies, and Biomedical Applications

KAUST Repository

Croissant, Jonas G.; Fatieiev, Yevhen; Almalik, Abdulaziz; Khashab, Niveen M.

2017-01-01

organosilica, and fully hybridized organosilica (periodic mesoporous organosilicas) governs not only the physico-chemical properties but also the biosafety of the nanoparticles. The impact of the hybridization on the biocompatibility, protein corona

MCM-41 mesoporous silica nanoparticles functionalized with aptamer and radiolabelled with 90Y and 159Gd as a potential therapeutic agent against colorectal cancer

International Nuclear Information System (INIS)

Ferreira, Carolina de Aguiar

2014-01-01

Colorectal cancer (CRC) is a malignancy that affects large intestine and rectum, and it is the most common malignancy of the gastrointestinal tract, the third most commonly diagnosed type of cancer in the world and the second leading cause of cancer-related death in the United States. Nowadays, available therapeutic procedures for this type of cancer are limited and ineffective. Conventional radiotherapy is not an often used approach in the treatment of CRC due to the fact that peristaltic movements hamper the targeting of ionizing radiation and this type of treatment is used as adjuvant and palliative to control symptoms. Therefore, surgical intervention is the primary therapeutic choice against this disease. Researches based on the combination of radioisotopes and nanostructured carriers systems have demonstrated significant results in improving the selectivity action as well as reducing the radiation dose into healthy tissues. MCM-41 mesoporous silica nanoparticles have unique characteristics such as high surface area and well-defined pore diameters making these nanoparticles an ideal candidate of therapeutic agent carrier. Thus, the objective of this work is to synthesize and characterize MCM-41 mesoporous silica nanoparticles conjugated with yttrium-90 and gadolinium-159 and evaluate this system as a potential therapeutic agent. The nanoparticles were synthesized via sol-gel method. The sample was characterized using FTIR, SAXS, PCS, Zeta Potential analysis, Thermal analysis, CHN elemental analysis, nitrogen adsorption, scanning and transmission electron microscopy. The ability to incorporate Y +3 and Gd +3 ion was determined in vitro using different ratios (1:1, 1:3, 1:5 v/v) of YCL 3 and Gd 2 O 3 and silica nanoparticles dispersed in saline, pH 7.4. The non-incorporated Y +3 and Gd +3 ions were removed by ultracentrifugation procedure and the concentration of ions in the supernatant was determined by ICP-AES. Cell viability was assessed by colorimetric MTT

A Highly Stable and Magnetically Recyclable Nanocatalyst System: Mesoporous Silica Spheres Embedded with FeCo/Graphitic Shell Magnetic Nanoparticles and Pt Nanocatalysts.

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Kim, Da Jeong; Li, Yan; Kim, Yun Jin; Hur, Nam Hwi; Seo, Won Seok

2015-12-01

We have developed a highly stable and magnetically recyclable nanocatalyst system for alkene hydrogenation. The materials are composed of mesoporous silica spheres (MSS) embedded with FeCo/graphitic shell (FeCo/GC) magnetic nanoparticles and Pt nanocatalysts (Pt-FeCo/GC@MSS). The Pt-FeCo/GC@MSS have superparamagnetism at room temperature and show type IV isotherm typical for mesoporous silica, thereby ensuring a large enough inner space (surface area of 235.3 m(2)  g(-1), pore volume of 0.165 cm(3)  g(-1), and pore diameter of 2.8 nm) to undergo catalytic reactions. We have shown that the Pt-FeCo/GC@MSS system readily converts cyclohexene into cyclohexane, which is the only product isolated and Pt-FeCo/GC@MSS can be seperated very quickly by an external magnetic field after the catalytic reaction is finished. We have demonstrated that the recycled Pt-FeCo/GC@MSS can be reused further for the same hydrogenation reaction at least four times without loss in the initial catalytic activity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liver cancer cells: targeting and prolonged-release drug carriers consisting of mesoporous silica nanoparticles and alginate microspheres

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Liao YT

2014-06-01

Full Text Available Yu-Te Liao,1 Chia-Hung Liu,2 Jiashing Yu,1 Kevin C-W Wu1,3 1Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan; 2Department of Urology, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan; 3Division of Medical Engineering Research, National Health Research Institutes, Zhunan Township, Miaoli County, Taiwan Abstract: A new microsphere consisting of inorganic mesoporous silica nanoparticles (MSNs and organic alginate (denoted as MSN@Alg was successfully synthesized by air-dynamic atomization and applied to the intracellular drug delivery systems (DDS of liver cancer cells with sustained release and specific targeting properties. MSN@Alg microspheres have the advantages of MSN and alginate, where MSN provides a large surface area for high drug loading and alginate provides excellent biocompatibility and COOH functionality for specific targeting. Rhodamine 6G was used as a model drug, and the sustained release behavior of the rhodamine 6G-loaded MSN@Alg microspheres can be prolonged up to 20 days. For targeting therapy, the anticancer drug doxorubicin was loaded into MSN@Alg microspheres, and the (lysine4-tyrosine-arginine-glycine-aspartic acid (K4YRGD peptide was functionalized onto the surface of MSN@Alg for targeting liver cancer cells, hepatocellular carcinoma (HepG2. The results of the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT assay and confocal laser scanning microscopy indicate that the MSN@Alg microspheres were successfully uptaken by HepG2 without apparent cytotoxicity. In addition, the intracellular drug delivery efficiency was greatly enhanced (ie, 3.5-fold for the arginine-glycine-aspartic acid (RGD-labeled, doxorubicin-loaded MSN@Alg drug delivery system compared with the non-RGD case. The synthesized MSN@Alg microspheres show great potential as drug vehicles with high biocompatibility, sustained release, and targeting features for future intracellular DDS. Keywords

Ordered mesoporous silica (OMS) as an adsorbent and membrane for separation of carbon dioxide (CO2).

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Chew, Thiam-Leng; Ahmad, Abdul L; Bhatia, Subhash

2010-01-15

Separation of carbon dioxide (CO(2)) from gaseous mixture is an important issue for the removal of CO(2) in natural gas processing and power plants. The ordered mesoporous silicas (OMS) with uniform pore structure and high density of silanol groups, have attracted the interest of researchers for separation of carbon dioxide (CO(2)) using adsorption process. These mesoporous silicas after functionalization with amino groups have been studied for the removal of CO(2). The potential of functionalized ordered mesoporous silica membrane for separation of CO(2) is also recognized. The present paper reviews the synthesis of mesoporous silicas and important issues related to the development of mesoporous silicas. Recent studies on the CO(2) separation using ordered mesoporous silicas (OMS) as adsorbent and membrane are highlighted. The future prospectives of mesoporous silica membrane for CO(2) adsorption and separation are also presented and discussed. Copyright 2009 Elsevier B.V. All rights reserved.

Tumor vascular-targeted co-delivery of anti-angiogenesis and chemotherapeutic agents by mesoporous silica nanoparticle-based drug delivery system for synergetic therapy of tumor

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Li X

2015-12-01

Full Text Available Xiaoyu Li, Meiying Wu, Limin Pan, Jianlin Shi State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, People’s Republic of China Abstract: To overcome the drawback of drug non-selectivity in traditional chemotherapy, the construction of multifunctional targeting drug delivery systems is one of the most effective and prevailing approaches. The intratumoral anti-angiogenesis and the tumor cell-killing are two basic approaches in fighting tumors. Herein we report a novel tumor vascular-targeting multidrug delivery system using mesoporous silica nanoparticles as carrier to co-load an antiangiogenic agent (combretastatin A4 and a chemotherapeutic drug (doxorubicin and conjugate with targeting molecules (iRGD peptide for combined anti-angiogenesis and chemotherapy. Such a dual-loaded drug delivery system is capable of delivering the two agents at tumor vasculature and then within tumors through a differentiated drug release strategy, which consequently results in greatly improved antitumor efficacy at a very low doxorubicin dose of 1.5 mg/kg. The fast release of the antiangiogenic agent at tumor vasculatures led to the disruption of vascular structure and had a synergetic effect with the chemotherapeutic drug slowly released in the following delivery of chemotherapeutic drug into tumors. Keywords: mesoporous silica nanoparticles, drug delivery, tumor vasculatures targeting, antiangiogenic agent

Ion-Exchange-Induced Selective Etching for the Synthesis of Amino-Functionalized Hollow Mesoporous Silica for Elevated-High-Temperature Fuel Cells.

Science.gov (United States)

Zhang, Jin; Liu, Jian; Lu, Shanfu; Zhu, Haijin; Aili, David; De Marco, Roland; Xiang, Yan; Forsyth, Maria; Li, Qingfeng; Jiang, San Ping

2017-09-20

As differentiated from conventional synthetic processes, amino-functionalized hollow mesoporous silica (NH 2 -HMS) has been synthesized using a new and facile strategy of ion-exchange-induced selective etching of amino-functionalized mesoporous silica (NH 2 -meso-silica) by an alkaline solution. Nuclear magnetic resonance (NMR) spectroscopy and in situ time-resolved small-angle X-ray scattering (SAXS) reveal that ion-exchange-induced selective etching arises from the gradient distribution of OH - in the NH 2 -meso-silica nanospheres. Moreover, the ion-exchange-induced selective etching mechanism is verified through a successful synthesis of hollow mesoporous silica. After infiltration with phosphotungstic acid (PWA), PWA-NH 2 -HMS nanoparticles are dispersed in the poly(ether sulfone)-polyvinylpyrrolidone (PES-PVP) matrix, forming a hybrid PWA-NH 2 -HMS/PES-PVP nanocomposite membrane. The resultant nanocomposite membrane with an optimum loading of 10 wt % of PWA-NH 2 -HMS showed an enhanced proton conductivity of 0.175 S cm -1 and peak power density of 420 mW cm -2 at 180 °C under anhydrous conditions. Excellent durability of the hybrid composite membrane fuel cell has been demonstrated at 200 °C. The results of this study demonstrated the potential of the facile synthetic strategy in the fabrication of NH 2 -HMS with controlled mesoporous structure for application in nanocomposite membranes as a technology platform for elevated-temperature proton exchange membrane fuel cells.

Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery

Science.gov (United States)

Gao, Lin; Sun, Jihong; Li, Yuzhen

2011-08-01

The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N 2 adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation ft= ktn was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties.

Mannose-functionalized porous silica-coated magnetic nanoparticles for two-photon imaging or PDT of cancer cells

International Nuclear Information System (INIS)

Perrier, Marine; Gary-Bobo, Magali; Lartigue, Lenaïc; Brevet, David; Morère, Alain; Garcia, Marcel; Maillard, Philippe; Raehm, Laurence; Guari, Yannick; Larionova, Joulia; Durand, Jean-Olivier; Mongin, Olivier; Blanchard-Desce, Mireille

2013-01-01

An original fluorophore engineered for two-photon excitation or a porphyrin derivative were entrapped in the silica shell of magnetic porous silica nanoparticles during the synthesis of the silica moiety without damaging the structure of the organic part. The mild conditions involved allowed obtaining microporous or mesoporous silica magnetic nanoparticles, respectively. Mannose was grafted on the surface of the nanoparticles to target MCF-7 breast cancer cells. The studies of magnetic properties of these hybrid nanoparticles show that they present a blocking temperature at 190 K. The nano-objects designed with the two-photon fluorophore were efficient for two-photon imaging of MCF-7 cancer cells, whereas the nano-objects with the photosensitizer efficiently killed cancer cells. The presence of the mannose moiety was demonstrated to improve both imaging and therapy properties.

Mannose-functionalized porous silica-coated magnetic nanoparticles for two-photon imaging or PDT of cancer cells

Energy Technology Data Exchange (ETDEWEB)

Perrier, Marine [UMR 5253 CNRS-UM2-ENSCM-UM1, Institut Charles Gerhardt Montpellier (France); Gary-Bobo, Magali [Faculte de Pharmacie, Universite Montpellier 1, Universite Montpellier 2, Institut des Biomolecules Max Mousseron UMR 5247 CNRS (France); Lartigue, Lenaiec; Brevet, David [UMR 5253 CNRS-UM2-ENSCM-UM1, Institut Charles Gerhardt Montpellier (France); Morere, Alain; Garcia, Marcel [Faculte de Pharmacie, Universite Montpellier 1, Universite Montpellier 2, Institut des Biomolecules Max Mousseron UMR 5247 CNRS (France); Maillard, Philippe [Universite Paris-Sud, UMR 176 CNRS, Institut Curie (France); Raehm, Laurence; Guari, Yannick, E-mail: yannick.guari@um2.fr; Larionova, Joulia; Durand, Jean-Olivier, E-mail: durand@univ-montp2.fr [UMR 5253 CNRS-UM2-ENSCM-UM1, Institut Charles Gerhardt Montpellier (France); Mongin, Olivier [Universite de Rennes 1, Institut des Sciences Chimiques de Rennes, CNRS UMR 6226 (France); Blanchard-Desce, Mireille [Universite Bordeaux, Institut des Sciences Moleculaires, UMR CNRS 5255 (France)

2013-05-15

An original fluorophore engineered for two-photon excitation or a porphyrin derivative were entrapped in the silica shell of magnetic porous silica nanoparticles during the synthesis of the silica moiety without damaging the structure of the organic part. The mild conditions involved allowed obtaining microporous or mesoporous silica magnetic nanoparticles, respectively. Mannose was grafted on the surface of the nanoparticles to target MCF-7 breast cancer cells. The studies of magnetic properties of these hybrid nanoparticles show that they present a blocking temperature at 190 K. The nano-objects designed with the two-photon fluorophore were efficient for two-photon imaging of MCF-7 cancer cells, whereas the nano-objects with the photosensitizer efficiently killed cancer cells. The presence of the mannose moiety was demonstrated to improve both imaging and therapy properties.

The Effect of Mesoporous Carbon Nitride Modification by Titanium Oxide Nanoparticles on Photocatalytic Degradation of 1,3-Dinitrobenzene

Directory of Open Access Journals (Sweden)

Seyyed Ershad Moradi

2015-11-01

Full Text Available In the present work, well ordered, mesoporous carbon nitride (MCN sorbent with uniform mesoporous wall, high surface area and pore volume has been fabricated using the simple polymerization reaction between ethylene diamine and carbon tetrachloride in mesoporous silica media, and then modified by TiO2 nanoparticles (Ti-MCN. The structural order and textural properties of the nanoporous materials were studied by XRD, elemental analysis, and nitrogen adsorption–desorption experiments. Photodegradation experiments for 1,3-dinitrobenzene were conducted in batch mode, the Ti-MCN catalysts were found to be more active compared to the free TiO2 nanoparticles for 1,3-dinitrobenzene degradation.

