WorldWideScience

Sample records for color-coded nanoparticle probes

  1. Gauge color codes

    DEFF Research Database (Denmark)

    Bombin Palomo, Hector

    2015-01-01

    Color codes are topological stabilizer codes with unusual transversality properties. Here I show that their group of transversal gates is optimal and only depends on the spatial dimension, not the local geometry. I also introduce a generalized, subsystem version of color codes. In 3D they allow t...... the transversal implementation of a universal set of gates by gauge fixing, while error-dectecting measurements involve only four or six qubits....

  2. Doubled Color Codes

    Science.gov (United States)

    Bravyi, Sergey

    Combining protection from noise and computational universality is one of the biggest challenges in the fault-tolerant quantum computing. Topological stabilizer codes such as the 2D surface code can tolerate a high level of noise but implementing logical gates, especially non-Clifford ones, requires a prohibitively large overhead due to the need of state distillation. In this talk I will describe a new family of 2D quantum error correcting codes that enable a transversal implementation of all logical gates required for the universal quantum computing. Transversal logical gates (TLG) are encoded operations that can be realized by applying some single-qubit rotation to each physical qubit. TLG are highly desirable since they introduce no overhead and do not spread errors. It has been known before that a quantum code can have only a finite number of TLGs which rules out computational universality. Our scheme circumvents this no-go result by combining TLGs of two different quantum codes using the gauge-fixing method pioneered by Paetznick and Reichardt. The first code, closely related to the 2D color code, enables a transversal implementation of all single-qubit Clifford gates such as the Hadamard gate and the π / 2 phase shift. The second code that we call a doubled color code provides a transversal T-gate, where T is the π / 4 phase shift. The Clifford+T gate set is known to be computationally universal. The two codes can be laid out on the honeycomb lattice with two qubits per site such that the code conversion requires parity measurements for six-qubit Pauli operators supported on faces of the lattice. I will also describe numerical simulations of logical Clifford+T circuits encoded by the distance-3 doubled color code. Based on a joint work with Andrew Cross.

  3. Color coded duplex sonography. Interdisciplinary vascular ultrasonography

    International Nuclear Information System (INIS)

    Kubale, R.; Stiegler, H.

    2002-01-01

    An interdisciplinary team of experts impart the state of the art in color coded duplex sonography applied for examination of all anatomic areas. Detailed information is given for every vascular area, describing the examination procedure, possible origins of mistakes or faults, and means to avoid them. In addition to the classical applications, eg. for examination of the extra- and intracranial vessels, vessels of the limbs, visceral vessels and the vessels of liver and kidney, there are chapters devoted to: haemodialysis shunts, arteriovenous malformations, duplex sonography of the penis, tumor vascularisation. (orig./CB) [de

  4. An Eye-Tracking Study of How Color Coding Affects Multimedia Learning

    Science.gov (United States)

    Ozcelik, Erol; Karakus, Turkan; Kursun, Engin; Cagiltay, Kursat

    2009-01-01

    Color coding has been proposed to promote more effective learning. However, insufficient evidence currently exists to show how color coding leads to better learning. The goal of this study was to investigate the underlying cause of the color coding effect by utilizing eye movement data. Fifty-two participants studied either a color-coded or…

  5. Fault-tolerant error correction with the gauge color code

    Science.gov (United States)

    Brown, Benjamin J.; Nickerson, Naomi H.; Browne, Dan E.

    2016-01-01

    The constituent parts of a quantum computer are inherently vulnerable to errors. To this end, we have developed quantum error-correcting codes to protect quantum information from noise. However, discovering codes that are capable of a universal set of computational operations with the minimal cost in quantum resources remains an important and ongoing challenge. One proposal of significant recent interest is the gauge color code. Notably, this code may offer a reduced resource cost over other well-studied fault-tolerant architectures by using a new method, known as gauge fixing, for performing the non-Clifford operations that are essential for universal quantum computation. Here we examine the gauge color code when it is subject to noise. Specifically, we make use of single-shot error correction to develop a simple decoding algorithm for the gauge color code, and we numerically analyse its performance. Remarkably, we find threshold error rates comparable to those of other leading proposals. Our results thus provide the first steps of a comparative study between the gauge color code and other promising computational architectures. PMID:27470619

  6. Detecting and Tracking Nonfluorescent Nanoparticles Probes in Live Cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Gufeng; Fang, Ning

    2012-01-17

    Precisely imaging and tracking dynamic biological processes in live cells are crucial for both fundamental research in life sciences and biomedical applications. Nonfluorescent nanoparticles are emerging as important optical probes in live-cell imaging because of their excellent photostability, large optical cross sections, and low cytotoxicity. Here, we provide a review of recent development in optical imaging of nonfluorescent nanoparticle probes and their applications in dynamic tracking and biosensing in live cells. A brief discussion on cytotoxicity of nanoparticle probes is also provided.

  7. Topological color code and symmetry-protected topological phases

    Science.gov (United States)

    Yoshida, Beni

    2015-06-01

    We study (d -1 ) -dimensional excitations in the d -dimensional color code that are created by transversal application of the Rd phase operators on connected subregions of qubits. We find that such excitations are the superpositions of electric charges and can be characterized by the fixed-point wave functions of (d -1 ) -dimensional bosonic symmetry-protected topological (SPT) phases with (Z2) ⊗d symmetry. While these SPT excitations are localized on (d -1 ) -dimensional boundaries, their creation requires operations acting on all qubits inside the boundaries, reflecting the nontriviality of emerging SPT wave functions. Moreover, these SPT excitations can be physically realized as transparent gapped domain walls which exchange excitations in the color code. Namely, in the three-dimensional color code, the domain wall, associated with the transversal R3 operator, exchanges a magnetic flux and a composite of a magnetic flux and the looplike SPT excitation, revealing rich possibilities of boundaries in higher-dimensional TQFTs. We also find that magnetic fluxes and the looplike SPT excitations exhibit nontrivial three-loop braiding statistics in three dimensions as a result of the fact that the R3 phase operator belongs to the third level of the Clifford hierarchy. We believe that the connection between SPT excitations, fault-tolerant logical gates and gapped domain walls, established in this paper, can be generalized to a large class of topological quantum codes and TQFTs.

  8. Topological color codes and two-body quantum lattice Hamiltonians

    Science.gov (United States)

    Kargarian, M.; Bombin, H.; Martin-Delgado, M. A.

    2010-02-01

    Topological color codes are among the stabilizer codes with remarkable properties from the quantum information perspective. In this paper, we construct a lattice, the so-called ruby lattice, with coordination number 4 governed by a two-body Hamiltonian. In a particular regime of coupling constants, in a strong coupling limit, degenerate perturbation theory implies that the low-energy spectrum of the model can be described by a many-body effective Hamiltonian, which encodes the color code as its ground state subspace. Ground state subspace corresponds to a vortex-free sector. The gauge symmetry Z2×Z2 of the color code could already be realized by identifying three distinct plaquette operators on the ruby lattice. All plaquette operators commute with each other and with the Hamiltonian being integrals of motion. Plaquettes are extended to closed strings or string-net structures. Non-contractible closed strings winding the space commute with Hamiltonian but not always with each other. This gives rise to exact topological degeneracy of the model. A connection to 2-colexes can be established via the coloring of the strings. We discuss it at the non-perturbative level. The particular structure of the two-body Hamiltonian provides a fruitful interpretation in terms of mapping onto bosons coupled to effective spins. We show that high-energy excitations of the model have fermionic statistics. They form three families of high-energy excitations each of one color. Furthermore, we show that they belong to a particular family of topological charges. The emergence of invisible charges is related to the string-net structure of the model. The emerging fermions are coupled to nontrivial gauge fields. We show that for particular 2-colexes, the fermions can see the background fluxes in the ground state. Also, we use the Jordan-Wigner transformation in order to test the integrability of the model via introducing Majorana fermions. The four-valent structure of the lattice prevents the

  9. Effect of Color-Coded Notation on Music Achievement of Elementary Instrumental Students.

    Science.gov (United States)

    Rogers, George L.

    1991-01-01

    Presents results of a study of color-coded notation to teach music reading to instrumental students. Finds no clear evidence that color-coded notation enhances achievement on performing by memory, sight-reading, or note naming. Suggests that some students depended on the color-coding and were unable to read uncolored notation well. (DK)

  10. Probing nanoparticle effect in protein-surfactant complexes

    Science.gov (United States)

    Mehan, Sumit; Aswal, V. K.; Kohlbrecher, J.

    2015-06-01

    SANS experiments have been carried to probe the role of anionic silica nanoparticles in the anionic BSA protein-cationic DTAB surfactant complexes. In protein-surfactant complex, surfactant molecules aggregate to form micelle-like clusters along the unfolded polypeptide chains of the protein. The nanoparticle aggregation mediated by oppositely charged protein-surfactant complex coexists with the free protein-surfactant complexes in the nanoparticle-protein-surfactant system. There is rearrangement of micelles in adsorbed protein-surfactant complex on nanoparticles in leading to their (nanoparticle) aggregation. On the other hand, the unfolding of protein in free protein-surfactant complex is found to be significantly enhanced in presence of nanoparticles.

  11. Ultrasensitive, Ultradense Nanoelectronic Biosensing with Nanoparticle Probes

    National Research Council Canada - National Science Library

    Mirkin, Chad A; Ratner, Mark

    2006-01-01

    A robust and effective model for determining the presence or absence of an analyte in a DPN-assembled gold nanoparticle/DNA conjugate structure in the limit of single molecule binding was developed...

  12. Electrospun fibre colorimetric probe based on gold nanoparticles for ...

    African Journals Online (AJOL)

    1Department of Chemistry, Rhodes University, PO Box 94, Grahamstown 6140, South Africa. ABSTRACT. An on-site colorimetric probe, based on gold nanoparticles incorporated into electrospun polystyrene nanofibres, for the detection of oestrogenic compounds, as represented by 17β-estradiol, in dairy effluents is ...

  13. New approaches to nanoparticle sample fabrication for atom probe tomography

    International Nuclear Information System (INIS)

    Felfer, P.; Li, T.; Eder, K.; Galinski, H.; Magyar, A.P.; Bell, D.C.; Smith, G.D.W.; Kruse, N.; Ringer, S.P.; Cairney, J.M.

    2015-01-01

    Due to their unique properties, nano-sized materials such as nanoparticles and nanowires are receiving considerable attention. However, little data is available about their chemical makeup at the atomic scale, especially in three dimensions (3D). Atom probe tomography is able to answer many important questions about these materials if the challenge of producing a suitable sample can be overcome. In order to achieve this, the nanomaterial needs to be positioned within the end of a tip and fixed there so the sample possesses sufficient structural integrity for analysis. Here we provide a detailed description of various techniques that have been used to position nanoparticles on substrates for atom probe analysis. In some of the approaches, this is combined with deposition techniques to incorporate the particles into a solid matrix, and focused ion beam processing is then used to fabricate atom probe samples from this composite. Using these approaches, data has been achieved from 10–20 nm core–shell nanoparticles that were extracted directly from suspension (i.e. with no chemical modification) with a resolution of better than ±1 nm. - Highlights: • Samples for APT of nanoparticles were fabricated from particle powders and dispersions. • Electrophoresis was suitable for producing samples from dispersions. • Powder lift-out was successfully producing samples from particle agglomerates. • Dispersion application/coating delivered the highest quality results.

  14. New approaches to nanoparticle sample fabrication for atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Felfer, P., E-mail: peter.felfer@sydney.edu.au [School for Aerospace, Mechanical and Mechatronic Engineering/Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Li, T. [School for Aerospace, Mechanical and Mechatronic Engineering/Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Materials Department, The University of Oxford, Oxford (United Kingdom); Eder, K. [School for Aerospace, Mechanical and Mechatronic Engineering/Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Galinski, H. [School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 (United States); Magyar, A.P.; Bell, D.C. [School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 (United States); Center for Nanoscale Systems, Harvard University, Cambridge, MA 02138 (United States); Smith, G.D.W. [Materials Department, The University of Oxford, Oxford (United Kingdom); Kruse, N. [Chemical Physics of Materials (Catalysis-Tribology), Université Libre de Bruxelles, Campus Plaine, CP 243, 1050 Brussels (Belgium); Ringer, S.P.; Cairney, J.M. [School for Aerospace, Mechanical and Mechatronic Engineering/Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia)

    2015-12-15

    Due to their unique properties, nano-sized materials such as nanoparticles and nanowires are receiving considerable attention. However, little data is available about their chemical makeup at the atomic scale, especially in three dimensions (3D). Atom probe tomography is able to answer many important questions about these materials if the challenge of producing a suitable sample can be overcome. In order to achieve this, the nanomaterial needs to be positioned within the end of a tip and fixed there so the sample possesses sufficient structural integrity for analysis. Here we provide a detailed description of various techniques that have been used to position nanoparticles on substrates for atom probe analysis. In some of the approaches, this is combined with deposition techniques to incorporate the particles into a solid matrix, and focused ion beam processing is then used to fabricate atom probe samples from this composite. Using these approaches, data has been achieved from 10–20 nm core–shell nanoparticles that were extracted directly from suspension (i.e. with no chemical modification) with a resolution of better than ±1 nm. - Highlights: • Samples for APT of nanoparticles were fabricated from particle powders and dispersions. • Electrophoresis was suitable for producing samples from dispersions. • Powder lift-out was successfully producing samples from particle agglomerates. • Dispersion application/coating delivered the highest quality results.

  15. 29 CFR 1910.144 - Safety color code for marking physical hazards.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Safety color code for marking physical hazards. 1910.144 Section 1910.144 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... § 1910.144 Safety color code for marking physical hazards. (a) Color identification—(1) Red. Red shall be...

  16. How Color Coding Formulaic Writing Enhances Organization: A Qualitative Approach for Measuring Student Affect

    Science.gov (United States)

    Geigle, Bryce A.

    2014-01-01

    The aim of this thesis is to investigate and present the status of student synthesis with color coded formula writing for grade level six through twelve, and to make recommendations for educators to teach writing structure through a color coded formula system in order to increase classroom engagement and lower students' affect. The thesis first…

  17. New approaches to nanoparticle sample fabrication for atom probe tomography.

    Science.gov (United States)

    Felfer, P; Li, T; Eder, K; Galinski, H; Magyar, A P; Bell, D C; Smith, G D W; Kruse, N; Ringer, S P; Cairney, J M

    2015-12-01

    Due to their unique properties, nano-sized materials such as nanoparticles and nanowires are receiving considerable attention. However, little data is available about their chemical makeup at the atomic scale, especially in three dimensions (3D). Atom probe tomography is able to answer many important questions about these materials if the challenge of producing a suitable sample can be overcome. In order to achieve this, the nanomaterial needs to be positioned within the end of a tip and fixed there so the sample possesses sufficient structural integrity for analysis. Here we provide a detailed description of various techniques that have been used to position nanoparticles on substrates for atom probe analysis. In some of the approaches, this is combined with deposition techniques to incorporate the particles into a solid matrix, and focused ion beam processing is then used to fabricate atom probe samples from this composite. Using these approaches, data has been achieved from 10-20 nm core-shell nanoparticles that were extracted directly from suspension (i.e. with no chemical modification) with a resolution of better than ± 1 nm. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Encapsulation method for atom probe tomography analysis of nanoparticles.

    Science.gov (United States)

    Larson, D J; Giddings, A D; Wu, Y; Verheijen, M A; Prosa, T J; Roozeboom, F; Rice, K P; Kessels, W M M; Geiser, B P; Kelly, T F

    2015-12-01

    Open-space nanomaterials are a widespread class of technologically important materials that are generally incompatible with analysis by atom probe tomography (APT) due to issues with specimen preparation, field evaporation and data reconstruction. The feasibility of encapsulating such non-compact matter in a matrix to enable APT measurements is investigated using nanoparticles as an example. Simulations of field evaporation of a void, and the resulting artifacts in ion trajectory, underpin the requirement that no voids remain after encapsulation. The approach is demonstrated by encapsulating Pt nanoparticles in an ZnO:Al matrix created by atomic layer deposition, a growth technique which offers very high surface coverage and conformality. APT measurements of the Pt nanoparticles are correlated with transmission electron microscopy images and numerical simulations in order to evaluate the accuracy of the APT reconstruction. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Sensitive determination of nucleic acids using organic nanoparticle fluorescence probes

    Science.gov (United States)

    Zhou, Yunyou; Bian, Guirong; Wang, Leyu; Dong, Ling; Wang, Lun; Kan, Jian

    2005-06-01

    This paper describes the preparation of organic nanoparticles by reprecipitation method under sonication and vigorous stirring. Transmission electron microscopy (TEM) was used to characterize the size and size distribution of the luminescent nanoparticles. Their average diameter was about 25 nm with a size variation of ±18%. The fluorescence decay lifetime of the nanoparticles also was determined on a self-equipped fluorospectrometer with laser light source. The lifetime (˜0.09 μs) of nanoparticles is about three times long as that of the monomer. The nanoparticles were in abundant of hydrophilic groups, which increased their miscibility in aqueous solution. These organic nanoparticles have high photochemical stability, excellent resistance to chemical degradation and photodegradation, and a good fluorescence quantum yield (25%). The fluorescence can be efficiently quenched by nucleic acids. Based on the fluorescence quenching of nanoparticles, a fluorescence quenching method was developed for determination of microamounts of nucleic acids by using the nanoparticles as a new fluorescent probe. Under optimal conditions, maximum fluorescence quenching is produced, with maximum excitation and emission wavelengths of 345 and 402 nm, respectively. Under optimal conditions, the calibration graphs are linear over the range 0.4-19.0 μg ml -1 for calf thymus DNA (ct-DNA) and 0.3-19.0 μg ml -1 for fish sperm DNA (fs-DNA). The corresponding detection limits are 0.25 μg ml -1 for ct-DNA and 0.17 μg ml -1 for fs-DNA. The relative standard deviation of six replicate measurements is 1.3-2.1%. The method is simple, rapid and sensitive with wide linear range. The recovery and relative standard deviation are very satisfactory.

  20. Quantitatively Probing the Means of Controlling Nanoparticle Assembly on Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Patete, J.m.; Wong, S.; Peng, X.; Serafin, J.M.

    2011-05-17

    As a means of developing a simple, cost-effective, and reliable method for probing nanoparticle behavior, we have used atomic force microscopy to gain a quantitative 3D visual representation of the deposition patterns of citrate-capped Au nanoparticles on a substrate as a function of (a) sample preparation, (b) the choice of substrate, (c) the dispersion solvent, and (d) the number of loading steps. Specifically, we have found that all four parameters can be independently controlled and manipulated in order to alter the resulting pattern and quantity of as-deposited nanoparticles. From these data, the sample preparation technique appears to influence deposition patterns most broadly, and the dispersion solvent is the most convenient parameter to use in tuning the quantity of nanoparticles deposited onto the surface under spin-coating conditions. Indeed, we have quantitatively measured the effect of surface coverage for both mica and silicon substrates under preparation techniques associated with (i) evaporation under ambient air, (ii) heat treatment, and (iii) spin-coating preparation conditions. In addition, we have observed a decrease in nanoparticle adhesion to a substrate when the ethylene glycol content of the colloidal dispersion solvent is increased, which had the effect of decreasing interparticle-substrate interactions. Finally, we have shown that substrates prepared by these diverse techniques have potential applicability in surface-enhanced Raman spectroscopy.

  1. Quantitatively Probing the Means of Controlling Nanoparticle Assembly on Surfaces

    International Nuclear Information System (INIS)

    Patete, J.M.; Wong, S.; Peng, X.; Serafin, J.M.

    2011-01-01

    As a means of developing a simple, cost-effective, and reliable method for probing nanoparticle behavior, we have used atomic force microscopy to gain a quantitative 3D visual representation of the deposition patterns of citrate-capped Au nanoparticles on a substrate as a function of (a) sample preparation, (b) the choice of substrate, (c) the dispersion solvent, and (d) the number of loading steps. Specifically, we have found that all four parameters can be independently controlled and manipulated in order to alter the resulting pattern and quantity of as-deposited nanoparticles. From these data, the sample preparation technique appears to influence deposition patterns most broadly, and the dispersion solvent is the most convenient parameter to use in tuning the quantity of nanoparticles deposited onto the surface under spin-coating conditions. Indeed, we have quantitatively measured the effect of surface coverage for both mica and silicon substrates under preparation techniques associated with (i) evaporation under ambient air, (ii) heat treatment, and (iii) spin-coating preparation conditions. In addition, we have observed a decrease in nanoparticle adhesion to a substrate when the ethylene glycol content of the colloidal dispersion solvent is increased, which had the effect of decreasing interparticle-substrate interactions. Finally, we have shown that substrates prepared by these diverse techniques have potential applicability in surface-enhanced Raman spectroscopy.

  2. Color-coded volume rendering for three-dimensional reconstructions of CT data

    International Nuclear Information System (INIS)

    Rieker, O.; Mildenberger, P.; Thelen, M.

    1999-01-01

    Purpose: To evaluate a technique of colored three-dimensional reconstructions without segmentation. Material and methods: Color-coded volume rendered images were reconstructed from the volume data of 25 thoracic, abdominal, musculoskeletal, and vascular helical CT scans using commercial software. The CT volume rendered voxels were encoded with color in the following manner. Opacity, hue, lightness, and chroma were assigned to each of four classes defined by CT number. Color-coded reconstructions were compared to the corresponding grey-scale coded reconstructions. Results: Color-coded volume rendering enabled realistic visualization of pathologic findings when there was sufficient difference in CT density. Segmentation was necessary in some cases to demonstrate small details in a complex volume. Conclusion: Color-coded volume rendering allowed lifelike visualisation of CT volumes without the need of segmentation in most cases. (orig.) [de

  3. Parametric color coding of digital subtraction angiography in the evaluation of carotid cavernous fistulas.

    Science.gov (United States)

    Gölitz, P; Struffert, T; Lücking, H; Rösch, J; Knossalla, F; Ganslandt, O; Deuerling-Zheng, Y; Doerfler, A

    2013-06-01

    Angiographic assessment of carotid cavernous fistulas (CCFs) can be complex. Our purpose was to examine whether the use of parametric color coding in the postprocessing of DSA series is advantageous in the evaluation of CCFs. We enrolled 16 patients with angiographically proven CCFs. Endovascular treatment was performed in 14 cases. For postprocessing of digital subtraction angiography (DSA) series, a newly implemented algorithm of parametric color coding was used, turning sequential images of two-dimensional (2D)-DSA series into a single color-coded image. Angiographic data of initial, interventional, and postinterventional 2D-DSA series were compared with color-coded images. Whether parametric color coding could facilitate evaluation of fistula architecture and provide a more precise estimation of fistula venous drainage patterns as well as whether flow analysis could reveal objective changes during and after treatment were investigated. In 56 % of the cases, parametric color coding was observed to facilitate visualization of fistula angioarchitecture. Estimation of fistula drainage flow patterns was considered to be improved in 31 % of the cases. For assessment of hemodynamic changes during and after treatment, parametric color coding was assumed to be helpful in 21 % of the cases, especially because revealing flow changes that were not visible on 2D-DSA series were now visible. Parametric color coding is a fast application tool that might provide additional support in the angiographic evaluation of CCFs. Visualization of complex fistula architecture could be facilitated, and flow analysis might improve assessment of venous drainage patterns, thereby increasing overall diagnostic confidence. During and after treatment, hemodynamic changes that were not visible on 2D-DSA series could now be depicted.

  4. NanoString, a novel digital color-coded barcode technology: current and future applications in molecular diagnostics.

    Science.gov (United States)

    Tsang, Hin-Fung; Xue, Vivian Weiwen; Koh, Su-Pin; Chiu, Ya-Ming; Ng, Lawrence Po-Wah; Wong, Sze-Chuen Cesar

    2017-01-01

    Formalin-fixed, paraffin-embedded (FFPE) tissue sample is a gold mine of resources for molecular diagnosis and retrospective clinical studies. Although molecular technologies have expanded the range of mutations identified in FFPE samples, the applications of existing technologies are limited by the low nucleic acids yield and poor extraction quality. As a result, the routine clinical applications of molecular diagnosis using FFPE samples has been associated with many practical challenges. NanoString technologies utilize a novel digital color-coded barcode technology based on direct multiplexed measurement of gene expression and offer high levels of precision and sensitivity. Each color-coded barcode is attached to a single target-specific probe corresponding to a single gene which can be individually counted without amplification. Therefore, NanoString is especially useful for measuring gene expression in degraded clinical specimens. Areas covered: This article describes the applications of NanoString technologies in molecular diagnostics and challenges associated with its applications and the future development. Expert commentary: Although NanoString technology is still in the early stages of clinical use, it is expected that NanoString-based cancer expression panels would play more important roles in the future in classifying cancer patients and in predicting the response to therapy for better personal therapeutic care.

  5. Color coding of control room displays: the psychocartography of visual layering effects.

    Science.gov (United States)

    Van Laar, Darren; Deshe, Ofer

    2007-06-01

    To evaluate which of three color coding methods (monochrome, maximally discriminable, and visual layering) used to code four types of control room display format (bars, tables, trend, mimic) was superior in two classes of task (search, compare). It has recently been shown that color coding of visual layers, as used in cartography, may be used to color code any type of information display, but this has yet to be fully evaluated. Twenty-four people took part in a 2 (task) x 3 (coding method) x 4 (format) wholly repeated measures design. The dependent variables assessed were target location reaction time, error rates, workload, and subjective feedback. Overall, the visual layers coding method produced significantly faster reaction times than did the maximally discriminable and the monochrome methods for both the search and compare tasks. No significant difference in errors was observed between conditions for either task type. Significantly less perceived workload was experienced with the visual layers coding method, which was also rated more highly than the other coding methods on a 14-item visual display quality questionnaire. The visual layers coding method is superior to other color coding methods for control room displays when the method supports the user's task. The visual layers color coding method has wide applicability to the design of all complex information displays utilizing color coding, from the most maplike (e.g., air traffic control) to the most abstract (e.g., abstracted ecological display).

  6. A high brightness probe of polymer nanoparticles for biological imaging

    Science.gov (United States)

    Zhou, Sirong; Zhu, Jiarong; Li, Yaping; Feng, Liheng

    2018-03-01

    Conjugated polymer nanoparticles (CPNs) with high brightness in long wavelength region were prepared by the nano-precipitation method. Based on fluorescence resonance energy transfer (FRET) mechanism, the high brightness property of the CPNs was realized by four different emission polymers. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) displayed that the CPNs possessed a spherical structure and an average diameter of 75 nm. Analysis assays showed that the CPNs had excellent biocompatibility, good photostability and low cytotoxicity. The CPNs were bio-modified with a cell penetrating peptide (Tat, a targeted element) through covalent link. Based on the entire wave fluorescence emission, the functionalized CPNs1-4 can meet multichannel and high throughput assays in cell and organ imaging. The contribution of the work lies in not only providing a new way to obtain a high brightness imaging probe in long wavelength region, but also using targeted cell and organ imaging.