Selective oxidation of cyclohexene through gold functionalized silica monolith microreactors

Science.gov (United States)

Alotaibi, Mohammed T.; Taylor, Martin J.; Liu, Dan; Beaumont, Simon K.; Kyriakou, Georgios

2016-04-01

Two simple, reproducible methods of preparing evenly distributed Au nanoparticle containing mesoporous silica monoliths are investigated. These Au nanoparticle containing monoliths are subsequently investigated as flow reactors for the selective oxidation of cyclohexene. In the first strategy, the silica monolith was directly impregnated with Au nanoparticles during the formation of the monolith. The second approach was to pre-functionalize the monolith with thiol groups tethered within the silica mesostructure. These can act as evenly distributed anchors for the Au nanoparticles to be incorporated by flowing a Au nanoparticle solution through the thiol functionalized monolith. Both methods led to successfully achieving even distribution of Au nanoparticles along the length of the monolith as demonstrated by ICP-OES. However, the impregnation method led to strong agglomeration of the Au nanoparticles during subsequent heating steps while the thiol anchoring procedure maintained the nanoparticles in the range of 6.8 ± 1.4 nm. Both Au nanoparticle containing monoliths as well as samples with no Au incorporated were tested for the selective oxidation of cyclohexene under constant flow at 30 °C. The Au free materials were found to be catalytically inactive with Au being the minimum necessary requirement for the reaction to proceed. The impregnated Au-containing monolith was found to be less active than the thiol functionalized Au-containing material, attributable to the low metal surface area of the Au nanoparticles. The reaction on the thiol functionalized Au-containing monolith was found to depend strongly on the type of oxidant used: tert-butyl hydroperoxide (TBHP) was more active than H2O2, likely due to the thiol induced hydrophobicity in the monolith.

o-Vanillin functionalized mesoporous silica – coated magnetite nanoparticles for efficient removal of Pb(II) from water

Energy Technology Data Exchange (ETDEWEB)

Culita, Daniela C., E-mail: danaculita@yahoo.co.uk [“Ilie Murgulescu” Institute of Physical Chemistry, Splaiul Independentei 202, Bucharest (Romania); Simonescu, Claudia Maria; Patescu, Rodica-Elena [Politehnica University, Faculty of Applied Chemistry and Materials Science, Bucharest (Romania); Dragne, Mioara [S.C. KEMCRISTAL S.R.L., Muncii Str., No. 51, Fundulea, Călăraşi (Romania); Stanica, Nicolae [“Ilie Murgulescu” Institute of Physical Chemistry, Splaiul Independentei 202, Bucharest (Romania); Oprea, Ovidiu [Politehnica University, Faculty of Applied Chemistry and Materials Science, Bucharest (Romania)

2016-06-15

o-Vanillin functionalized mesoporous silica – coated magnetite (Fe{sub 3}O{sub 4}@MCM-41-N-oVan) was synthesized and fully characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, N{sub 2} adsorption–desorption technique and magnetic measurements. The capacity of Fe{sub 3}O{sub 4}@MCM-41-N-oVan to adsorb Pb(II) from aqueous solutions was evaluated in comparison with raw mesoporous silica – coated magnetite (Fe{sub 3}O{sub 4}@MCM-41) and amino – modified mesoporous silica coated magnetite (Fe{sub 3}O{sub 4}@MCM-41-NH{sub 2}). The effect of adsorption process parameters such us pH, contact time, initial Pb(II) concentration was also investigated. The adsorption data were successfully fitted with the Langmuir model, exhibiting a maximum adsorption capacity of 155.71 mg/g at pH=4.4 and T=298 K. The results revealed that the adsorption rate was very high at the beginning of the adsorption process, 80–90% of the total amount of Pb(II) being removed within the first 60 min, depending on the initial concentration. The results of the present work suggest that Fe{sub 3}O{sub 4}@MCM-41-N-oVan is a suitable candidate for the separation of Pb(II) from contaminated water. - Graphical abstract: A novel magnetic adsorbent based on o-vanillin functionalized mesoporous silica – coated magnetite was synthesized and fully characterized and its adsorption capacity for Pb(II) ions in aqueous solutions was evaluated. The maximum adsorption capacity for Pb(II) ions was determined to be 155.71 mg g{sup −1}. The adsorption rate was very high at the beginning of the adsorption process, 90% of the total amount of Pb(II) being removed within the first 60 min. Display Omitted.

o-Vanillin functionalized mesoporous silica – coated magnetite nanoparticles for efficient removal of Pb(II) from water

International Nuclear Information System (INIS)

Culita, Daniela C.; Simonescu, Claudia Maria; Patescu, Rodica-Elena; Dragne, Mioara; Stanica, Nicolae; Oprea, Ovidiu

2016-01-01

o-Vanillin functionalized mesoporous silica – coated magnetite (Fe 3 O 4 @MCM-41-N-oVan) was synthesized and fully characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, N 2 adsorption–desorption technique and magnetic measurements. The capacity of Fe 3 O 4 @MCM-41-N-oVan to adsorb Pb(II) from aqueous solutions was evaluated in comparison with raw mesoporous silica – coated magnetite (Fe 3 O 4 @MCM-41) and amino – modified mesoporous silica coated magnetite (Fe 3 O 4 @MCM-41-NH 2 ). The effect of adsorption process parameters such us pH, contact time, initial Pb(II) concentration was also investigated. The adsorption data were successfully fitted with the Langmuir model, exhibiting a maximum adsorption capacity of 155.71 mg/g at pH=4.4 and T=298 K. The results revealed that the adsorption rate was very high at the beginning of the adsorption process, 80–90% of the total amount of Pb(II) being removed within the first 60 min, depending on the initial concentration. The results of the present work suggest that Fe 3 O 4 @MCM-41-N-oVan is a suitable candidate for the separation of Pb(II) from contaminated water. - Graphical abstract: A novel magnetic adsorbent based on o-vanillin functionalized mesoporous silica – coated magnetite was synthesized and fully characterized and its adsorption capacity for Pb(II) ions in aqueous solutions was evaluated. The maximum adsorption capacity for Pb(II) ions was determined to be 155.71 mg g −1 . The adsorption rate was very high at the beginning of the adsorption process, 90% of the total amount of Pb(II) being removed within the first 60 min. Display Omitted

Durable PROX catalyst based on gold nanoparticles and hydrophobic silica

KAUST Repository

Laveille, Paco; Guillois, Kevin; Tuel, Alain; Petit, Corine; Basset, Jean-Marie; Caps, Valerie

2016-01-01

3 nm gold nanoparticles (Au NP) obtained by direct chemical reduction of AuPPh3Cl in the presence of methyl-terminated silica exhibit superior durability for low temperature CO oxidation in the presence of hydrogen (PROX). The activity of hydrophobic Au/SiO2-R972 indeed appears much more stable with time-on-stream than those of the OH-terminated, hydrophilic Au/TiO2 and Au/Al2O3 catalysts, with similar Au NP size. This enhanced stability is attributed to the peculiar catalyst surface of Au/SiO2-R972. Not only may the support hydrophobicity concentrate and facilitate reactant adsorption and product desorption over Au NP, but methyl-terminated SiO2-R972 likely also inhibits carbonatation of the Au/support interface. Hence, at a temperature at which H2/H2O “cleaning” of the carbonate-contaminated Au/Al2O3 and Au/TiO2 surface is inefficient (< 100°C), passivated Au/SiO2-R972 displays much more stable PROX activity. Besides, the virtual absence of surface hydroxyl groups, which provide sites for water formation in H2/O2 atmospheres, can also account for the improved PROX selectivity (>85%) observed over Au/SiO2-R972. This new example, of CO oxidation activity of gold nanoparticles dispersed over a hydrophobic, “inert” support, clearly emphasizes the role of hydrogen as a promoter for the gold-catalyzed oxidation of CO at low temperature. Unlike support-mediated oxygen activation, hydrogen-only mediated oxygen activation takes full advantage of the hydrophobic surface, which is much more resistant against CO2 and thus remains free of poisonous carbonate species, as compared with hydroxyl-terminated catalysts. Hence, although the absence of surface hydroxyl groups prevents the hydrophobic Au/SiO2-R972 catalyst to reach the state-of-the-art activities initially displayed by Au/TiO2 and Au/Al2O3, it brings long-term stability with time-on-stream and superior selectivity, which opens up promising perspectives in the development of viable PROX catalysts based on gold.

Durable PROX catalyst based on gold nanoparticles and hydrophobic silica

KAUST Repository

Laveille, Paco

2016-01-20

3 nm gold nanoparticles (Au NP) obtained by direct chemical reduction of AuPPh3Cl in the presence of methyl-terminated silica exhibit superior durability for low temperature CO oxidation in the presence of hydrogen (PROX). The activity of hydrophobic Au/SiO2-R972 indeed appears much more stable with time-on-stream than those of the OH-terminated, hydrophilic Au/TiO2 and Au/Al2O3 catalysts, with similar Au NP size. This enhanced stability is attributed to the peculiar catalyst surface of Au/SiO2-R972. Not only may the support hydrophobicity concentrate and facilitate reactant adsorption and product desorption over Au NP, but methyl-terminated SiO2-R972 likely also inhibits carbonatation of the Au/support interface. Hence, at a temperature at which H2/H2O “cleaning” of the carbonate-contaminated Au/Al2O3 and Au/TiO2 surface is inefficient (< 100°C), passivated Au/SiO2-R972 displays much more stable PROX activity. Besides, the virtual absence of surface hydroxyl groups, which provide sites for water formation in H2/O2 atmospheres, can also account for the improved PROX selectivity (>85%) observed over Au/SiO2-R972. This new example, of CO oxidation activity of gold nanoparticles dispersed over a hydrophobic, “inert” support, clearly emphasizes the role of hydrogen as a promoter for the gold-catalyzed oxidation of CO at low temperature. Unlike support-mediated oxygen activation, hydrogen-only mediated oxygen activation takes full advantage of the hydrophobic surface, which is much more resistant against CO2 and thus remains free of poisonous carbonate species, as compared with hydroxyl-terminated catalysts. Hence, although the absence of surface hydroxyl groups prevents the hydrophobic Au/SiO2-R972 catalyst to reach the state-of-the-art activities initially displayed by Au/TiO2 and Au/Al2O3, it brings long-term stability with time-on-stream and superior selectivity, which opens up promising perspectives in the development of viable PROX catalysts based on gold.

Toward Anhydrous Proton Conductivity Based on Imidazole Functionalized Mesoporous Silica/Nafion Composite Membranes

International Nuclear Information System (INIS)

Amiinu, Ibrahim Saana; Li, Wei; Wang, Guangjin; Tu, Zhengkai; Tang, Haolin; Pan, Mu; Zhang, Haining

2015-01-01

Highlights: • Imidazole-functionalized mesoporous silica/Nafion composite is formed. • Electrostatic interaction between ionic clusters leads to enhanced molecular rigidity and T g . • Charge transfer resistance decreases with increase in temperature up to 130 °C. • The composite membrane exhibited considerable stability over 70 h at 130 °C. - Abstract: Although Nafion is regarded as the most preferred electrolyte membrane and often used as a benchmark for comparative evaluation of other electrolyte membranes, its wide spread for commercial PEM fuel cells is limited by the poor electrochemical properties at elevated temperatures and low relative humidity conditions. Herein, sol–gel synthesized mesoporous silica functionalized with a protogenic molecule (imidazole) is introduced into the Nafion matrix via a colloid mediated process. The formation of a stable colloid enables homogeneous dispersion of the silica-imidazole nanoparticles without aggregation. Under non-humidified conditions, the amphoteric and self-dissociative character of the tethered imidazole within the matrix functions as a transporting medium to facilitate proton conductivity. The structural and chemical phases are characterized, and qualitatively evaluated by XRD, TEM, FT-IR, TGA, and DMA. The results show that the average proton conductivity of the composite membrane with the optimal amount of functionalized nanoparticles increases progressively to 1.06 × 10 −2 S cm −1 at 130 °C, corresponding to an activation energy of 6.95 kJ mol −1 under non-humidified conditions. The mechanism governing the dynamics of proton conductivity and structural limitations as a function of temperature is discussed

Preparation and controlled drug delivery applications of mesoporous silica polymer nanocomposites through the visible light induced surface-initiated ATRP

Energy Technology Data Exchange (ETDEWEB)

Huang, Long; Liu, Meiying; Mao, Liucheng; Xu, Dazhuang; Wan, Qing; Zeng, Guangjian; Shi, Yingge [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Wen, Yuanqing, E-mail: m18600788382@163.com [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Zhang, Xiaoyong, E-mail: xiaoyongzhang1980@gmail.com [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Wei, Yen, E-mail: weiyen@tsinghua.edu.cn [Department of Chemistry and The Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing, 100084 (China)

2017-08-01

Graphical abstract: A novel strategy for surface PEGylation of mesoporous silica nanoparticles was developed based on the light induced surface-initiated atom transfer radical polymerization. - Highlights: • Surface modification of silica nanoparticles through light induced surface-initiated ATRP. • MSNs-NH{sub 2}-poly(IA-co-PEGMA) nanocomposites show high water dispersity. • MSNs-NH{sub 2}-poly(IA-co-PEGMA) nanocomposites are promising for biomedical applications. • The light induced ATRP possesses many advantages as compared with traditional ATRP. - Abstract: The mesoporous materials with large pore size, high specific surface area and high thermal stability have been widely utilized in a variety of fields ranging from environmental remediation to separation and biomedicine. However, surface modification of these silica nanomaterials is required to endow novel properties and achieve better performance for most of these applications. In this work, a new method has been established for surface modification of mesoporous silica nanoparticles (MSNs) that relied on the visible light induced atom transfer radical polymerization (ATRP). In the procedure, the copolymers composited with itaconic acid (IA) and poly(ethylene glycol)methyl acrylate (PEGMA) were grafted from MSNs using IA and PEGMA as the monomers and 10-Phenylphenothiazine(PTH) as the organic catalyst. The successful preparation of final polymer nanocomposites (named as MSNs-NH{sub 2}-poly(IA-co-PEGMA)) were evidenced by a series of characterization techniques. More importantly, the anticancer agent cisplatin can be effectively loaded on MSNs-NH{sub 2}-poly(IA-co-PEGMA) and controlled release it from the drug-loading composites with pH responsive behavior. As compared with conventional ATRP, the light induced surface-initiated ATRP could also be utilized for preparation of various silica polymer nanocomposites under rather benign conditions (e.g. absent of transition metal ions, low polymerization

Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery

International Nuclear Information System (INIS)

Gao Lin; Sun Jihong; Li Yuzhen

2011-01-01

The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N 2 adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation f t =kt n was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties. - Graphical abstract: Loading (A) and release profiles (B) of aspirin in N-BMMs and N-MCM-41 indicated that BMMs have more drug loading capacity and faster release rate than that MCM-41. Highlights: → Bimodal mesoporous silicas (BMMs) and MCM-41 modified with amino group via post-treatment procedure. → Loading and release profiles of aspirin in modified BMMs and MCM-41. → Modified BMMs have more drug loading capacity and faster release rate than that modified MCM-41.

Few-layer graphene sheets with embedded gold nanoparticles for electrochemical analysis of adenine

Directory of Open Access Journals (Sweden)

Biris AR

2013-04-01

Full Text Available Alexandru R Biris,1 Stela Pruneanu,1 Florina Pogacean,1 Mihaela D Lazar,1 Gheorghe Borodi,1 Stefania Ardelean,1 Enkeleda Dervishi,2 Fumiya Watanabe,2 Alexandru S Biris2 1National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj-Napoca, Romania; 2Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, Little Rock, AR, USA Abstract: This work describes the synthesis of few-layer graphene sheets embedded with various amounts of gold nanoparticles (Gr-Au-x over an Aux/MgO catalytic system (where x = 1, 2, or 3 wt%. The sheet-like morphology of the Gr-Au-x nanostructures was confirmed by transmission electron microscopy and high resolution transmission electron microscopy, which also demonstrated that the number of layers within the sheets varied from two to seven. The sample with the highest percentage of gold nanoparticles embedded within the graphitic layers (Gr-Au-3 showed the highest degree of crystallinity. This distinct feature, along with the large number of edge-planes seen in high resolution transmission electron microscopic images, has a crucial effect on the electrocatalytic properties of this material. The reaction yields (40%–50% and the final purity (96%–98% of the Gr-Au-x composites were obtained by thermogravimetric analysis. The Gr-Au-x composites were used to modify platinum substrates and subsequently to detect adenine, one of the DNA bases. For the bare electrode, no oxidation signal was recorded. In contrast, all of the modified electrodes showed a strong electrocatalytic effect, and a clear peak for adenine oxidation was recorded at approximately +1.05 V. The highest increase in the electrochemical signal was obtained using a platinum/Gr-Au-3-modified electrode. In addition, this modified electrode had an exchange current density (I0, obtained from the Tafel plot one order of magnitude higher than that of the bare platinum electrode, which also confirmed that

Designing Hybrids of Graphene Oxide and Gold Nanoparticles for Nonlinear Optical Response

Science.gov (United States)

Yadav, Rajesh Kumar; Aneesh, J.; Sharma, Rituraj; Abhiramnath, P.; Maji, Tuhin Kumar; Omar, Ganesh Ji; Mishra, A. K.; Karmakar, Debjani; Adarsh, K. V.

2018-04-01

Nonlinear optical absorption of light by materials is weak due to its perturbative nature, although a strong nonlinear response is of crucial importance to applications in optical limiting and switching. Here we demonstrate experimentally and theoretically an extremely efficient scheme of excited-state absorption by charge transfer between donor and acceptor materials as a method to enhance the nonlinear absorption by orders of magnitude. With this idea, we demonstrate a strong excited-state absorption (ESA) in reduced graphene oxide that otherwise shows an increased transparency at high fluence and enhancement of ESA by one order of magnitude in graphene oxide by attaching gold nanoparticles (Au NP) in the tandem configuration that acts as an efficient charge-transfer pair when excited at the plasmonic wavelength. To explain the unprecedented enhancement, we develop a five-level rate-equation model based on the charge transfer between the two materials and numerically simulate the results. To understand the correlation of interfacial charge transfer with the concentration and type of the functional ligands attached to the graphene oxide sheet, we investigate the Au-NP—graphene oxide interface with various possible ligand configurations from first-principles calculations. By using the strong ESA of our hybrid materials, we fabricate liquid cell-based high-performance optical limiters with important device parameters better than that of the benchmark optical limiters.

Large pore bi-functionalised mesoporous silica for metal ion pollution treatment

International Nuclear Information System (INIS)

Burke, Aoife M.; Hanrahan, John P.; Healy, David A.; Sodeau, John R.; Holmes, Justin D.; Morris, Michael A.

2009-01-01

Here we demonstrate aminopropyl and mercatopropyl functionalised and bi-functionalised large pore mesoporous silica spheres to extract various metal ions from aqueous solutions towards providing active sorbents for mitigation of metal ion pollution. Elemental analysis (EA) and FTIR techniques were used to quantify the attachment of the aminopropyl and mercatopropyl functional groups to the mesoporous silica pore wall. Functionalisation was achieved by post-synthesis reflux procedures. For all functionalised silicas the functionalisation refluxing does not alter particle morphology/agglomeration of the particles. It was found that sorptive capacities of the mesoporous silica towards the functional groups were unaffected by co-functionalisation. Powder X-ray diffraction (PXRD) and nitrogen adsorption techniques were used to establish the pore diameters, packing of the pores and specific surface areas of the modified mesoporous silica spheres. Atomic absorption (AA) spectroscopy and inductively coupled plasma-atomic emission spectrometry (ICP-AES) techniques were used to measure the extraction efficiencies of each metal ion species from solution at varying pHs. Maximum sorptive capacities (as metal ions) were determined to be 384 μmol g -1 for Cr, 340 μmol g -1 for Ni, 358 μmol g -1 for Fe, 364 μmol g -1 for Mn and 188 μmol g -1 for Pd

Large pore bi-functionalised mesoporous silica for metal ion pollution treatment

Energy Technology Data Exchange (ETDEWEB)

Burke, Aoife M.; Hanrahan, John P. [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Environmental Research Institute (ERI), Lee Road, Cork (Ireland); Healy, David A.; Sodeau, John R. [Department of Chemistry, Centre of Research in Atmospheric Chemistry, University College Cork, Cork (Ireland); Holmes, Justin D. [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland); Morris, Michael A. [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Environmental Research Institute (ERI), Lee Road, Cork (Ireland); Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland)], E-mail: m.morris@ucc.ie

2009-05-15

Here we demonstrate aminopropyl and mercatopropyl functionalised and bi-functionalised large pore mesoporous silica spheres to extract various metal ions from aqueous solutions towards providing active sorbents for mitigation of metal ion pollution. Elemental analysis (EA) and FTIR techniques were used to quantify the attachment of the aminopropyl and mercatopropyl functional groups to the mesoporous silica pore wall. Functionalisation was achieved by post-synthesis reflux procedures. For all functionalised silicas the functionalisation refluxing does not alter particle morphology/agglomeration of the particles. It was found that sorptive capacities of the mesoporous silica towards the functional groups were unaffected by co-functionalisation. Powder X-ray diffraction (PXRD) and nitrogen adsorption techniques were used to establish the pore diameters, packing of the pores and specific surface areas of the modified mesoporous silica spheres. Atomic absorption (AA) spectroscopy and inductively coupled plasma-atomic emission spectrometry (ICP-AES) techniques were used to measure the extraction efficiencies of each metal ion species from solution at varying pHs. Maximum sorptive capacities (as metal ions) were determined to be 384 {mu}mol g{sup -1} for Cr, 340 {mu}mol g{sup -1} for Ni, 358 {mu}mol g{sup -1} for Fe, 364 {mu}mol g{sup -1} for Mn and 188 {mu}mol g{sup -1} for Pd.

Ordered mesoporous silica materials with complicated structures

KAUST Repository

Han, Yu; Zhang, Daliang

2012-01-01

Periodically ordered mesoporous silicas constitute one of the most important branches of porous materials that are extensively employed in various chemical engineering applications including adsorption, separation and catalysis. This short review

Functional graphene-gold nano-composite fabricated electrochemical biosensor for direct and rapid detection of bisphenol A.

Science.gov (United States)

Pan, Daodong; Gu, Yuanyuan; Lan, Hangzhen; Sun, Yangying; Gao, Huiju

2015-01-01

In this research, the graphene with excellent dispersity is prepared successfully by introducing gold nanoparticle to separate the individual sheets. Various techniques are adopted to characterize the prepared graphene and graphene-gold nanoparticle composite materials. This fabricated new composite material is used as the support material to construct a novel tyrosinase based biosensor for detection of bisphenol A (BPA). The electrochemical performances of the proposed new enzyme biosensor were investigated by differential pulse voltammetry (DPV) method. The proposed biosensor exhibited excellent performance for BPA determination with a wide linear range (2.5×10(-3)-3.0 μM), a highly reproducible response (RSD of 2.7%), low interferences and long-term stability. And more importantly, the calculated detection limit of the proposed biosensor was as low as 1 nM. Compared with other detection methods, this graphene-gold nanoparticle composite based tyrosinase biosensor is proved to be a promising and reliable tool for rapid detection of BPA for on-site analysis of emergency BPA related pollution affairs. Copyright © 2014 Elsevier B.V. All rights reserved.

Raman spectroscopy of pharmaceutical cocrystals in nanosized pores of mesoporous silica

International Nuclear Information System (INIS)

Ohta, Ryuichi; Ajito, Katsuhiro; Ueno, Yuko

2017-01-01

The Raman spectroscopy of pharmaceutical cocrystals based on caffeine and oxalic acid in nanosized pores of mesoporous silica has been demonstrated at various molar amounts. The Raman peak shifts of caffeine molecules express the existence of pharmaceutical cocrystals in mesoporous silica. The molar amount dependence of the peak shifts describes that caffeine and oxalic acid cocrystallized on the surface of the nanosized pores and piled up layer by layer. This is the first report that shows the Raman spectroscopy is a powerful tool to observe the synthesis of pharmaceutical cocrystals incorporated in the nanosized pores of mesoporous silica. The results indicate a way to control the size of cocrystals on a nanometer scale, which will provide higher bioavailability of pharmaceuticals. (author)

Thermo-responsive mesoporous silica/lipid bilayer hybrid nanoparticles for doxorubicin on-demand delivery and reduced premature release.

Science.gov (United States)

Zhang, Qing; Chen, Xuanxuan; Shi, Huihui; Dong, Gaoqiu; Zhou, Meiling; Wang, Tianji; Xin, Hongliang

2017-12-01

Hybrid nanocarriers based on mesoporous silica nanoparticles (MSNs) and supported lipid bilayer (SLB) have been studied as drug delivery system. It still remains challenges to develop these nanocarriers (SLB-MSNs) with on-demand drug release profile for chemotherapy. Here, we reported the biocompatible SLB-MSNs with high drug loading, which could release doxorubicin (DOX) in response to hyperthermia and reduce premature release. After synthesis of MSNs via a sol-gel procedure, the thermo-responsive SLB was deposited on the MSNs by sonication to completely seal the mesopores. The obtained SLB-MSNs consisted of 50 nm-sized MSN cores and 6.3 nm-thick SLB shells. Due to the big surface and pore volume of MSNs, the high drug loading content (7.30±0.02%) and encapsulation efficiency (91.16±0.28%) were achieved. The SLB blocking the mesopores reduced 50% of premature release and achieved on-demand release in a thermo-responsive manner. Moreover, SLB-MSNs showed good hemocompatibility at any tested concentration (25-700μg/mL), while bare MSNs caused 100% of hemolysis at concentration larger than 325μg/mL. In addition, in vitro U251 cell uptake experiment demonstrated that compared with uncapped MSNs, SLB-MSNs could prevent untargeted cellular uptake of DOX owing to reduced premature release and steric hindrance of PEG, which would be beneficial to minimize toxicity for healthy tissues. These results indicated that SLB-MSNs with thermo-responsive release capacity possessed great potential in future synergistic thermo-chemotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Colloidal Gold Nanoclusters Spiked Silica Fillers in Mixed Matrix Coatings: Simultaneous Detection and Inhibition of Healthcare-Associated Infections.

Science.gov (United States)

Alsaiari, Shahad K; Hammami, Mohammed A; Croissant, Jonas G; Omar, Haneen W; Neelakanda, Pradeep; Yapici, Tahir; Peinemann, Klaus-Viktor; Khashab, Niveen M

2017-03-01

Healthcare-associated infections (HAIs) are the infections that patients get while receiving medical treatment in a medical facility with bacterial HAIs being the most common. Silver and gold nanoparticles (NPs) have been successfully employed as antibacterial motifs; however, NPs leaching in addition to poor dispersion and overall reproducibility are major hurdles to further product development. In this study, the authors design and fabricate a smart antibacterial mixed-matrix membrane coating comprising colloidal lysozyme-templated gold nanoclusters as nanofillers in poly(ethylene oxide)/poly(butylene terephthalate) amphiphilic polymer matrix. Mesoporous silica nanoparticles-lysozyme functionalized gold nanoclusters disperse homogenously within the polymer matrix with no phase separation and zero NPs leaching. This mixed-matrix coating can successfully sense and inhibit bacterial contamination via a controlled release mechanism that is only triggered by bacteria. The system is coated on a common radiographic dental imaging device (photostimulable phosphor plate) that is prone to oral bacteria contamination. Variation and eventually disappearance of the red fluorescence surface under UV light signals bacterial infection. Kanamycin, an antimicrobial agent, is controllably released to instantly inhibit bacterial growth. Interestingly, the quality of the images obtained with these coated surfaces is the same as uncoated surfaces and thus the safe application of such smart coatings can be expanded to include other medical devices without compromising their utility. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Colloidal Gold Nanoclusters Spiked Silica Fillers in Mixed Matrix Coatings: Simultaneous Detection and Inhibition of Healthcare-Associated Infections

KAUST Repository

Alsaiari, Shahad K.

2017-01-25

Healthcare-associated infections (HAIs) are the infections that patients get while receiving medical treatment in a medical facility with bacterial HAIs being the most common. Silver and gold nanoparticles (NPs) have been successfully employed as antibacterial motifs; however, NPs leaching in addition to poor dispersion and overall reproducibility are major hurdles to further product development. In this study, the authors design and fabricate a smart antibacterial mixed-matrix membrane coating comprising colloidal lysozyme-templated gold nanoclusters as nanofillers in poly(ethylene oxide)/poly(butylene terephthalate) amphiphilic polymer matrix. Mesoporous silica nanoparticles-lysozyme functionalized gold nanoclusters disperse homogenously within the polymer matrix with no phase separation and zero NPs leaching. This mixed-matrix coating can successfully sense and inhibit bacterial contamination via a controlled release mechanism that is only triggered by bacteria. The system is coated on a common radiographic dental imaging device (photostimulable phosphor plate) that is prone to oral bacteria contamination. Variation and eventually disappearance of the red fluorescence surface under UV light signals bacterial infection. Kanamycin, an antimicrobial agent, is controllably released to instantly inhibit bacterial growth. Interestingly, the quality of the images obtained with these coated surfaces is the same as uncoated surfaces and thus the safe application of such smart coatings can be expanded to include other medical devices without compromising their utility.

Colloidal Gold Nanoclusters Spiked Silica Fillers in Mixed Matrix Coatings: Simultaneous Detection and Inhibition of Healthcare-Associated Infections

KAUST Repository

Alsaiari, Shahad K.; Hammami, Mohamed Amen; Croissant, Jonas G.; Omar, Haneen; Neelakanda, Pradeep; Yapici, Tahir; Peinemann, Klaus-Viktor; Khashab, Niveen M.

2017-01-01

Healthcare-associated infections (HAIs) are the infections that patients get while receiving medical treatment in a medical facility with bacterial HAIs being the most common. Silver and gold nanoparticles (NPs) have been successfully employed as antibacterial motifs; however, NPs leaching in addition to poor dispersion and overall reproducibility are major hurdles to further product development. In this study, the authors design and fabricate a smart antibacterial mixed-matrix membrane coating comprising colloidal lysozyme-templated gold nanoclusters as nanofillers in poly(ethylene oxide)/poly(butylene terephthalate) amphiphilic polymer matrix. Mesoporous silica nanoparticles-lysozyme functionalized gold nanoclusters disperse homogenously within the polymer matrix with no phase separation and zero NPs leaching. This mixed-matrix coating can successfully sense and inhibit bacterial contamination via a controlled release mechanism that is only triggered by bacteria. The system is coated on a common radiographic dental imaging device (photostimulable phosphor plate) that is prone to oral bacteria contamination. Variation and eventually disappearance of the red fluorescence surface under UV light signals bacterial infection. Kanamycin, an antimicrobial agent, is controllably released to instantly inhibit bacterial growth. Interestingly, the quality of the images obtained with these coated surfaces is the same as uncoated surfaces and thus the safe application of such smart coatings can be expanded to include other medical devices without compromising their utility.

Multifunctional material based on ionic transition metal complexes and gold-silica nanoparticles: synthesis and photophysical characterization for application in imaging and therapy.

Science.gov (United States)

Ricciardi, Loredana; Martini, Matteo; Tillement, Olivier; Sancey, Lucie; Perriat, Pascal; Ghedini, Mauro; Szerb, Elisabeta I; Yadav, Yogesh J; La Deda, Massimo

2014-11-01

A new combination of luminescent ionic transition-metal complexes (M = Ru(II) or Ir(III)) with gold silica-based nanoparticles (GSNPs) gives a promising nanomaterial for application in biomedical fields. Herein we report the synthesis and the photophysical properties of Ru(II) and Ir(III) complexes doped gold core-polysiloxane shell particles prepared by microemulsion method and characterized by Transmission Electron Microscopy, Dynamic Light Scattering and UV-Vis spectroscopy. The cytotoxicity and photodynamic activity of the obtained 50 nm-diameter nanoparticles were evaluated in vitro, providing noteworthy results. Furthermore, their intrinsic phosphorescence allows the localization of the photosensitizing nanoparticles into the cytosol of tumor cells by fluorescence confocal microscope. These valuable features designate them as multifunctional nanoplatforms for theranostic purposes.

Reduced Graphene Oxide-Gold Nanoparticle Nanoframework as a Highly Selective Separation Material for Aflatoxins.

Science.gov (United States)

Guo, Wenbo; Wu, Lidong; Fan, Kai; Nie, Dongxia; He, Weijing; Yang, Junhua; Zhao, Zhihui; Han, Zheng

2017-11-03

Graphene-based materials have been studied in many applications, owing to the excellent electrical, mechanical, and thermal properties of graphene. In the current study, an environmentally friendly approach to the preparation of a reduced graphene oxide-gold nanoparticle (rGO-AuNP) nanocomposite was developed by using L-cysteine and vitamin C as reductants under mild reaction conditions. The rGO-AuNP material showed a highly selective separation ability for 6 naturally occurring aflatoxins, which are easily adsorbed onto traditional graphene materials but are difficult to be desorbed. The specificity of the nanocomposite was evaluated in the separation of 6 aflatoxin congeners (aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, aflatoxin M1 and aflatoxin M2) from 23 other biotoxins (including, ochratoxin A, citrinin, and deoxynivalenol). The results indicated that this material was specific for separating aflatoxin congeners. The synthesized material was further validated by determining the recovery (77.6-105.0%), sensitivity (limit of detection in the range of 0.05-0.21 μg kg -1 ), and precision (1.5-11.8%), and was then successfully applied to the separation of aflatoxins from real-world maize, wheat and rice samples.