  7. Probing and controlling fluorescence blinking of single semiconductor nanoparticles

    Directory of Open Access Journals (Sweden)

    Hsien-Chen Ko

    2011-02-01

    Full Text Available In this review we present an overview of the experimental and theoretical development on fluorescence intermittency (blinking and the roles of electron transfer in semiconductor crystalline nanoparticles. Blinking is a very interesting phenomenon commonly observed in single molecule/particle experiments. Under continuous laser illumination, the fluorescence time trace of these single nanoparticles exhibit random light and dark periods. Since its first observation in the mid-1990s, this intriguing phenomenon has attracted wide attention among researchers from many disciplines. We will first present the historical background of the discovery and the observation of unusual inverse power-law dependence for the waiting time distributions of light and dark periods. Then, we will describe our theoretical modeling efforts to elucidate the causes for the power-law behavior, to probe the roles of electron transfer in blinking, and eventually to control blinking and to achieve complete suppression of the blinking, which is an annoying feature in many applications of quantum dots as light sources and fluorescence labels for biomedical imaging.

  8. Braiding by Majorana tracking and long-range CNOT gates with color codes

    Science.gov (United States)

    Litinski, Daniel; von Oppen, Felix

    2017-11-01

    Color-code quantum computation seamlessly combines Majorana-based hardware with topological error correction. Specifically, as Clifford gates are transversal in two-dimensional color codes, they enable the use of the Majoranas' non-Abelian statistics for gate operations at the code level. Here, we discuss the implementation of color codes in arrays of Majorana nanowires that avoid branched networks such as T junctions, thereby simplifying their realization. We show that, in such implementations, non-Abelian statistics can be exploited without ever performing physical braiding operations. Physical braiding operations are replaced by Majorana tracking, an entirely software-based protocol which appropriately updates the Majoranas involved in the color-code stabilizer measurements. This approach minimizes the required hardware operations for single-qubit Clifford gates. For Clifford completeness, we combine color codes with surface codes, and use color-to-surface-code lattice surgery for long-range multitarget CNOT gates which have a time overhead that grows only logarithmically with the physical distance separating control and target qubits. With the addition of magic state distillation, our architecture describes a fault-tolerant universal quantum computer in systems such as networks of tetrons, hexons, or Majorana box qubits, but can also be applied to nontopological qubit platforms.

  9. CoCo trial: Color-coded blood pressure Control, a randomized controlled study.

    Science.gov (United States)

    Chmiel, Corinne; Senn, Oliver; Rosemann, Thomas; Del Prete, Valerio; Steurer-Stey, Claudia

    2014-01-01

    Inadequate blood pressure (BP) control is a frequent challenge in general practice. The objective of this study was to determine whether a color-coded BP booklet using a traffic light scheme (red, >180 mmHg systolic BP and/or >110 mmHg diastolic BP; yellow, >140-180 mmHg systolic BP or >90-110 mmHg diastolic BP; green, ≤140 mmHg systolic BP and ≤90 mmHg diastolic BP) improves BP control and adherence with home BP measurement. In this two-group, randomized controlled trial, general practitioners recruited adult patients with a BP >140 mmHg systolic and/or >90 mmHg diastolic. Patients in the control group received a standard BP booklet and the intervention group used a color-coded booklet for daily home BP measurement. The main outcomes were changes in BP, BP control (treatment goal Color-coded BP self-monitoring significantly improved BP control (number needed to treat of 5, meaning that every fifth patient utilizing color-coded self-monitoring achieved better BP control after 6 months), but no significant between-group difference was observed in BP change. A markedly higher percentage of patients achieved BP values in the normal range. This simple, inexpensive approach of color-coded BP self-monitoring is user-friendly and applicable in primary care, and should be implemented in the care of patients with arterial hypertension.

  10. The work function of doped polyaniline nanoparticles observed by Kelvin probe force microscopy

    International Nuclear Information System (INIS)

    Park, Jinsung; Jang, Kuewhan; Na, Sungsoo; Bang, Doyeon; Haam, Seungjoo; Yang, Jaemoon

    2012-01-01

    The work function of polyaniline nanoparticles in the emeraldine base state was determined by Kelvin probe force microscopy to be ∼270 meV higher than that of similar nanoparticles in the emeraldine salt state. Normal tapping mode atomic force microscopy could not be used to distinguish between the particles due to their similar morphologies and sizes. Moreover, other potential measurement systems, such as using zeta potentials, were not suitable for the measurement of surface charges of doped nanoparticles due to their encapsulation by interfering chemical groups. Kelvin probe force microscopy can be used to overcome these limitations and unambiguously distinguish between the bare and doped polyaniline nanoparticles. (paper)

  11. Autofluorescent gelatin nanoparticles as imaging probes to monitor matrix metalloproteinase metabolism of cancer cells.

    Science.gov (United States)

    Cai, Bo; Rao, Lang; Ji, Xinghu; Bu, Lin-Lin; He, Zhaobo; Wan, Da; Yang, Yi; Liu, Wei; Guo, Shishang; Zhao, Xing-Zhong

    2016-11-01

    In this paper, autofluorescent gelatin nanoparticles were synthesized as matrix metalloproteinase (MMP) responsive probes for cancer cell imaging. A modified two-step desolvation method was employed to generate these nanoparticles whose size was controllable and had stable autofluorescence. As glutaraldehyde was introduced as the crosslinking agent, the generation of Schiff base (CN) and double carbon bond (CC) between glutaraldehyde and gelatin endowed these gelatin nanoparticles distinct autofluorescence. Considering MMPs were usually overexpressed on the surface of cancer cells and they had degradation ability toward gelatin, we utilized these nanoparticles as imaging probes to responsively monitor the MMP metabolism of cancer cells according to the luminance change. As fluorescent probes, these nanoparticles had facile synthesis procedure and good biocompatibility, and provided a smart strategy to monitor cancer cell behaviors. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2854-2860, 2016. © 2016 Wiley Periodicals, Inc.

  12. Wavelength-Dependent Differential Interference Contrast Microscopy: Selectively Imaging Nanoparticle Probes in Live Cells

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei; Wang, Gufeng; Fang, Ning; and Yeung, Edward S.

    2009-11-15

    Gold and silver nanoparticles display extraordinarily large apparent refractive indices near their plasmon resonance (PR) wavelengths. These nanoparticles show good contrast in a narrow spectral band but are poorly resolved at other wavelengths in differential interference contrast (DIC) microscopy. The wavelength dependence of DIC contrast of gold/silver nanoparticles is interpreted in terms of Mie's theory and DIC working principles. We further exploit this wavelength dependence by modifying a DIC microscope to enable simultaneous imaging at two wavelengths. We demonstrate that gold/silver nanoparticles immobilized on the same glass slides through hybridization can be differentiated and imaged separately. High-contrast, video-rate images of living cells can be recorded both with and without illuminating the gold nanoparticle probes, providing definitive probe identification. Dual-wavelength DIC microscopy thus presents a new approach to the simultaneous detection of multiple probes of interest for high-speed live-cell imaging.

  13. Optical imaging of non-fluorescent nanoparticle probes in live cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Gufeng; Stender, Anthony S.; Sun, Wei; and Fang, Ning

    2009-12-17

    Precise imaging of cellular and subcellular structures and dynamic processes in live cells is crucial for fundamental research in life sciences and in medical applications. Non-fluorescent nanoparticles are an important type of optical probe used in live-cell imaging due to their photostability, large optical cross-sections, and low toxicity. Here, we provide an overview of recent developments in the optical imaging of non-fluorescent nanoparticle probes in live cells.

  14. Colorimetric DNA detection of transgenic plants using gold nanoparticles functionalized with L-shaped DNA probes

    Science.gov (United States)

    Nourisaeid, Elham; Mousavi, Amir; Arpanaei, Ayyoob

    2016-01-01

    In this study, a DNA colorimetric detection system based on gold nanoparticles functionalized with L-shaped DNA probes was prepared and evaluated. We investigated the hybridization efficiency of the L-shaped probes and studied the effect of nanoparticle size and the L-shaped DNA probe length on the performance of the as-prepared system. Probes were attached to the surface of gold nanoparticles using an adenine sequence. An optimal sequence of 35S rRNA gene promoter from the cauliflower mosaic virus, which is frequently used in the development of transgenic plants, and the two complementary ends of this gene were employed as model target strands and probe molecules, respectively. The spectrophotometric properties of the as-prepared systems indicated that the large NPs show better changes in the absorption spectrum and consequently present a better performance. The results of this study revealed that the probe/Au-NPs prepared using a vertical spacer containing 5 thymine oligonucleotides exhibited a stronger spectrophotometric response in comparison to that of larger probes. These results in general indicate the suitable performance of the L-shaped DNA probe-functionalized Au-NPs, and in particular emphasize the important role of the gold nanoparticle size and length of the DNA probes in enhancing the performance of such a system.

  15. Combining Topological Hardware and Topological Software: Color-Code Quantum Computing with Topological Superconductor Networks

    Science.gov (United States)

    Litinski, Daniel; Kesselring, Markus S.; Eisert, Jens; von Oppen, Felix

    2017-07-01

    We present a scalable architecture for fault-tolerant topological quantum computation using networks of voltage-controlled Majorana Cooper pair boxes and topological color codes for error correction. Color codes have a set of transversal gates which coincides with the set of topologically protected gates in Majorana-based systems, namely, the Clifford gates. In this way, we establish color codes as providing a natural setting in which advantages offered by topological hardware can be combined with those arising from topological error-correcting software for full-fledged fault-tolerant quantum computing. We provide a complete description of our architecture, including the underlying physical ingredients. We start by showing that in topological superconductor networks, hexagonal cells can be employed to serve as physical qubits for universal quantum computation, and we present protocols for realizing topologically protected Clifford gates. These hexagonal-cell qubits allow for a direct implementation of open-boundary color codes with ancilla-free syndrome read-out and logical T gates via magic-state distillation. For concreteness, we describe how the necessary operations can be implemented using networks of Majorana Cooper pair boxes, and we give a feasibility estimate for error correction in this architecture. Our approach is motivated by nanowire-based networks of topological superconductors, but it could also be realized in alternative settings such as quantum-Hall-superconductor hybrids.

  16. Color-coded duplex sonography in the study of thyroid pathologic conditions

    International Nuclear Information System (INIS)

    Anguissola, R.; Bozzini, A.; Campani, R.; Bottinelli, O.; Genovese, E.; Guglielmoni, B.; Fulle, I.; Bandi, G.

    1991-01-01

    The authors examined 110 patients with suspected pathologic conditions of the thyroid by means of color-coded duplex US. In addition to the information yielded by conventional US, this technique allows organ vascularization to be demonstrated. Five normal patients were considered as a control group: no tissue vascularization was demonstrated in these cases. In 8 patients presenting with carcinoma or recurrences, vascularization was markedly increased both peripheral and central to the nodule. A few doubts are still to be solved as to the diagnostic value of color-coded duplex US in the evaluation of non-carcinomas nodular pathologic conditions. As a matter of fact, non-functioning avascular adenomas can be demonstrated only in a very low percentage of cases (66%). Color-coded duplex US proved extremely sensitive and specific in depicting malignant neoplasms. Moreover, the use of fine.needle biopsy could be optimized and subsequently reduced. Color-coded duplex US proved to be markedly superior to othe rmethods and techniques in the study of thyroid diseases, especially thyroiditis and multiple pathologic conditions. The simultaneous presence of hypocapture at scintigraphy and peripheral and central vascularization in a single nodule or within multinodular struma at color-Doppler was highly suggestive of malignant thyroid neoplasm. Color-coded duplex US is a low-cost technique, which can be performed on an outpatient basis. Moreover, it is not invasive, nor does it damage the thyroid. That is why its use is almost mandatory in the study of pathologic conditions of the thyroid

  17. Sequential electrochemical oxidation and site-selective growth of nanoparticles onto AFM probes.

    Science.gov (United States)

    Wang, Haitao; Tian, Tian; Zhang, Yong; Pan, Zhiqiang; Wang, Yong; Xiao, Zhongdang

    2008-08-19

    In this work, we reported an approach for the site-selective growth of nanoparticle onto the tip apex of an atomic force microscopy (AFM) probe. The silicon AFM probe was first coated with a self-assembled monolayer (SAM) of octadecyltrichlorosilane (OTS) through a chemical vapor deposition (CVD) method. Subsequently, COOH groups were selectively generated at the tip apex of silicon AFM probes by applying an appropriate bias voltage between the tip and a flat gold electrode. The transformation of methyl to carboxylic groups at the tip apex of the AFM probe was investigated through measuring the capillary force before and after electrochemical oxidation. To prepare the nanoparticle terminated AFM probe, the oxidized AFM probe was then immersed in an aqueous solution containing positive metal ions, for example, Ag+, to bind positive metal ions to the oxidized area (COOH terminated area), followed by chemical reduction with aqueous NaBH 4 and further development (if desired) to give a metal nanoparticle-modified AFM probe. The formation of a metal nanoparticle at the tip apex of the AFM probe was confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA).

  18. Diffusion-Weighted Imaging with Color-Coded Images: Towards a Reduction in Reading Time While Keeping a Similar Accuracy

    Directory of Open Access Journals (Sweden)

    Felipe Campos Kitamura

    2016-01-01

    Full Text Available The aim of this study was to develop a diagnostic tool capable of providing diffusion and apparent diffusion coefficient (ADC map information in a single color-coded image and to assess the performance of color-coded images compared with their corresponding diffusion and ADC map. The institutional review board approved this retrospective study, which sequentially enrolled 36 head MRI scans. Diffusion-weighted images (DWI and ADC maps were compared to their corresponding color-coded images. Four raters had their interobserver agreement measured for both conventional (DWI and color-coded images. Differences between conventional and color-coded images were also estimated for each of the 4 raters. Cohen’s kappa and percent agreement were used. Also, paired-samples t-test was used to compare reading time for rater 1. Conventional and color-coded images had substantial or almost perfect agreement for all raters. Mean reading time of rater 1 was 47.4 seconds for DWI and 27.9 seconds for color-coded images (P=.00007. These findings are important because they support the role of color-coded images as being equivalent to that of the conventional DWI in terms of diagnostic capability. Reduction in reading time (which makes the reading easier is also demonstrated for one rater in this study.

  19. Diffusion-Weighted Imaging with Color-Coded Images: Towards a Reduction in Reading Time While Keeping a Similar Accuracy.

    Science.gov (United States)

    Campos Kitamura, Felipe; de Medeiros Alves, Srhael; Antônio Tobaru Tibana, Luis; Abdala, Nitamar

    2016-01-01

    The aim of this study was to develop a diagnostic tool capable of providing diffusion and apparent diffusion coefficient (ADC) map information in a single color-coded image and to assess the performance of color-coded images compared with their corresponding diffusion and ADC map. The institutional review board approved this retrospective study, which sequentially enrolled 36 head MRI scans. Diffusion-weighted images (DWI) and ADC maps were compared to their corresponding color-coded images. Four raters had their interobserver agreement measured for both conventional (DWI) and color-coded images. Differences between conventional and color-coded images were also estimated for each of the 4 raters. Cohen's kappa and percent agreement were used. Also, paired-samples t-test was used to compare reading time for rater 1. Conventional and color-coded images had substantial or almost perfect agreement for all raters. Mean reading time of rater 1 was 47.4 seconds for DWI and 27.9 seconds for color-coded images (P = .00007). These findings are important because they support the role of color-coded images as being equivalent to that of the conventional DWI in terms of diagnostic capability. Reduction in reading time (which makes the reading easier) is also demonstrated for one rater in this study.

  20. Biomedical Probes Based on Inorganic Nanoparticles for Electrochemical and Optical Spectroscopy Applications

    Science.gov (United States)

    Yakoh, Abdulhadee; Pinyorospathum, Chanika; Siangproh, Weena; Chailapakul, Orawon

    2015-01-01

    Inorganic nanoparticles usually provide novel and unique physical properties as their size approaches nanometer scale dimensions. The unique physical and optical properties of nanoparticles may lead to applications in a variety of areas, including biomedical detection. Therefore, current research is now increasingly focused on the use of the high surface-to-volume ratios of nanoparticles to fabricate superb chemical- or biosensors for various detection applications. This article highlights various kinds of inorganic nanoparticles, including metal nanoparticles, magnetic nanoparticles, nanocomposites, and semiconductor nanoparticles that can be perceived as useful materials for biomedical probes and points to the outstanding results arising from their use in such probes. The progress in the use of inorganic nanoparticle-based electrochemical, colorimetric and spectrophotometric detection in recent applications, especially bioanalysis, and the main functions of inorganic nanoparticles in detection are reviewed. The article begins with a conceptual discussion of nanoparticles according to types, followed by numerous applications to analytes including biomolecules, disease markers, and pharmaceutical substances. Most of the references cited herein, dating from 2010 to 2015, generally mention one or more of the following characteristics: a low detection limit, good signal amplification and simultaneous detection capabilities. PMID:26343676

  1. Probing interaction of charged nanoparticles with uncharged micelles

    Science.gov (United States)

    Kumar, Sugam; Aswal, V. K.; Kohlbrecher, J.

    2013-02-01

    Small-angle neutron scattering (SANS) and dynamic light scattering (DLS) studies have been carried out to study interaction of anionic nanoparticles with uncharged (non-ionic) C12E10 micelles. DLS results show increase in the effective size of nanoparticles on addition of C12E10. Contrast variation SANS confirms the micelles decoration of nanoparticles which is believed to be driven by the hydrogen bonding between them. The number of adsorbed micelles per nanoparticle increases with the increase in the nanoparticle size. Surface number density is also found to be increasing with increase in particle size indicating favored adsorption for larger curvature.

  2. A high capacity text steganography scheme based on LZW compression and color coding

    Directory of Open Access Journals (Sweden)

    Aruna Malik

    2017-02-01

    Full Text Available In this paper, capacity and security issues of text steganography have been considered by employing LZW compression technique and color coding based approach. The proposed technique uses the forward mail platform to hide the secret data. This algorithm first compresses secret data and then hides the compressed secret data into the email addresses and also in the cover message of the email. The secret data bits are embedded in the message (or cover text by making it colored using a color coding table. Experimental results show that the proposed method not only produces a high embedding capacity but also reduces computational complexity. Moreover, the security of the proposed method is significantly improved by employing stego keys. The superiority of the proposed method has been experimentally verified by comparing with recently developed existing techniques.

  3. Undergraduate Laboratory Experiment Modules for Probing Gold Nanoparticle Interfacial Phenomena

    Science.gov (United States)

    Karunanayake, Akila G.; Gunatilake, Sameera R.; Ameer, Fathima S.; Gadogbe, Manuel; Smith, Laura; Mlsna, Deb; Zhang, Dongmao

    2015-01-01

    Three gold-nanoparticle (AuNP) undergraduate experiment modules that are focused on nanoparticles interfacial phenomena have been developed. Modules 1 and 2 explore the synthesis and characterization of AuNPs of different sizes but with the same total gold mass. These experiments enable students to determine how particle size affects the AuNP…

  4. Dual-Color Fluorescence Imaging of Magnetic Nanoparticles in Live Cancer Cells Using Conjugated Polymer Probes

    Science.gov (United States)

    Sun, Minjie; Sun, Bin; Liu, Yun; Shen, Qun-Dong; Jiang, Shaojun

    2016-01-01

    Rapid growth in biological applications of nanomaterials brings about pressing needs for exploring nanomaterial-cell interactions. Cationic blue-emissive and anionic green-emissive conjugated polymers are applied as dual-color fluorescence probes to the surface of negatively charged magnetic nanoparticles through sequentially electrostatic adsorption. These conjugated polymers have large extinction coefficients and high fluorescence quantum yield (82% for PFN and 62% for ThPFS). Thereby, one can visualize trace amount (2.7 μg/mL) of fluorescence-labeled nanoparticles within cancer cells by confocal laser scanning microscopy. Fluorescence labeling by the conjugated polymers is also validated for quantitative determination of the internalized nanoparticles in each individual cell by flow cytometry analysis. Extensive overlap of blue and green fluorescence signals in the cytoplasm indicates that both conjugated polymer probes tightly bind to the surface of the nanoparticles during cellular internalization. The highly charged and fluorescence-labeled nanoparticles non-specifically bind to the cell membranes, followed by cellular uptake through endocytosis. The nanoparticles form aggregates inside endosomes, which yields a punctuated staining pattern. Cellular internalization of the nanoparticles is dependent on the dosage and time. Uptake efficiency can be enhanced three-fold by application of an external magnetic field. The nanoparticles are low cytotoxicity and suitable for simultaneously noninvasive fluorescence and magnetic resonance imaging application. PMID:26931282

  5. The detection of HBV DNA with gold-coated iron oxide nanoparticle gene probes

    International Nuclear Information System (INIS)

    Xi Dong; Luo Xiaoping; Lu Qianghua; Yao Kailun; Liu Zuli; Ning Qin

    2008-01-01

    Gold-coated iron oxide nanoparticle Hepatitis B virus (HBV) DNA probes were prepared, and their application for HBV DNA measurement was studied. Gold-coated iron oxide nanoparticles were prepared by the citrate reduction of tetra-chloroauric acid in the presence of iron oxide nanoparticles which were added as seeds. With a fluorescence-based method, the maximal surface coverage of hexaethiol 30-mer oligonucleotides and the maximal percentage of hybridization strands on gold-coated iron oxide nanoparticles were (120 ± 8) oligonucleotides per nanoparticle, and (14 ± 2%), respectively, which were comparable with those of (132 ± 10) and (22 ± 3%) in Au nanoparticle groups. Large network aggregates were formed when gold-coated iron oxide nanoparticle HBV DNA gene probe was applied to detect HBV DNA molecules as evidenced by transmission electron microscopy and the high specificity was verified by blot hybridization. Our results further suggested that detecting DNA with iron oxide nanoparticles and magnetic separator was feasible and might be an alternative effective method

  6. Probing individual redox PEGylated gold nanoparticles by electrochemical--atomic force microscopy.

    Science.gov (United States)

    Huang, Kai; Anne, Agnès; Bahri, Mohamed Ali; Demaille, Christophe

    2013-05-28

    Electrochemical-atomic force microscopy (AFM-SECM) was used to simultaneously probe the physical and electrochemical properties of individual ~20 nm sized gold nanoparticles functionalized by redox-labeled PEG chains. The redox PEGylated nanoparticles were assembled onto a gold electrode surface, forming a random nanoarray, and interrogated in situ by a combined AFM-SECM nanoelectrode probe. We show that, in this so-called mediator-tethered (Mt) mode, AFM-SECM affords the nanometer resolution required for resolving the position of individual nanoparticles and measuring their size, while simultaneously electrochemically directly contacting the redox-PEG chains they bear. The dual measurement of the size and current response of single nanoparticles uniquely allows the statistical distribution in grafting density of PEG on the nanoparticles to be determined and correlated to the nanoparticle diameter. Moreover, because of its high spatial resolution, Mt/AFM-SECM allows "visualizing" simultaneously but independently the PEG corona and the gold core of individual nanoparticles. Beyond demonstrating the achievement of single-nanoparticle resolution using an electrochemical microscopy technique, the results reported here also pave the way toward using Mt/AFM-SECM for imaging nano-objects bearing any kind of suitably redox-labeled (bio)macromolecules.

  7. Gold nanoparticle-coated biomaterial as SERS micro-probes

    Indian Academy of Sciences (India)

    Abstract. We report for the first time, on the utility of plant-based biomaterial as enhanced-Raman scattering probes. The bio-substrate used in this study are commonly found in plant extracts, and are cost-effective, mecha- nically robust, flexible and easily transportable. The probe was fabricated by coating the plant extract ...

  8. Gold nanoparticle-coated biomaterial as SERS micro-probes

    Indian Academy of Sciences (India)

    ... and the ability to detect biomolecules are demonstrated herein. We envision these bio-probes as potential candidates for enhanced Raman sensing in chemical, environmental, and archaeological applications. By further engineering the shape, morphology, and surface chemistry of these micro-probes, we foresee their ...

  9. Controlled Clustering of Gold Nanoparticles using Solid-support for Surface-enhanced Raman Spectroscopic Probes

    International Nuclear Information System (INIS)

    Chang, Hyejin; Chae, Jinjoo; Jeong, Hong; Kang, Homan; Lee, Yoonsik

    2014-01-01

    We fabricated small clusters of gold nanoparticles by using solid-supported aggregation of gold nanoparticles. The fabricated Au nanoclusters consisting mainly of dimers showed homogeneous characteristics in cluster size and SERS intensity. The SERS enhancement of 4-ABT molecules in an effective area within 2-nm gap appeared to be approximately 10. Detachment process by ultrasonication was successively carried out in order to use the nanoclusters as SERS probes. The possibility of these clusters as SERS probe was proved in terms of signal and cluster size. Single molecule-level sensitivity of surface-enhanced Raman scattering (SERS) was known approximately fifteen years ago. Ever since there have been many different applications benefiting from the ultra-high sensitivity such as single molecule detection, chemical sensing and bio-molecular probes. Especially, SERS has drawn much attention in bio-multiplexing probes owing to its unique optical characteristics claiming extremely narrow bandwidth, high sensitivity of light signals, and non-bleaching feature

  10. Gazetteer of Planetary Nomenclature: Moon: 1:10 million-scale Shaded Relief and Color-coded Topography: Near Side

    Data.gov (United States)

    National Aeronautics and Space Administration — These lunar maps display the four different areas of the moon with color-coded topography in low and high resolution approved by the International Astronomical Union...

  11. Gazetteer of Planetary Nomenclature: Moon: 1:10 million-scale Shaded Relief and Color-coded Topography: South Pole

    Data.gov (United States)

    National Aeronautics and Space Administration — These lunar maps display the four different areas of the moon with color-coded topography in low and high resolution approved by the International Astronomical Union...

  12. Gazetteer of Planetary Nomenclature: Moon: 1:10 million-scale Shaded Relief and Color-coded Topography: Far Side

    Data.gov (United States)

    National Aeronautics and Space Administration — These lunar maps display the four different areas of the moon with color-coded topography in low and high resolution approved by the International Astronomical Union...

  13. Attention Filtering in the Design of Electronic Map Displays: A Comparison of Color-Coding, Intensity Coding, and Decluttering Techniques

    National Research Council Canada - National Science Library

    Yeh, Michelle; Wickens, Christopher D

    2000-01-01

    In a series of experiments, the use of color-coding, intensity coding, and decluttering were compared order to assess their potential benefits for accessing information from electronic map displays...

  14. Gazetteer of Planetary Nomenclature: Moon: 1:10 million-scale Shaded Relief and Color-coded Topography: North Pole

    Data.gov (United States)

    National Aeronautics and Space Administration — These lunar maps display the four different areas of the moon with color-coded topography in low and high resolution approved by the International Astronomical Union...

  15. Nano-bio-optomechanics: nanoaperture tweezers probe single nanoparticles, proteins, and their interactions

    Science.gov (United States)

    Gordon, Reuven

    2015-09-01

    Nanoparticles in the single digit nanometer range can be easily isolated and studied with low optical powers using nanoaperture tweezers. We have studied individual proteins and their interactions with small molecules, DNA and antibodies. Recently, using the fluctuations of the trapped object, we have pioneered a new way to "listen" to the vibrations of nanoparticles in the 100 GHz - 1 THz range; the approach is called extraordinary acoustic Raman (EAR). EAR gives unprecedented low frequency spectra of individual proteins in solution, allowing for identification and analysis, as well as probing their role in biological functions. We have also used EAR to study the elastic properties, shape and size of various individual nanoparticles.

  16. A portable Hall magnetometer probe for characterization of magnetic iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Jefferson F.D.F.; Costa, Mateus C.; Louro, Sonia R.W.; Bruno, Antonio C., E-mail: acbruno@puc-rio.br

    2017-03-15

    We have built a portable Hall magnetometer probe, for measuring magnetic properties of iron oxide nanoparticles, that can be used for bulk materials and liquid samples as well. The magnetometer probe consists of four voltage-programmable commercial Hall sensors and a thin acrylic plate for positioning the sensors. In order to operate, it needs to be attached to a pole of an electromagnet and connected to an AD converter and a computer. It acquires a complete magnetization curve in a couple of minutes and has a magnetic moment sensitivity of 3.5×10{sup −7} Am{sup 2}. We tested its performance with magnetic nanoparticles containing an iron oxide core and having coating layers with different sizes. The magnetization results obtained were compared with measurements performed on commercial stand-alone magnetometers, and exhibited errors of about ±0.2 Am{sup 2}/kg (i.e 0.4%) at saturation and below 0.5 Am{sup 2}/kg (i.e. 10%) at remanence. - Highlights: • A low-cost portable Hall magnetometer probe has been built. • The Hall magnetometer probe can be attached to any electromagnet. • The Hall probe was calibrated and successfully compared to industry standard magnetometers. • The Hall probe was able to measure iron oxide nanoparticles with different coatings.

  17. Probing Au nanoparticle uptake by enzyme following the digestion of a starch-Au-nanoparticle composite.

    Science.gov (United States)

    Deka, Jashmini; Paul, Anumita; Ramesh, A; Chattopadhyay, Arun

    2008-09-16

    In this letter, we report on the digestion of starch, when present as a composite with Au nanoparticles (NPs), by alpha-amylase. It has been observed that the rate of digestion of free starch and that in the composite were identical. Also, the well-established iodine test could be carried out to investigate the kinetics in the presence of Au NPs. The investigations revealed that following the digestion of starch in the composite the NPs were released and subsequently attached to the enzyme only and not to the degraded products of starch. Also, the enzyme attached to NPs, following digestion, retained its catalytic activity. The particle sizes of the NPs were not affected in the process because no agglomeration was observed. Experimental observations indicated the possibility of oriented attachment of alpha-amylase to the NPs in comparison to amyloglucosidase, another digestive enzyme. Finally, we observed a change in the surface plasmon resonance (SPR) of the NPs following the digestion of starch in the composite, and thus we could demonstrate that the SPR of the NPs could be used as a direct probe for monitoring the digestion of the composite by the enzyme.

  18. A study of multifunctionalization of fluorescent nanoparticle probes

    Science.gov (United States)

    Wong, Hon Tung

    In this project, structural, luminescent and magnetic properties of multifunctional trivalent rare-earth ion (RE3+)-doped down- and up-converting nanoparticles with intrinsic magnetism and luminescence have been investigated. Syntheses, characterizations and surface modifications of multifunctional RE3+-doped nanoparticles have been carried out. All the multifunctional RE3+-doped down- and up-converting nanophosphors were synthesized using a facile hydrothermal method and a novel solution-based method. A variety of characterization techniques have been performed on the obtained phosphors, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), photoluminescent spectroscopy (PL), photoluminescent excitation spectroscopy (PLE), lifetime measurement, laser power measurement, vibrating sample magnetometer (VSM), Raman spectroscopy and confocal microscopy. An overview of the studies performed in this project is as follows. Different oxide and fluoride hosts have been synthesized and studied, including Gd 2O3, GdF3, YF3, NaYF4, and the seldom reported KGdF4. Different RE3+ ions have been doped into the above mentioned hosts for the realization of multifunctional nanoparticles with down- and up-conversion. For downconverting phosphors, Eu3+, Tb3+ and Tm3+ ions have been doped to obtain red, green, and blue emission. For upconverting phosphors, Tm3+/Yb3+ and Er3+/Yb 3+ ions have been doped to attain near-infrared to near-infrared and near-infrared to visible upconversion. The effects of hosts on the structural, luminescent and magnetic properties have been systemically studied. It is found that both hosts and dopants concentrations play a major role in determining the spectral features and the luminescent emission intensity. Particularly, nearly pure near-infrared to near-infrared upconversion is obtained in a specific GdF3 host. Characterizations of magnetic properties

  19. Mathematical study of probe arrangement and nanoparticle injection effects on heat transfer during cryosurgery.

    Science.gov (United States)

    Mirkhalili, Seyyed Mostafa; Ramazani S A, Ahmad; Nazemidashtarjandi, Saeed

    2015-11-01

    Blood vessels, especially large vessels have a greater thermal effect on freezing tissue during cryosurgery. Vascular networks act as heat sources in tissue, and cause failure in cryosurgery and reappearance of cancer. The aim of this study is to numerically simulate the effect of probe location and multiprobe on heat transfer distribution. Furthermore, the effect of nanoparticles injection is studied. It is shown that the small probes location near large blood vessels could help to reduce the necessary time for tissue freezing. Nanoparticles injection shows that the thermal effect of blood vessel in tissue is improved. Using Au, Ag and diamond nanoparticles have the most growth of ice ball during cryosurgery. However, polytetrafluoroethylene (PTFE) nanoparticle can be used to protect normal tissue around tumor cell due to its influence on reducing heat transfer in tissue. Introduction of Au, Ag and diamond nanoparticles combined with multicryoprobe in this model causes reduction of tissue average temperature about 50% compared to the one probe. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. TiO2 Nanoparticles as a Soft X-ray Molecular Probe

    Energy Technology Data Exchange (ETDEWEB)

    Larabell, Carolyn; Ashcroft, Jared M.; Gu, Weiwei; Zhang, Tierui; Hughes, Steven M.; Hartman, Keith B.; Hofmann, Cristina; Kanaras, Antonios G.; Kilcoyne, David A.; Le Gros, Mark; Yin, Yadong; Alivisatos, A. Paul; Larabell, Carolyn A.

    2007-06-30

    With the emergence of soft x-ray techniques for imaging cells, there is a pressing need to develop protein localization probes that can be unambiguously identified within the region of x-ray spectrum used for imaging. TiO2 nanocrystal colloids, which have a strong absorption cross-section within the "water-window" region of x-rays, areideally suited as soft x-ray microscopy probes. To demonstrate their efficacy, TiO2-streptavidin nanoconjugates were prepared and subsequently labeled microtubules polymerized from biotinylated tubulin. The microtubules were imaged using scanning transmission x-ray microscopy (STXM), and the TiO2 nanoparticle tags were specifically identified using x-ray absorption near edge spectroscopy (XANES). These experiments demonstrate that TiO2 nanoparticles are potential probes for protein localization analyses using soft x-ray microscopy.

  1. Variability of emergency color codes for critical events between hospitals in Riyadh.

    Science.gov (United States)

    Ashworth, Isa; El Dali, AbdelMoneim; ElDeib, Omar; Altoub, AbdulAziz; Pasha, Farooq; Butt, Taimur

    2015-01-01

    Emergency color codes were developed to alert healthcare personnel in a hospital to critical situations. They are often developed independently by each hospital, leading to variability. This could be a source of confusion to healthcare personnel, who move frequently between hospitals and may work at multiple hospitals. This study evaluated the variability of emergency codes for different critical events in hospitals in Riyadh. A prospective, cross-sectional survey was carried out on a representative sample of hospitals. Twenty-four of 28 hospitals took part in the study. Semi-structured questionnaires were completed by the Quality/Safety Department of each hospital, on general hospital characteristics, emergency department characteristics, code-response mock-up, code determination, emergency codes used and code meanings. Thirty-four different codes were used across hospitals. The codes used most variably were yellow (10 meanings), orange, black, green (7 meanings each), and gray (5 meanings), while the most consistently used code was 'Code Red' for 'Fire' in 75% of hospitals. Another source of variability was the use of non-color codes, representing 7.7% of total codes. There is large variability in the type and meaning of emergency codes between hospitals in Riyadh City, reflecting a lack of standardization. Hospitals use color and non-color emergency codes, which could cause confusion to responders and mitigate the effectiveness and speed of response in critical events.

  2. A color-coded particle tracking velocimeter with application to natural convection

    Science.gov (United States)

    Wung, T.-S.; Tseng, F.-G.

    1992-08-01

    This paper introduces a novel concept of the image-processing technique to visualize a two-dimensional flow field and to generate streaks with embedded time marks in real time. Grey levels of a pixel are used in this work to encode the temporal information rather than the intensity of particle trajectories used in conventional image-processing systems. To do this, the incoming video image is first binarized by a step function predefined in an input look-up table, with the height of the step varying with time to bear temporal marks. A real-time arithmetic-logic unit and an image-frame buffer are used to accumulate the images. These processes result in continuous streaks with embedded time marks which have many advantages over those recorded by conventional techniques. Pseudo-color output look-up tables and color monitor provide more direct and intuitive means for human visual perception. This color-coded particle tracking velocimetry was applied to investigate natural convection in an enclosure heated from below with an isothermal extrusion. By quantifying the color-coded streaks, velocity vectors were obtained at a discrete number of points with less labor. The present technique provides an elaborate tool for simultaneous qualitative and quantitative realizations of steady and slowly varying flow fields.

  3. Encapsulation method for atom probe tomography analysis of nanoparticles

    NARCIS (Netherlands)

    Larson, D.J.; Giddings, A.D.; Wub, Y.; Verheijen, M.A.; Prosa, T.J.; Roozeboom, F.; Rice, K.P.; Kessels, W.M.M.; Geiser, B.P.; Kelly, T.F.

    2015-01-01

    Open-space nanomaterials are a widespread class of technologically important materials that are generally incompatible with analysis by atom probe tomography (APT) due to issues with specimen preparation, field evaporation and data reconstruction. The feasibility of encapsulating such non-compact

  4. CoCo trial: Color-coded blood pressure Control, a randomized controlled study

    Directory of Open Access Journals (Sweden)

    Chmiel C

    2014-10-01

    Full Text Available Corinne Chmiel, Oliver Senn, Thomas Rosemann, Valerio Del Prete, Claudia Steurer-Stey Institute of General Practice and Health Services Research, University of Zurich, Zurich, Switzerland Background: Inadequate blood pressure (BP control is a frequent challenge in general practice. The objective of this study was to determine whether a color-coded BP booklet using a traffic light scheme (red, >180 mmHg systolic BP and/or >110 mmHg diastolic BP; yellow, >140–180 mmHg systolic BP or >90–110 mmHg diastolic BP; green, ≤140 mmHg systolic BP and ≤90 mmHg diastolic BP improves BP control and adherence with home BP measurement.Methods: In this two-group, randomized controlled trial, general practitioners recruited adult patients with a BP >140 mmHg systolic and/or >90 mmHg diastolic. Patients in the control group received a standard BP booklet and the intervention group used a color-coded booklet for daily home BP measurement. The main outcomes were changes in BP, BP control (treatment goal <140/90 mmHg, and adherence with home BP measurement after 6 months.Results: One hundred and twenty-one of 137 included patients qualified for analysis. After 6 months, a significant decrease in systolic and diastolic BP was achieved in both groups, with no significant difference between the groups (16.1/7.9 mmHg in the intervention group versus 13.1/8.6 mmHg in the control group, P=0.3/0.7. BP control (treatment target <140/90 mmHg was achieved significantly more often in the intervention group (43% versus 25%; P=0.037; number needed to treat of 5. Adherence with home BP measurement overall was high, with a trend in favor of the intervention group (98.6% versus 96.2%; P=0.1Conclusion: Color-coded BP self-monitoring significantly improved BP control (number needed to treat of 5, meaning that every fifth patient utilizing color-coded self-monitoring achieved better BP control after 6 months, but no significant between-group difference was

  5. Porphyrins as SERRS spectral probes of chemically functionalized Ag nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Šišková, Karolína; Vlčková, B.; Turpin, P. Y.; Thorel, A.; Grosjean, A.

    2008-01-01

    Roč. 48, č. 1 (2008), s. 44-52 ISSN 0924-2031. [International Conference on Advanced Vibrational Spectroscopy (ICAVS-4) /4./. Corfu, 10.06.2007-15.06.2007] R&D Projects: GA ČR GA203/07/0717 Institutional research plan: CEZ:AV0Z40500505 Keywords : SERRS * citrate-modified Ag nanoparticles * laser ablation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.810, year: 2008

  6. Synthesis and Bioconjugation of Gold Nanoparticles as Potential Molecular Probes for Light-Based Imaging Techniques

    Directory of Open Access Journals (Sweden)

    Raja Gopal Rayavarapu

    2007-01-01

    Full Text Available We have synthesized and characterized gold nanoparticles (spheres and rods with optical extinction bands within the “optical imaging window.” The intense plasmon resonant driven absorption and scattering peaks of these nanoparticles make them suitable as contrast agents for optical imaging techniques. Further, we have conjugated these gold nanoparticles to a mouse monoclonal antibody specific to HER2 overexpressing SKBR3 breast carcinoma cells. The bioconjugation protocol uses noncovalent modes of binding based on a combination of electrostatic and hydrophobic interactions of the antibody and the gold surface. We discuss various aspects of the synthesis and bioconjugation protocols and the characterization results of the functionalized nanoparticles. Some proposed applications of these potential molecular probes in the field of biomedical imaging are also discussed.

  7. Nanospot soldering polystyrene nanoparticles with an optical fiber probe laser irradiating a metallic AFM probe based on the near-field enhancement effect.

    Science.gov (United States)

    Cui, Jianlei; Yang, Lijun; Wang, Yang; Mei, Xuesong; Wang, Wenjun; Hou, Chaojian

    2015-02-04

    With the development of nanoscience and nanotechnology for the bottom-up nanofabrication of nanostructures formed from polystyrene nanoparticles, joining technology is an essential step in the manufacturing and assembly of nanodevices and nanostructures in order to provide mechanical integration and connection. To study the nanospot welding of polystyrene nanoparticles, we propose a new nanospot-soldering method using the near-field enhancement effect of a metallic atomic force microscope (AFM) probe tip that is irradiated by an optical fiber probe laser. On the basis of our theoretical analysis of the near-field enhancement effect, we set up an experimental system for nanospot soldering; this approach is carried out by using an optical fiber probe laser to irradiate the AFM probe tip to sinter the nanoparticles, providing a promising technical approach for the application of nanosoldering in nanoscience and nanotechnology.

  8. 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.

  9. SANS study to probe nanoparticle dispersion in nanocomposite membranes of aromatic polyamide and functionalized silica nanoparticles.

    Science.gov (United States)

    Jadav, Ghanshyam L; Aswal, Vinod K; Singh, Puyam S

    2010-11-01

    Silica nanoparticles produced from organically functionalized silicon alkoxide precursors were incorporated into polyamide film to produce a silica-polyamide nanocomposite membrane with enhanced properties. The dispersion of the silica nanoparticles in the nanocomposite membrane was characterized by performing small-angle neutron scattering (SANS) measurements on dilute reactant systems and dilute solution suspensions of the final product. Clear scattering of monodisperse spherical particles of 10-18 A R(g) were observed from dilute solutions of the initial reactant system. These silica nanoparticles initially reacted with diamine monomers of polyamide and subsequently were transformed into polyamide-coated silica nanoparticles; finally nanoparticle aggregates of 27-45 A R(g) were formed. The nanoparticle dispersion of the membrane as the nanosized aggregates is in corroboration with ring- or chain-like assemblies of the nanoparticles dispersed in the bulk polyamide phase as observed by transmission electron microscopy. It is demonstrated that dispersions of silica nanoparticles as the nanosized aggregates in the polyamide phase could be achieved in the nanocomposite membrane with a silica content up to about 2 wt.%. Nanocomposite membranes with higher silica loading approximately 10 wt.% lead to the formation of large aggregates of sizes over 100 A R(g) in addition to the nanosized aggregates. Copyright 2010 Elsevier Inc. All rights reserved.

  10. Use of fluorescent proteins and color-coded imaging to visualize cancer cells with different genetic properties.

    Science.gov (United States)

    Hoffman, Robert M

    2016-03-01

    Fluorescent proteins are very bright and available in spectrally-distinct colors, enable the imaging of color-coded cancer cells growing in vivo and therefore the distinction of cancer cells with different genetic properties. Non-invasive and intravital imaging of cancer cells with fluorescent proteins allows the visualization of distinct genetic variants of cancer cells down to the cellular level in vivo. Cancer cells with increased or decreased ability to metastasize can be distinguished in vivo. Gene exchange in vivo which enables low metastatic cancer cells to convert to high metastatic can be color-coded imaged in vivo. Cancer stem-like and non-stem cells can be distinguished in vivo by color-coded imaging. These properties also demonstrate the vast superiority of imaging cancer cells in vivo with fluorescent proteins over photon counting of luciferase-labeled cancer cells.

  11. Transcranial color-coded duplex sonography in suspected acute basilar artery occlusion.

    Science.gov (United States)

    Kermer, Pawel; Wellmer, Andreas; Crome, Olaf; Mohr, Alexander; Knauth, Michael; Bähr, Mathias

    2006-03-01

    Transcranial color-coded duplex sonography (TCDS) is a noninvasive, quick and inexpensive diagnostic tool used routinely to assess vascular abnormalities in cerebral ischemia. The value of TCDS for diagnosis and follow-up of acute basilar artery (BA) ischemia in comparison/combination with spiral CT angiography (CTA) and/or digital subtraction angiography (DSA) has not yet been studied. We prospectively studied 15 consecutive patients with clinically suspected acute BA occlusion (BAO) by TCDS as well as 3 to 5 d later in those with proven BAO. BA ischemia was verified in 11 patients. During follow-up, all BAO patients showed recanalization of the BA independent of thrombolytic treatment. In conclusion, TCDS appears to be an efficient method for BAO diagnosis when immediate angiography is not available. Together with CTA it increases diagnostic safety before performing an invasive and cost-intensive DSA.

  12. Color-coded Live Imaging of Heterokaryon Formation and Nuclear Fusion of Hybridizing Cancer Cells.

    Science.gov (United States)

    Suetsugu, Atsushi; Matsumoto, Takuro; Hasegawa, Kosuke; Nakamura, Miki; Kunisada, Takahiro; Shimizu, Masahito; Saji, Shigetoyo; Moriwaki, Hisataka; Bouvet, Michael; Hoffman, Robert M

    2016-08-01

    Fusion of cancer cells has been studied for over half a century. However, the steps involved after initial fusion between cells, such as heterokaryon formation and nuclear fusion, have been difficult to observe in real time. In order to be able to visualize these steps, we have established cancer-cell sublines from the human HT-1080 fibrosarcoma, one expressing green fluorescent protein (GFP) linked to histone H2B in the nucleus and a red fluorescent protein (RFP) in the cytoplasm and the other subline expressing RFP in the nucleus (mCherry) linked to histone H2B and GFP in the cytoplasm. The two reciprocal color-coded sublines of HT-1080 cells were fused using the Sendai virus. The fused cells were cultured on plastic and observed using an Olympus FV1000 confocal microscope. Multi-nucleate (heterokaryotic) cancer cells, in addition to hybrid cancer cells with single-or multiple-fused nuclei, including fused mitotic nuclei, were observed among the fused cells. Heterokaryons with red, green, orange and yellow nuclei were observed by confocal imaging, even in single hybrid cells. The orange and yellow nuclei indicate nuclear fusion. Red and green nuclei remained unfused. Cell fusion with heterokaryon formation and subsequent nuclear fusion resulting in hybridization may be an important natural phenomenon between cancer cells that may make them more malignant. The ability to image the complex processes following cell fusion using reciprocal color-coded cancer cells will allow greater understanding of the genetic basis of malignancy. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  13. Effects of Gender Color-Coding on Toddlers' Gender-Typical Toy Play.

    Science.gov (United States)

    Wong, Wang I; Hines, Melissa

    2015-07-01

    Gender color-coding of children's toys may make certain toys more appealing or less appealing to a given gender. We observed toddlers playing with two gender-typical toys (a train, a doll), once in gender-typical colors and once in gender-atypical colors. Assessments occurred twice, at 20-40 months of age and at 26-47 months of age. A Sex × Time × Toy × Color ANOVA showed expected interactions between Sex and Toy and Sex and Color. Boys played more with the train than girls did and girls played more with the doll and with pink toys than boys did. The Sex × Toy × Color interaction was not significant, but, at both time points, boys and girls combined played more with the gender-atypical toy when its color was typical for their sex than when it was not. This effect appeared to be caused largely by boys' preference for, or avoidance of, the doll and by the use of pink. Also, at both time points, gender differences in toy preferences were larger in the gender-typical than in the gender-atypical color condition. At Time 2, these gender differences were present only in the gender-typical color condition. Overall, the results suggest that, once acquired, gender-typical color preferences begin to influence toy preferences, especially those for gender-atypical toys and particularly in boys. They thus could enlarge differences between boys' and girls' toy preferences. Because boys' and girls' toys elicit different activities, removing the gender color-coding of toys could encourage more equal learning opportunities.

  14. Folate receptor targeting silica nanoparticle probe for two-photon fluorescence bioimaging

    Science.gov (United States)

    Wang, Xuhua; Yao, Sheng; Ahn, Hyo-Yang; Zhang, Yuanwei; Bondar, Mykhailo V.; Torres, Joseph A.; Belfield, Kevin D.

    2010-01-01

    Narrow dispersity organically modified silica nanoparticles (SiNPs), diameter ~30 nm, entrapping a hydrophobic two-photon absorbing fluorenyl dye, were synthesized by hydrolysis of triethoxyvinylsilane and (3-aminopropyl)triethoxysilane in the nonpolar core of Aerosol-OT micelles. The surface of the SiNPs were functionalized with folic acid, to specifically deliver the probe to folate receptor (FR) over-expressing Hela cells, making these folate two-photon dye-doped SiNPs potential candidates as probes for two-photon fluorescence microscopy (2PFM) bioimaging. In vitro studies using FR over-expressing Hela cells and low FR expressing MG63 cells demonstrated specific cellular uptake of the functionalized nanoparticles. One-photon fluorescence microscopy (1PFM) imaging, 2PFM imaging, and two-photon fluorescence lifetime microscopy (2P-FLIM) imaging of Hela cells incubated with folate-modified two-photon dye-doped SiNPs were demonstrated. PMID:21258480

  15. A lectin-based gold nanoparticle assay for probing glycosylation of glycoproteins.

    Science.gov (United States)

    Sánchez-Pomales, Germarie; Morris, Todd A; Falabella, James B; Tarlov, Michael J; Zangmeister, Rebecca A

    2012-09-01

    We report a glycoanalysis method in which lectins are used to probe the glycans of therapeutic glycoproteins that are adsorbed on gold nanoparticles. A model mannose-presenting glycoprotein, ribonuclease B (RNase B), and the therapeutic monoclonal antibody (mAb) rituximab, were found to adsorb spontaneously and non-specifically to bare gold nanoparticles such that glycans were accessible for lectin binding. Addition of a multivalent binding lectin, such as concanavalin A (Con A), to a solution of the modified gold nanoparticles resulted in cross-linking of the nanoparticles. This phenomenon was evidenced within 1 min by a change in the hydrodynamic diameter, D(H), measured by dynamic light scattering (DLS) and a shift and increase in absorbance of the plasmon resonance band of the gold nanoparticles. By combining the sugar-binding specificity and the cross-linking capabilities of lectins, the non-specific adsorption of glycoproteins to gold surfaces, and the unique optical reporting properties of gold nanoparticles, a glycosylation pattern of rituximab could be generated. This assay provides advantages over currently used glycoanalysis methods in terms of short analysis time, simplicity of the conjugation method, convenience of simple spectroscopic detection, and feasibility of providing glycan characterization of the protein drug product by using a variety of binding lectins. Copyright © 2012 Wiley Periodicals, Inc.

  16. Dual imaging probes for magnetic resonance imaging and fluorescence microscopy based on perovskite manganite nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Kačenka, M.; Kaman, Ondřej; Kotek, J.; Falteisek, L.; Černý, J.; Jirák, D.; Herynek, V.; Zacharovová, K.; Berková, A.; Jendelová, Pavla; Kupčík, Jaroslav; Pollert, Emil; Veverka, Pavel; Lukeš, I.

    2011-01-01

    Roč. 21, č. 1 (2011), s. 157-164 ISSN 0959-9428 R&D Projects: GA AV ČR KAN200200651 Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z50390703; CEZ:AV0Z40720504 Keywords : cellular labelling * dual probe * magnetic nanoparticles * MRI * silica coating Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.968, year: 2011

  17. Electrical sintering of silver nanoparticle ink studied by in-situ TEM probing.

    Directory of Open Access Journals (Sweden)

    Magnus Hummelgård

    Full Text Available Metallic nanoparticle inks are used for printed electronics, but to reach acceptable conductivity the structures need to be sintered, usually using a furnace. Recently, sintering by direct resistive heating has been demonstrated. For a microscopic understanding of this Joule heating sintering method, we studied the entire process in real time inside a transmission electron microscope equipped with a movable electrical probe. We found an onset of Joule heating induced sintering and coalescence of nanoparticles at power levels of 0.1-10 mW/μm³. In addition, a carbonization of the organic shells that stabilize the nanoparticles were found, with a conductivity of 4 10⁵ Sm⁻¹.