Encapsulation of antigen-loaded silica nanoparticles into microparticles for intradermal powder injection.

Science.gov (United States)

Deng, Yibin; Mathaes, Roman; Winter, Gerhard; Engert, Julia

2014-10-15

Epidermal powder immunisation (EPI) is being investigated as a promising needle-free delivery methods for vaccination. The objective of this work was to prepare a nanoparticles-in-microparticles (nano-in-micro) system, integrating the advantages of nanoparticles and microparticles into one vaccine delivery system for epidermal powder immunisation. Cationic mesoporous silica nanoparticles (MSNP-NH2) were prepared and loaded with ovalbumin as a model antigen. Loading was driven by electrostatic interactions. Ovalbumin-loaded silica nanoparticles were subsequently formulated into sugar-based microparticles by spray-freeze-drying. The obtained microparticles meet the size requirement for EPI. Confocal microscopy was used to demonstrate that the nanoparticles are homogeneously distributed in the microparticles. Furthermore, the silica nanoparticles in the dry microparticles can be re-dispersed in aqueous solution showing no aggregation. The recovered ovalbumin shows integrity compared to native ovalbumin. The present nano-in-micro system allows (1) nanoparticles to be immobilized and finely distributed in microparticles, (2) microparticle formation and (3) re-dispersion of nanoparticles without subsequent aggregation. The nanoparticles inside microparticles can (1) adsorb proteins to cationic shell/surface voids in spray-dried products without detriment to ovalbumin stability, (2) deliver antigens in nano-sized modes to allow recognition by the immune system. Copyright © 2014 Elsevier B.V. All rights reserved.

Chemical and thermal stability of core-shelled magnetite nanoparticles and solid silica

Science.gov (United States)

Cendrowski, Krzysztof; Sikora, Pawel; Zielinska, Beata; Horszczaruk, Elzbieta; Mijowska, Ewa

2017-06-01

Pristine nanoparticles of magnetite were coated by solid silica shell forming core/shell structure. 20 nm thick silica coating significantly enhanced the chemical and thermal stability of the iron oxide. Chemical and thermal stability of this structure has been compared to the magnetite coated by mesoporous shell and pristine magnetite nanoparticles. It is assumed that six-membered silica rings in a solid silica shell limit the rate of oxygen diffusion during thermal treatment in air and prevent the access of HCl molecules to the core during chemical etching. Therefore, the core/shell structure with a solid shell requires a longer time to induce the oxidation of iron oxide to a higher oxidation state and, basically, even strong concentrated acid such as HCl is not able to dissolve it totally in one month. This leads to the desired performance of the material in potential applications such as catalysis and environmental protection.

A multifunctional role of trialkylbenzenes for the preparation of aqueous colloidal mesostructured/mesoporous silica nanoparticles with controlled pore size, particle diameter, and morphology

Science.gov (United States)

Yamada, Hironori; Ujiie, Hiroto; Urata, Chihiro; Yamamoto, Eisuke; Yamauchi, Yusuke; Kuroda, Kazuyuki

2015-11-01

Both the pore size and particle diameter of aqueous colloidal mesostructured/mesoporous silica nanoparticles (CMSS/CMPS) derived from tetrapropoxysilane were effectively and easily controlled by the addition of trialkylbenzenes (TAB). Aqueous highly dispersed CMPS with large pores were successfully obtained through removal of surfactants and TAB by a dialysis process. The pore size (from 4 nm to 8 nm) and particle diameter (from 50 nm to 380 nm) were more effectively enlarged by the addition of 1,3,5-triisopropylbenzene (TIPB) than 1,3,5-trimethylbenzene (TMB), and the enlargement did not cause the variation of the mesostructure and particle morphology. The larger molecular size and higher hydrophobicity of TIPB than TMB induce the incorporation of TIPB into micelles without the structural change. When TMB was used as TAB, the pore size of CMSS was also enlarged while the mesostructure and particle morphology were varied. Interestingly, when tetramethoxysilane and TIPB were used, CMSS with a very small particle diameter (20 nm) with concave surfaces and large mesopores were obtained, which may strongly be related to the initial nucleation of CMSS. A judicious choice of TAB and Si sources is quite important to control the mesostructure, size of mesopores, particle diameter, and morphology.Both the pore size and particle diameter of aqueous colloidal mesostructured/mesoporous silica nanoparticles (CMSS/CMPS) derived from tetrapropoxysilane were effectively and easily controlled by the addition of trialkylbenzenes (TAB). Aqueous highly dispersed CMPS with large pores were successfully obtained through removal of surfactants and TAB by a dialysis process. The pore size (from 4 nm to 8 nm) and particle diameter (from 50 nm to 380 nm) were more effectively enlarged by the addition of 1,3,5-triisopropylbenzene (TIPB) than 1,3,5-trimethylbenzene (TMB), and the enlargement did not cause the variation of the mesostructure and particle morphology. The larger molecular size

Mesoporous Silica Molecular Sieve based Nanocarriers: Transpiring Drug Dissolution Research.

Science.gov (United States)

Pattnaik, Satyanarayan; Pathak, Kamla

2017-01-01

Improvement of oral bioavailability through enhancement of dissolution for poorly soluble drugs has been a very promising approach. Recently, mesoporous silica based molecular sieves have demonstrated excellent properties to enhance the dissolution velocity of poorly water-soluble drugs. Current research in this area is focused on investigating the factors influencing the drug release from these carriers, the kinetics of drug release and manufacturing approaches to scale-up production for commercial manufacture. This comprehensive review provides an overview of different methods adopted for synthesis of mesoporous materials, influence of processing factors on properties of these materials and drug loading methods. The drug release kinetics from mesoporous silica systems, the manufacturability and stability of these formulations are reviewed. Finally, the safety and biocompatibility issues related to these silica based materials are discussed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

X-ray spectroscopy study of electronic structure of laser-irradiated Au nanoparticles in a silica film

International Nuclear Information System (INIS)

Jonnard, P.; Bercegol, H.; Lamaignere, L.; Morreeuw, J.-P.; Rullier, J.-L.; Cottancin, E.; Pellarin, M.

2005-01-01

The electronic structure of gold nanoparticles embedded in a silica film is studied, both before and after irradiation at 355 nm by a laser. The Au 5d occupied valence states are observed by x-ray emission spectroscopy. They show that before irradiation the gold atoms are in metallic states within the nanoparticles. After irradiation with a fluence of 0.5 J/cm 2 , it is found that gold valence states are close to those of a metal-poor gold silicide; thanks to a comparison of the experimental Au 5d states with the calculated ones for gold silicides using the density-functional theory. The formation of such a compound is driven by the diffusion of the gold atoms into the silica film upon the laser irradiation. At higher fluence, 1 J/cm 2 , we find a higher percentage of metallic gold that could be attributed to annealing in the silica matrix

In situ synthesis of Cu-BTC (HKUST-1) in macro-/mesoporous silica monoliths for continuous flow catalysis.

Science.gov (United States)

Sachse, Alexander; Ameloot, Rob; Coq, Bernard; Fajula, François; Coasne, Benoît; De Vos, Dirk; Galarneau, Anne

2012-05-16

The metal-organic framework Cu-BTC has been successfully synthesized as nanoparticles inside the mesopores of silica monoliths featuring a homogeneous macropore network enabling the use of Cu-BTC for continuous flow applications in liquid phase with low pressure drop. High productivity was reached with this catalyst for the Friedländer reaction. This journal is © The Royal Society of Chemistry 2012

Mesoporous anatase TiO2/reduced graphene oxide nanocomposites: A simple template-free synthesis and their high photocatalytic performance

International Nuclear Information System (INIS)

Zhou, Qi; Zhong, Yong-Hui; Chen, Xing; Huang, Xing-Jiu; Wu, Yu-Cheng

2014-01-01

Graphical abstract: - Highlights: • Mesoporous TiO 2 nanoparticles with anatase phase were assembled on reduced graphene oxide via a template-free one-step hydrothermal method. • The TiO 2 /rGO nanocomposites have better adsorption capacity and photocatalytic degradation efficiency for dyes removal. • Improved dye adsorption and photogenerated charge separation are responsible for enhanced activity. - Abstract: Mesoporous anatase phase TiO 2 was assembled on reduced graphene oxide (rGO) using a template-free one-step hydrothermal process. The nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and Brunauer–Emmett–Teller (BET) surface area. Morphology of TiO 2 was related to the content of graphene oxide. TiO 2 /rGO nanocomposites exhibited excellent photocatalytic activity for the photo-degradation of methyl orange. The degradation rate was 4.5 times greater than that of pure TiO 2 nanoparticles. This difference was attributed to the thin two-dimensional graphene sheet. The graphene sheet had a large surface area, high adsorption capacity, and acted as a good electron acceptor for the transfer of photo-generated electrons from the conduction band of TiO 2 . The enhanced surface adsorption characteristics and excellent charge transport separation were independent properties of the photocatalytic degradation process

Bone tissue engineering using silica-based mesoporous nanobiomaterials:Recent progress.

Science.gov (United States)

Shadjou, Nasrin; Hasanzadeh, Mohammad

2015-10-01

Bone disorders are of significant concern due to increase in the median age of our population. It is in this context that tissue engineering has been emerging as a valid approach to the current therapies for bone regeneration/substitution. Tissue-engineered bone constructs have the potential to alleviate the demand arising from the shortage of suitable autograft and allograft materials for augmenting bone healing. Silica based mesostructured nanomaterials possessing pore sizes in the range 2-50 nm and surface reactive functionalities have elicited immense interest due to their exciting prospects in bone tissue engineering. In this review we describe application of silica-based mesoporous nanomaterials for bone tissue engineering. We summarize the preparation methods, the effect of mesopore templates and composition on the mesopore-structure characteristics, and different forms of these materials, including particles, fibers, spheres, scaffolds and composites. Also, the effect of structural and textural properties of mesoporous materials on development of new biomaterials for production of bone implants and bone cements was discussed. Also, application of different mesoporous materials on construction of manufacture 3-dimensional scaffolds for bone tissue engineering was discussed. It begins by giving the reader a brief background on tissue engineering, followed by a comprehensive description of all the relevant components of silica-based mesoporous biomaterials on bone tissue engineering, going from materials to scaffolds and from cells to tissue engineering strategies that will lead to "engineered" bone. Copyright © 2015 Elsevier B.V. All rights reserved.

Adsorption behavior of natural anthocyanin dye on mesoporous silica

Science.gov (United States)

Kohno, Yoshiumi; Haga, Eriko; Yoda, Keiko; Shibata, Masashi; Fukuhara, Choji; Tomita, Yasumasa; Maeda, Yasuhisa; Kobayashi, Kenkichiro

2014-01-01

Because of its non-toxicity, naturally occurring anthocyanin is potentially suitable as a colorant for foods and cosmetics. To the wider use of the anthocyanin, the immobilization on the inorganic host for an easy handling as well as the improvement of the stability is required. This study is focused on the adsorption of significant amount of the natural anthocyanin dye onto mesoporous silica, and on the stability enhancement of the anthocyanin by the complexation. The anthocyanin has successfully been adsorbed on the HMS type mesoporous silica containing small amount of aluminum. The amount of the adsorbed anthocyanin has been increased by modifying the pore wall with n-propyl group to make the silica surface hydrophobic. The light fastness of the adsorbed anthocyanin has been improved by making the composite with the HMS samples containing aluminum, although the degree of the improvement is not so large. It has been proposed that incorporation of the anthocyanin molecule deep inside the mesopore is required for the further enhancement of the stability.

Ion-Exchange-Induced Selective Etching for the Synthesis of Amino-Functionalized Hollow Mesoporous Silica for Elevated-High-Temperature Fuel Cells

DEFF Research Database (Denmark)

Zhang, Jin; Liu, Jian; Lu, Shanfu

2017-01-01

is verified through a successful synthesis of hollow mesoporous silica. After infiltration with phosphotungstic acid (PWA), PWA–NH2–HMS nanoparticles are dispersed in the poly(ether sulfone)–polyvinylpyrrolidone (PES–PVP) matrix, forming a hybrid PWA–NH2–HMS/PES–PVP nanocomposite membrane. The resultant...

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.

Triconstituent co-assembly to ordered mesostructured polymer-silica and carbon-silica nanocomposites and large-pore mesoporous carbons with high surface areas.

Science.gov (United States)

Liu, Ruili; Shi, Yifeng; Wan, Ying; Meng, Yan; Zhang, Fuqiang; Gu, Dong; Chen, Zhenxia; Tu, Bo; Zhao, Dongyuan

2006-09-06

Highly ordered mesoporous polymer-silica and carbon-silica nanocomposites with interpenetrating networks have been successfully synthesized by the evaporation-induced triconstituent co-assembly method, wherein soluble resol polymer is used as an organic precursor, prehydrolyzed TEOS is used as an inorganic precursor, and triblock copolymer F127 is used as a template. It is proposed for the first time that ordered mesoporous nanocomposites have "reinforced concrete"-structured frameworks. By adjusting the initial mass ratios of TEOS to resol, we determined the obtained nanocomposites possess continuous composition with the ratios ranging from zero to infinity for the two constituents that are "homogeneously" dispersed inside the pore walls. The presence of silicates in nanocomposites dramatically inhibits framework shrinkage during the calcination, resulting in highly ordered large-pore mesoporous carbon-silica nanocomposites. Combustion in air or etching in HF solution can remove carbon or silica from the carbon-silica nanocomposites and yield ordered mesoporous pure silica or carbon frameworks. The process generates plenty of small pores in carbon or/and silica pore walls. Ordered mesoporous carbons can then be obtained with large pore sizes of approximately 6.7 nm, pore volumes of approximately 2.0 cm(3)/g, and high surface areas of approximately 2470 m(2)/g. The pore structures and textures can be controlled by varying the sizes and polymerization degrees of two constituent precursors. Accordingly, by simply tuning the aging time of TEOS, ordered mesoporous carbons with evident bimodal pores at 2.6 and 5.8 nm can be synthesized.

Utilization of a by-product produced from oxidative desulfurization process over Cs-mesoporous silica catalysts.

Science.gov (United States)

Kim, Hyeonjoo; Jeong, Kwang-Eun; Jeong, Soon-Yong; Park, Young-Kwon; Kim, Do Heui; Jeon, Jong-Ki

2011-02-01

We investigated the use of Cs-mesoporous silica catalysts to upgrade a by-product of oxidative desulfurization (ODS). Cs-mesoporous silica catalysts were characterized through N2 adsorption, XRD, CO2-temperature-programmed desorption, and XRF. Cs-mesoporous silica prepared by the direct incorporation method showed higher catalytic performance than a Cs/MCM-41 catalyst by impregnation method for the catalytic decomposition of sulfone compounds produced from ODS process.

Investigating unexpected magnetism of mesoporous silica-supported Pd and PdO nanoparticles

KAUST Repository

Song, Hyon Min

2015-01-13

The synthesis and magnetic behavior of matrix-supported Pd and PdO nanoparticles (NPs) are described. Mesoporous silica with hexagonal columnal packing is selected as a template, and the impregnation method with thermal annealing is used to obtain supported Pd and PdO NPs. The heating rate and the annealing conditions determine the particle size and the phase of the NPs, with a fast heating rate of 30 °C/min producing the largest supported Pd NPs. Unusual magnetic behaviors are observed. (1) Contrary to the general belief that smaller Pd NPs or cluster size particles have higher magnetization, matrix-supported Pd NPs in this study maintain the highest magnetization with room temperature ferromagnetism when the size is the largest. (2) Twin boundaries along with stacking faults are more pronounced in these large Pd NPs and are believed to be the reason for this high magnetization. Similarly, supported PdO NPs were prepared under air conditions with different heating rates. Their phase is tetragonal (P42/mmc) with cell parameters of a = 3.050 Å and c = 5.344 Å, which are slightly larger than in the bulk phase (a = 3.03 Å, c = 5.33 Å). Faster heating rate of 30 °C/min also produces larger particles and larger magnetic hysteresis loop, although magnetization is smaller and few twin boundaries are observed compared to the supported metallic Pd NPs.