  18. Electrogenerated chemiluminescence detection for deoxyribonucleic acid hybridization based on gold nanoparticles carrying multiple probes

    International Nuclear Information System (INIS)

    Wang Hui; Zhang Chengxiao; Li Yan; Qi Honglan

    2006-01-01

    A novel sensitive electrogenerated chemiluminescence (ECL) method for the detection deoxyribonucleic acid (DNA) hybridization based on gold nanoparticles carrying multiple probes was developed. Ruthenium bis(2,2'-bipyridine)(2,2'-bipyridine-4,4'-dicarboxylic acid)-N-hydroxysuccinimide ester (Ru(bpy) 2 (dcbpy)NHS) was used as a ECL label and gold nanoparticle as a carrier. Probe single strand DNA (ss-DNA) was self-assembled at the 3'-terminal with a thiol group to the surface of gold nanoparticle and covalently labeled at the 5'-terminal of a phosphate group with Ru(bpy) 2 (dcbpy)NHS and the resulting conjugate (Ru(bpy) 2 (dcbpy)NHS)-ss-DNA-Au, was taken as a ECL probe. When target analyte ss-DNA was immobilized on a gold electrode by self-assembled monolayer technique and then hybridized with the ECL probe to form a double-stranded DNA (ds-DNA), a strong ECL response was electrochemically generated. The ECL intensity was linearly related to the concentration of the complementary sequence (target ss-DNA) in the range from 1.0 x 10 -11 to 1.0 x 10 -8 mol L -1 , and the linear regression equation was S = 57301 + 4579.6 lg C (unit of C is mol L -1 ). A detection limit of 5.0 x 10 -12 mol L -1 for target ss-DNA was achieved. The ECL signal generated from many reporters of ECL probe prepared is greatly amplified, compared to the convention scheme which is based on one reporter per hybridization event

  19. Quantifying Aflatoxin B1 in peanut oil using fabricating fluorescence probes based on upconversion nanoparticles

    Science.gov (United States)

    Sun, Cuicui; Li, Huanhuan; Koidis, Anastasios; Chen, Quansheng

    2016-08-01

    Rare earth doped upconversion nanoparticles convert near-infrared excitation light into visible emission light. Compared to organic fluorophores and semiconducting nanoparticles, upconversion nanoparticles (UCNPs) offer high photochemical stability, sharp emission bandwidths, and large anti-Stokes shifts. Along with the significant light penetration depth and the absence of autofluorescence in biological samples under infrared excitation, these UCNPs have attracted more and more attention on toxin detection and biological labelling. Herein, the fluorescence probe based on UCNPs was developed for quantifying Aflatoxin B1 (AFB1) in peanut oil. Based on a specific immunity format, the detection limit for AFB1 under optimal conditions was obtained as low as 0.2 ng·ml- 1, and in the effective detection range 0.2 to 100 ng·ml- 1, good relationship between fluorescence intensity and AFB1 concentration was achieved under the linear ratios up to 0.90. Moreover, to check the feasibility of these probes on AFB1 measurements in peanut oil, recovery tests have been carried out. A good accuracy rating (93.8%) was obtained in this study. Results showed that the nanoparticles can be successfully applied for sensing AFB1 in peanut oil.

  20. A new method for mapping the three-dimensional atomic distribution within nanoparticles by atom probe tomography (APT).

    Science.gov (United States)

    Kim, Se-Ho; Kang, Phil Woong; Park, O Ok; Seol, Jae-Bok; Ahn, Jae-Pyoung; Lee, Ji Yeong; Choi, Pyuck-Pa

    2018-04-13

    We present a new method of preparing needle-shaped specimens for atom probe tomography from freestanding Pd and C-supported Pt nanoparticles. The method consists of two steps, namely electrophoresis of nanoparticles on a flat Cu substrate followed by electrodeposition of a Ni film acting as an embedding matrix for the nanoparticles. Atom probe specimen preparation can be subsequently carried out by means of focused-ion-beam milling. Using this approach, we have been able to perform correlative atom probe tomography and transmission electron microscopy analyses on both nanoparticle systems. Reliable mass spectra and three-dimensional atom maps could be obtained for Pd nanoparticle specimens. In contrast, atom probe samples prepared from C-supported Pt nanoparticles showed uneven field evaporation and hence artifacts in the reconstructed atom maps. Our developed method is a viable means of mapping the three-dimensional atomic distribution within nanoparticles and is expected to contribute to an improved understanding of the structure-composition-property relationships of various nanoparticle systems. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Gold nanoparticle-based probes for the colorimetric detection of Mycobacterium avium subspecies paratuberculosis DNA.

    Science.gov (United States)

    Ganareal, Thenor Aristotile Charles S; Balbin, Michelle M; Monserate, Juvy J; Salazar, Joel R; Mingala, Claro N

    2018-02-12

    Gold nanoparticle (AuNP) is considered to be the most stable metal nanoparticle having the ability to be functionalized with biomolecules. Recently, AuNP-based DNA detection methods captured the interest of researchers worldwide. Paratuberculosis or Johne's disease, a chronic gastroenteritis in ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP), was found to have negative effect in the livestock industry. In this study, AuNP-based probes were evaluated for the specific and sensitive detection of MAP DNA. AuNP-based probe was produced by functionalization of AuNPs with thiol-modified oligonucleotide and was confirmed by Fourier-Transform Infrared (FTIR) spectroscopy. UV-Vis spectroscopy and Scanning Electron Microscopy (SEM) were used to characterize AuNPs. DNA detection was done by hybridization of 10 μL of DNA with 5 μL of probe at 63 °C for 10 min and addition of 3 μL salt solution. The method was specific to MAP with detection limit of 103 ng. UV-Vis and SEM showed dispersion and aggregation of the AuNPs for the positive and negative results, respectively, with no observed particle growth. This study therefore reports an AuNP-based probes which can be used for the specific and sensitive detection of MAP DNA. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. An improved gold nanoparticle probe-based assay for HCV core antigen ultrasensitive detection.

    Science.gov (United States)

    Yin, Hui-Qiong; Ji, Chang-Fu; Yang, Xi-Qin; Wang, Rui; Yang, Shu; Zhang, He-Qiu; Zhang, Jin-Gang

    2017-05-01

    A gold nanoparticle probe-based assay (GNPA) was developed for ultrasensitive detection of Hepatitis C virus (HCV) core antigen. In the GNPA, after anti-HCV core antigen polyclonal antibodies and single-stranded barcode signal DNA were labeled on gold nanoparticle probe (NP), DNA enzyme was used to degrade the unbound barcode DNAs. The anti-HCV core antigen monoclonal antibodies were coated on magnetic microparticles probe (MMP). Then the NP-HCV core antigen-MMP sandwich immuno-complex was formed when the target antigen protein was added and captured. Magnetically separated, the immuno-complex containing the single-stranded barcode signal DNA was characterized by TaqMan probe based real-time fluorescence PCR. A detection limit of 1 fg/ml was determined for the HCV core antigen which is magnitude greater than that of ELISA (2ng/ml). The coefficients of variation (CV) of intra-assay and inter-assay respectively ranged from 0.22-2.62% and 1.92-3.01%. The improved GNPA decreased the interference of unbound barcode DNAs and may be an new way for HCV core antigen detection. Copyright © 2017. Published by Elsevier B.V.

  3. Thermal probes of nanoparticle interfaces: Thermodiffusion and thermal conductivity of nanoparticle suspensions

    Science.gov (United States)

    Putnam, Shawn Arthur

    This dissertation presents an experimental study of heat transport and mass transport in nanoparticle composites. The 3o-method was used for high precision thermal conductivity measurements of PMMA polymers filled with alumina nanoparticles. A microfluidic beam deflection technique, developed in this thesis, was used to measure both the thermal conductivity (Λ) and the thermodiffusion coefficient (DT) of nanoparticle suspensions. Thermal conductivity studies of polymer nanocomposites used effective medium theory and data for the changes in thermal conductivity to estimate the thermal conductance of PMMA/alumina interfaces in the temperature range of 40 30 nm. Thermal conductivity studies of nanoparticle suspensions measured the thermal diffusivity to a precision better than 1%. Solutions of G60--C 70 fullerenes and alkanethiolate-protected Au nanoparticles were measured to maximum volume fractions of 0.6% and 0.35 vol%, respectively. Anomalous enhancements in Λ were not observed. The largest enhancement in Λ was 1.3 +/- 0.8% for 4 nm diameter Au particles suspended in ethanol. Thermodiffusion studies investigated aqueous suspensions of charged polystyrene nanoparticles, proteins of T4 lysozyme, and mutant variants of T4 lysozyme at small particle concentrations (cp ≈ 1-2 vol%). DT was measured as a function of temperature, particle size, particle charge, ionic strength, and ionic species. At room temperature and high salt concentrations (>100 mM), DT for 26 nm polystyrene nanoparticles varied systematically within the range --0.9x10-7 cm2 K -1 50°C, the thermodiffusion coefficients were positive with a value consistent with the predictions of a theoretical model originally proposed by B. Derjaguin that is based on the enthalpy changes due to polarization of water molecules in the double-layer. At high temperatures, DT was also independent of particle size.

  4. Learning about Probability from Text and Tables: Do Color Coding and Labeling through an Interactive-User Interface Help?

    Science.gov (United States)

    Clinton, Virginia; Morsanyi, Kinga; Alibali, Martha W.; Nathan, Mitchell J.

    2016-01-01

    Learning from visual representations is enhanced when learners appropriately integrate corresponding visual and verbal information. This study examined the effects of two methods of promoting integration, color coding and labeling, on learning about probabilistic reasoning from a table and text. Undergraduate students (N = 98) were randomly…

  5. Feasibility of use of color-coded rings by nurse midwives: An appropriate technology based on partographic principles

    Directory of Open Access Journals (Sweden)

    Asha K Pratinidhi

    2013-01-01

    Full Text Available Objectives: To study the feasibility of use of color-coded rings as a proxy for partograph for early identification of slow progress of labor. Materials and Methods: Color-coded rings were devised as a tool using appropriate technology to translate the partographic principles into simpler, easy to understand methodology. The rings were in pairs of 4 colors i.e., red, blue, yellow, and green, ranging from 3 cm to 10 cm in diameter with a difference of 4 cm between rings of the same color. The midwife performed p/v examination of the woman in labor to assess the initial cervical dilatation and identify corresponding ring. P/V was to be repeated after 4 hours to reassess the cervical dilatation and compare it with the bigger ring of the same color indicating expected cervical dilatation. If existing cervical dilatation measured lesser, it was interpreted as slow progress of labor indicating referral. Results: 44 women [23 (22.1% primis and 21 (13% multis] showed delayed progress of labor as judged by use of color-coded rings. 20 women (4 primis and 16 multis showed satisfactory progress or delivered by the time arrangements for referral were made. Conclusion: Use of color-coded rings may serve as a valuable tool based on appropriate technology to assess slow progress of labor not only in the hands of nurse midwives but it also can serve as a training tool for TBAs to help facilitate timely referral of such cases.

  6. Collateral configuration of the circle of Willis: transcranial color-coded duplex ultrasonography and comparison with postmortem anatomy

    NARCIS (Netherlands)

    Hoksbergen, A. W.; Fülesdi, B.; Legemate, D. A.; Csiba, L.

    2000-01-01

    BACKGROUND AND PURPOSE: The anterior communicating artery (AcoA) and posterior communicating arteries (PcoA) of the circle of Willis provide the main route for collateral blood flow in cases of carotid artery obstruction. Transcranial color-coded duplex ultrasonography (TCCD) allows real-time

  7. Clinical evaluation of a novel LMA with a color-coded pressure gauge.

    Science.gov (United States)

    Martin, David P; Bhalla, Tarun; Thung, Arlyne; Tobias, Joseph D

    2013-01-01

    Unintended hyperinflation of the cuff of a laryngeal mask airway (LMA) may be associated with increased airway morbidity and postoperative pain. While the manufacturers recommend a cuff pressure of ≤ 60 cmH(2)O, in usual clinical practice, there is no method used to determine the intracuff pressure. The purpose of this prospective study was to evaluate the accuracy of a newly designed LMA with a built in pressure gauge intended to alert the clinician to elevated intracuff pressures. The pressure gauge has a color code system intended to reflect the intracuff pressure with green being 40-60 cmH(2)O. There was no change dictated in clinical practice for these patients. Per our usual practice, the LMA was removed from the package and inserted with the cuff partially inflated. Additional air was added to the cuff using a syringe as needed to ensure a seal during positive pressure ventilation to a peak inflating pressure (peak ventilating pressure) of 20-25 cmH(2)O. The clinicians placing the LMA did not use the pressure gauge for clinical feedback during cuff inflation. Immediately after LMA placement, the pressure in the cuff of the LMA was measured using a hand held manometer by an independent reviewer not part of the patient's anesthetic management. The color indicated on the pressure gauge (yellow, green or red) was recorded prior to pressure sampling. Additional data collected included the patient's demographic data (age, weight, and gender), the size of the LMA, and whether air was added to the cuff. The study cohort included 100 children, ranging in age from 3 months to 19 years and in weight from 5.4 to 80.1 kg. One patient was excluded due to malfunction of the pressure gauge and pilot balloon of the LMA. The intracuff pressure as measured by manometer correlated appropriately with the color coding of the pressure gauge in 94 of the 99 (95%) of the LMA's tested. Given the potential association of excessive intracuff pressures with postoperative sore throat

  8. Dual-cycle dielectrophoretic collection rates for probing the dielectric properties of nanoparticles.

    Science.gov (United States)

    Bakewell, David J; Holmes, David

    2013-04-01

    A new DEP spectroscopy method and supporting theoretical model is developed to systematically quantify the dielectric properties of nanoparticles using continuously pulsed DEP collection rates. Initial DEP collection rates, that are dependent on the nanoparticle dielectric properties, are an attractive alternative to the crossover frequency method for determining dielectric properties. The new method introduces dual-cycle amplitude modulated and frequency-switched DEP (dual-cycle DEP) where the first collection rate with a fixed frequency acts as a control, and the second collection rate frequency is switched to a chosen value, such that, it can effectively probe the dielectric properties of the nanoparticles. The application of the control means that measurement variation between DEP collection experiments is reduced so that the frequency-switched probe collection is more effective. A mathematical model of the dual-cycle method is developed that simulates the temporal dynamics of the dual-cycle DEP nanoparticle collection system. A new statistical method is also developed that enables systematic bivariate fitting of the multifrequency DEP collection rates to the Clausius-Mossotti function, and is instrumental for determining dielectric properties. A Monte-Carlo simulation validates that collection rates improve estimation of the dielectric properties, compared with the crossover method, by exploiting a larger number of independent samples. Experiments using 200 nm diameter latex nanospheres suspended in 0.2 mS/m KCl buffer yield a nanoparticle conductivity of 26 mS/m that lies within 8% of the expected value. The results show that the dual-frequency method has considerable promise particularly for automated DEP investigations and associated technologies. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Tc-99m DTPA perfusion scintigraphy and color coded duplex sonography in the evaluation of minimal renal allograft perfusion

    International Nuclear Information System (INIS)

    Bair, H.J.; Platsch, G.; Wolf, F.; Guenter, E.; Becker, D.; Rupprecht, H.; Neumayer, H.H.

    1997-01-01

    Aim: The clinical impact of perfusion scintigraphy versus color coded Duplex sonography was evaluated, with respect to their potential in assessing minimal allograft perfusion in vitally threatened kidney transplants, i.e. oligoanuric allografts suspected to have either severe rejection or thrombosis of the renal vein or artery. Methods: From July 1990 to August 1994 the grafts of 15 out of a total of 315 patients were vitally threatened. Technetium-99m DTPA scintigraphy and color coded Duplex sonography were performed in all patients. For scintigraphic evaluation of transplant perfusion analog scans up to 60 min postinjection, and time-activity curves over the first 60 sec after injection of 370-440 MBq Tc-99m diethylenetriaminepentaacetate acid (DTPA) were used and classified by a perfusion score, the time between renal and iliac artery peaks (TDiff) and the washout of the renogram curve. Additionally, evaluation of excretion function and assessment of vascular or urinary leaks were performed. By color coded Duplex sonography the perfusion in all sections of the graft as well as the vascular anastomoses were examined and the maximal blood flow velocity (Vmax) and the resistive index (RI) in the renal artery were determined by means of the pulsed Doppler device. Pathologic-anatomical diagnosis was achieved by either biopsy or post-explant histology in all grafts. Results: Scintigraphy and color coded Duplex sonography could reliably differentiate minimal (8/15) and not perfused (7/15) renal allografts. The results were confirmed either by angiography in digital subtraction technique (DSA) or the clinical follow up. Conclusion: In summary, perfusion scintigraphy and color coded Duplex sonography are comparable modalities to assess kidney graft perfusion. In clinical practice scintigraphy and colorcoded Doppler sonography can replace digital subtraction angiography in the evaluation of minimal allograft perfusion. (orig.) [de

  10. An x-ray probe of nickel nanoparticles generated by laser ablation

    Science.gov (United States)

    Lehmann, C. S.; Doumy, G.; Southworth, S. H.; March, A. M.; Dichiara, A. D.; Gao, Y.; Kanter, E. P.; Krässig, B.; Moonshiram, D.; Young, L.; Chapman, K. W.; Chupas, P. J.

    2014-05-01

    A plume of nickel atoms and nanoparticles can be generated by an intense laser pulse hitting a solid nickel surface. We set up a Ni ablation source in a vacuum chamber on an x-ray beamline at the Advanced Photon Source and used x-ray absorption, x-ray emission, and ion spectroscopies to probe the ablation plume at x-ray energies above the Ni K-edge at 8.33 keV. The laser and x-ray pulses were overlapped in time and space with variable delay to measure the time evolution of the ablation plume. Measurements of the charge states produced by x-ray absorption were not possible due to the intense prompt ions ejected in the ablation process. However, Ni K α x-ray emission was measured as functions of laser fluence and pump-probe delay. The fluorescence yield was also used to record the near-edge x-ray absorption spectrum of the nanoparticles in the plume. The nanoparticles were collected and their diameters were determined to be ~9 nm from x-ray scattering pair-distribution-function measurements. The experiments demonstrate the use of x-ray techniques to characterize laser ablation processes. Work supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, US Dept of Energy, Contract DE-AC02-06CH11357.

  11. Gold nanoparticle-based 2'-O-methyl modified DNA probes for breast cancerous theranostics.

    Science.gov (United States)

    Li, Jing; Huang, Jin; Yang, Xiaohai; Yang, Yanjing; Quan, Ke; Xie, Nuli; Wu, Yanan; Ma, Changbei; Wang, Kemin

    2018-06-01

    MicroRNAs (miRNAs) are a class of small non-coding RNAs that regulated diverse cellular processes including differentiation, proliferation, apoptosis, metabolism and signal transduction pathways. An increasing number of data suggested that miRNA-21 could be identified as diagnostic and therapeutic biomarker for breast cancer. Meanwhile, inhibiting the function of miRNA-21, resulting in cells growth inhibition and apoptotic cells death. To realize miRNA-21detection and inhibition to diagnostic and therapeutic breast cancer cells, we developed gold nanoparticle-based 2'-O-methyl modified DNA probes (AuNP-2'-OMe-DNA probes) for diagnostic and therapeutic breast cancer. Gold nanoparticles were functionalized with chemically modified miRNA-21 inhibitor to suppress the function of miRNA-21 for the therapeutic breast cancer, at the same time, fluorophore-labeled DNA molecules were hybridized with antimiRNA-21 for diagnostic breast cancer. The results showed that the 2'-O-methyl modified DNA can improve stability, increase binding affinity to target strands and enhance the therapeutic effects. The experimental results also demonstrated that antimiR-21 were efficiently introduced into the cells and knocked down miRNA-21 to inhibit its function, leading to growth inhibition and apoptotic cells death. We prospected that chemically modified miRNA-21 inhibitor based on gold nanoparticles would be as a promising diagnostic and therapeutic platform for breast cancer clinically. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Color coded multiple access scheme for bidirectional multiuser visible light communications in smart home technologies

    Science.gov (United States)

    Tiwari, Samrat Vikramaditya; Sewaiwar, Atul; Chung, Yeon-Ho

    2015-10-01

    In optical wireless communications, multiple channel transmission is an attractive solution to enhancing capacity and system performance. A new modulation scheme called color coded multiple access (CCMA) for bidirectional multiuser visible light communications (VLC) is presented for smart home applications. The proposed scheme uses red, green and blue (RGB) light emitting diodes (LED) for downlink and phosphor based white LED (P-LED) for uplink to establish a bidirectional VLC and also employs orthogonal codes to support multiple users and devices. The downlink transmission for data user devices and smart home devices is provided using red and green colors from the RGB LEDs, respectively, while uplink transmission from both types of devices is performed using the blue color from P-LEDs. Simulations are conducted to verify the performance of the proposed scheme. It is found that the proposed bidirectional multiuser scheme is efficient in terms of data rate and performance. In addition, since the proposed scheme uses RGB signals for downlink data transmission, it provides flicker-free illumination that would lend itself to multiuser VLC system for smart home applications.

  13. Color-Coded Front-of-Pack Nutrition Labels-An Option for US Packaged Foods?

    Science.gov (United States)

    Dunford, Elizabeth K; Poti, Jennifer M; Xavier, Dagan; Webster, Jacqui L; Taillie, Lindsey Smith

    2017-05-10

    The implementation of a standardized front-of-pack-labelling (FoPL) scheme would likely be a useful tool for many consumers trying to improve the healthfulness of their diets. Our objective was to examine what the traffic light labelling scheme would look like if implemented in the US. Data were extracted from Label Insight's Open Access branded food database in 2017. Nutrient levels and the proportion of products classified as "Red" (High), "Amber" (Medium) or "Green" (Low) in total fat, saturated fat, total sugar and sodium for food and beverage items were examined. The proportion of products in each category that had each possible combination of traffic light colors, and met the aggregate score for "healthy" was examined. Out of 175,198 products, >50% of all US packaged foods received a "Red" rating for total sugar and sodium. "Confectionery" had the highest mean total sugar (51.9 g/100 g) and "Meat and meat alternatives" the highest mean sodium (781 mg/100 g). The most common traffic light label combination was "Red" for total fat, saturated fat and sodium and "Green" for sugar. Only 30.1% of products were considered "healthy". A wide variety ( n = 80) of traffic light color combinations were observed. A color coded traffic light scheme appears to be an option for implementation across the US packaged food supply to support consumers in making healthier food choices.

  14. Novel 2D-sequential color code system employing Image Sensor Communications for Optical Wireless Communications

    Directory of Open Access Journals (Sweden)

    Trang Nguyen

    2016-06-01

    Full Text Available The IEEE 802.15.7r1 Optical Wireless Communications Task Group (TG7r1, also known as the revision of the IEEE 802.15.7 Visible Light Communication standard targeting the commercial usage of visible light communication systems, is of interest in this paper. The paper is mainly concerned with Image Sensor Communications (ISC of TG7r1; however, the major challenge facing ISC, as addressed in the Technical Consideration Document (TCD of TG7r1, is Image Sensor Compatibility among the variety of different commercial cameras on the market. One of the most challenging but interesting compatibility requirements is the need to support the verified presence of frame rate variation. This paper proposes a novel design for 2D-sequential color code. Compared to a QR-code-based sequential transmission, the proposed design of 2D-sequential code can overcome the above challenge that it is compatible with different frame rate variations and different shutter operations, and has the ability to mitigate the rolling effect as well as the rotating effect while effectively minimizing transmission overhead. Practical implementations are demonstrated and a performance comparison is presented.

  15. Color coded duplex sonography. Interdisciplinary vascular ultrasonography; Farbkodierte Duplexsonographie. Interdisziplinaerer vaskulaerer Ultraschall

    Energy Technology Data Exchange (ETDEWEB)

    Kubale, R. [Institut fuer Radiologie, Sonographie und Nuklearmedizin, Pirmasens (Germany); Stiegler, H. [Staedtisches Krankenhaus Schwabing, Muenchen (Germany). 7. Medizinische Abt.

    2002-07-01

    An interdisciplinary team of experts impart the state of the art in color coded duplex sonography applied for examination of all anatomic areas. Detailed information is given for every vascular area, describing the examination procedure, possible origins of mistakes or faults, and means to avoid them. In addition to the classical applications, eg. for examination of the extra- and intracranial vessels, vessels of the limbs, visceral vessels and the vessels of liver and kidney, there are chapters devoted to: haemodialysis shunts, arteriovenous malformations, duplex sonography of the penis, tumor vascularisation. (orig./CB) [German] Ein interdisziplinaeres Autorenteam vermittelt Ihnen den State of the Art der FKDS fuer alle anatomischen Regionen. Fuer jede der Gefaessregionen werden detaillierte Angaben zum Untersuchungsablauf, zu moeglichen Fehlerquellen und zu deren Vermeidung geboten. Neben den klassischen Anwendungen bei der Untersuchung - der extra- und intrakraniellen Gefaesse, - der Extremitaetengefaesse, - der viszeralen Gefaesse sowie der Gefaesse von Niere und Leber finden Sie Kapitel zu den Themen: Haemodialyseshunt, arteriovenoese Malformationen, Duplexsonographie des Penis und Tumorvaskularisation. (orig./AJ)

  16. The research on multi-projection correction based on color coding grid array

    Science.gov (United States)

    Yang, Fan; Han, Cheng; Bai, Baoxing; Zhang, Chao; Zhao, Yunxiu

    2017-10-01

    There are many disadvantages such as lower timeliness, greater manual intervention in multi-channel projection system, in order to solve the above problems, this paper proposes a multi-projector correction technology based on color coding grid array. Firstly, a color structured light stripe is generated by using the De Bruijn sequences, then meshing the feature information of the color structured light stripe image. We put the meshing colored grid intersection as the center of the circle, and build a white solid circle as the feature sample set of projected images. It makes the constructed feature sample set not only has the perceptual localization, but also has good noise immunity. Secondly, we establish the subpixel geometric mapping relationship between the projection screen and the individual projectors by using the structure of light encoding and decoding based on the color array, and the geometrical mapping relation is used to solve the homography matrix of each projector. Lastly the brightness inconsistency of the multi-channel projection overlap area is seriously interfered, it leads to the corrected image doesn't fit well with the observer's visual needs, and we obtain the projection display image of visual consistency by using the luminance fusion correction algorithm. The experimental results show that this method not only effectively solved the problem of distortion of multi-projection screen and the issue of luminance interference in overlapping region, but also improved the calibration efficient of multi-channel projective system and reduced the maintenance cost of intelligent multi-projection system.

  17. Cranioplasty and Duraplasty with Transcranial Color-Coded Duplex Sonography after Aneurysmal Subarachnoid Hemorrhage.

    Science.gov (United States)

    Sadahiro, Hirokazu; Inamura, Akinori; Sugimoto, Kazutaka; Yamane, Akiko; Ishihara, Hideyuki; Shirao, Satoshi; Yoneda, Hiroshi; Suzuki, Michiyasu

    2015-11-01

    Transcranial color-coded duplex sonography (TCCS) is a noninvasive technique for monitoring of cerebral vasospasm after neurosurgery for aneurismal subarachnoid hemorrhage. In this surgery, surgical materials are used. The goal of the study was to identify materials that can be used with ultrasound and to propose methods for cranioplasty and duraplasty using materials that permit TCCS. The chosen neurosurgical materials were titanium mesh plate (TMP), Gore-tex, SEAMDURA, gelatinous sponge, and oxidized cellulose. B-mode imaging was recorded with the materials placed between urethane resin 10 mm in diameter and the urethane phantom model. TCCS was performed to detect middle cerebral artery flow through TMP and Gore-tex. TMP and SEAMDURA permitted penetration of ultrasound in B-mode and Doppler imaging, but the other materials did not do so. A postcraniotomy window (PCW) on a line extending from the horizontal portion of M1 using only TMP permitted flow imaging with TCCS. In external decompression, TCCS was effective only without use of Gore-tex around the postcraniotomy window. This method allows the middle cerebral artery flow to be detected easily. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  18. Absolute and direct microRNA quantification using DNA-gold nanoparticle probes.

    Science.gov (United States)

    Degliangeli, Federica; Kshirsagar, Prakash; Brunetti, Virgilio; Pompa, Pier Paolo; Fiammengo, Roberto

    2014-02-12

    DNA-gold nanoparticle probes are implemented in a simple strategy for direct microRNA (miRNA) quantification. Fluorescently labeled DNA-probe strands are immobilized on PEGylated gold nanoparticles (AuNPs). In the presence of target miRNA, DNA-RNA heteroduplexes are formed and become substrate for the endonuclease DSN (duplex-specific nuclease). Enzymatic hydrolysis of the DNA strands yields a fluorescence signal due to diffusion of the fluorophores away from the gold surface. We show that the molecular design of our DNA-AuNP probes, with the DNA strands immobilized on top of the PEG-based passivation layer, results in nearly unaltered enzymatic activity toward immobilized heteroduplexes compared to substrates free in solution. The assay, developed in a real-time format, allows absolute quantification of as little as 0.2 fmol of miR-203. We also show the application of the assay for direct quantification of cancer-related miR-203 and miR-21 in samples of extracted total RNA from cell cultures. The possibility of direct and absolute quantification may significantly advance the use of microRNAs as biomarkers in the clinical praxis.

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

    Science.gov (United States)

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

    2013-01-30

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

  20. A two-level space-time color-coding method for 3D measurements using structured light

    International Nuclear Information System (INIS)

    Xue, Qi; Wang, Zhao; Huang, Junhui; Gao, Jianmin; Qi, Zhaoshuai

    2015-01-01

    Color-coding methods have significantly improved the measurement efficiency of structured light systems. However, some problems, such as color crosstalk and chromatic aberration, decrease the measurement accuracy of the system. A two-level space-time color-coding method is thus proposed in this paper. The method, which includes a space-code level and a time-code level, is shown to be reliable and efficient. The influence of chromatic aberration is completely mitigated when using this method. Additionally, a self-adaptive windowed Fourier transform is used to eliminate all color crosstalk components. Theoretical analyses and experiments have shown that the proposed coding method solves the problems of color crosstalk and chromatic aberration effectively. Additionally, the method guarantees high measurement accuracy which is very close to the measurement accuracy using monochromatic coded patterns. (paper)

  1. Pathway Detection from Protein Interaction Networks and Gene Expression Data Using Color-Coding Methods and A* Search Algorithms

    Directory of Open Access Journals (Sweden)

    Cheng-Yu Yeh

    2012-01-01

    Full Text Available With the large availability of protein interaction networks and microarray data supported, to identify the linear paths that have biological significance in search of a potential pathway is a challenge issue. We proposed a color-coding method based on the characteristics of biological network topology and applied heuristic search to speed up color-coding method. In the experiments, we tested our methods by applying to two datasets: yeast and human prostate cancer networks and gene expression data set. The comparisons of our method with other existing methods on known yeast MAPK pathways in terms of precision and recall show that we can find maximum number of the proteins and perform comparably well. On the other hand, our method is more efficient than previous ones and detects the paths of length 10 within 40 seconds using CPU Intel 1.73GHz and 1GB main memory running under windows operating system.

  2. T7 bacteriophage induced changes of gold nanoparticle morphology: biopolymer capped gold nanoparticles as versatile probes for sensitive plasmonic biosensors.

    Science.gov (United States)

    Kannan, Palanisamy; Los, Marcin; Los, Joanna M; Niedziolka-Jonsson, Joanna

    2014-07-21

    The morphological changes of gold nanoparticles induced by T7 virus (bacteriophage) and the determination of its femtomolar concentration by a plasmonic method are presented. Carboxymethyl chitosan capped gold nanoparticles (CMC-AuNPs) are used as plasmonic probes and are synthesized by a simple one pot wet chemical method. HR-TEM images show that the spherical structure of the CMC-AuNPs is changed into chain-like nanostructures after the addition of T7 virus due to the strong coordination of CMC-AuNPs with T7. Since T7 capsids comprise a repeating motif of capsomers built from proteins that bind to the acid groups of chitosan, the conjugation of carboxymethyl chitosan-linked AuNPs with T7 virions enables colorimetric biosensing detection. The absorbance intensity (∼610 nm) increases in the concentration range of T7 from 2 × 10(-15) M to 2 × 10(-13) M and the detection limit is found to be 2 × 10(-15) M (2 fM). The present work demonstrates eco-friendly biopolymer stabilized AuNPs as potential nanomaterials for biosensing of viruses. Our method is very simple, low cost, selective and highly sensitive, and provides new insight into virus induced chain-like morphology of AuNPs.

  3. Aptamer biosensor for dopamine based on a gold electrode modified with carbon nanoparticles and thionine labeled gold nanoparticles as probe

    International Nuclear Information System (INIS)

    Xu, Yaqiong; Hun, Xu; Liu, Fang; Wen, Xiaolong; Luo, Xiliang

    2015-01-01

    We describe a biosensor for dopamine that is based on the use of a gold electrode modified with carbon nanoparticles (CNPs) coupled to thionine labeled gold nanoparticles (AuNPs) acting as signal amplifiers. The biosensor was constructed by first modifying the CNPs on the gold electrode and adsorbing the thionine on the surface of the AuNPs, and then linking the complementary strand of the dopamine aptamer to the AuNPs via gold-thiol chemistry. Next, dopamine aptamer is added and the duplex is formed on the surface. On addition of a sample containing dopamine, it will interact with aptamer and cause the release of the electrochemical probe which then will be adsorbed on the surface of the CNP-modified gold electrode and detected by differential pulse voltammetry. The current is linearly related to the concentration of dopamine in the 30 nM to 6.0 μM ranges. The detection limit is as low as 10 nM, and the RSD is 3.1 % at a 0.3 μM level (for n = 11). The protocol was successfully applied to the determination of dopamine in spiked human urine samples. We perceive that this method holds promise as a widely applicable platform for aptamer-based electrochemical detection of small molecules. (author)

  4. DNA probe functionalized QCM biosensor based on gold nanoparticle amplification for Bacillus anthracis detection.

    Science.gov (United States)

    Hao, Rong-Zhang; Song, Hong-Bin; Zuo, Guo-Min; Yang, Rui-Fu; Wei, Hong-Ping; Wang, Dian-Bing; Cui, Zong-Qiang; Zhang, ZhiPing; Cheng, Zhen-Xing; Zhang, Xian-En

    2011-04-15

    The rapid detection of Bacillus anthracis, the causative agent of anthrax disease, has gained much attention since the anthrax spore bioterrorism attacks in the United States in 2001. In this work, a DNA probe functionalized quartz crystal microbalance (QCM) biosensor was developed to detect B. anthracis based on the recognition of its specific DNA sequences, i.e., the 168 bp fragment of the Ba813 gene in chromosomes and the 340 bp fragment of the pag gene in plasmid pXO1. A thiol DNA probe was immobilized onto the QCM gold surface through self-assembly via Au-S bond formation to hybridize with the target ss-DNA sequence obtained by asymmetric PCR. Hybridization between the target DNA and the DNA probe resulted in an increase in mass and a decrease in the resonance frequency of the QCM biosensor. Moreover, to amplify the signal, a thiol-DNA fragment complementary to the other end of the target DNA was functionalized with gold nanoparticles. The results indicate that the DNA probe functionalized QCM biosensor could specifically recognize the target DNA fragment of B. anthracis from that of its closest species, such as Bacillus thuringiensis, and that the limit of detection (LOD) reached 3.5 × 10(2)CFU/ml of B. anthracis vegetative cells just after asymmetric PCR amplification, but without culture enrichment. The DNA probe functionalized QCM biosensor demonstrated stable, pollution-free, real-time sensing, and could find application in the rapid detection of B. anthracis. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Formulation of novel lipid-coated magnetic nanoparticles as the probe for in vivo imaging

    Directory of Open Access Journals (Sweden)

    Mou Chung-Yuan

    2009-09-01

    Full Text Available Abstract Background Application of superparamagnetic iron oxide nanoparticles (SPIOs as the contrast agent has improved the quality of magnetic resonance (MR imaging. Low efficiency of loading the commercially available iron oxide nanoparticles into cells and the cytotoxicity of previously formulated complexes limit their usage as the image probe. Here, we formulated new cationic lipid nanoparticles containing SPIOs feasible for in vivo imaging. Methods Hydrophobic SPIOs were incorporated into cationic lipid 1,2-dioleoyl-3-(trimethylammonium propane (DOTAP and polyethylene-glycol-2000-1,2-distearyl-3-sn-phosphatidylethanolamine (PEG-DSPE based micelles by self-assembly procedure to form lipid-coated SPIOs (L-SPIOs. Trace amount of Rhodamine-dioleoyl-phosphatidylethanolamine (Rhodamine-DOPE was added as a fluorescent indicator. Particle size and zeta potential of L-SPIOs were determined by Dynamic Light Scattering (DLS and Laser Doppler Velocimetry (LDV, respectively. HeLa, PC-3 and Neuro-2a cells were tested for loading efficiency and cytotoxicity of L-SPIOs using fluorescent microscopy, Prussian blue staining and flow cytometry. L-SPIO-loaded CT-26 cells were tested for in vivo MR imaging. Results The novel formulation generates L-SPIOs particle with the average size of 46 nm. We showed efficient cellular uptake of these L-SPIOs with cationic surface charge into HeLa, PC-3 and Neuro-2a cells. The L-SPIO-loaded cells exhibited similar growth potential as compared to unloaded cells, and could be sorted by a magnet stand over ten-day duration. Furthermore, when SPIO-loaded CT-26 tumor cells were injected into Balb/c mice, the growth status of these tumor cells could be monitored using optical and MR images. Conclusion We have developed a novel cationic lipid-based nanoparticle of SPIOs with high loading efficiency, low cytotoxicity and long-term imaging signals. The results suggested these newly formulated non-toxic lipid-coated magnetic

  6. Synthesis of improved upconversion nanoparticles as ultrasensitive fluorescence probe for mycotoxins

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Quansheng, E-mail: q.s.chen@hotmail.com; Hu, Weiwei; Sun, Cuicui; Li, Huanhuan; Ouyang, Qin

    2016-09-28

    Rare earth-doped upconversion nanoparticles (UCNPs) have promising potentials in biodetection due to their unique frequency upconverting capability and high detection sensitivity. This paper reports an improved UCNPs-based fluorescence probe for dual-sensing of Aflatoxin B1 (AFB1) and Deoxynivalenol (DON) using a magnetism-induced separation and the specific formation of antibody-targets complex. Herein, the improved UCNPs, which were namely NaYF{sub 4}:Yb/Ho/Gd and NaYF{sub 4}:Yb/Tm/Gd, were systematically studied based on the optimization of reaction time, temperature and the concentration of dopant ions with simultaneous phase and size controlled NaYF{sub 4} nanoparticles; and the targets were detected using the pattern of competitive combination assay. Under an optimized condition, the advanced fluorescent probes revealed stronger fluorescent properties, broader biological applications and better storage stabilities compared to traditional UCNPs-based ones; and ultrasensitive determinations of AFB1 and DON were achieved under a wide sensing range of 0.001–0.1 ng ml{sup −1} with the limit of detection (LOD) of 0.001 ng ml{sup −1}. Additionally, the applicability of the improved nanosensor for the detection of mycotoxins was also confirmed in adulterated oil samples. - Highlights: • Improved rare earth-doped upconversion nanoparticles were prepared with detailed optimizations. • Setup of an upconversion fluorescence spectrometer. • An advanced UCNPs-based immunosensor for dual-sensing mycotoxins was developed with a LOD of 0.001 ng ml{sup −1}. • Application of this biosensor to detect targets in real samples were confirmed with satisfied results.

  7. Colorimetric detection of Cucumber green mottle mosaic virus using unmodified gold nanoparticles as colorimetric probes.

    Science.gov (United States)

    Wang, Lin; Liu, Zhanmin; Xia, Xueying; Yang, Cuiyun; Huang, Junyi; Wan, Sibao

    2017-05-01

    Cucumber green mottle mosaic virus (CGMMV)causes a severe mosaic symptom of watermelon and cucumber, and can be transmitted via infected cucumber seeds, leaves and soil. It remains a challenge to detect this virus to prevent its introduction and infection and spread in fields. For this purpose, a simple and sensitive label-free colorimetric detection method for CGMMV has been developed with unmodified gold nanoparticles (AuNPs) as colorimetric probes. The method is based on the finding that the presence of RT-PCR target products of CGMMV and species-specific probes results in color change of AuNPs from red to blue after NaCl induction. Normally, species-specific probes attach to the surface of AuNPs and thereby increasing their resistance to NaCl-induced aggregation. The concentration of sodium, probes in the reaction system and evaluation of specificity and sensitivity of a novel assay, visual detection of Cucumber green mottle mosaic virus using unmodified AuNPs has been carried out with simple preparation of samples in our study. Through this assay, as low as 30pg/μL of CGMMV RNA was thus detected visually, by the naked eye, without the need for any sophisticated, expensive instrumentation and biochemical reagents. The specificity was 100% and exhibited good reproducibility in our assays. The results note that this assay is highly species-specific, simple, low-cost, and visual for easy detection of CGMMV in plant tissues. Therefore, visual assay is a potentially useful tool for middle or small-scales corporations and entry-exit inspection and quarantine bureau to detect CGMMV in cucumber seeds or plant tissues. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Visual Screening and Colorimetric Determination of Clenbuterol and Ractopamine Using Unmodified Gold Nanoparticles as Probe.

    Science.gov (United States)

    Luo, Yeli; Liu, Xin; Guo, Jiajia; Gao, Hanting; Li, Ying; Xu, Jingyue; Shen, Fei; Sun, Chunyan

    2016-01-01

    In this paper, a sensitive method for the colorimetric detection of clenbuterol and ractopamine using citrate-stabilized gold nanoparticles (AuNPs) as probe was developed. The concentration of clenbuterol and ractopamine could be determined with naked eyes or a UV-vis spectrometer. By optimizing the influence of NaHSO₄ and incubation time, clenbuterol could be detected in the linear range of 0.1-4 µg/mL with the detection limit of 0.0158 µg/mL, and ractopamine could be detected in the linear range of 1-9 µg/mL with the detection limit of 0.0229 µg/mL. The proposed method could be successfully applied to detect clenbuterol and ractopamine in pig urines by a simple pre-treatment with excellent recoveries. The proposed colorimetric assay exhibits good reproducibility and accuracy, providing a simple and rapid method for the analysis of clenbuterol and ractopamine.

  9. Probing surface plasmons in individual Ag nanoparticles in the ultra-violet spectral regime.

    Science.gov (United States)

    Chu, Ming-Wen; Sharma, Pradeep; Chang, Ching-Pin; Liou, Sz Chian; Tsai, Kun-Tong; Wang, Juen-Kai; Wang, Yuh-Lin; Chen, Cheng Hsuan

    2009-06-10

    Previous investigations of surface plasmons in Ag largely focused on their excitations in the visible spectral regime. Using scanning transmission electron microscopy with an electron beam of 0.2 nm in conjunction with electron energy-loss spectroscopy, we spectrally and spatially probe the surface plasmons in individual Ag nanoparticles (approximately 30 nm), grown on Si, in the ultra-violet spectral regime. The nanomaterials show respective sharp and broad surface-plasmon resonances at approximately 3.5 eV (approximately 355 nm) and approximately 7.0 eV (approximately 177 nm), and the correlated spectral calculations established their multipolar characteristics. The near-field distributions of the surface plasmons on the nanoparticles were also mapped out, revealing the predominant dipolar nature of the 3.5 eV excitation with obvious near-field enhancements at one end of the nano-object. The unveiled near-field enhancements have potential applications in plasmonics and molecular sensing.

  10. Probing surface plasmons in individual Ag nanoparticles in the ultra-violet spectral regime

    International Nuclear Information System (INIS)

    Chu, M-W; Chang, C-P; Liou, S C; Wang, J-K; Chen, C H; Sharma, Pradeep; Tsai, K-T; Wang, Y-L

    2009-01-01

    Previous investigations of surface plasmons in Ag largely focused on their excitations in the visible spectral regime. Using scanning transmission electron microscopy with an electron beam of 0.2 nm in conjunction with electron energy-loss spectroscopy, we spectrally and spatially probe the surface plasmons in individual Ag nanoparticles (∼30 nm), grown on Si, in the ultra-violet spectral regime. The nanomaterials show respective sharp and broad surface-plasmon resonances at ∼3.5 eV (∼355 nm) and ∼7.0 eV (∼177 nm), and the correlated spectral calculations established their multipolar characteristics. The near-field distributions of the surface plasmons on the nanoparticles were also mapped out, revealing the predominant dipolar nature of the 3.5 eV excitation with obvious near-field enhancements at one end of the nano-object. The unveiled near-field enhancements have potential applications in plasmonics and molecular sensing.

  11. Laser-material interaction during atom probe tomography of oxides with embedded metal nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, Deodatta; Arnoldi, Laurent; Devaraj, Arun; Vella, Angela

    2016-10-28

    Oxide-supported metal nano-particles are of great interest in catalysis but also in the development of new large-spectrum-absorption materials. The design of such nano materials requires three-dimensional characterization with a high spatial resolution and elemental selectivity. The laser assisted Atom Probe Tomography (La-APT) presents both these capacities if an accurate understanding of laser-material interaction is developed. In this paper, we focus on the fundamental physics of field evaporation as a function of sample geometry, laser power, and DC electric field for Au nanoparticles embedded in MgO. By understanding the laser-material interaction through experiments and a theoretical model of heat diffusion inside the sample after the interaction with laser pulse, we point out the physical origin of the noise and determine the conditions to reduce it by more than one order of magnitude, improving the sensitivity of the La-APT for metal-dielectric composites. Published by AIP Publishing.

  12. Comparison of diagnostic quality and accuracy in color-coded versus gray-scale DCE-MR imaging display

    Energy Technology Data Exchange (ETDEWEB)

    Mehndiratta, A. [German Cancer Research Center (DKFZ), Department of Radiology, Heidelberg (Germany); Indian Institute of Technology (IIT), School of Medical Science and Technology, Kharagpur (India); Knopp, M.V. [The Ohio State University, Department of Radiology, Columbus (United States); Zechmann, C.M.; Owsijewitsch, M.; Tengg-Kobligk, H. von; Zamecnik, P.; Kauczor, H.U. [German Cancer Research Center (DKFZ), Department of Radiology, Heidelberg (Germany); Choyke, P.L. [National Institutes of Health, Clinical Center, Bethesda (United States); Giesel, F.L. [German Cancer Research Center (DKFZ), Department of Radiology, Heidelberg (Germany); National Institutes of Health, Clinical Center, Bethesda (United States)

    2009-09-15

    The purpose of this study was to evaluate the diagnostic value and tumor-vascular display properties (microcirculation) of two different functional MRI post-processing and display (color and gray-scale display) techniques used in oncology. The study protocol was approved by the IRB and written informed consent was obtained from all patients. 38 dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) data sets of patients with malignant pleural-mesothelioma were acquired and post-processed. DCE-MRI was performed at 1.5 tesla with a T1-weighted 2D gradient-echo-sequence (TR 7.0 ms, TE 3.9 ms, 15 axial slices, 22 sequential repetitions), prior and during chemotherapy. Subtracting first image of contrast-enhanced-dynamic series from the last, produced gray-scale images. Color images were produced using a pharmacokinetic two-compartment model. Eight raters, blinded to diagnosis, by visual assessment of post-processed images evaluated both diagnostic quality of the images and vasculature of the tumor using a rating scale ranging from -5 to +5. The scores for vasculature were assessed by correlating with the maximum amplitude of the total-tumor-ROI for accuracy. Color coded images were rated as significantly higher in diagnostic quality and tumor vascular score than gray-scale images (p<0.001, 0.005). ROI signal amplitude analysis and vascular ratings on color coded images were better correlated compared to gray-scale images rating (p<0.05). Color coded images were shown to have higher diagnostic quality and accuracy with respect to tumor vasculature in DCE-MRI, therefore their implementation in clinical assessment and follow-up should be considered for wider application. (orig.)

  13. Direct Probes of 4 nm Diameter Gold Nanoparticles Interacting with Supported Lipid Bylayers

    Energy Technology Data Exchange (ETDEWEB)

    Troiano, Julianne; Olenick, Laura L.; Kuech, Thomas R.; Melby, Eric S.; Hu, Dehong; Lohse, Samuel E.; Mensch, Arielle C.; Dogangun, Merve; Vartanian, Arlane M.; Torelli, Marco; Ehimiaghe, Eseohi; Walter, Stephanie R.; Fu, Li; Anderton, Christopher R.; Zhu, Zihua; Wang, Hongfei; Orr, Galya; Murphy, Catherine; Hamers, Robert J.; Pedersen, Joel A.; Geiger, Franz M.

    2015-01-08

    Interfacial charge densities and potentials are determined for silica-supported phospholipid bilayers formed from lipids having zwitterionic, negatively charged, and positively charged headgroups. Quartz crystal microbalance with dissipation (QCM-D), fluorescence recovery after photobleaching (FRAP), and atomic force microscopy demonstrate the presence of well-formed supported lipid bilayers, which, as probed by vibrational sum frequency generation (SFG), undergo negligible structural changes along their alkyl chains when NaCl concentration is raised from 0.001 to 0.1 M. From second harmonic generation (SHG) measurements we estimate that each zwitterionic headgroup of the bilayer formed from pure DOPC is associated with an apparent charge of -0.028(+0.008/-0.007)×10-¹⁹C, corresponding to 1.8 ± 0.5 % of an elementary negative charge. Moreover, we show that a supported lipid bilayer carrying an apparent negative interfacial potential may interact with not just positively charged 4-nm diameter gold nanoparticles but also negatively charged gold nanoparticles. In this latter case, charge-charge repulsion does not appear to inhibit particle-bilayer interactions and is likely overcome by multivalent interactions that are estimated to involve 3-5 hydrogen-bond equivalents. FRAP, QCM-D, and SFG measurements indicate that the bilayers remain intact under the conditions of the experiments. SHG charge screening experiments are consistent with an apparent zero net charge density associated with the positively charged gold nanoparticles when they are attached to a supported lipid bilayer carrying an apparent negative potential. The results presented here serve to benchmark experimental and computational studies of the nano-bio interface.

  14. Assaying multiple restriction endonucleases functionalities and inhibitions on DNA microarray with multifunctional gold nanoparticle probes.

    Science.gov (United States)

    Ma, Lan; Zhu, Zhijun; Li, Tao; Wang, Zhenxin

    2014-02-15

    Herein, a double-stranded (ds) DNA microarray-based resonance light scattering (RLS) assay with multifunctional gold nanoparticle (GNP) probes has been developed for studying restriction endonuclease functionality and inhibition. Because of decreasing significantly melting temperature, the enzyme-cleaved dsDNAs easily unwind to form single-stranded (ss) DNAs. The ssDNAs are hybridized with multiplex complementary ssDNAs functionalized GNP probes followed by silver enhancement and RLS detection. Three restriction endonucleases (EcoRI, BamHI and EcoRV) and three potential inhibitors (doxorubicin hydrochloride (DOX), ethidium bromide (EB) and an EcoRI-derived helical peptide (α4)) were selected to demonstrate capability of the assay. Enzyme activities of restriction endonucleases are detected simultaneously with high specificity down to the limits of 2.0 × 10(-2)U/mL for EcoRI, 1.1 × 10(-2)U/mL for BamHI and 1.6 × 10(-2)U/mL for EcoRV, respectively. More importantly, the inhibitory potencies of three inhibitors are showed quantitatively, indicating that our approach has great promise for high-throughput screening of restriction endonuclease inhibitors. © 2013 Elsevier B.V. All rights reserved.

  15. Ultrahigh relaxivity and safe probes of manganese oxide nanoparticles for in vivo imaging.

    Science.gov (United States)

    Xiao, J; Tian, X M; Yang, C; Liu, P; Luo, N Q; Liang, Y; Li, H B; Chen, D H; Wang, C X; Li, L; Yang, G W

    2013-12-05

    Mn-based nanoparticles (NPs) have emerged as new class of probes for magnetic resonance imaging due to the impressive contrast ability. However, the reported Mn-based NPs possess low relaxivity and there are no immunotoxicity data regarding Mn-based NPs as contrast agents. Here, we demonstrate the ultrahigh relaxivity of water protons of 8.26 mM(-1) s(-1) from the Mn3O4 NPs synthesized by a simple and green technique, which is twice higher than that of commercial gadolinium (Gd)-based contrast agents (4.11 mM(-1) s(-1)) and the highest value reported to date for Mn-based NPs. We for the first time demonstrate these Mn3O4 NPs biocompatibilities both in vitro and in vivo are satisfactory based on systematical studies of the intrinsic toxicity including cell viability of human nasopharyngeal carcinoma cells, normal nasopharyngeal epithelium, apoptosis in cells and in vivo immunotoxicity. These findings pave the way for the practical clinical diagnosis of Mn based NPs as safe probes for in vivo imaging.

  16. Probing the interaction between nanoparticles and lipid membranes by quartz crystal microbalance with dissipation monitoring

    Directory of Open Access Journals (Sweden)

    Nariman Yousefi

    2016-12-01

    Full Text Available There is increasing interest in using quartz crystal microbalance with dissipation monitoring (QCM-D to investigate the interaction of nanoparticles (NPs with model surfaces. The high sensitivity, ease of use and the ability to monitor interactions in real-time has made it a popular technique for colloid chemists, biologists, bioengineers and biophysicists. QCM-D has been recently used to probe the interaction of NPs with supported lipid bilayers (SLBs as model cell membranes. The interaction of NPs with SLBs is highly influenced by the quality of the lipid bilayers. Unlike many surface sensitive techniques, using QCM-D, the quality of SLBs can be assessed in real-time¬, hence QCM-D studies on SLB-NP interactions are less prone to the artefacts arising from bilayers that are not well formed. The ease of use and commercial availability of a wide range of sensor surfaces also have made QCM-D a versatile tool for studying NP interactions with lipid bilayers. In this review, we summarize the state-of-the-art on QCM-D based techniques for probing the interactions of NPs with lipid bilayers.