Micromolding in inverted polymer opals (MIPO): synthesis of hexagonal mesoporous silica opals

Energy Technology Data Exchange (ETDEWEB)

Yang Sanming; Coombs, N.; Ozin, G.A. [Toronto Univ., Ont. (Canada). Materials Chemistry Research Group

2000-12-15

Regular arrays of hexagonal mesoporous silica spheres are crucial for a number of applications, but until now control of the diameter, dispersity, and packing of the spheres has not proved possible. These authors report a new method-micromolding in inverted polymer opals-that allows the synthesis of such hexagonal mesoporous silica opals for the first time. (orig.)

Preparation of magnetic graphene/mesoporous silica composites with phenyl-functionalized pore-walls as the restricted access matrix solid phase extraction adsorbent for the rapid extraction of parabens from water-based skin toners.

Science.gov (United States)

Feng, Jianan; He, Xinying; Liu, Xiaodan; Sun, Xueni; Li, Yan

2016-09-23

In this work, phenyl-functionalized magnetic graphene/mesoporous silica composites (MG-mSiO2-Ph) were prepared and applied as restricted access matrix solid phase extraction (RAM-SPE) adsorbents to determine the parabens in commercially available retail cosmetics. MG-mSiO2-Ph composites were synthesized by a surfactant-mediated co-condensation reaction in which mesoporous silica with phenyl-functionalized pore-walls was coated on a magnetic graphene sheet. The obtained nano-composites were proven to be of sufficient quality for an ideal RAM-SPE adsorbent with a large specific surface area of 369m(2)g(-1), uniform mesopores of 2.8nm, and special phenyl-functionalized pore-walls. Parabens, such as methyl paraben, ethyl paraben and propyl paraben, were extracted from water-based skin toners using one step of the RAM-SPE and were then analysed by a HPLC-DAD system. The SPE conditions were optimized by studying the parameters, such as the adsorbent amount, elution solvent type, adsorption time and desorption time, that influence the extraction efficiency. For each analyte, there were good linearities of approximately 0.10-120μgmL(-1) with determination coefficients (R(2))>0.995. The sensitivity was as low as 0.01-0.025μgmL(-1) for the LOD, and the percent recoveries were 98.37-105.84%. The intra-day and inter-day RSDs were 1.44-6.11% (n=6) and 3.12-11.70% (n=6), respectively. The results indicated that this method with novel RAM-SPE adsorbents is sensitive and convenient. The results also offered an attractive alternative for the extraction and determination of paraben preservatives in a complex matrix, such as cosmetics. Copyright © 2016 Elsevier B.V. All rights reserved.

Surface enhanced Raman scattering of gold nanoparticles supported on copper foil with graphene as a nanometer gap

International Nuclear Information System (INIS)

Xiang, Quan; Zhu, Xupeng; Chen, Yiqin; Duan, Huigao

2016-01-01

Gaps with single-nanometer dimensions (<10 nm) between metallic nanostructures enable giant local field enhancements for surface enhanced Raman scattering (SERS). Monolayer graphene is an ideal candidate to obtain a sub-nanometer gap between plasmonic nanostructures. In this work, we demonstrate a simple method to achieve a sub-nanometer gap by dewetting a gold film supported on monolayer graphene grown on copper foil. The Cu foil can serve as a low-loss plasmonically active metallic film that supports the imaginary charge oscillations, while the graphene can not only create a stable sub-nanometer gap for massive plasmonic field enhancements but also serve as a chemical enhancer. We obtained higher SERS enhancements in this graphene-gapped configuration compared to those in Au nanoparticles on Cu film or on graphene–SiO 2 –Si. Also, the Raman signals measured maintained their fine features and intensities over a long time period, indicating the stability of this Au–graphene–Cu hybrid configuration as an SERS substrate. (paper)

Surface modification to improve the sorption property of U(VI) on mesoporous silica

International Nuclear Information System (INIS)

Lijuan Song; Yulong Wang; Lu Zhu; Bolong Guo; Suwen Chen; Wangsuo Wu

2014-01-01

Polyoxometalates K 7 [α-PW 11 O 39 ]·14H 2 O (PW11) modified mesoporous silica (MCM-48) with cubic structure, was prepared by impregnation and calcination methods. The modified mesoporous silica sorbent (PW11/MCM-48) was studied as a potential adsorbent for U(VI) from aqueous solutions. MCM-48 and PW11/MCM-48 were confirmed by X-ray diffraction and nitrogen physisorption techniques. The results indicate the original keggin structure of PW11 and mesoporous structure of MCM-48 are maintained after supporting PW11 on mesoporous silica MCM-48. The effects of contact time, solid-to-liquid ratio (m/V), solution pH and ionic strength on U(VI) sorption behaviors of the pure and modified mesoporous silicas were also studied. Typical sorption isotherms such as Langmuir and Freundlich isotherms were determined for sorption process. The results suggest that the sorption of U(VI) on MCM-48 or PW11/MCM-48 are strongly dependent on pH values but independent of ionic strength. The sorption capacity of PW11/MCM-48 for U(VI) is about ten times more than that of MCM-48. (author)

Mesoporous silica-coated NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} particles for drug release

Energy Technology Data Exchange (ETDEWEB)

Kong Deyan; Fan Yong; Zhang Cuimiao; Lin Jun, E-mail: jlin@ciac.jl.c [Chinese Academy of Sciences, State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry (China)

2010-02-15

NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} nanoparticles were successfully prepared by a polyol process using diethyleneglycol (DEG) as solvent. These NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} nanoparticles can be coated with mesoporous silica using nonionic triblock copolymer EO{sub 20}PO{sub 70}EO{sub 20} (P 123) as structure-directing agent and other materials. The composites can load ibuprofen and release the drug in the phosphate buffer solution (PBS). The composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen absorption/desorption isotherms, fluorescence spectra, and UV/Vis absorption spectra, respectively. The composites have the mesoporous structure. In addition, the composites emit red fluorescence (from Er{sup 3+}) under 980 nm near infrared laser excitation, which can be used as fluorescent probes in the drug-delivery system.

Hyaluronic acid oligosaccharide modified redox-responsive mesoporous silica nanoparticles for targeted drug delivery.

Science.gov (United States)

Zhao, Qinfu; Geng, Hongjian; Wang, Ying; Gao, Yikun; Huang, Jiahao; Wang, Yan; Zhang, Jinghai; Wang, Siling

2014-11-26

A redox-responsive delivery system based on colloidal mesoporous silica (CMS) has been developed, in which 6-mercaptopurine (6-MP) was conjugated to vehicles by cleavable disulfide bonds. The oligosaccharide of hyaluronic acid (oHA) was modified on the surface of CMS by disulfide bonds as a targeting ligand and was able to increase the stability and biocompatibility of CMS under physiological conditions. In vitro release studies indicated that the cumulative release of 6-MP was less than 3% in the absence of glutathione (GSH), and reached nearly 80% within 2 h in the presence of 3 mM GSH. Confocal microscopy and fluorescence-activated cell sorter (FACS) methods were used to evaluate the cellular uptake performance of fluorescein isothiocyanate (FITC) labeled CMS, with and without oHA modification. The CMS-SS-oHA exhibited a higher cellular uptake performance via CD44 receptor-mediated endocytosis in HCT-116 (CD44 receptor-positive) cells than in NIH-3T3 (CD44 receptor-negative) cells. 6-MP loaded CMS-SS-oHA exhibited greater cytotoxicity against HCT-116 cells than NIH-3T3 cells due to the enhanced cell uptake behavior of CMS-SS-oHA. This study provides a novel strategy to covalently link bioactive drug and targeting ligand to the interiors and exteriors of mesoporous silica to construct a stimulus-responsive targeted drug delivery system.

Fabrication of gold-nanoparticle arrays using photolithography and thermal dewetting

NARCIS (Netherlands)

de Vreede, Lennart; Göeken, Kristian; Göeken, Kristian; Gill, Ron; Gill, Ron; van den Berg, Albert; Eijkel, Jan C.T.; Zengerle, R.

2013-01-01

We demonstrate a new manufacturing method using only basic cleanroom techniques to produce an array of 106 100 nm diameter gold-nanoparticles (GNPs) of equal shape and 5 μm spacing on a fused silica surface. Photolithography and sputtering are used to produce gold islets, followed by a simple

Unconventional route to encapsulated ultrasmall gold nanoparticles for high-temperature catalysis.

Science.gov (United States)

Zhang, Tingting; Zhao, Hongyu; He, Shengnan; Liu, Kai; Liu, Hongyang; Yin, Yadong; Gao, Chuanbo

2014-07-22

Ultrasmall gold nanoparticles (us-AuNPs, gold hydroxide nanoparticles, which have excellent affinity to silica, then carrying out controllable silica coating in reverse micelles, and finally converting gold hydroxide particles into well-protected us-AuNPs. With a single-core/shell configuration that prevents sintering of nearby us-AuNPs and amino group modification of the Au/SiO2 interface that provides additional coordinating interactions, the resulting us-AuNP@SiO2 nanospheres are highly stable at high temperatures and show high activity in catalytic CO oxidation reactions. A dramatic and continuous increase in the catalytic activity has been observed when the size of the us-AuNPs decreases from 2.3 to 1.5 nm, which reflects the intrinsic size effect of the Au nanoparticles on an inert support. The synthesis scheme described in this work is believed to be extendable to many other ultrasmall metal@oxide nanostructures for much broader catalytic applications.

Catalytic reduction of organic dyes at gold nanoparticles impregnated silica materials: influence of functional groups and surfactants

International Nuclear Information System (INIS)

Azad, Uday Pratap; Ganesan, Vellaichamy; Pal, Manas

2011-01-01

Gold nanoparticles (Au NPs) in three different silica based sol–gel matrixes with and without surfactants are prepared. They are characterized by UV–vis absorbance and transmission electron microscopic (TEM) studies. The size and shape of Au NPs varied with the organo-functional group present in the sol–gel matrix. In the presence of mercaptopropyl functionalized organo-silica, large sized (200–280 nm) spherical Au NPs are formed whereas in the presence of aminopropyl functionalized organo-silica small sized (5–15 nm) Au NPs are formed inside the tube like organo-silica. Further, it is found that Au NPs act as efficient catalyst for the reduction of organic dyes. The catalytic rate constant is evaluated from the decrease in absorbance of the dye molecules. Presence of cationic or anionic surfactants greatly influences the catalytic reaction. The other factors like hydrophobicity of the organic dyes, complex formation of the dyes with anionic surfactants, repulsion between dyes and cationic surfactant, adsorption of dyes on the Au NPs also play important role on the reaction rate.

Catalytic reduction of organic dyes at gold nanoparticles impregnated silica materials: influence of functional groups and surfactants

Energy Technology Data Exchange (ETDEWEB)

Azad, Uday Pratap; Ganesan, Vellaichamy, E-mail: velganesh@yahoo.com; Pal, Manas [Banaras Hindu University, Department of Chemistry, Faculty of Science (India)

2011-09-15

Gold nanoparticles (Au NPs) in three different silica based sol-gel matrixes with and without surfactants are prepared. They are characterized by UV-vis absorbance and transmission electron microscopic (TEM) studies. The size and shape of Au NPs varied with the organo-functional group present in the sol-gel matrix. In the presence of mercaptopropyl functionalized organo-silica, large sized (200-280 nm) spherical Au NPs are formed whereas in the presence of aminopropyl functionalized organo-silica small sized (5-15 nm) Au NPs are formed inside the tube like organo-silica. Further, it is found that Au NPs act as efficient catalyst for the reduction of organic dyes. The catalytic rate constant is evaluated from the decrease in absorbance of the dye molecules. Presence of cationic or anionic surfactants greatly influences the catalytic reaction. The other factors like hydrophobicity of the organic dyes, complex formation of the dyes with anionic surfactants, repulsion between dyes and cationic surfactant, adsorption of dyes on the Au NPs also play important role on the reaction rate.

Intermediate-range order in mesoporous silicas investigated by a high-energy X-ray diffraction technique

International Nuclear Information System (INIS)

Wakihara, Toru; Fan, Wei; Ogura, Masaru; Okubo, Tatsuya; Kohara, Shinji; Sankar, Gopinathan

2008-01-01

We perform a high-energy X-ray diffraction study comparing bulk amorphous silica with MCM-41 and SBA-15 that are representative mesoporous silicas prepared in basic and acidic conditions, respectively. It is revealed that mesoporous silicas, especially SBA-15, have less ordered structures and contain larger fractions of three- and four-membered rings than does bulk amorphous silica. (author)

Pore Characteristics and Hydrothermal Stability of Mesoporous Silica: Role of Oleic Acid

Directory of Open Access Journals (Sweden)

Junhyun Choi

2014-01-01

Full Text Available Silicate mesoporous materials were synthesized with nonionic surfactant and their surfaces were modified by oleic acid adsorption. Infrared spectrometer, nitrogen adsorption-desorption isotherm, scanning electron microscopy, and thermogravimetric analyses were used to investigate the structure of oleic acid modified mesoporous material. The effects of heat treatment at various temperatures on oleic acid modified materials were also studied. Oleic acids on silica surfaces were found to be bonded chemically and/or physically and be capable of enduring up to 180°C. The adsorbed oleic acid improved the hydrothermal stability of mesoporous silica and assisted mesopore structure to grow more in hydrothermal treatment process by preventing the approach of water.

Catalytic properties of Thallium-containing mesoporous silicas

Directory of Open Access Journals (Sweden)

A. Baradji

2017-02-01

Full Text Available The benzylation of benzene by benzyl chloride over a series of Thallium-containing mesoporous silicas with different Tl contents has been investigated. These materials (Tl-HMS-n have been characterized by chemical analysis, N2 adsorption/desorption isotherm and X-ray diffraction (XRD. The mesoporous Thallium-containing materials showed both high activity and high selectivity for the benzylation of benzene. More interesting is the observation that these catalysts are always active and selective for large molecules like naphthenic compounds such as methoxynaphthalene.

Immobilization of mesoporous silica particles on stainless steel plates

International Nuclear Information System (INIS)

Pasqua, Luigi; Morra, Marco

2017-01-01

A preliminary study aimed to the nano-engineering of stainless steel surface is presented. Aminopropyl-functionalized mesoporous silica is covalently and electrostatically anchored on the surface of stainless steel plates. The anchoring is carried out through the use of a nanometric spacer, and two different spacers are proposed (both below 2 nm in size). The first sample is obtained by anchoring to the stainless steel amino functionalized, a glutaryl dichloride spacer. This specie forms an amide linkage with the amino group while the unreacted acyl groups undergo hydrolysis giving a free carboxylic group. The so-obtained functionalized stainless steel plate is used as substrate for anchoring derivatized mesoporous silica particles. The second sample is prepared using 2-bromo-methyl propionic acid as spacer (BMPA). Successively, the carboxylic group of propionic acid is condensed to the aminopropyl derivatization on the external surface of the mesoporous silica particle through covalent bond. In both cases, a continuous deposition (coating thickness is around 10 μm) is obtained, in fact, XPS data do not reveal the metal elements constituting the plate. The nano-engineering of metal surfaces can represent an intriguing opportunity for producing long-term drug release or biomimetic surface.

Immobilization of mesoporous silica particles on stainless steel plates

Energy Technology Data Exchange (ETDEWEB)

Pasqua, Luigi, E-mail: luigi.pasqua@unical.it [University of Calabria, Department of Environmental and Chemical Engineering (Italy); Morra, Marco, E-mail: mmorra@nobilbio.com [Via Valcastellana 26 (Italy)

2017-03-15

A preliminary study aimed to the nano-engineering of stainless steel surface is presented. Aminopropyl-functionalized mesoporous silica is covalently and electrostatically anchored on the surface of stainless steel plates. The anchoring is carried out through the use of a nanometric spacer, and two different spacers are proposed (both below 2 nm in size). The first sample is obtained by anchoring to the stainless steel amino functionalized, a glutaryl dichloride spacer. This specie forms an amide linkage with the amino group while the unreacted acyl groups undergo hydrolysis giving a free carboxylic group. The so-obtained functionalized stainless steel plate is used as substrate for anchoring derivatized mesoporous silica particles. The second sample is prepared using 2-bromo-methyl propionic acid as spacer (BMPA). Successively, the carboxylic group of propionic acid is condensed to the aminopropyl derivatization on the external surface of the mesoporous silica particle through covalent bond. In both cases, a continuous deposition (coating thickness is around 10 μm) is obtained, in fact, XPS data do not reveal the metal elements constituting the plate. The nano-engineering of metal surfaces can represent an intriguing opportunity for producing long-term drug release or biomimetic surface.

Fabrication of mesoporous silica/polymer composites through solvent evaporation process and investigation of their excellent low thermal expansion property.

Science.gov (United States)

Suzuki, Norihiro; Kiba, Shosuke; Yamauchi, Yusuke

2011-03-21

We fabricate mesoporous silica/epoxy polymer composites through a solvent evaporation process. The easy penetration of the epoxy polymers into mesopores is achieved by using a diluted polymer solution including a volatile organic solvent. After the complete solvent evaporation, around 90% of the mesopores are estimated to be filled with the epoxy polymer chains. Here we carefully investigate the thermal expansion behavior of the obtained mesoporous silica/polymer composites. Thermal mechanical analysis (TMA) charts revealed that coefficient of linear thermal expansion (CTE) gradually decreases, as the amount of the doped mesoporous silica increases. Compared with spherical silica particle without mesopores, mesoporous silica particles show a greater effect on lowering the CTE values. Interestingly, it is found that the CTE values are proportionally decreased with the decrease of the total amount of the polymers outside the mesopores. These data demonstrate that polymers embedded inside the mesopores become thermally stable, and do not greatly contribute to the thermal expansion behavior of the composites.

Photocatalytic degradation of methyl red dye by silica nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Badr, Y. [National Institute of Laser Enhanced Science, Cairo University, Cairo (Egypt); Abd El-Wahed, M.G. [Chemistry Department, Faculty of Science, Zagazig University, Zagazig (Egypt); Mahmoud, M.A. [Chemistry Department, Faculty of Science, Zagazig University, Zagazig (Egypt)], E-mail: mahmoudchem@yahoo.com

2008-06-15

Silica nanoparticles (SiO{sub 2} NPs) were found to be photocatalytically active for degradation of methyl red dye (MR). The SiO{sub 2} NPs and SiO{sub 2} NPs doped with silver (and or) gold nanoparticles were prepared. From the transmission electron microscopy (TEM) images the particle size and particle morphology of catalysts were monitored. Moreover, SiO{sub 2} NPs doped with silver and gold ions were used as a photocatalyst for degradation of MR. The rate of photocatalytic degradation of MR was found to be increased in the order of SiO{sub 2} NPs, SiO{sub 2} NPs coated with gold nanoparticles (Au NPs) and silver nanoparticles (Ag NPs), SiO{sub 2} NPs coated with Ag NPs, SiO{sub 2} NPs coated with Au NPs, Ag{sup +}-doped SiO{sub 2} NPs, and Au{sup 3+}-doped SiO{sub 2} NPs. The kinetic and mechanism of photocatalytic reaction were studied and accorded well with experimental results.

Preparation of hierarchical micro-mesoporous aluminosilicate composites by simple Y zeolite/MCM-48 silica assembly

Energy Technology Data Exchange (ETDEWEB)

Enterría, Marina, E-mail: marina@incar.csic.es; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M.D.

2014-01-15

Highlights: • Hierarchical micro-mesoporous aluminosilicates were synthesized. • Y zeolite core/MCM-48 silica shell structures were obtained. • Y zeolite favors the formation of the mesostructure. • Porosity and structure can be varied by modifying the preparation variables. • Duration of the hydrothermal step has a great effect on the materials properties. -- Abstract: A simple procedure to obtain hierarchical micro-mesoporous aluminosilicate composites was developed by growing MCM-48 silica over commercial Y zeolite. The obtained hierarchical composites have a microporous core and a mesoporous shell. The process consists in assembling dispersed Y zeolite with a mesoporous silica phase that is formed “in situ” by “soft-templating” with cetryltrimethylammonium bromide (CTAB) as surfactant. The Y zeolite/MCM-48 silica ratio and aging time were varied to study their effects on the final porosity and structure of the hierarchical composites. The pore textural and structural characteristics of the composites did not match those of the corresponding Y zeolite/MCM-48 silica physical mixtures. This implies that the synthesized composites integrate micropores and mesopores in the same bulk. The obtained composites exhibited micropore and mesopore volumes ranging between 0.15–0.31 and 0.30–0.51 cm{sup 3}/g, respectively. X-ray diffraction and N{sub 2} adsorption results revealed that the presence of zeolite in the reaction medium favors the formation of mesopores in the obtained materials, especially for short hydrothermal treatments. TEM results showed that the obtained adsorbents are constituted by an integrated micro-mesoporous bimodal system in which Y zeolite is surrounded by a thin cover of MCM-48 silica.

Preparation of hierarchical micro-mesoporous aluminosilicate composites by simple Y zeolite/MCM-48 silica assembly

International Nuclear Information System (INIS)

Enterría, Marina; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M.D.

2014-01-01

Highlights: • Hierarchical micro-mesoporous aluminosilicates were synthesized. • Y zeolite core/MCM-48 silica shell structures were obtained. • Y zeolite favors the formation of the mesostructure. • Porosity and structure can be varied by modifying the preparation variables. • Duration of the hydrothermal step has a great effect on the materials properties. -- Abstract: A simple procedure to obtain hierarchical micro-mesoporous aluminosilicate composites was developed by growing MCM-48 silica over commercial Y zeolite. The obtained hierarchical composites have a microporous core and a mesoporous shell. The process consists in assembling dispersed Y zeolite with a mesoporous silica phase that is formed “in situ” by “soft-templating” with cetryltrimethylammonium bromide (CTAB) as surfactant. The Y zeolite/MCM-48 silica ratio and aging time were varied to study their effects on the final porosity and structure of the hierarchical composites. The pore textural and structural characteristics of the composites did not match those of the corresponding Y zeolite/MCM-48 silica physical mixtures. This implies that the synthesized composites integrate micropores and mesopores in the same bulk. The obtained composites exhibited micropore and mesopore volumes ranging between 0.15–0.31 and 0.30–0.51 cm 3 /g, respectively. X-ray diffraction and N 2 adsorption results revealed that the presence of zeolite in the reaction medium favors the formation of mesopores in the obtained materials, especially for short hydrothermal treatments. TEM results showed that the obtained adsorbents are constituted by an integrated micro-mesoporous bimodal system in which Y zeolite is surrounded by a thin cover of MCM-48 silica

Hindered disulfide bonds to regulate release rate of model drug from mesoporous silica.

Science.gov (United States)

Nadrah, Peter; Maver, Uroš; Jemec, Anita; Tišler, Tatjana; Bele, Marjan; Dražić, Goran; Benčina, Mojca; Pintar, Albin; Planinšek, Odon; Gaberšček, Miran

2013-05-01

With the advancement of drug delivery systems based on mesoporous silica nanoparticles (MSNs), a simple and efficient method regulating the drug release kinetics is needed. We developed redox-responsive release systems with three levels of hindrance around the disulfide bond. A model drug (rhodamine B dye) was loaded into MSNs' mesoporous voids. The pore opening was capped with β-cyclodextrin in order to prevent leakage of drug. Indeed, in absence of a reducing agent the systems exhibited little leakage, while the addition of dithiothreitol cleaved the disulfide bonds and enabled the release of cargo. The release rate and the amount of released dye were tuned by the level of hindrance around disulfide bonds, with the increased hindrance causing a decrease in the release rate as well as in the amount of released drug. Thus, we demonstrated the ability of the present mesoporous systems to intrinsically control the release rate and the amount of the released cargo by only minor structural variations. Furthermore, an in vivo experiment on zebrafish confirmed that the present model delivery system is nonteratogenic.

Soft-Templating Synthesis of Mesoporous Silica-Based Materials for Environmental Applications

Science.gov (United States)

Gunathilake, Chamila Asanka

Dissertation research is mainly focus on: 1) the development of mesoporous silica materials with organic pendant and bridging groups (isocyanurate, amidoxime, benzene) and incorporated metal (aluminum, zirconium, calcium, and magnesium) species for high temperature carbon dioxide (CO2) sorption, 2) phosphorous-hydroxy functionalized mesoporous silica materials for water treatment, and 3) amidoxime-modified ordered mesoporous silica materials for uranium sorption under seawater conditions. The goal is to design composite materials for environmental applications with desired porosity, surface area, and functionality by selecting proper metal oxide precursors, organosilanes, tetraethylorthosilicate, (TEOS), and block copolymer templates and by adjusting synthesis conditions. The first part of dissertation presents experimental studies on the merge of aluminum, zirconium, calcium, and magnesium oxides with mesoporous silica materials containing organic pendant (amidoxime) and bridging groups (isocyanurate, benzene) to obtain composite sorbents for CO2 sorption at ambient (0-25 °C) and elevated (60-120 °C) temperatures. These studies indicate that the aforementioned composite sorbents are fairly good for CO2 capture at 25 °C via physisorption mechanism and show a remarkably high affinity toward CO2 chemisorption at 60-120 °C. The second part of dissertation is devoted to silica-based materials with organic functionalities for removal of heavy metal ions such as lead from contaminated water and for recovery of metal ions such as uranium from seawater. First, ordered mesoporous organosilica (OMO) materials with diethylphosphatoethyl and hydroxyphosphatoethyl surface groups were examined for Pb2+ adsorption and showed unprecedented adsorption capacities up to 272 mg/g and 202 mg/g, respectively However, the amidoxime-modified OMO materials were explored for uranium extraction under seawater conditions and showed remarkable capacities reaching 57 mg of uranium per gram

Gold Nanoparticles Supported on Fibrous Silica Nanospheres (KCC-1) as Efficient Heterogeneous Catalysts for CO Oxidation

KAUST Repository

Qureshi, Ziyauddin S.; Sarawade, Pradip B.; Hussain, Irshad; Zhu, Haibo; Al-Johani, Hind; Anjum, Dalaver H.; Hedhili, Mohamed N.; Maity, Niladri; D'Elia, Valerio; Basset, Jean-Marie

2016-01-01

Gold nanoparticles (Au NPs) of different sizes were supported on fibrous silica nanospheres (KCC-1) by various methods. The size and the location of the Au NPs on the support were found to depend on the preparation method. The KCC-1-supported Au NPs were thoroughly characterized by using HR-TEM, XRD, X-ray photoelectron spectroscopy, UV, and Brunauer-Emmett-Teller surface area measurements and were applied in catalysis for the oxidation of CO. The catalytic performance is discussed in relation to the morphological properties of KCC-1. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gold Nanoparticles Supported on Fibrous Silica Nanospheres (KCC-1) as Efficient Heterogeneous Catalysts for CO Oxidation

KAUST Repository

Qureshi, Ziyauddin S.

2016-04-13

Gold nanoparticles (Au NPs) of different sizes were supported on fibrous silica nanospheres (KCC-1) by various methods. The size and the location of the Au NPs on the support were found to depend on the preparation method. The KCC-1-supported Au NPs were thoroughly characterized by using HR-TEM, XRD, X-ray photoelectron spectroscopy, UV, and Brunauer-Emmett-Teller surface area measurements and were applied in catalysis for the oxidation of CO. The catalytic performance is discussed in relation to the morphological properties of KCC-1. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Amperometric xanthine biosensors using glassy carbon electrodes modified with electrografted porous silica nanomaterials loaded with xanthine oxidase

International Nuclear Information System (INIS)

Saadaoui, Maroua; Sánchez, Alfredo; Díez, Paula; Raouafi, Noureddine; Pingarrón, José M.; Villalonga, Reynaldo

2016-01-01

Glassy carbon electrodes were modified with silica materials such as silica nanoparticles, mesoporous silica nanoparticles and mesoporous silica thin films with the aim to introduce scaffolds suitable for the immobilization of enzymes. Xanthine oxidase was selected as a model enzyme, and xanthine as the target analyte. A comparison of the modified electrodes showed the biosensor prepared with mesoporous silica nanoparticles to perform best. By using the respective biosensor, xanthine can be amperometrically determined (via measurement of enzymatically formed hydrogen peroxide) at a working voltage of 0.7 V (vs. Ag/AgCl) with a 0.28 μM detection limit. The biosensor was evaluated in terms of potential interferences, reproducibility and stability, and applied to the determination of fish freshness via sensing of xanthine. (author)

Phosphoryl functionalized mesoporous silica for uranium adsorption

International Nuclear Information System (INIS)

Xue, Guo; Yurun, Feng; Li, Ma; Dezhi, Gao; Jie, Jing; Jincheng, Yu; Haibin, Sun; Hongyu, Gong; Yujun, Zhang

2017-01-01

Highlights: • Phosphoryl functionalized mesoporous silica (TBP-SBA-15) is synthesized. • The amino and phosphoryl groups are successfully grafted on SBA-15. • TBP-SBA-15 has high and rapid uranium adsorption capacity in broad pH range. • The U(VI) adsorption of TBP-SBA-15 is spontaneous and belongs to chemical adsorption. - Abstract: Phosphoryl functionalized mesoporous silica (TBP-SBA-15) was synthesized by modified mesoporous silica with γ-amino propyl triethoxy silane and tributyl phosphate. The obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), small angle X-ray diffraction (SAXRD), thermo-gravimetric/differential thermalanalyzer (TG/DTA), N_2 adsorption–desorption (BET) and Fourier transform infrared spectroscopy (FT-IR) techniques. Results showed that TBP-SBA-15 had large surface areas with ordered channel structure. Moreover, the effects of adsorption time, sorbent dose, solution pH, initial uranium concentration and temperature on the uranium adsorption behaviors were investigated. TBP-SBA-15 showed a high uranium adsorption capacity in a broad range of pH values. The U(VI) adsorption rate of TBP-SBA-15 was fast and nearly achieved completion in 10 min with the sorbent dose of 1 g/L. The U(VI) adsorption of TBP-SBA-15 followed the pseudo-second-order kinetic model and Freundlich isotherm model, indicating that the process was belonged to chemical adsorption. Furthermore, the thermodynamic parameters (ΔG"0, ΔH"0 and ΔS"0) confirmed that the adsorption process was endothermic and spontaneous.

Phosphoryl functionalized mesoporous silica for uranium adsorption

Energy Technology Data Exchange (ETDEWEB)

Xue, Guo; Yurun, Feng; Li, Ma; Dezhi, Gao; Jie, Jing; Jincheng, Yu; Haibin, Sun [Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Hongyu, Gong, E-mail: gong_hongyu@163.com [Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Yujun, Zhang, E-mail: yujunzhangcn@163.com [Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Jinan 250061 (China)

2017-04-30

Highlights: • Phosphoryl functionalized mesoporous silica (TBP-SBA-15) is synthesized. • The amino and phosphoryl groups are successfully grafted on SBA-15. • TBP-SBA-15 has high and rapid uranium adsorption capacity in broad pH range. • The U(VI) adsorption of TBP-SBA-15 is spontaneous and belongs to chemical adsorption. - Abstract: Phosphoryl functionalized mesoporous silica (TBP-SBA-15) was synthesized by modified mesoporous silica with γ-amino propyl triethoxy silane and tributyl phosphate. The obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), small angle X-ray diffraction (SAXRD), thermo-gravimetric/differential thermalanalyzer (TG/DTA), N{sub 2} adsorption–desorption (BET) and Fourier transform infrared spectroscopy (FT-IR) techniques. Results showed that TBP-SBA-15 had large surface areas with ordered channel structure. Moreover, the effects of adsorption time, sorbent dose, solution pH, initial uranium concentration and temperature on the uranium adsorption behaviors were investigated. TBP-SBA-15 showed a high uranium adsorption capacity in a broad range of pH values. The U(VI) adsorption rate of TBP-SBA-15 was fast and nearly achieved completion in 10 min with the sorbent dose of 1 g/L. The U(VI) adsorption of TBP-SBA-15 followed the pseudo-second-order kinetic model and Freundlich isotherm model, indicating that the process was belonged to chemical adsorption. Furthermore, the thermodynamic parameters (ΔG{sup 0}, ΔH{sup 0} and ΔS{sup 0}) confirmed that the adsorption process was endothermic and spontaneous.