  17. Probing the interaction between nanoparticles and lipid membranes by quartz crystal microbalance with dissipation monitoring

    Science.gov (United States)

    Yousefi, Nariman; Tufenkji, Nathalie

    2016-12-01

    There is increasing interest in using quartz crystal microbalance with dissipation monitoring (QCM-D) to investigate the interaction of nanoparticles (NPs) with model surfaces. The high sensitivity, ease of use and the ability to monitor interactions in real-time has made it a popular technique for colloid chemists, biologists, bioengineers and biophysicists. QCM-D has been recently used to probe the interaction of NPs with supported lipid bilayers (SLBs) as model cell membranes. The interaction of NPs with SLBs is highly influenced by the quality of the lipid bilayers. Unlike many surface sensitive techniques, using QCM-D, the quality of SLBs can be assessed in real-time, hence QCM-D studies on SLB-NP interactions are less prone to the artefacts arising from bilayers that are not well formed. The ease of use and commercial availability of a wide range of sensor surfaces also have made QCM-D a versatile tool for studying NP interactions with lipid bilayers. In this review, we summarize the state-of-the-art on QCM-D based techniques for probing the interactions of NPs with lipid bilayers.

  18. Click synthesis of podand triazole-linked gold nanoparticles as highly selective and sensitive colorimetric probes for lead(II) ions.

    Science.gov (United States)

    Li, Haibing; Zheng, Qiuling; Han, Cuiping

    2010-06-01

    Podand triazole-linked gold nanoparticles were designed via an in situ'click' reaction. The resulting gold nanoparticles were characterized by UV-vis spectroscopy, FT-IR spectroscopy, transmission electron microscopy (TEM). Podand triazole-linked gold nanoparticles were utilized as colorimetric probes for Pb(2+)via Pb(2+)-induced gold nanoparticle aggregation which incorporates two podand molecules from different nanoparticles forming an intermolecule type of association. Moreover, the application of the resulting gold nanoparticles to evaluate the exceeding standard of lead ions in drinking water and leaded paint was investigated.

  19. Color coding of televised task elements in remote work: a literature review with practical recommendations for a fuel reprocessing facility

    International Nuclear Information System (INIS)

    Clarke, M.M.; Preston-Anderson, A.

    1981-11-01

    The experimental literature on the effects of color visual displays was reviewed with particular reference to the performance of remote work in a Hot Experimental Facility (HEF) using real scene closed-circult television systems. It was also reviewed with more general reference to the broader range of work-related issues of operator learning and preference, and display specifications. Color has been shown to enhance the performance of tasks requiring search and location and may also enhance tracking/transportation tasks. However, both HEF large-volume searching and tracking can be computer augmented, alleviating some of the necessity for a color code to assist an operator. Although color enhances long-term memory and is preferred to black and white displays, it has not been shown to have a specific advantage in the performance of unique tasks (where computer augmentation is more problematic and visual input to operator is critical). Practical display specifications are discussed with reference to hue and size of color code, target size, ambient illumination, multiple displays, and coatings. The authors conclude that the disadvantages to color television in the HEF far outweigh any possible advantages and recommend the use of high-resolution black and white systems, unless future experiments unequivocally indicate that (1) color is superior to black and white for in-situ task performance or (2) it is imperative in terms of long-range psychological well-being

  20. Sensitive bioassay for detection of PPAR{alpha} potentially hazardous ligands with gold nanoparticle probe

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Wei; Wan, Yan-Jian [Minister of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei Province 430030 (China); Wang, Xianliang [Division of Environmental Pollution and Human Health, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Li, Yuan-yuan; Yang, Wen-Jie; Wang, Chun-Xiang [Minister of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei Province 430030 (China); Xu, Shun-qing, E-mail: shunqing@mails.tjmu.edu.cn [Minister of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei Province 430030 (China)

    2011-09-15

    Highlights: {yields} We develop a sensitive and high throughput method to screen PPAR{alpha} ligands. {yields} This method is based on the ligand-receptor interaction on microplate. {yields} The sensitivity is increased through sliver enhancement on captured gold nanoparticle probes. {yields} There is a significant correlation between the bioassay and LC-MS for water spiked samples. - Abstract: There are so many kinds of peroxisome proliferator-activated receptor {alpha} (PPAR{alpha}) ligands with hazardous effect for human health in the environment, such as certain herbicides, plasticizers and drugs. Among these agonists, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and mono-(2-ethylhexyl) phthalate (MEHP) are mostly investigated due to their persistence and accumulation in environment and their potential toxicity via PPAR{alpha}. This investigation aims at developing a bioassay method to detect PPAR{alpha} ligands based on the ligand-receptor interaction on microplate. PPAR{alpha}, which formed heterodimers with retinoid X receptor-{alpha} (RXR{alpha}), were activated by PPAR{alpha} ligands to form ligands-PPAR{alpha}-RXR{alpha} complexes. Then the complexes were transferred into a microplate and captured via monoclonal anti-PPAR{alpha} antibody. The PPAR{alpha} responsive elements (PPRE) modified-gold nanoparticle probes were captured by the ligand-PPAR{alpha}-RXR{alpha} complexes immobilized on the microplate, and then could be quantified through measuring the optical density after silver enhancement. The results showed that PFOS was quantified with a linear range from 100 pM to 1 {mu}M and the detection limit was 10 pM. In addition to PFOS, PFOA and MEHP were also quantified within a proper range through the proposed bioassay. This bioassay was compared with that of liquid chromatography tandem-mass spectrometry (LC-MS) for water spiked samples with a significant correlation (r = 0.9893). This study provides a high-throughput detection

  1. Poly[acrylonitrile-co-(N-vinyl pyrrolidone)] nanoparticles - Composition-dependent skin penetration enhancement of a dye probe and biocompatibility.

    Science.gov (United States)

    Zhang, Nan; Said, André; Wischke, Christian; Kral, Vivian; Brodwolf, Robert; Volz, Pierre; Boreham, Alexander; Gerecke, Christian; Li, Wenzhong; Neffe, Axel T; Kleuser, Burkhard; Alexiev, Ulrike; Lendlein, Andreas; Schäfer-Korting, Monika

    2017-07-01

    Nanoparticles can improve topical drug delivery: size, surface properties and flexibility of polymer nanoparticles are defining its interaction with the skin. Only few studies have explored skin penetration for one series of structurally related polymer particles with systematic alteration of material composition. Here, a series of rigid poly[acrylonitrile-co-(N-vinyl pyrrolidone)] model nanoparticles stably loaded with Nile Red or Rhodamin B, respectively, was comprehensively studied for biocompatibility and functionality. Surface properties were altered by varying the molar content of hydrophilic NVP from 0 to 24.1% and particle size ranged from 35 to 244nm. Whereas irritancy and genotoxicity were not revealed, lipophilic and hydrophilic nanoparticles taken up by keratinocytes affected cell viability. Skin absorption of the particles into viable skin ex vivo was studied using Nile Red as fluorescent probe. Whilst an intact stratum corneum efficiently prevented penetration, almost complete removal of the horny layer allowed nanoparticles of smaller size and hydrophilic particles to penetrate into viable epidermis and dermis. Hence, systematic variations of nanoparticle properties allows gaining insights into critical criteria for biocompatibility and functionality of novel nanocarriers for topical drug delivery and risks associated with environmental exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Nanoparticle-based and bioengineered probes and sensors to detect physiological and pathological biomarkers in neural cells

    Directory of Open Access Journals (Sweden)

    Dusica eMaysinger

    2015-12-01

    Full Text Available Nanotechnology, a rapidly evolving field, provides simple and practical tools to investigate the nervous system in health and disease. Among these tools are nanoparticle-based probes and sensors that detect biochemical and physiological properties of neurons and glia, and generate signals proportionate to physical, chemical, and/or electrical changes in these cells. In this context, quantum dots (QDs, carbon-based structures (C-dots, graphene and nanodiamonds and gold nanoparticles are the most commonly used nanostructures. They can detect and measure enzymatic activities of proteases (metalloproteinases, caspases, ions, metabolites, and other biomolecules under physiological or pathological conditions in neural cells. Here, we provide some examples of nanoparticle-based and genetically engineered probes and sensors that are used to reveal changes in protease activities and calcium ion concentrations. Although significant progress in developing these tools has been made for probing neural cells, several challenges remain. We review many common hurdles in sensor development, while highlighting certain advances. In the end, we propose some future directions and ideas for developing practical tools for neural cell investigations, based on the maxim Measure what is measurable, and make measurable what is not so (Galileo Galilei.

  3. Dynamic Probing of Nanoparticle Stability In Vivo: A Liposomal Model Assessed Using In Situ Microdialysis and Optical Imaging

    Directory of Open Access Journals (Sweden)

    Chien-Chung Jeng

    2011-01-01

    Full Text Available Nanoparticle-mediated drug delivery and controlled release has been a vigorous research area in contemporary nanomedicine. The in vivo stability of nanoparticle delivered on site is a prerequisite for the design of drug-controlled release by any means. In this study, the first methodology comprised of microdialysis and optical imaging to assess the liposome stability in vivo is reported. Macroscopically, we demonstrated the DPPG liposomes with negative surface charge fast accumulated in the rat liver upon their i.v. administration using optical imaging. Microscopically, the concurrent analysis of fluorescent molecules leaching from the liposomes, in situ sampled using microdialysis probe, provides the dynamic information of stability of DPPG liposomes locus in quo. The current combination of in situ microdialysis and optical imaging possesses a great potential for use as a platform technology to evaluate the nanoparticle stability and the bioavailability of drug payload released on targeted site in vivo.

  4. Development of oleic acid-functionalized magnetite nanoparticles as hydrophobic probes for concentrating peptides with MALDI-TOF-MS analysis.

    Science.gov (United States)

    Chen, Hemei; Liu, Shasha; Li, Yan; Deng, Chunhui; Zhang, Xiangmin; Yang, Pengyuan

    2011-03-01

    The oleic acid-functionalized magnetite nanoparticles (OA-Fe(3) O(4) ) with mean diameter of about 15 nm were synthesized through a low-cost, one-pot method and were designed as hydrophobic probes to realize the convenient, efficient and fast concentration of low-concentration peptides followed by MALDI-TOF-MS analysis. The capability of OA-Fe(3) O(4) nanoparticles in concentration of low-abundance peptides from simple and complex solutions were evaluated by comparing them with a sort of C8-modified magnetic microspheres. Samples of standard peptide solution, protein digest solution and human serum were introduced in the evaluating process, and the OA-Fe(3) O(4) nanoparticles exhibited good surface affinity toward low-concentration peptides. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Probing the toxicity of nanoparticles: a unified in silico machine learning model based on perturbation theory.

    Science.gov (United States)

    Concu, Riccardo; Kleandrova, Valeria V; Speck-Planche, Alejandro; Cordeiro, M Natália D S

    2017-09-01

    Nanoparticles (NPs) are part of our daily life, having a wide range of applications in engineering, physics, chemistry, and biomedicine. However, there are serious concerns regarding the harmful effects that NPs can cause to the different biological systems and their ecosystems. Toxicity testing is an essential step for assessing the potential risks of the NPs, but the experimental assays are often very expensive and usually too slow to flag the number of NPs that may cause adverse effects. In silico models centered on quantitative structure-activity/toxicity relationships (QSAR/QSTR) are alternative tools that have become valuable supports to risk assessment, rationalizing the search for safer NPs. In this work, we develop a unified QSTR-perturbation model based on artificial neural networks, aimed at simultaneously predicting general toxicity profiles of NPs under diverse experimental conditions. The model is derived from 54,371 NP-NP pair cases generated by applying the perturbation theory to a set of 260 unique NPs, and showed an accuracy higher than 97% in both training and validation sets. Physicochemical interpretation of the different descriptors in the model are additionally provided. The QSTR-perturbation model is then employed to predict the toxic effects of several NPs not included in the original dataset. The theoretical results obtained for this independent set are strongly consistent with the experimental evidence found in the literature, suggesting that the present QSTR-perturbation model can be viewed as a promising and reliable computational tool for probing the toxicity of NPs.

  6. Probing safety of nanoparticles by outlining sea urchin sensing and signaling cascades.

    Science.gov (United States)

    Alijagic, Andi; Pinsino, Annalisa

    2017-10-01

    Among currently identified issues presenting risks and benefits to human and ocean health, engineered nanoparticles (ENP) represent a priority. Predictions of their economic and social impact appear extraordinary, but their release in the environment at an uncontrollable rate is in striking contrast with the extremely limited number of studies on environmental impact, especially on the marine environment. The sea urchin has a remarkable sensing environmental system whose function and diversity came into focus during the recent years, after sea urchin genome sequencing. The complex immune system may be the basis wherefore sea urchins can adapt to a dynamic environment and survive even in hazardous conditions both in the adult and in the embryonic life. This review is aimed at discussing the literature in nanotoxicological/ecotoxicological studies with a focus on stress and innate immune signaling in sea urchins. In addition, here we introduce our current development of in vitro-driven probes that could be used to dissect ENP aftermaths, suggesting their future use in immune-nanotoxicology. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. In situ probing of intracellular pH by fluorescence from inorganic nanoparticles.

    Science.gov (United States)

    Guo, Junhong; Xiong, Shijie; Wu, Xinglong; Shen, Jiancang; Chu, Paul K

    2013-12-01

    Intracellular pH (pHi) plays a critical role in the physiological processes of cells. Nanoscale sensors based on pH-sensitive fluorescent proteins attached on nanoparticles (NPs) have been designed but inorganic NP-dependent fluorescent nanosensors have not yet been explored. Herein we describe a pH sensitive inorganic semiconductor fluorescent probe based on ultrathin 3C-SiC NPs which can effectively monitor pH in the range of 5.6-7.4 by taking advantage of the linear dependence between the fluorescent intensity ratio of the surface OH(-) and H(+) bonding states to band-to-band recombination and pH. Detection of pHi is demonstrated in living HeLa cells. In particular, pHi measurements during apoptosis confirm the validity and sensitivity of this technique in monitoring real-time changes in the intracellular environment. Toxicity assessment and confocal laser scanning microscopy indicate that the 3C-SiC NPs have low cytotoxicity and are compatible with living cells. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Melamine functionalized silver nanoparticles as the probe for electrochemical sensing of clenbuterol.

    Science.gov (United States)

    Miao, Peng; Han, Kun; Sun, Haixuan; Yin, Jian; Zhao, Jing; Wang, Bidou; Tang, Yuguo

    2014-06-11

    Clenbuterol, a member of β-agonist family, has now been a serious threat to human health due to its illegal usage in the livestock feeding. Herein, we describe the application of melamine functionalized silver nanoparticles (M-AgNPs) as the electrochemical probe for simple, fast, highly sensitive and selective detection of clenbuterol. Generally, AgNPs are prepared and functionalized by melamine. After interacting with melamine modified gold electrode in the presence of clenbuterol, M-AgNPs can be immobilized on the surface of the electrode via the hydrogen-bonding interactions between clenbuterol and melamine. This sandwich structure permits sensitive and selective detection of clenbuterol. Since M-AgNPs can provide a couple of well-defined sharp silver stripping peaks, which stands for a highly characteristic solid-state Ag/AgCl reaction, a rather low detection limit of 10 pM can be achieved. The detection range is from 10 pM to 100 nM, which is quite wide. This developed biosensor can potentially be used for clenbuterol detection in biological fluids in the presence of various interferences.

  9. Absence of Doppler signal in transcranial color-coded ultrasonography may be confirmatory for brain death: A case report

    Directory of Open Access Journals (Sweden)

    Mehmet Akif Topçuoğlu

    2015-08-01

    Full Text Available Transcranial Doppler ultrasonography (TCD is a valuable tool for demonstrating cerebral circulatory arrest (CCA in the setting of brain death. Complete reversal of diastolic flow (to-and-fro flow and systolic spikes in bilateral terminal internal carotid arteries and vertebrobasilar circulation are considered as specific sonogram configurations supporting the diagnosis of CCA. Because of the possibility of sonic bone window impermeability, absence of any waveform in TCD is not confirmatory for CCA unless there is documentation of disappearance of a previously well detected signal by the same recording settings. Transcranial color-coded sonography (TCCS with B-mode imaging can reliably detect adequacy of bone windows with clarity contralateral skull and ipsilateral planum temporale visualization. Therefore, absence of detectable intracranial Doppler signal along with available ultrasound window in TCCS can confirm clinical diagnosis of brain death. We herein discuss this entity from the frame of a representative case.

  10. Synthesis and bioconjugation of gold nanoparticles as potential molecular probes for light-based imaging techniques

    NARCIS (Netherlands)

    Rayavarapu, Raja Gopal; Petersen, Wilma; Ungureanu, Constantin; Post, Janine N.; van Leeuwen, Ton G.; Manohar, Srirang

    2007-01-01

    We have synthesized and characterized gold nanoparticles (spheres and rods) with optical extinction bands within the "optical imaging window." The intense plasmon resonant driven absorption and scattering peaks of these nanoparticles make them suitable as contrast agents for optical imaging

  11. Probing cytotoxicity of nanoparticles and organic compounds using scanning proton microscopy, scanning electron microscopy and fluorescence microscopy

    International Nuclear Information System (INIS)

    Tong Yongpeng; Li Changming; Liang Feng; Chen Jianmin; Zhang Hong; Liu Guoqing; Sun Huibin; Luong, John H.T.

    2008-01-01

    Scanning proton microscopy, scanning electron microscopy (SEM) and fluorescence microscopy have been used to probe the cytotoxicity effect of benzo[a]pyrene (BaP), ethidium bromide (EB) and nanoparticles (ZnO, Al 2 O 3 and TiO 2 ) on a T lymphoblastic leukemia Jurkat cell line. The increased calcium ion (from CaCl 2 ) in the culture medium stimulated the accumulation of BaP and EB inside the cell, leading to cell death. ZnO, Al 2 O 3 and TiO 2 nanoparticles, however, showed a protective effect against these two organic compounds. Such inorganic nanoparticles complexed with BaP or EB which became less toxic to the cell. Fe 2 O 3 nanoparticles as an insoluble particle model scavenged by macrophage were investigated in rats. They were scavenged out of the lung tissue about 48 h after infection. This result suggest that some insoluble inorganic nanoparticles of PM (particulate matters) showed protective effects on organic toxins induced acute toxic effects as they can be scavenged by macrophage cells. Whereas, some inorganic ions such as calcium ion in PM may help environmental organic toxins to penetrate cell membrane and induce higher toxic effect.

  12. Probing cytotoxicity of nanoparticles and organic compounds using scanning proton microscopy, scanning electron microscopy and fluorescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tong Yongpeng [Institute of Nuclear Techniques, Shenzhen University, Nanhai Avenue 3688, Shenzhen 518060 (China)], E-mail: yongpengt@yahoo.com.cn; Li Changming [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457 (Singapore); Liang Feng [Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200025 (China); Chen Jianmin [Shenzhen Municipal Hospital for Chronic Disease Control and Prevention, Guangdong 518020 (China); Zhang Hong; Liu Guoqing; Sun Huibin [Institute of Nuclear Techniques, Shenzhen University, Nanhai Avenue 3688, Shenzhen 518060 (China); Luong, John H.T. [Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, H4P 2R2 (Canada)

    2008-12-15

    Scanning proton microscopy, scanning electron microscopy (SEM) and fluorescence microscopy have been used to probe the cytotoxicity effect of benzo[a]pyrene (BaP), ethidium bromide (EB) and nanoparticles (ZnO, Al{sub 2}O{sub 3} and TiO{sub 2}) on a T lymphoblastic leukemia Jurkat cell line. The increased calcium ion (from CaCl{sub 2}) in the culture medium stimulated the accumulation of BaP and EB inside the cell, leading to cell death. ZnO, Al{sub 2}O{sub 3} and TiO{sub 2} nanoparticles, however, showed a protective effect against these two organic compounds. Such inorganic nanoparticles complexed with BaP or EB which became less toxic to the cell. Fe{sub 2}O{sub 3} nanoparticles as an insoluble particle model scavenged by macrophage were investigated in rats. They were scavenged out of the lung tissue about 48 h after infection. This result suggest that some insoluble inorganic nanoparticles of PM (particulate matters) showed protective effects on organic toxins induced acute toxic effects as they can be scavenged by macrophage cells. Whereas, some inorganic ions such as calcium ion in PM may help environmental organic toxins to penetrate cell membrane and induce higher toxic effect.

  13. Visualization of Protease Activity In Vivo Using an Activatable Photo-Acoustic Imaging Probe Based on CuS Nanoparticles

    Science.gov (United States)

    Yang, Kai; Zhu, Lei; Nie, Liming; Sun, Xiaolian; Cheng, Liang; Wu, Chenxi; Niu, Gang; Chen, Xiaoyuan; Liu, Zhuang

    2014-01-01

    Herein, we for the first time report a novel activatable photoacoustic (PA) imaging nano-probe for in vivo detection of cancer-related matrix metalloproteinases (MMPs). A black hole quencher 3 (BHQ3) which absorbs red light is conjugated to near-infrared (NIR)-absorbing copper sulfide (CuS) nanoparticles via a MMP-cleavable peptide linker. The obtained CuS-peptide-BHQ3 (CPQ) nano-probe exhibits two distinctive absorption peaks at 630 nm and 930 nm. Inside the tumor microenviorment where MMPs present, the MMP-sensitive peptide would be cleaved, releasing BHQ3 from the CuS nanoparticles, the former of which as a small molecule is then rapidly cleared out from the tumor, whereas the latter of which as large nanoparticles would retain inside the tumor for a much longer period of time. As the result, the PA signal at 680 nm which is contributed by BHQ3 would be quickly diminished while that at 930 nm would be largely retained. The PA signal ratio of 680 nm / 930 nm could thus serve as an in vivo indicator of MMPs activity inside the tumor. Our work presents a novel strategy of in vivo sensing of MMPs based on PA imaging, which should offer remarkably improved detection depth compared with traditional optical imaging techniques. PMID:24465271

  14. Post-Processing of Dynamic Gadolinium-Enhanced Magnetic Resonance Imaging Exams of the Liver: Explanation and Potential Clinical Applications for Color-Coded Qualitative and Quantitative Analysis

    International Nuclear Information System (INIS)

    Wang, L.; Bos, I.C. Van den; Hussain, S.M.; Pattynama, P.M.; Vogel, M.W.; Kr estin, G.P.

    2008-01-01

    The purpose of this article is to explain and illustrate the current status and potential applications of automated and color-coded post-processing techniques for the analysis of dynamic multiphasic gadolinium-enhanced magnetic resonance imaging (MRI) of the liver. Post-processing of these images on dedicated workstations allows the generation of time-intensity curves (TIC) as well as color-coded images, which provides useful information on (neo)-angiogenesis within a liver lesion, if necessary combined with information on enhancement patterns of the surrounding liver parenchyma. Analysis of TIC and color-coded images, which are based on pharmacokinetic modeling, provides an easy-to-interpret schematic presentation of tumor behavior, providing additional characteristics for adequate differential diagnosis. Inclusion of TIC and color-coded images as part of the routine abdominal MRI workup protocol may help to further improve the specificity of MRI findings, but needs to be validated in clinical decision-making situations. In addition, these tools may facilitate the diagnostic workup of disease for detection, characterization, staging, and monitoring of antitumor therapy, and hold incremental value to the widely used tumor response criteria

  15. Higher-Order Thinking and Metacognition in the First-Year Core-Education Classroom: A Case Study in the Use of Color-Coded Drafts

    Science.gov (United States)

    Murray, Jeffrey W.

    2014-01-01

    This article seeks to provide some modest insights into the pedagogy of higher-order thinking and metacognition and to share the use of color-coded drafts as a best practice in service of both higher-order thinking and metacognition. This article will begin with a brief theoretical exploration of thinking and of thinking about thinking--the latter…

  16. Probing nanoparticle-macromolecule interaction and resultant structure by small-angle neutron scattering

    International Nuclear Information System (INIS)

    Aswal, V.K.

    2013-01-01

    Nanoparticles display unique and distinct characteristics from those of their constituent atoms and bulk materials which are being employed in numerous applications in the fields of medicine, electronics, optics, communications, energy, environment etc. Many of these applications require adjoining of nanoparticles with macromolecules such as proteins, polymers and surfactants to obtain functional objects. For example, nanoparticle-protein complexes are of great importance in controlling enzymatic behavior, targeted drug delivery and developing biocompatible materials. The nanoparticles interfaced with polymers are shown to be useful in developing protein sensor arrays. Interaction of surfactants with nanoparticles is utilized extensively for technical and industrial applications associated with colloidal stability, detergency and design of nanostructured functional interfaces. The interaction of two components, nanoparticles and macromolecule, strongly depends on the characteristics of both the nanoparticles (size, shape, surface roughness, charge density etc.) and macromolecules (type, charge, shape and solution conditions etc.) used. The interaction of macromolecule on nanoparticle surface is a cumulative effect of a number of forces such as electrostatic force, covalent bonding, hydrogen bonding, non-polar interaction, hydrophobic interactions etc. These interactions depending on the system conditions can lead to various structures. Small-angle neutron scattering (SANS) with the possibility to vary contrast is an ideal technique to study such multi-component systems. In this talk, some of our results of SANS from the complexes of nanoparticle-protein and nanoparticle surfactant systems will be discussed. (author)

  17. Experimental artefacts occurring during atom probe tomography analysis of oxide nanoparticles in metallic matrix: Quantification and correction

    Science.gov (United States)

    Hatzoglou, C.; Radiguet, B.; Pareige, P.

    2017-08-01

    Oxide Dispersion Strengthened (ODS) steels are promising candidates for future nuclear reactors, partly due to the fine dispersion of the nanoparticles they contain. Until now, there was no consensus as to the nature of the nanoparticles because their analysis pushed the techniques to their limits and in consequence, introduced some artefacts. In this study, the artefacts that occur during atom probe tomography analysis are quantified. The artefacts quantification reveals that the particles morphology, chemical composition and atomic density are biased. A model is suggested to correct these artefacts in order to obtain a fine and accurate characterization of the nanoparticles. This model is based on volume fraction calculation and an analytical expression of the atomic density. Then, the studied ODS steel reveals nanoparticles, pure in Y, Ti and O, with a core/shell structure. The shell is rich in Cr. The Cr content of the shell is dependent on that of the matrix by a factor of 1.5. This study also shows that 15% of the atoms that were initially in the particles are not detected during the analysis. This only affects O atoms. The particle stoichiometry evolves from YTiO2 for the smallest observed (8 nm).