Sugar and pH dual-responsive mesoporous silica nanocontainers based on competitive binding mechanisms

Science.gov (United States)

Yilmaz, M. Deniz; Xue, Min; Ambrogio, Michael W.; Buyukcakir, Onur; Wu, Yilei; Frasconi, Marco; Chen, Xinqi; Nassar, Majed S.; Stoddart, J. Fraser; Zink, Jeffrey I.

2014-12-01

A sugar and pH dual-responsive controlled release system, which is highly specific towards molecular stimuli, has been developed based on the binding between catechol and boronic acid on a platform of mesoporous silica nanoparticles (MSNs). By grafting phenylboronic acid stalks onto the silica surface, catechol-containing β-cyclodextrins can be attached to the orifices of the MSNs' nanopores through formation of boronate esters which block access to the nanopores. These esters are stable enough to prevent cargo molecules from escaping. The boronate esters disassociate in the presence of sugars, enabling the molecule-specific controlled-release feature of this hybrid system. The rate of release has been found to be tunable by varying both the structures and the concentrations of sugars, as a result of the competitive binding nature associated with the mechanism of its operation. Acidification also induces the release of cargo molecules. Further investigations show that the presence of both a low pH and sugar molecules provides cooperative effects which together control the rate of release.A sugar and pH dual-responsive controlled release system, which is highly specific towards molecular stimuli, has been developed based on the binding between catechol and boronic acid on a platform of mesoporous silica nanoparticles (MSNs). By grafting phenylboronic acid stalks onto the silica surface, catechol-containing β-cyclodextrins can be attached to the orifices of the MSNs' nanopores through formation of boronate esters which block access to the nanopores. These esters are stable enough to prevent cargo molecules from escaping. The boronate esters disassociate in the presence of sugars, enabling the molecule-specific controlled-release feature of this hybrid system. The rate of release has been found to be tunable by varying both the structures and the concentrations of sugars, as a result of the competitive binding nature associated with the mechanism of its operation

Radiolabeling Silica-Based Nanoparticles via Coordination Chemistry: Basic Principles, Strategies, and Applications.

Science.gov (United States)

Ni, Dalong; Jiang, Dawei; Ehlerding, Emily B; Huang, Peng; Cai, Weibo

2018-03-20

As one of the most biocompatible and well-tolerated inorganic nanomaterials, silica-based nanoparticles (SiNPs) have received extensive attention over the last several decades. Recently, positron emission tomography (PET) imaging of radiolabeled SiNPs has provided a highly sensitive, noninvasive, and quantitative readout of the organ/tissue distribution, pharmacokinetics, and tumor targeting efficiency in vivo, which can greatly expedite the clinical translation of these promising NPs. Encouraged by the successful PET imaging of patients with metastatic melanoma using 124 I-labeled ultrasmall SiNPs (known as Cornell dots or C dots) and their approval as an Investigational New Drug (IND) by the United States Food and Drug Administration, different radioisotopes ( 64 Cu, 89 Zr, 18 F, 68 Ga, 124 I, etc.) have been reported to radiolabel a wide variety of SiNPs-based nanostructures, including dense silica (dSiO 2 ), mesoporous silica (MSN), biodegradable mesoporous silica (bMSN), and hollow mesoporous silica nanoparticles (HMSN). With in-depth knowledge of coordination chemistry, abundant silanol groups (-Si-O-) on the silica surface or inside mesoporous channels not only can be directly used for chelator-free radiolabeling but also can be readily modified with the right chelators for chelator-based labeling. However, integrating these labeling strategies for constructing stably radiolabeled SiNPs with high efficiency has proven difficult because of the complexity of the involved key parameters, such as the choice of radioisotopes and chelators, nanostructures, and radiolabeling strategy. In this Account, we present an overview of recent progress in the development of radiolabeled SiNPs for cancer theranostics in the hope of speeding up their biomedical applications and potential translation into the clinic. We first introduce the basic principles and mechanisms for radiolabeling SiNPs via coordination chemistry, including general rules of selecting proper

Ageing-induced enhancement of open porosity of mesoporous silica films studied by positron annihilation spectroscopy

International Nuclear Information System (INIS)

He Chunqing; Muramatsu, Makoto; Oshima, Nagayasu; Ohdaira, Toshiyuki; Kinomura, Atsushi; Suzuki, Ryoichi

2006-01-01

We show that ageing of the silica sol in a closed vessel enhanced the open porosity of calcined mesoporous silica film studied by positron. Positron annihilation lifetime spectroscopy (PALS) based on a pulsed slow positron beam was used to estimate the mesopore size. 2-dimensional PALS (2D-PALS) and ortho-positronium time-of-flight (Ps-TOF) were used to evaluate the open porosity, interconnectivity and tortuosity of mesopores in the silica films. Results revealed that little change in pore size but significant enhancement of open porosity and/or pore interconnectivity occurred in the silica film deposited after the precursor solution aged for a relative longer time

Biological Fate of Fe3O4 Core-Shell Mesoporous Silica Nanoparticles Depending on Particle Surface Chemistry

Science.gov (United States)

Rascol, Estelle; Daurat, Morgane; Da Silva, Afitz; Maynadier, Marie; Dorandeu, Christophe; Charnay, Clarence; Garcia, Marcel; Lai-Kee-Him, Joséphine; Bron, Patrick; Auffan, Mélanie; Angeletti, Bernard; Devoisselle, Jean-Marie; Guari, Yannick; Gary-Bobo, Magali; Chopineau, Joël

2017-01-01

The biological fate of nanoparticles (NPs) for biomedical applications is highly dependent of their size and charge, their aggregation state and their surface chemistry. The chemical composition of the NPs surface influences their stability in biological fluids, their interaction with proteins, and their attraction to the cell membranes. In this work, core-shell magnetic mesoporous silica nanoparticles (Fe3O4@MSN), that are considered as potential theranostic candidates, are coated with polyethylene glycol (PEG) or 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayer. Their biological fate is studied in comparison to the native NPs. The physicochemical properties of these three types of NPs and their suspension behavior in different media are investigated. The attraction to a membrane model is also evaluated using a supported lipid bilayer. The surface composition of NPs strongly influences their dispersion in biological fluids mimics, protein binding and their interaction with cell membrane. While none of these types of NPs is found to be toxic on mice four days after intravenous injection of a dose of 40 mg kg−1 of NPs, their surface coating nature influences the in vivo biodistribution. Importantly, NP coated with DMPC exhibit a strong accumulation in liver and a very low accumulation in lung in comparison with nude or PEG ones. PMID:28665317

Utilization of rice husk ash as silica source for the synthesis of mesoporous silicas and their application to CO2 adsorption through TREN/TEPA grafting

International Nuclear Information System (INIS)

Bhagiyalakshmi, Margandan; Yun, Lee Ji; Anuradha, Ramani; Jang, Hyun Tae

2010-01-01

Mesoporous MCM-41, MCM-48 and SBA-15 were synthesized using Rice husk ash (RHA) as the silica source and their defective Si-OH sites were functionalized by 3-cholropropyltrimethoxysilane (CPTMS) which was subsequently grafted with amine compounds, Tris(2-aminoethyl)amine (TREN) and Tetraethylenepentamine (TEPA). X-ray powder diffraction (XRD) and BET results of the parent mesoporous silica suggested their closeness of structural properties to those obtained from conventional silica sources. CO 2 adsorption of branched amine TREN and straight chain amine TEPA at 25, 50 and 75 deg. C was obtained by Thermogravimetric Analyser (TGA) at atmospheric pressure. TREN grafted mesoporous silica showed 7% of CO 2 adsorption while TEPA grafted mesoporous silicas showed less CO 2 adsorption, which is due to the presence of isolated amine groups in TREN. TREN grafted mesoporous silicas were also observed to be selective towards CO 2 , thermally stable and recyclable. The order of CO 2 adsorption with respect to amount of amine grafting was observed to be MCM-48/TREN > MCM-41/TREN > SBA-15/TREN.

One-pot synthesis of redox-responsive polymers-coated mesoporous silica nanoparticles and their controlled drug release.

Science.gov (United States)

Sun, Jiao-Tong; Piao, Ji-Gang; Wang, Long-Hai; Javed, Mohsin; Hong, Chun-Yan; Pan, Cai-Yuan

2013-09-01

A versatile one-pot strategy for the preparation of reversibly cross-linked polymer-coated mesoporous silica nanoparticles (MSNs) via surface reversible addition-fragmentation chain transfer (RAFT) polymerization is presented for the first time in this paper. The less reactive monomer oligo(ethylene glycol) acrylate (OEGA) and the more reactive cross-linker N,N'-cystaminebismethacrylamide (CBMA) are chosen to be copolymerized on the external surfaces of RAFT agent-functionalized MSNs to form the cross-linked polymer shells. Owing to the reversible cleavage and restoration of disulfide bonds via reduction/oxidation reactions, the polymer shells can control the on/off switching of the nanopores and regulate the drug loading and release. The redox-responsive release of doxorubicin (DOX) from this drug carrier is realized. The protein adsorption, in vitro cytotoxicity assays, and endocytosis studies demonstrate that this biocompatible vehicle is a potential candidate for delivering drugs. It is expected that this versatile grafting strategy may help fabricate satisfying MSN-based drug delivery systems for clinical application. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and characterization of mesoporous silica core-shell particles

Directory of Open Access Journals (Sweden)

Milan Nikolić

2010-06-01

Full Text Available Core-shell particles were formed by deposition of primary silica particles synthesized from sodium silicate solution on functionalized silica core particles (having size of ~0.5 µm prepared by hydrolysis and condensation of tetraethylortosilicate. The obtained mesoporous shell has thickness of about 60 nm and consists of primary silica particles with average size of ~21 nm. Scanning electron microscopy and zeta potential measurements showed that continuous silica shell exists around functionalized core particles which was additionally proved by FTIR and TEM results.

Composite hydrogel based on surface modified mesoporous silica and poly[(2-acryloyloxy)ethyl trimethylammonium chloride

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Torres, Cecilia C.; Urbano, Bruno F.; Campos, Cristian H.; Rivas, Bernabé L.; Reyes, Patricio

2015-01-01

This work focused on the synthesis, characterization and water absorbency of a composite hydrogel based on poly[(2-acryloyloxy)ethyl trimethylammonium chloride] and mesoporous silica, MCM-41. The MCM-41 was synthesized and later surface functionalized with triethoxyvinylsilane (VTES) and 3-trimethoxysilylpropylmethacrylate (TMSPM) by a post-grafting procedure. The composite hydrogels were obtained by in-situ polymerization using a mixture of monomer, crosslinker and initiator in the presence of functionalized MCM-41. Diverse characterization techniques were used at the different stages of synthesis, namely, FT-IR, TEM, SEM, DRX, 29 Si and 13 C solid state NMR, and N 2 adsorption isotherms at 77 K. Finally, the water uptake performance of the composites was tested as a function of time, mesoporous silica loading and coupling agent used at the functionalization. The composites using non-functionalized MCM-41 reached the highest water uptake, whereas those composite with MCM-41 TMSPM exhibited the lowest sorption. - Highlights: • Hydrophilic crosslinked polymer-mesoporous silica was obtained. • Mesoporous silica MCM-41 was synthesized and functionalized with organosilane. • Functionalization of MCM-41 affects the water uptake of composite. • Mesoporous silica is covalently bound to the polymer acting as crosslinked point

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

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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.

Mesoporous Structure Control of Silica in Room-Temperature Synthesis under Basic Conditions

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Jeong Wook Seo

2015-01-01

Full Text Available Various types of mesoporous silica, such as continuous cubic-phase MCM-48, hexagonal-phase MCM-41, and layer-phase spherical silica particles, have been synthesized at room temperature using cetyltrimethylammonium bromide as a surfactant, ethanol as a cosurfactant, tetraethyl orthosilicate as a silica precursor, and ammonia as a condensation agent. Special care must be taken both in the filtering of the resultant solid products and in the drying process. In the drying process, further condensation of the silica after filtering was induced. As the surfactant and cosurfactant concentrations in the reaction mixture increased and the NH3 concentration decreased, under given conditions, continuous cubic MCM-48 and layered silica became the dominant phases. A cooperative synthesis mechanism, in which both the surfactant and silica were involved in the formation of mesoporous structures, provided a good explanation of the experimental results.

Facile synthesis of functionalized ionic surfactant templated mesoporous silica for incorporation of poorly water-soluble drug.

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Li, Jing; Xu, Lu; Yang, Baixue; Wang, Hongyu; Bao, Zhihong; Pan, Weisan; Li, Sanming

2015-08-15

The present paper reported amino group functionalized anionic surfactant templated mesoporous silica (Amino-AMS) for loading and release of poorly water-soluble drug indomethacin (IMC) and carboxyl group functionalized cationic surfactant templated mesoporous silica (Carboxyl-CMS) for loading and release of poorly water-soluble drug famotidine (FMT). Herein, Amino-AMS and Carboxyl-CMS were facilely synthesized using co-condensation method through two types of silane coupling agent. Amino-AMS was spherical nanoparticles, and Carboxyl-CMS was well-formed spherical nanosphere with a thin layer presented at the edge. Drug loading capacity was obviously enhanced when using Amino-AMS and Carboxyl-CMS as drug carriers due to the stronger hydrogen bonding force formed between surface modified carrier and drug. Amino-AMS and Carboxyl-CMS had the ability to transform crystalline state of loaded drug from crystalline phase to amorphous phase. Therefore, IMC loaded Amino-AMS presented obviously faster release than IMC because amorphous phase of IMC favored its dissolution. The application of asymmetric membrane capsule delayed FMT release significantly, and Carboxyl-CMS favored sustained release of FMT due to its long mesoporous channels and strong interaction formed between its carboxyl group and amino group of FMT. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of polyvinylpyrrolidone on mesoporous silica morphology and esterification of lauric acid with 1-butanol catalyzed by immobilized enzyme

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Zhang, Jinyu; Zhou, Guowei, E-mail: guoweizhou@hotmail.com; Jiang, Bin; Zhao, Minnan; Zhang, Yan

2014-05-01

Mesoporous silica materials with a range of morphology evolution, i.e., from curved rod-shaped mesoporous silica to straight rod-shaped mesoporous silica, were successfully prepared using polyvinylpyrrolidone (PVP) and triblock copolymer as dual template. The effects of PVP molecular weight and concentration on mesoporous silica structure parameters were studied. Results showed that surface area and pore volume continuously decreased with increased PVP molecular weight. Mesoporous silica prepared with PVP K30 also possessed larger pore diameter, interplanar spacing (d{sub 100}), and cell parameter (a{sub 0}) than that prepared with PVP K15 and PVP K90. In addition, with increased PVP concentration, d{sub 100} and a{sub 0} continuously decreased. The mechanism of morphology evolution caused by the change in PVP concentration was investigated. The conversion rate of lauric acid with 1-butanol catalyzed by immobilized Porcine pancreatic lipase (PPL) was also evaluated. Results showed that PPL immobilized on amino-functionalized straight rod-shaped mesoporous silica maintained 50% of its esterification conversion rate even after five cycles of use with a maximum conversion rate was about 90.15%. - Graphical abstract: Curved rod-shaped mesoporous silica can be obtained at low and the highest PVP concentration, while straight rod-shaped mesoporous silica can be obtained at higher PVP concentration. - Highlights: • Mesoporous silica with morphology evolution from CRMS to SRMS were prepared. • Effects of PVP molecular weight and concentration on silica morphology were studied. • A possible mechanism for the formation of morphology evolution SiO{sub 2} was proposed. • Esterification of lauric acid with 1-butanol catalyzed by immobilized PPL.