  18. Encapsulation-Stabilized, Europium Containing Nanoparticle as a Probe for Time-Resolved luminescence Detection of Cardiac Troponin I

    Directory of Open Access Journals (Sweden)

    Ka Ram Kim

    2017-10-01

    Full Text Available The use of a robust optical signaling probe with a high signal-to-noise ratio is important in the development of immunoassays. Lanthanide chelates are a promising material for this purpose, which provide time-resolved luminescence (TRL due to their large Stokes shift and long luminescence lifetime. From this, they have attracted considerable interest in the in vitro diagnostics field. However, the direct use of lanthanide chelates is limited because their luminescent signal can be easily affected by various quenchers. To overcome this drawback, strategies that rely on the entrapment of lanthanide chelates inside nanoparticles, thereby enabling the protection of the lanthanide chelate from water, have been reported. However, the poor stability of the lanthanide-entrapped nanoparticles results in a significant fluctuation in TRL signal intensity, and this still remains a challenging issue. To address this, we have developed a Lanthanide chelate-Encapsulated Silica Nano Particle (LESNP as a new immunosensing probe. In this approach, the lanthanide chelate is covalently crosslinked within the silane monomer during the silica nanoparticle formation. The resulting LESNP is physically stable and retains TRL properties of the parent lanthanide chelate. Using the probe, a highly sensitive, sandwich-based TRL immunoassay for the cardiac troponin I was conducted, exhibiting a limit of detection of 48 pg/mL. On the basis of the features of the LESNP such as TRL signaling capability, stability, and the ease of biofunctionalization, we expect that the LESNP can be widely applied in the development of TRL-based immunosensing.

  19. In vivo Raman measurement of levofloxacin lactate in blood using a nanoparticle-coated optical fiber probe

    Science.gov (United States)

    Liu, Shupeng; Rong, Ming; Zhang, Heng; Chen, Na; Pang, Fufei; Chen, Zhenyi; Wang, Tingyun; Yan, Jianshe

    2016-01-01

    Monitoring drug concentrations in vivo is very useful for adjusting a drug dosage during treatment and for drug research. Specifically, cutting-edge “on-line” drug research relies on knowing how drugs are metabolized or how they interact with the blood in real-time. Thus, this study explored performing in vivo Raman measurements of the model drug levofloxacin lactate in the blood using a nanoparticle-coated optical fiber probe (optical fiber nano-probe). The results show that we were able to measure real-time changes in the blood concentration of levofloxacin lactate, suggesting that this technique could be helpful for performing drug analyses and drug monitoring in a clinical setting without repeatedly withdrawing blood from patients. PMID:27231590

  20. Probing suitable therapeutic nanoparticles for controlled drug delivery and diagnostic reproductive health biomarker development

    Energy Technology Data Exchange (ETDEWEB)

    Jha, Rakhi [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721 302 (India); National Institute of Animal Welfare, Ministry of Environment, Forest and Climate Change, Faridabad, Haryana 121 004 (India); Jha, Pradeep K., E-mail: jha.rk.pk@gmail.com [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721 302 (India); Gupta, Santosh; Bhuvaneshwaran, S.P. [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721 302 (India); Hossain, Maidul [Department of Chemistry & Chemical Technology, Vidyasagar University, Midnapore 721102 (India); Guha, Sujoy K. [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721 302 (India)

    2016-04-01

    Nanomaterial mediated drug delivery represents a highly promising technique while its selectivity for reproductive healthcare application still remains a challenge. Since the delicate structure and functional role of reproductive tissue and gametes require the use of biocompatible nanomedicine/devices that do not affect fertility or the development of resulting offspring, this paper reports an intercomparative study of human spermatozoa interaction with three different nanoparticles (NPs) namely; iron oxide (Fe{sub 3}O{sub 4)}, multiwalled carbon nanotubes (MWCNT) and graphene platelet nanopowder (GPN) to probe their suitability for drug delivery carrier and biomarker development purposes. ATR–FTIR results revealed that the sperm cell interaction with GPN had maximum amide I absorption for cell proteins and C=O stretching of the peptide backbone at the band around 1657 cm{sup −1} followed by iron oxide NPs whereas MWCNT had no absorption. These results showed that GPN followed by iron oxide NPs got maximally entrapped by cell membrane protein with maximum disruption but MWCNT exhibited less entrapment but significantly higher internalization which was further validated by morphological analysis of these cell NP interaction by SEM, HRTEM and fluorescence microscopy. The uptake kinetics and penetration mechanism of NPs were examined with isothermal titration calorimetry (ITC). Interestingly, ITC results confirmed ATR–FTIR and morphological observations that the binding of GPN and Fe{sub 3}O{sub 4} NPs with cell was exothermic and their bindings were favored by both negative enthalpy and positive entropy whereas in the case of MWCNT it was endothermic supported by unfavorable positive enthalpy and a favorable entropy change. Hence, it was evident that MWCNT had better internalization efficiency without disrupting the sperm lipid membrane compared to Fe{sub 3}O{sub 4} and GPN NPs. Therefore, this work proposes CNT as promising means. - Highlights: • Biophysical

  1. Synthesis and bioconjugation of gold nanoparticles as potential molecular probes for light-based imaging techniques

    NARCIS (Netherlands)

    Rayavarapu, R.G.; Petersen, Wilhelmina; Ungureanu, C.; Post, Janine Nicole; van Leeuwen, Ton; Manohar, Srirang

    2007-01-01

    We have synthesized and characterized gold nanoparticles (spheres and rods) with optical extinction bands within the “optical imaging window.” The intense plasmon resonant driven absorption and scattering peaks of these nanoparticles make them suitable as contrast agents for optical imaging

  2. Direct Probing of Dispersion Quality of ZrO2 Nanoparticles Coated by Polyelectrolyte at Different Concentrated Suspensions

    Science.gov (United States)

    Sarraf, Hamid; Qian, Zhenghua; Škarpová, Ludmila; Wang, Bin; Herbig, Reinhard; Maryška, Martin; Bartovska, Lidmila; Havrda, Jiří; Anvari, Bahman

    2015-12-01

    This study reports useful application of the electrokinetic sonic amplitude (ESA) technique in combination with rheometry and electron microscopy techniques for direct probing the stability of low and high-concentrated zirconia (ZrO2) nanosuspensions in the presence of an alkali-free anionic polyelectrolyte dispersant Dolapix CE64. A comparative study of the electrokinetic characteristics and the rheological behavior of concentrated ZrO2 nanosuspensions has been done. Good agreement was obtained from relationship between the electrokinetic characteristics (zeta potential, ESA signal), viscosity, and its pH dependence for each concentrated ZrO2 nanosuspension with different dispersant concentration in the range of 0.9-1.5 mass%. A nanoscale colloidal hypothesis is proposed to illustrate that the addition of different amounts of dispersant influences on both the stability and the electrokinetic and rheological properties of concentrated ZrO2 nanosuspensions. It is found that an optimum amount of 1.4 mass% dispersant at the inherent pH (>9.2) can be attached fully onto the nanoparticles with sufficient electrosteric dispersion effects, suitable for casting applications. Supplementary scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) analyses followed by colorization effect were taken to verify the visible interaction between dispersant and nanoparticles surfaces. SEM and HR-TEM images proved the existence of visible coverage of dispersant on the surface of individual nanoparticles and showed that thin polyelectrolyte layers were physically bound onto the particles' surfaces. This study will be of interest to materials scientists and engineers who are dealing with dispersion technology, nanoparticle surface treatments, functionalization, characterization, and application of bio/nanoparticle suspensions at various concentrations using different types of polymers.

  3. Impedimetric genosensor for detection of hepatitis C virus (HCV1) DNA using viral probe on methylene blue doped silica nanoparticles.

    Science.gov (United States)

    Singhal, Chaitali; Ingle, Aviraj; Chakraborty, Dhritiman; Pn, Anoop Krishna; Pundir, C S; Narang, Jagriti

    2017-05-01

    An impedimetric genosensor was fabricated for detection of hepatitis C virus (HCV) genotype 1 in serum, based on hybridization of the probe with complementary target cDNA from sample. To achieve it, probe DNA complementary to HCVgene was immobilized on the surface of methylene blue (MB) doped silica nanoparticles MB@SiNPs) modified fluorine doped tin oxide (FTO) electrode. The synthesized MB@SiNPs was characterized using scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) pattern. This modified electrode (ssDNA/MB@SiNPs/FTO) served both as a signal amplification platform (due to silica nanoparticles (SiNPs) as well as an electrochemical indicator (due to methylene blue (MB)) for the detection of the HCV DNA in patient serum sample. The genosensor was optimized and evaluated. The sensor showed a dynamic linear range 100-10 6 copies/mL, with a detection limit of 90 copies/mL. The sensor was applied for detection of HCV in sera of hepatitis patient and could be renewed. The half life of the sensor was 4 weeks. The MB@SiNPs/FTO electrode could be used for preparation of other gensensors also. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Tunable and noncytotoxic PET/SPECT-MRI multimodality imaging probes using colloidally stable ligand-free superparamagnetic iron oxide nanoparticles

    Science.gov (United States)

    Pham, TH Nguyen; Lengkeek, Nigel A; Greguric, Ivan; Kim, Byung J; Pellegrini, Paul A; Bickley, Stephanie A; Tanudji, Marcel R; Jones, Stephen K; Hawkett, Brian S; Pham, Binh TT

    2017-01-01

    Physiologically stable multimodality imaging probes for positron emission tomography/single-photon emission computed tomography (PET/SPECT)-magnetic resonance imaging (MRI) were synthesized using the superparamagnetic maghemite iron oxide (γ-Fe2O3) nanoparticles (SPIONs). The SPIONs were sterically stabilized with a finely tuned mixture of diblock copolymers with either methoxypolyethylene glycol (MPEG) or primary amine NH2 end groups. The radioisotope for PET or SPECT imaging was incorporated with the SPIONs at high temperature. 57Co2+ ions with a long half-life of 270.9 days were used as a model for the radiotracer to study the kinetics of radiolabeling, characterization, and the stability of the radiolabeled SPIONs. Radioactive 67Ga3+ and Cu2+-labeled SPIONs were also produced successfully using the optimized conditions from the 57Co2+-labeling process. No free radioisotopes were detected in the aqueous phase for the radiolabeled SPIONs 1 week after dispersion in phosphate-buffered saline (PBS). All labeled SPIONs were not only well dispersed and stable under physiological conditions but also noncytotoxic in vitro. The ability to design and produce physiologically stable radiolabeled magnetic nanoparticles with a finely controlled number of functionalizable end groups on the SPIONs enables the generation of a desirable and biologically compatible multimodality PET/SPECT-MRI agent on a single T2 contrast MRI probe. PMID:28184160

  5. Color-Coding Politics

    Directory of Open Access Journals (Sweden)

    Benjamin Gross

    2013-02-01

    Full Text Available During the 2000 Presidential election between George H. W. Bush and Al Gore, journalists often used the terms blue states and red states to describe the political landscape within the United States. This article studies the framing of these terms during the years 2004 through 2007. Using latent and manifest qualitative content analyses, six different news media frames were found in a sample of 337 newspaper articles. Two hypotheses were also tested indicating that framing patterns varied slightly by time period and article types. However, the argument that increased levels of political polarization in the United States have been created by predominantly conflict-oriented coverage may not be true. Instead, these terms became journalistic heuristics that were used to organize how people think about politics in a way that fit with contemporary media practices, and there is no single agreed upon interpretation of these terms within this reporting.

  6. MFM probe control of magnetic vortex chirality in elliptical Co nanoparticles

    International Nuclear Information System (INIS)

    Mironov, V.L.; Gribkov, B.A.; Fraerman, A.A.; Gusev, S.A.; Vdovichev, S.N.; Karetnikova, I.R.; Nefedov, I.M.; Shereshevsky, I.A.

    2007-01-01

    Magnetic force microscopy (MFM) methods were applied to investigate the peculiarities of magnetization distribution in elliptical 400x600x27 nm Co particles. Reversible transitions between the uniform and vortex states under inhomogeneous magnetic field of MFM probe were observed. Possibility to control the chirality of a magnetic vortex in these particles by MFM probe manipulation was shown

  7. Detection of Helicobacter Pylori Genome with an Optical Biosensor Based on Hybridization of Urease Gene with a Gold Nanoparticles-Labeled Probe

    Science.gov (United States)

    Shahrashoob, M.; Mohsenifar, A.; Tabatabaei, M.; Rahmani-Cherati, T.; Mobaraki, M.; Mota, A.; Shojaei, T. R.

    2016-05-01

    A novel optics-based nanobiosensor for sensitive determination of the Helicobacter pylori genome using a gold nanoparticles (AuNPs)-labeled probe is reported. Two specific thiol-modified capture and signal probes were designed based on a single-stranded complementary DNA (cDNA) region of the urease gene. The capture probe was immobilized on AuNPs, which were previously immobilized on an APTES-activated glass, and the signal probe was conjugated to different AuNPs as well. The presence of the cDNA in the reaction mixture led to the hybridization of the AuNPs-labeled capture probe and the signal probe with the cDNA, and consequently the optical density of the reaction mixture (AuNPs) was reduced proportionally to the cDNA concentration. The limit of detection was measured at 0.5 nM.

  8. Importance of angle correction in transcranial color-coded duplex insonation of arteries at the base of the brain.

    Science.gov (United States)

    Lepić, Toplica; Veljancić, Dragana; Jovanikić, Olivera; Lepić, Milan; Slankamenac, Petar; Raicević, Ranko

    2015-12-01

    Transcranial color-coded duplex (TCCD) sonography allows visualization of the vessels being examined and measurement of the angle of insonation. The published literature suggests that blood vessels are insonated at the angle lower than 30 degrees, hence no correction for the angle is necessary. The aim of this study was to determine the availability of intracranial blood vessels for insonation, and the percentage of arteries and their segments which can be insonated at the angles lower than 30 degrees. The study included 120 patients (mean age 51). For each of the segments the angle of insonation was registered based on TCCD vizualization, and hemodynamic parameters were measured. The angle of insonation was measured using combined B-mode and color Doppler vizualization, as the angle between the direction of the ultrasound beam and the axis of the shown arterial segment. The total success rate of insonation was 86.33% (1,554 out of 1,800). The mean angle of insonation value in all the examined arterial segments was 42 degrees. The insonation angle was higher than 30 degrees in about three quarters of the examined segments, especially in the A2 segment of the anterior cerebral artery (98%), the P1 segmet of the posterior cerebral artery (87%) and in the terminal internal carotid artery (83%). The A1 segment of the anterior cerebral artery showed the best insonation conditions with the angle of insonation lower than 30 degrees in 53% of the cases. The presented results of angles of insonation measurements for the anterior, middle and posterior cerebral arteries and their segments, as well as the terminal portion of the internal carotid artery clearly indicate that their average values in tested segments were very often higher than 30 degrees, which can cause an error in blood flow velocity measurement that cannot be ignored. The results confirm the necessity of correcting flow velocity values on the basis of the angle of insonation in TCCD sonography.

  9. Narrowing of the middle cerebral artery: artificial intelligence methods and comparison of transcranial color coded duplex sonography with conventional TCD.

    Science.gov (United States)

    Swiercz, Miroslaw; Swiat, Maciej; Pawlak, Mikolaj; Weigele, John; Tarasewicz, Roman; Sobolewski, Andrzej; Hurst, Robert W; Mariak, Zenon D; Melhem, Elias R; Krejza, Jaroslaw

    2010-01-01

    The goal of the study was to compare performances of transcranial color-coded duplex sonography (TCCS) and transcranial Doppler sonography (TCD) in the diagnosis of the middle cerebral artery (MCA) narrowing in the same population of patients using statistical and nonstatistical intelligent models for data analysis. We prospectively collected data from 179 consecutive routine digital subtraction angiography (DSA) procedures performed in 111 patients (mean age 54.17+/-14.4 years; 59 women, 52 men) who underwent TCD and TCCS examinations simultaneously. Each patient was examined independently using both ultrasound techniques, 267 M1 segments of MCA were assessed and narrowings were classified as 50% lumen reduction. Diagnostic performance was estimated by two statistical and two artificial neural networks (ANN) classification methods. Separate models were constructed for the TCD and TCCS sonographic data, as well as for detection of "any narrowing" and "severe narrowing" of the MCA. Input for each classifier consisted of the peak-systolic, mean and end-diastolic velocities measured with each sonographic method; the output was MCA narrowing. Arterial narrowings less or equal 50% of lumen reduction were found in 55 and >50% narrowings in 26 out of 267 arteries, as indicated by DSA. In the category of "any narrowing" the rate of correct assignment by all models was 82% to 83% for TCCS and 79% to 81% for TCD. In the diagnosis of >50% narrowing the overall classification accuracy remained in the range of 89% to 90% for TCCS data and 90% to 91% for TCD data. For the diagnosis of any narrowing, the sensitivity of the TCCS was significantly higher than that of the TCD, while for diagnosis of >50% MCA narrowing, sensitivity of the TCCS was similar to sensitivity of the TCD. Our study showed that TCCS outperforms conventional TCD in detection of 50% MCA narrowing. (E-mail: jaroslaw.krejza@uphs.upenn.edu).

  10. Functionalized Au@Ag-Au nanoparticles as an optical and SERS dual probe for lateral flow sensing.

    Science.gov (United States)

    Bai, Tingting; Wang, Meng; Cao, Min; Zhang, Juan; Zhang, Kangzhen; Zhou, Ping; Liu, Zhengxia; Liu, Ying; Guo, Zhirui; Lu, Xiang

    2018-02-14

    Lateral flow assay strips (LFASs) with Au nanoparticles (NPs) have been widely used as a probe for biomarkers in point-of-care testing; however, there still remain challenges in detection sensitivity and quantitative analysis. In this study, we developed a surface-enhanced Raman scattering (SERS)-based LFAS for quantitative analysis of a biomarker in the low concentration range. Moreover, apart from conventional Au NPs, three other types of citrate-capped Au-Ag bimetallic NPs: Au core with Ag shell NPs (Au@Ag NPs), rattle-like Au core in Ag-Au shell NPs (Au@Ag-Au NPs) and Ag-Au NPs were prepared and functionalized, and their solution-based SERS activities were comprehensively studied by experimental measurement and theoretical analysis. The results clearly indicated that the citrate-capped Au@Ag-Au NPs exhibited the highest SERS activity among the probes tested. Au@Ag-Au NPs were used as both optical and SERS probes in a SERS-based LFAS. In the presence of the analyte at high concentrations, a purple color appeared in the test zone. Highly sensitive and quantitative analysis was realized by measurement of SERS signals from the test lines. One of the most specific markers for cardiac injury, cardiac troponin I (cTnI), was chosen as the detection model. The detection limit of the SERS-based LFAS for cardiac troponin I was 0.09 ng/mL, lowered by nearly 50 times compared with visual results, and could be further lowered by optimization. These results demonstrated that the SERS-based LFAS using citrate-capped Au@Ag-Au NPs as probes can be a powerful tool for highly sensitive and quantitative detection of biomarkers. Graphical abstract A surface-enhanced Raman scattering (SERS)-based lateral flow assay strip using rattle-like Au core in Ag-Au shell (Au@Ag-Au) nanoparticles as probes was developed for quantitative analysis of a biomarker, with a detection limit nearly 50 times lower than that of visual assessment. C control line, T test line.

  11. Color-coded prefilled medication syringes decrease time to delivery and dosing errors in simulated prehospital pediatric resuscitations: A randomized crossover trial.

    Science.gov (United States)

    Stevens, Allen D; Hernandez, Caleb; Jones, Seth; Moreira, Maria E; Blumen, Jason R; Hopkins, Emily; Sande, Margaret; Bakes, Katherine; Haukoos, Jason S

    2015-11-01

    Medication dosing errors remain commonplace and may result in potentially life-threatening outcomes, particularly for pediatric patients where dosing often requires weight-based calculations. Novel medication delivery systems that may reduce dosing errors resonate with national healthcare priorities. Our goal was to evaluate novel, prefilled medication syringes labeled with color-coded volumes corresponding to the weight-based dosing of the Broselow Tape, compared to conventional medication administration, in simulated prehospital pediatric resuscitation scenarios. We performed a prospective, block-randomized, cross-over study, where 10 full-time paramedics each managed two simulated pediatric arrests in situ using either prefilled, color-coded syringes (intervention) or their own medication kits stocked with conventional ampoules (control). Each paramedic was paired with two emergency medical technicians to provide ventilations and compressions as directed. The ambulance patient compartment and the intravenous medication port were video recorded. Data were extracted from video review by blinded, independent reviewers. Median time to delivery of all doses for the intervention and control groups was 34 (95% CI: 28-39) seconds and 42 (95% CI: 36-51) seconds, respectively (difference=9 [95% CI: 4-14] seconds). Using the conventional method, 62 doses were administered with 24 (39%) critical dosing errors; using the prefilled, color-coded syringe method, 59 doses were administered with 0 (0%) critical dosing errors (difference=39%, 95% CI: 13-61%). A novel color-coded, prefilled syringe decreased time to medication administration and significantly reduced critical dosing errors by paramedics during simulated prehospital pediatric resuscitations. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Hydrophobically Modified Glycol Chitosan Nanoparticles for Targeting Breast Cancer Microcalcification Using Alendronate Probes

    Science.gov (United States)

    Vishnu, Kamalakannan

    In 2016, invasive breast cancer was diagnosed in about 246,660 women and 2,600 men. An additional 61,000 new cases of in situ breast cancer was diagnosed in women. Microcalcifications are most common abnormalities detected by mammography for breast cancer, present in about 30% of all malignant breast lesions. Tumor specific biomarkers are used for targeting these abnormalities. Nanoparticles with multimodal and combinatorial therapies and conjunction of bio-ligands for specific molecular targeting using surface modifications effectually deliver a variety of drugs and are simultaneously used to image tumor progression. Alendronate, a germinal bisphosphonate conjugation as a targeting ligand would improve the nanoparticle's direct binding to hydroxyapatite (HA) mimicking calcified spots in breast cancer lesions. In this study, the hydrophobically modified glycol chitosan (HGC) micelle was modified with alendronate surface functionalization using a biotin-avidin interaction to improve the nanomicelle's calcification targeting ability. Biotinylated, avidinlyated hydrophobically modified iv glycol chitosan particles were linked to biotinylated alendronate via a strong biotin-avidin linkage. Cyanine 3, a red fluorescent dye was conjugated to the amine groups on HGC for visualization of micelles. The size of the nanoparticles measured was 254.0 +/- 0.43 nm and 209.7 +/- 1.0 nm for Cy3- BHGCA and Cy3-BHGCA-BALN nanoparticles respectively. The average surface charge was measured to be +26.9 +/- 0.19 mV and +27.68 +/- 0.20 mV for Cy3-BHGCA and Cy3-BHGCA- BALN nanoparticles respectively. Binding affinity using hydroxyapatite (HA) revealed that both Cy3 BHGCA BALN and Cy3 BHGCA nanoparticles displayed 95% binding in 24 hours. However, the biotin quenched nanoparticle Cy3 BHGCAB displayed 68% binding in 24 hours. The synthesis and binding chemistry was verified using Fourier transform infrared spectroscopy (FTIR).

  13. Probing strong optical fields in compact aggregates of silver nanoparticles by SERRS of protoporphyrin IX.

    Science.gov (United States)

    Sládkova, Magdalena; Vlcková, Blanka; Mojzes, Peter; Slouf, Miroslav; Naudin, Coralie; Le Bourdon, Gwenelle

    2006-01-01

    TEM images and measurements of SERRS (surface-enhanced resonance Raman scattering) spectra as a function of the porphyrin concentrations in systems with unmodified and chloride-modified Ag nanoparticles and protoporphyrin IX (PPIX) are reported. TEM images have shown formation of compact aggregates in systems with chloride modified Ag nanoparticles, as opposed to systems with the unmodified particles constituted by isolated particles. SERRS spectra of PPIX as a function of PPIX concentration were measured and subjected to factor analysis. Two spectral components were identified and tentatively attributed to unperturbed PPIX and to Ag+ -PPIX surface species. Concentration value of the SERRS spectral detection limit of the latter species was determined to be nearly three orders of magnitude lower in the system with the compact aggregates than in the system with separated nanoparticles and achieves the value of 1 x 10(-10) M in a macrosampling Raman experiment. TEM images and SERRS-micro-Raman spectra of single compact aggregates of chloride-modified Ag nanoparticles incorporating PPIX molecules were acquired from a sample prepared by attachment of the aggregates to amine groups of derivatized, SiOx/formvar coated copper grids for TEM. The SERRS signal has shown large temporal fluctuations as well as variations from one aggregate to another. Within the signal fluctuations, a SERRS spectrum showing the characteristic bands of both SERRS spectral forms of PPIX and originating most probably from a few PPIX molecules located in hot spots in the interstices between the Ag nanoparticles, was obtained.

  14. Importance of angle corection in transcranial color-coded duplex insonation of arteries at the base of the brain

    Directory of Open Access Journals (Sweden)

    Lepić Toplica

    2015-01-01

    Full Text Available Background/Aim. Transcranial color-coded duplex (TCCD sonography allows visualization of the vessels being examined and measurement of the angle of insonation. The published literature suggests that blood vessels are insonated at the angle lower than 30 degrees, hence no correction for the angle is necessary. The aim of this study was to determine the availability of intracranial blood vessels for insonation, and the percentage of arteries and their segments which can be insonated at the angles lower than 30 degrees. Methods. The study included 120 patients (mean age 51. For each of the segments the angle of insonation was registered based on TCCD vizualization, and hemodynamic parameters were measured. The angle of insonation was measured using combined B-mode and color Doppler vizualization, as the angle between the direction of the ultrasound beam and the axis of the shown arterial segment. Results. The total success rate of insonation was 86.33% (1,554 out of 1,800. The mean angle of insonation value in all the examined arterial segments was 42 degrees. The insonation angle was higher than 30 degrees in about three quarters of the examined segments, especially in the A2 segment of the anterior cerebral artery (98%, the P1 segmet of the posterior cerebral artery (87% and in the terminal internal carotid artery (83%. The A1 segment of the anterior cerebral artery showed the best insonation conditions with the angle of insonation lower than 30 degrees in 53% of the cases. Conclusion. The presented results of angles of insonation measurements for the anterior, middle and posterior cerebral arteries and their segments, as well as the terminal portion of the internal carotid artery clearly indicate that their average values in tested segments were very often higher than 30 degrees, which can cause an error in blood flow velocity measurement that cannot be ignored. The results confirm the necessity of correcting flow velocity values on the basis of

  15. Probing atomic structure in magnetic core/shell nanoparticles using synchrotron radiation.

    Science.gov (United States)

    Baker, S H; Roy, M; Thornton, S C; Qureshi, M; Binns, C

    2010-09-29

    Core/shell Fe/Cu and Fe/Au nanoparticles were prepared directly by deposition from the gas phase. A detailed study of the atomic structure in both the cores and shells of the nanoparticles was undertaken by means of extended absorption fine structure (EXAFS) measurements. For Fe/Cu nanoparticles, a Cu shell ∼ 20 monolayers thick appears similar in structure to bulk Cu and is sufficient to cause the structure in the Fe core to switch from body centred cubic (bcc; as in bulk Fe) to face centred cubic. This is not the case for thinner Cu shells, 1-2 monolayers in thickness, in which there is a considerable contraction in nearest-neighbour interatomic distance as the shell structure changes to bcc. In Fe/Au nanoparticles, the crystal structure in the Fe core remains bcc for all Au thicknesses although there is some stretching of the lattice. In thin Au shells ∼ 2 monolayers thick, there is strong contraction in interatomic distances. There does not appear to be significant alloying at the Fe/Au interface.