High-performance liquid chromatography separation of unsaturated organic compounds by a monolithic silica column embedded with silver nanoparticles.

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Zhu, Yang; Morisato, Kei; Hasegawa, George; Moitra, Nirmalya; Kiyomura, Tsutomu; Kurata, Hiroki; Kanamori, Kazuyoshi; Nakanishi, Kazuki

2015-08-01

The optimization of a porous structure to ensure good separation performances is always a significant issue in high-performance liquid chromatography column design. Recently we reported the homogeneous embedment of Ag nanoparticles in periodic mesoporous silica monolith and the application of such Ag nanoparticles embedded silica monolith for the high-performance liquid chromatography separation of polyaromatic hydrocarbons. However, the separation performance remains to be improved and the retention mechanism as compared with the Ag ion high-performance liquid chromatography technique still needs to be clarified. In this research, Ag nanoparticles were introduced into a macro/mesoporous silica monolith with optimized pore parameters for high-performance liquid chromatography separations. Baseline separation of benzene, naphthalene, anthracene, and pyrene was achieved with the theoretical plate number for analyte naphthalene as 36,000 m(-1). Its separation function was further extended to cis/trans isomers of aromatic compounds where cis/trans stilbenes were chosen as a benchmark. Good separation of cis/trans-stilbene with separation factor as 7 and theoretical plate number as 76,000 m(-1) for cis-stilbene was obtained. The trans isomer, however, is retained more strongly, which contradicts the long- established retention rule of Ag ion chromatography. Such behavior of Ag nanoparticles embedded in a silica column can be attributed to the differences in the molecular geometric configuration of cis/trans stilbenes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, Characterization, and Catalytic Activity of Pd(II Salen-Functionalized Mesoporous Silica

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Rotcharin Sawisai

2017-01-01

Full Text Available Salen ligand synthesized from 2-hydroxybenzaldehyde and 2-hydroxy-1-naphthaldehyde was used as a palladium chelating ligand for the immobilization of the catalytic site. Mesoporous silica supported palladium catalysts were prepared by immobilizing Pd(OAc2 onto a mesoporous silica gel through the coordination of the imine-functionalized mesoporous silica gel. The prepared catalysts were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive X-ray (EDX, inductivity couple plasma (ICP, nitrogen adsorption-desorption, and Fourier transform infrared (FT-IR spectroscopy. The solid catalysts showed higher activity for the hydroamination of C-(tetra-O-acetyl-β-D-galactopyranosylallene with aromatic amines compared with the corresponding homogenous catalyst. The heterogeneous catalytic system can be easily recovered by simple filtration and reused for up to five cycles with no significant loss of catalytic activity.

A review on chemical methodologies for preparation of mesoporous silica and alumina based materials.

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Naik, Bhanudas; Ghosh, Narendra Nath

2009-01-01

The discovery of novel family of molecular sieves called M41S aroused a worldwide resurgence in the field of porous materials. According to IUPAC definition inorganic solids that contain pores with diameter in the size range of 20-500 A are considered mesoporous materials. Mesoporous silica and alumina based materials find applications in catalysis, adsorption, host- guest encapsulation etc. This article reviews the current state of art and outline the recent patents in mesoporous materials research in three general areas: Synthesis, various mechanisms involved for porous structure formation and applications of silica and alumina based mesoporous materials.

Ternary Hollow Mesoporous TiN/N-Graphene/Pt Hybrid Results in Enhanced Electrocatalytic Performance for Methanol Oxidation and Oxygen Reduction Reaction

International Nuclear Information System (INIS)

Liu, Baocang; Huo, Lili; Zhang, Geng; Zhang, Jun

2016-01-01

Highlights: • A novel hollow mesoporous ternary @M-TiN/N-G/Pt electrocatalysts were synthesized. • The @M-TiN/N-G/Pt electrocatalysts displayed outstanding activity and stability toward MOR and ORR. • The activity and stability of @M-TiN/N-G/Pt electrocatalysts were higher than Pt/TiN, @M-TiN/Pt, and Pt/C catalysts. • The excellent electrocatalytic performance rooted in its unique configuration. • Several reasons were proposed to explain the enhanced electrocatalytic performance of @M-TiN/N-G/Pt. - Abstract: A novel hollow mesoporous TiN/N-graphene (N-G) hybrid architecture (@M-TiN/N-G) composed of N-doped graphene wrapped mesoporous TiN nanoparticle shells was constructed for the first time. It can be used as an efficient support for creating a highly efficient ternary @M-TiN/N-G/Pt electrocatalyst with superior catalytic activity and stability for methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) through decorating well-dispersed Pt nanoparticles on @M-TiN/N-G surface. By optimizing the content of N-G in catalysts, the @M-TiN/N-G/Pt catalysts display superior catalytic activity and stability toward MOR and ORR to traditional Pt/C and graphene-free Pt/TiN and @M-TiN/Pt catalysts. The various characterization results reveal that the outstanding electrocatalytic performance of @M-TiN/N-G/Pt catalyst roots in its large surface area, high porosity, strong interaction among Pt, TiN, and N-G, excellent electron transfer property facilitated by N-doped graphene, and small size of Pt and TiN nanocrystals. The synthetic approach may be available for constructing other graphene based hollow metal nitrides, carbides, and phosphides for various electrocatalytic applications.

Staphylococcus aureus detection in blood samples by silica nanoparticle-oligonucleotides conjugates.

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Borsa, Baris A; Tuna, Bilge G; Hernandez, Frank J; Hernandez, Luiza I; Bayramoglu, Gulay; Arica, M Yakup; Ozalp, V Cengiz

2016-12-15

A fast, specific and sensitive homogeneous assay for Staphylococcus aureus detection was developed by measuring the activity of secreted nuclease from the bacteria via a modified DNA oligonucleotide. As biosensor format, an effective system, Nanokeepers as previously reported, were used for triggered release of confined fluorophores, and hence specific detection of S. aureus on nuclease activity was obtained. The interference from blood components for fluorescent quantification was eliminated by a pre-purification by aptamer-functionalized silica magnetic nanoparticles. The reported assay system was exclusively formed by nucleic acid oligos and magnetic or mesoporous silica nanoparticles, that can be used on blood samples in a stepwise manner. The assay was successfully used as a sensing platform for the specific detection of S. aureus cells as low as 682 CFU in whole blood. Copyright © 2016 Elsevier B.V. All rights reserved.

In vitro study of biocompatibility of a graphene composite with gold nanoparticles and hydroxyapatite on human osteoblasts.

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Crisan, Liana; Crisan, Bogdan; Soritau, Olga; Baciut, Mihaela; Biris, Alexandru Radu; Baciut, Grigore; Lucaciu, Ondine

2015-10-01

The purpose of this study was to evaluate the biocompatibility of some composites consisting of different proportions of graphene in combination with gold nanoparticles (AuNPs) and nanostructured hydroxyapatite (HA) on osteoblast viability, proliferation and differentiation. Au/HA@graphene composites synthesized by the catalytic chemical vapor deposition induction heating method with acetylene as the carbon source and over an Au/HA catalyst, were characterized by transmission electron microscopy, thermogravimetric analysis and Raman spectroscopy and showed that the few-layer graphene was grown over the Au/HA catalyst. The cytocompatibility study was performed using the fluorescein diacetate assay for assessment of the viability and proliferation of osteoblasts cultivated in the presence of HA, Au/HA and Au/HA@graphene composites as colloidal suspensions or as substrates. The most favorable composites for cell adhesion and proliferation were HA, Au/HA and Au/HA composites with 1.6% and 3.15% concentration of graphenes. Immunocytochemical staining performed after 19 days of osteoblasts cultivation on substrates showed that the graphene composites induced low expression of alkaline phosphatase compared to the control group and HA and Au/HA substrates. The presence of graphene in the substrate composition also induced an increased level of intracellular osteopontin and cytoskeleton reorganization (actin-F) depending on graphene concentration, suggesting cell activation, increased cellular adhesion and acquisition of a mechanosensorial osteocyte phenotype. Copyright © 2015 John Wiley & Sons, Ltd.

Three-dimensional structure of Au nanoparticles supported on amorphous silica and carbon substrates

International Nuclear Information System (INIS)

Bruma, A; Li, Z Y

2012-01-01

Scanning Transmission Electron Microscope (STEM) has been employed to study the three-dimensional structure of gold (Au) nanoparticles deposited by means of thermal evaporation in high vacuum on amorphous silica (a-SiO 2 ) and amorphous carbon (a-C) supports. By performing quantitative analysis on the evolution of the high angle annular dark field (HAADF) images, we studied the influence of the nature and the temperature of support on the growth mode of gold nanoparticles.

Synthesis of mesoporous silica microsphere from dual surfactant

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Venkatathri Narayanan

2008-12-01

Full Text Available A new procedure is reported to synthesis mesoporous silica micro sphere for the first time. In these method two surfactants namely Span 80 and Tween 80 were used. Small angle X ray diffraction and N2 adsorption analysis shows the synthesized material has mesoporous property. The material has spherical morphology with 1-10 µm particle size. Beside the material found to have microcapsule property as observed from the Transmission electron microscopy. The Fourier transform Infrared spectroscopic analysis reveals that the materials are similar to other mesoporous materials. We also encapsulated an UV-absorber Ibuprofen inside the microcapsule, by mixing it before the synthesis. This shows a possibility of the materials in cosmetic applications.

EpCAM aptamer-functionalized polydopamine-coated mesoporous silica nanoparticles loaded with DM1 for targeted therapy in colorectal cancer

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Li Y

2017-08-01

Full Text Available Yang Li,1,* Yanhong Duo,2,3,* Shiyun Bao,1 Lisheng He,4 Kai Ling,5 Jinfeng Luo,4 Yue Zhang,1 Hao Huang,2 Han Zhang,2 Xiaofang Yu1 1Department of Hepatobiliary and Pancreas Surgery, Second Clinical Medical College of Jinan University, Shenzhen People’s Hospital, 2Shenzhen Engineering Laboratory of Phosphorene and Optoelectronics, Collaborative Innovation Center for Optoelectronic Science and Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 3Key Laboratory of Plant Cell Activities and Stress Adaptation, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 4Department of Pathology, 5Institute of Respiratory Diseases, Second Clinical Medical College of Jinan University, Shenzhen People’s Hospital, Shenzhen, China *These authors contributed equally to this work Abstract: DM1, a maytansine derivative, is a highly potential cytotoxic agent but with severe side effects; therefore, its application in clinical cancer therapy is limited. Here, in order to mitigate this intrinsic drawback of DM1, we developed mesoporous silica nanoparticles (MSNs loaded with DM1 and surface-decorated with hydrochloride dopamine (PDA, polyethylene glycol (PEG, and epithelial cell adhesion molecule (EpCAM aptamer (APt for the targeted treatment of colorectal cancer (CRC. In this system, the PDA coating could be used as pH-sensitive gatekeepers to control the release of DM1 from MSNs in response to the pH stimulus and EpCAM APt-guided active targeting enables the increased delivery of DM1 to CRC as well as a reduction in toxicity and side effects by minimizing the exposure of normal tissues to DM1. Results demonstrated that DM1 inhibited the formation of microtubules and induced apoptosis in tumor cells via caspase signaling. In comparison with the control groups, the MSNs-DM1@PDA-PEG-APt bioconjugates exhibited

Micelle-Template Synthesis of Nitrogen-Doped Mesoporous Graphene as an Efficient Metal-Free Electrocatalyst for Hydrogen Production

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Huang, Xiaodan; Zhao, Yufei; Ao, Zhimin; Wang, Guoxiu

2014-12-01

Synthesis of mesoporous graphene materials by soft-template methods remains a great challenge, owing to the poor self-assembly capability of precursors and the severe agglomeration of graphene nanosheets. Herein, a micelle-template strategy to prepare porous graphene materials with controllable mesopores, high specific surface areas and large pore volumes is reported. By fine-tuning the synthesis parameters, the pore sizes of mesoporous graphene can be rationally controlled. Nitrogen heteroatom doping is found to remarkably render electrocatalytic properties towards hydrogen evolution reactions as a highly efficient metal-free catalyst. The synthesis strategy and the demonstration of highly efficient catalytic effect provide benchmarks for preparing well-defined mesoporous graphene materials for energy production applications.

Composite hydrogel based on surface modified mesoporous silica and poly[(2-acryloyloxy)ethyl trimethylammonium chloride

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Torres, Cecilia C. [Department of Organic Chemistry, Faculty of Chemical Science, University of Concepción (Chile); Urbano, Bruno F., E-mail: burbano@udec.cl [Department of Polymer Chemistry, Faculty of Chemical Science, University of Concepción (Chile); Campos, Cristian H. [Department of Organic Chemistry, Faculty of Chemical Science, University of Concepción (Chile); Rivas, Bernabé L. [Department of Polymer Chemistry, Faculty of Chemical Science, University of Concepción (Chile); Reyes, Patricio [Department of Physical Chemistry, Faculty of Chemical Science, University of Concepción (Chile)

2015-02-15

This work focused on the synthesis, characterization and water absorbency of a composite hydrogel based on poly[(2-acryloyloxy)ethyl trimethylammonium chloride] and mesoporous silica, MCM-41. The MCM-41 was synthesized and later surface functionalized with triethoxyvinylsilane (VTES) and 3-trimethoxysilylpropylmethacrylate (TMSPM) by a post-grafting procedure. The composite hydrogels were obtained by in-situ polymerization using a mixture of monomer, crosslinker and initiator in the presence of functionalized MCM-41. Diverse characterization techniques were used at the different stages of synthesis, namely, FT-IR, TEM, SEM, DRX, {sup 29}Si and {sup 13}C solid state NMR, and N{sub 2} adsorption isotherms at 77 K. Finally, the water uptake performance of the composites was tested as a function of time, mesoporous silica loading and coupling agent used at the functionalization. The composites using non-functionalized MCM-41 reached the highest water uptake, whereas those composite with MCM-41 TMSPM exhibited the lowest sorption. - Highlights: • Hydrophilic crosslinked polymer-mesoporous silica was obtained. • Mesoporous silica MCM-41 was synthesized and functionalized with organosilane. • Functionalization of MCM-41 affects the water uptake of composite. • Mesoporous silica is covalently bound to the polymer acting as crosslinked point.

A mesoporous silica composite scaffold: Cell behaviors, biomineralization and mechanical properties

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Xu, Yong; Gao, Dan; Feng, Pei; Gao, Chengde; Peng, Shuping; Ma, HaoTian; Yang, Sheng; Shuai, Cijun

2017-11-01

Mesoporous structure is beneficial to cellular response due to the large specific surface area and high pore volume. In this study, mesoporous silica (SBA15) was incorporated into poly-L-lactic acid (PLLA) to construct composite scaffold by selective laser sintering. The results showed that SBA15 facilitated cells proliferation, which was mainly attributed to its unique intrinsic mesoporous structure and the released bioactive silicon. Moreover, the hydrolyzate of soluble mesoporous silica can adsorb ions to form nucleation sites that promote biomineralization, leading to improve biological activity of the composite scaffold. In addition, the compressive strength, compressive modulus and Vickers hardness of the scaffold were increased by 47.6%, 35.5% and 29.53% respectively with 1.5 wt.% SBA15. It was found that the particle enhancement of uniform distributed SBA15 accounted for the mechanic reinforcement of the composite scaffold. It indicated that the PLLA-SBA15 composite scaffold had potential applications in bone tissue engineering.

Nano-structured silica coated mesoporous carbon micro-granules for potential application in water filtration

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