  16. AC susceptibility as a tool to probe the dipolar interaction in magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Landi, Gabriel T., E-mail: gtlandi@gmail.com [Universidade Federal do ABC, 09210-580 Santo André (Brazil); Arantes, Fabiana R. [Universidade Federal do ABC, 09210-580 Santo André (Brazil); Cornejo, Daniel R. [Instituto de Física da Universidade de São Paulo, São Paulo 05508-090 (Brazil); Bakuzis, Andris F. [Instituto de Física, Universidade Federal de Goiás, 74690-900 Goiânia-GO (Brazil); Andreu, Irene; Natividad, Eva [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC-Universidad de Zaragoza, Zaragoza 50018 (Spain)

    2017-01-01

    The dipolar interaction is known to substantially affect the properties of magnetic nanoparticles. This is particularly important when the particles are kept in a fluid suspension or packed within nano-carriers. In addition to its usual long-range nature, in these cases the dipolar interaction may also induce the formation of clusters of particles, thereby strongly modifying their magnetic anisotropies. In this paper we show how AC susceptibility may be used to obtain information regarding the influence of the dipolar interaction in a sample. We develop a model which includes both aspects of the dipolar interaction and may be fitted directly to the susceptibility data. The usual long-range nature of the interaction is implemented using a mean-field approximation, whereas the particle-particle aggregation is modeled using a distribution of anisotropy constants. The model is then applied to two samples studied at different concentrations. One consists of spherical magnetite nanoparticles dispersed in oil and the other of cubic magnetite nanoparticles embedded on polymeric nanospheres. We also introduce a simple technique to address the presence of the dipolar interaction in a given sample, based on the height of the AC susceptibility peaks for different driving frequencies. - Highlights: We discuss the importance of the dipolar interaction in magnetic nanoparticle samples. It is shown that AC susceptibility may be used to estimate the extent of this interaction. We develop a model that accounts for particle aggregation. The theoretical model is then fitted to distinct magnetite samples.

  17. Probing the impact of loading rate on the mechanical properties of viral nanoparticles

    NARCIS (Netherlands)

    Snijder, J.; Ivanovska, I.L.; Baclayon, M.; Roos, W.H.; Wuite, G.J.L.

    2012-01-01

    The effects of changes in the loading rate during the forced dissociation of single bonds have been studied for a wide variety of interactions. Less is known on the loading rate dependent behaviour of more complex systems that consist of multiple bonds. Here we focus on viral nanoparticles, in

  18. Tunable and noncytotoxic PET/SPECT-MRI multimodality imaging probes using colloidally stable ligand-free superparamagnetic iron oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Pham THN

    2017-01-01

    Full Text Available TH Nguyen Pham,1 Nigel A Lengkeek,2 Ivan Greguric,2 Byung J Kim,1 Paul A Pellegrini,2 Stephanie A Bickley,3 Marcel R Tanudji,3 Stephen K Jones,3 Brian S Hawkett,1 Binh TT Pham1 1Key Centre for Polymers and Colloids, School of Chemistry, University of Sydney, 2Radioisotopes and Radiotracers, NSTLI, Australian Nuclear Science and Technology Organisation, Sydney, 3Sirtex Medical Limited, North Sydney, NSW, Australia Abstract: Physiologically stable multimodality imaging probes for positron emission tomography/single-photon emission computed tomography (PET/SPECT-magnetic resonance imaging (MRI were synthesized using the superparamagnetic maghemite iron oxide (γ-Fe2O3 nanoparticles (SPIONs. The SPIONs were sterically stabilized with a finely tuned mixture of diblock copolymers with either methoxypolyethylene glycol (MPEG or primary amine NH2 end groups. The radioisotope for PET or SPECT imaging was incorporated with the SPIONs at high temperature. 57Co2+ ions with a long half-life of 270.9 days were used as a model for the radiotracer to study the kinetics of radiolabeling, characterization, and the stability of the radiolabeled SPIONs. Radioactive 67Ga3+ and Cu2+-labeled SPIONs were also produced successfully using the optimized conditions from the 57Co2+-labeling process. No free radioisotopes were detected in the aqueous phase for the radiolabeled SPIONs 1 week after dispersion in phosphate-buffered saline (PBS. All labeled SPIONs were not only well dispersed and stable under physiological conditions but also noncytotoxic in vitro. The ability to design and produce physiologically stable radiolabeled magnetic nanoparticles with a finely controlled number of functionalizable end groups on the SPIONs enables the generation of a desirable and biologically compatible multimodality PET/SPECT-MRI agent on a single T2 contrast MRI probe. Keywords: magnetic resonance imaging, positron emission tomography, single-photon emission computed tomography

  19. Preclinical detection of porcine circovirus type 2 infection using an ultrasensitive nanoparticle DNA probe-based PCR assay.

    Directory of Open Access Journals (Sweden)

    Yong Huang

    Full Text Available Porcine circovirus type 2 (PCV2 has emerged as one of the most important pathogens affecting swine production globally. Preclinical identification of PCV2 is very important for effective prophylaxis of PCV2-associated diseases. In this study, we developed an ultrasensitive nanoparticle DNA probe-based PCR assay (UNDP-PCR for PCV2 detection. Magnetic microparticles coated with PCV2 specific DNA probes were used to enrich PCV2 DNA from samples, then gold nanoparticles coated with PCV2 specific oligonucleotides were added to form a sandwich nucleic acid-complex. After the complex was formed, the oligonucleotides were released and characterized by PCR. This assay exhibited about 500-fold more sensitive than conventional PCR, with a detection limit of 2 copies of purified PCV2 genomic DNA and 10 viral copies of PCV2 in serum. The assay has a wide detection range for all of PCV2 genotypes with reliable reproducibility. No cross-reactivity was observed from the samples of other related viruses including porcine circovirus type 1, porcine parvovirus, porcine pseudorabies virus, porcine reproductive and respiratory syndrome virus and classical swine fever virus. The positive detection rate of PCV2 specific UNDP-PCR in 40 preclinical field samples was 27.5%, which appeared greater than that by conventional and real-time PCR and appeared application potency in evaluation of the viral loads levels of preclinical infection samples. The UNDP-PCR assay reported here can reliably rule out false negative results from antibody-based assays, provide a nucleic acid extraction free, specific, ultrasensitive, economic and rapid diagnosis method for preclinical PCV2 infection in field, which may help prevent large-scale outbreaks.

  20. A dual mode targeting probe for distinguishing HER2-positive breast cancer cells using silica-coated fluorescent magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jia [Medical School Southeast University, Department of Ultrasonography, Zhongda Hospital (China); An, Yan-Li; Zang, Feng-Chao [Southeast University, Jiangsu Key Laboratory of Molecular and Functional Imaging (China); Zong, Shen-Fei; Cui, Yi-Ping, E-mail: cyp@seu.edu.cn [Southeast University, Advanced Photonics Center (China); Teng, Gao-Jun, E-mail: gjteng@vip.sina.com [Southeast University, Jiangsu Key Laboratory of Molecular and Functional Imaging (China)

    2013-10-15

    We report a composite nanoprobe based on silica-coated magnetic nanoparticles (NPs) for distinguishing breast cancers at different HER2 statuses. The nanoprobe has a core-shell structure, with Fe{sub 3}O{sub 4} NPs as the magnetic core and dye-embedded silica as the fluorescent shell, whose average size is about 150 nm. Besides, the outmost surfaces of the probes were modified with specific antibodies to endow the probe with a targeting ability. With such a structure, the nanoprobe can accomplish dual mode targeting of human breast cancer cells based on fluorescence and magnetic resonance imaging (MRI). In the experiments, three human breast cancer cell lines were used to test the targeting ability of the nanoprobe. Specifically, SKBR3 cells with a high HER2 expression level were used as the model target cells, while MCF7 cells with a lower HER2 expression levels and HER2-negative MDA-MB-231 cells were used as the controls. Both the fluorescence and MRI imaging results confirmed that the nanoprobe can distinguish three cancer cell lines with different HER2 expression levels. With the dual mode imaging and specific targeting properties, we anticipate that the presented nanoprobe may have a great potential in the diagnosis and treatment of cancerous diseases.

  1. A dual mode targeting probe for distinguishing HER2-positive breast cancer cells using silica-coated fluorescent magnetic nanoparticles

    Science.gov (United States)

    Li, Jia; An, Yan-Li; Zang, Feng-Chao; Zong, Shen-Fei; Cui, Yi-Ping; Teng, Gao-Jun

    2013-10-01

    We report a composite nanoprobe based on silica-coated magnetic nanoparticles (NPs) for distinguishing breast cancers at different HER2 statuses. The nanoprobe has a core-shell structure, with Fe3O4 NPs as the magnetic core and dye-embedded silica as the fluorescent shell, whose average size is about 150 nm. Besides, the outmost surfaces of the probes were modified with specific antibodies to endow the probe with a targeting ability. With such a structure, the nanoprobe can accomplish dual mode targeting of human breast cancer cells based on fluorescence and magnetic resonance imaging (MRI). In the experiments, three human breast cancer cell lines were used to test the targeting ability of the nanoprobe. Specifically, SKBR3 cells with a high HER2 expression level were used as the model target cells, while MCF7 cells with a lower HER2 expression levels and HER2-negative MDA-MB-231 cells were used as the controls. Both the fluorescence and MRI imaging results confirmed that the nanoprobe can distinguish three cancer cell lines with different HER2 expression levels. With the dual mode imaging and specific targeting properties, we anticipate that the presented nanoprobe may have a great potential in the diagnosis and treatment of cancerous diseases.

  2. Au@Ag core/shell nanoparticles as colorimetric probes for cyanide sensing

    Science.gov (United States)

    Zeng, Jing-Bin; Cao, Ying-Ying; Chen, Jing-Jing; Wang, Xu-Dong; Yu, Jian-Feng; Yu, Bin-Bin; Yan, Zi-Feng; Chen, Xi

    2014-08-01

    We synthesize Au@Ag core/shell nanoparticles (NPs) using a Au NP assisted Tollens reaction. The as-synthesized NPs are used for the colorimetric cyanide sensing with a detection limit of 0.4 μM. The bimetallic NPs are immobilized into agarose gels as portable ``test strips''.We synthesize Au@Ag core/shell nanoparticles (NPs) using a Au NP assisted Tollens reaction. The as-synthesized NPs are used for the colorimetric cyanide sensing with a detection limit of 0.4 μM. The bimetallic NPs are immobilized into agarose gels as portable ``test strips''. Electronic supplementary information (ESI) available: Experimental procedures and Fig. S1-S14. See DOI: 10.1039/c4nr02560a

  3. Predictive value of vertebral artery extracranial color-coded duplex sonography for ischemic stroke-related vertigo

    Directory of Open Access Journals (Sweden)

    Li-Min Liou

    2013-12-01

    Full Text Available Vertigo can be a major presentation of posterior circulation stroke and can be easily misdiagnosed because of its complicated presentation. We thus prospectively assessed the predictive value of vertebral artery extracranial color-coded duplex sonography (ECCS for the prediction of ischemic stroke-related vertigo. The inclusion criteria were: (1 a sensation of whirling (vertigo; (2 intractable vertigo for more than 1 hour despite appropriate treatment; and (3 those who could complete cranial magnetic resonance imaging (MRI and vertebral artery (V2 segment ECCS studies. Eventually, 76 consecutive participants with vertigo were enrolled from Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung, Taiwan between August 2010 and August 2011. Demographic data, neurological symptoms, neurologic examinations, and V2 ECCS were assessed. We chose the parameters of peak systolic velocity (PSV, end diastolic velocity (EDV, PSV/EDV, mean velocity (MV, resistance index (RI, and pulsatility index (PI to represent the hemodynamics. Values from both sides of V2 segments were averaged. We then calculated the average RI (aRI, average PI (aPI, average PSV (aPSV/EDV, and average (aMV. Axial and coronal diffusion-weighted MRI findings determined the existence of acute ischemic stroke. We grouped and analyzed participants in two ways (way I and way II analyses based on the diffusion-weighted MRI findings (to determine whether there was acute stroke and neurological examinations. Using way I analysis, the “MRI (+” group had significantly higher impedance (aRI, aPI, and aPSV/EDV ratio and lower velocity (aPSV, aEDV, and aMV(PSV + EDV/2, compared to the “MRI (–” group. The cutoff value/sensitivity/specificity of aPSV, aEDV, aMV, aPI, aRI, and aPSV/EDV between the MRI (+ and MRI (– groups were 41.15/61.5/66.0 (p = 0.0101, 14.55/69.2/72.0 (p = 0.0003, 29.10/92.1/38.0 (p = 0.0013, 1.07/76.9/64.0 (p = 0.0066, 0.62/76.9/64.0 (p = 0.0076, and 2

  4. Nanoparticle-based luminescent probes for intracellular sensing and imaging of pH.

    Science.gov (United States)

    Schäferling, Michael

    2016-05-01

    Fluorescence imaging microscopy is an essential tool in biomedical research. Meanwhile, various fluorescent probes are available for the staining of cells, cell membranes, and organelles. Though, to monitor intracellular processes and dysfunctions, probes that respond to ubiquitous chemical parameters determining the cellular function such as pH, pO2 , and Ca(2+) are required. This review is focused on the progress in the design, fabrication, and application of photoluminescent nanoprobes for sensing and imaging of pH in living cells. The advantages of using nanoprobes carrying fluorescent pH indicators compared to single molecule probes are discussed as well as their limitations due to the mostly lysosomal uptake by cells. Particular attention is paid to ratiometric dual wavelength nanosensors that enable intrinsic referenced measurements. Referencing and proper calibration procedures are basic prerequisites to carry out reliable quantitative pH determinations in complex samples such as living cells. A variety of examples will be presented that highlight the diverseness of nanocarrier materials (polymers, micelles, silica, quantum dots, carbon dots, gold, photon upconversion nanocrystals, or bacteriophages), fluorescent pH indicators for the weak acidic range, and referenced sensing mechanisms, that have been applied intracellularly up to now. WIREs Nanomed Nanobiotechnol 2016, 8:378-413. doi: 10.1002/wnan.1366 For further resources related to this article, please visit the WIREs website. © 2015 Wiley Periodicals, Inc.

  5. Manipulation of pH induced sensitivity of a fluorescent probe in presence of silver nanoparticles

    International Nuclear Information System (INIS)

    Kacmaz, Sibel; Ertekin, Kadriye; Oter, Ozlem; Hizliateş, Cevher Gundogdu; Ergun, Yavuz; Celik, Erdal

    2015-01-01

    In this study, pH induced spectral response of the newly synthesized carbazole derivative (9-butyl-bis-3-(4-(dimethylamino) phenyl) allylidene)-9H-carbazole-3,6-diamine) has been declared. We utilized silver nanoparticles (AgNPs) along with ionic liquid as additives for manipulation of the spectral response. Plasticized ethyl cellulose (EC) was used as matrix material. Fibers and porous films were produced by electrospinning technique. The emission intensity at 631 nm has been followed as the analytical signal. Utilization of silver nanoparticles in electrospun polymeric fibers for pH sensing purposes resulted with many advantages such as tuned sensitivity, linear calibration plot for larger pH ranges, increased surface area and enhancement in all sensor dynamics. Additionally, we performed manipulation of the pKa within the same matrix exploiting the silver NPs. Characteristics of the pH induced response for the offered composition was superior with respect to the previously reported ones. When stored at the ambient air of the laboratory there was no significant drift in the signal intensity after 16 months. Our sensitivity and stability tests are still in progress. - Highlights: • A carbozole derivative was used for the first time for sensing of pH along with silver nanoparticles. • The sensor slides fabricated in form of nanofibers. • The Ag containing and Ag-free slides were produced by electrospinning technique. • pH Sensitivity of the dye was compared for both; Ag containing and Ag-free forms. • We performed manipulation of the pKa within the same matrix exploiting the silver NPs.

  6. sp Carbon chain interaction with silver nanoparticles probed by Surface Enhanced Raman Scattering

    Science.gov (United States)

    Lucotti, A.; Casari, C. S.; Tommasini, M.; Li Bassi, A.; Fazzi, D.; Russo, V.; Del Zoppo, M.; Castiglioni, C.; Cataldo, F.; Bottani, C. E.; Zerbi, G.

    2009-08-01

    Surface Enhanced Raman Spectroscopy (SERS) is exploited here to investigate the interaction of isolated sp carbon chains (polyynes) in a methanol solution with silver nanoparticles. Hydrogen-terminated polyynes show a strong interaction with silver colloids used as the SERS active medium revealing a chemical SERS effect. SERS spectra after mixing polyynes with silver colloids show a noticeable time evolution. Experimental results, supported by density functional theory (DFT) calculations of the Raman modes, allow us to investigate the behavior and stability of polyynes of different lengths and the overall sp conversion towards sp 2 phase.

  7. Quinolino-triazole linked gold nanoparticles as sensitive 'turn-on' fluorescent Cd2+ probes

    International Nuclear Information System (INIS)

    Yao Yao; Sun Zhongyue; Zou Zhilong; Li Haibing

    2011-01-01

    Quinoline derivatives were brought into the surface of gold nanoparticles (Au NPs) through click chemistry. The fluorescence was quenched by Au NPs because of electron transfer between Au NPs and quinoline. However, upon addition of Cd 2+ to the quinoline-triazole Au NP solution, it exhibited an effective switch-on fluorescence response, owing to the coordination between quinoline and Cd 2+ which can efficiently block the electron transfer. What's more, the fluorescent sensor can effectively detect Cd 2+ in aqueous solution with a detection limit of 1.0 x 10 -5 M.

  8. Probing the effect of charge transfer enhancement in off resonance mode SERS via conjugation of the probe dye between silver nanoparticles and metal substrates.

    Science.gov (United States)

    Selvakannan, Pr; Ramanathan, Rajesh; Plowman, Blake J; Sabri, Ylias M; Daima, Hemant K; O'Mullane, Anthony P; Bansal, Vipul; Bhargava, Suresh K

    2013-08-21

    The charge transfer-mediated surface enhanced Raman scattering (SERS) of crystal violet (CV) molecules that were chemically conjugated between partially polarized silver nanoparticles and optically smooth gold and silver substrates has been studied under off-resonant conditions. Tyrosine molecules were used as a reducing agent to convert silver ions into silver nanoparticles where oxidised tyrosine caps the silver nanoparticle surface with its semiquinone group. This binding through the quinone group facilitates charge transfer and results in partially oxidised silver. This establishes a chemical link between the silver nanoparticles and the CV molecules, where the positively charged central carbon of CV molecules can bind to the terminal carboxylate anion of the oxidised tyrosine molecules. After drop casting Ag nanoparticles bound with CV molecules it was found that the free terminal amine groups tend to bind with the underlying substrates. Significantly, only those CV molecules that were chemically conjugated between the partially polarised silver nanoparticles and the underlying gold or silver substrates were found to show SERS under off-resonant conditions. The importance of partial charge transfer at the nanoparticle/capping agent interface and the resultant conjugation of CV molecules to off resonant SERS effects was confirmed by using gold nanoparticles prepared in a similar manner. In this case the capping agent binds to the nanoparticle through the amine group which does not facilitate charge transfer from the gold nanoparticle and under these conditions SERS enhancement in the sandwich configuration was not observed.

  9. Accurate and visual discrimination of single-base mismatch by utilization of binary DNA probes in gold nanoparticles-based biosensing strategy.

    Science.gov (United States)

    Zhou, Weijun; Ren, Jiangtao; Zhu, Jinbo; Zhou, Zhixue; Dong, Shaojun

    2016-12-01

    Herein we report a colorimetric biosensing strategy to discriminate single-nucleotide mutation in DNA with high selectivity using unmodified gold nanoparticles (AuNPs) as indicators. In the AuNPs-based colorimetric strategy, binary DNA probes were produced by splitting a long DNA probe in the middle for sensitive differentiation of single-base mismatch. The detection limit of this method toward target DNA was 5nM. The developed system has superior advantages of utilization of inexpensive materials, simplicity and visualization. Moreover, binary DNA probes not only can distinguish single-base mutation in the target DNA very well, as compared to long DNA probe, but also can construct "AND" logic gate using two distinct target DNAs as inputs, which holds great potential for increasing the accuracy of disease diagnosis in clinical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Biosynthesis of Fluorescent Bi2S3 Nanoparticles and their Application as Dual-Function SPECT-CT Probe for Animal Imaging.

    Science.gov (United States)

    Uddin, Imran; Ahmad, Absar; Siddiqui, Ejaz Ahmad; Rahaman, Sk Hasanur; Gambhir, Sanjay

    2016-01-01

    Bismuth sulphide (Bi2S3) is an excellent semiconductor and its nanoparticles have numerous significant applications including photovoltaic materials, photodiode arrays, bio-imaging, etc. Nevertheless, these nanoparticles when fabricated by chemical and physical routes tend to easily aggregate in colloidal solutions, are eco-unfriendly, cumbrous and very broad in size distribution. The aim of the present manuscript was to ecologically fabricate water dispersible, safe and stable Bi2S3 nanoparticles such that these may find use in animal imaging, diagnostics, cell labeling and other biomedical applications. Herein, we for the first time have biosynthesized highly fluorescent, natural protein capped Bi2S3 nanoparticles by subjecting the fungus Fusarium oxysporum to bismuth nitrate pentahydrate [Bi(NO3)3.5H2O] alongwith sodium sulphite (Na2SO3) as precursor salts under ambient conditions of temperature, pressure and pH. The nanoparticles were completely characterized using recognized standard techniques. These natural protein capped Bi2S3 nanoparticles are quasi-spherical in shape with an average particle size of 15 nm, maintain long term stability and show semiconductor behavior having blue shift with a band gap of 3.04 eV. Semiconductor nanocrystals are fundamentally much more fluorescent than the toxic fluorescent chemical compounds (fluorophores) which are presently largely employed in imaging, immunohistochemistry, biochemistry, etc. Biologically fabricated fluorescent nanoparticles may replace organic fluorophores and aid in rapid development of biomedical nanotechnology. Thus, biodistribution study of the so-formed Bi2S3 nanoparticles in male Sprague Dawley rats was done by radiolabelling with Technitium-99m (Tc-99m) and clearance time from blood was calculated. The nanoparticles were then employed in SPECT-CT probe for animal imaging where these imparted iodine equivalent contrast.

  11. Using magnetic nanoparticles to probe protein damage in ferritin caused by freeze concentration

    Directory of Open Access Journals (Sweden)

    E. F. Chagas

    2015-11-01

    Full Text Available We demonstrate a method for monitoring the damage caused to a protein during freeze-thawing in the presence of glycerol, a cryo-protectant. For this work we synthesized magnetite nanoparticles doped with 2.5% cobalt inside the protein ferritin (CMF, dissolved them in different concentration glycerol solutions and measured their magnetization after freezing in a high applied field (5 T. As the temperature was raised, a step-like decrease in the sample magnetization was observed, corresponding to the onset of Brownian relaxation as the viscosity of the freeze-concentrated glycerol solution decreased. The position of the step reveals changes to the protein hydrodynamic radius that we attribute to protein unfolding, while its height depends on how much protein is trapped by ice during freeze concentration. Changes to the protein hydrodynamic radius are confirmed by dynamic light scattering (DLS measurements, but unlike DLS, the magnetic measurements can provide hydrodynamic data while the solution remains mainly frozen.

  12. Fluorescent carbon nanoparticles derived from natural materials of mango fruit for bio-imaging probes

    Science.gov (United States)

    Jeong, Chan Jin; Roy, Arup Kumer; Kim, Sung Han; Lee, Jung-Eun; Jeong, Ji Hoon; Insik; Park, Sung Young

    2014-11-01

    Water soluble fluorescent carbon nanoparticles (FCP) obtained from a single natural source, mango fruit, were developed as unique materials for non-toxic bio-imaging with different colors and particle sizes. The prepared FCPs showed blue (FCP-B), green (FCP-G) and yellow (FCP-Y) fluorescence, derived by the controlled carbonization method. The FCPs demonstrated hydrodynamic diameters of 5-15 nm, holding great promise for clinical applications. The biocompatible FCPs demonstrated great potential in biological fields through the results of in vitro imaging and in vivo biodistribution. Using intravenously administered FCPs with different colored particles, we precisely defined the clearance and biodistribution, showing rapid and efficient urinary excretion for safe elimination from the body. These findings therefore suggest the promising possibility of using natural sources for producing fluorescent materials.Water soluble fluorescent carbon nanoparticles (FCP) obtained from a single natural source, mango fruit, were developed as unique materials for non-toxic bio-imaging with different colors and particle sizes. The prepared FCPs showed blue (FCP-B), green (FCP-G) and yellow (FCP-Y) fluorescence, derived by the controlled carbonization method. The FCPs demonstrated hydrodynamic diameters of 5-15 nm, holding great promise for clinical applications. The biocompatible FCPs demonstrated great potential in biological fields through the results of in vitro imaging and in vivo biodistribution. Using intravenously administered FCPs with different colored particles, we precisely defined the clearance and biodistribution, showing rapid and efficient urinary excretion for safe elimination from the body. These findings therefore suggest the promising possibility of using natural sources for producing fluorescent materials. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04805a

  13. Diffusion anisotropy color-coded map of cerebral white matter: quantitative comparison between orthogonal anisotropic diffusion-weighted imaging and diffusion tensor imaging.

    Science.gov (United States)

    Uwano, Ikuko; Sasaki, Makoto; Kudo, Kohsuke; Fujiwara, Shunrou; Yamaguchi, Mao; Saito, Ayumi; Ogasawara, Kuniaki; Ogawa, Akira

    2013-04-01

    Diffusion anisotropy color-coded maps of cerebral white matter can be generated from orthogonal anisotropic diffusion-weighted imaging (DWI) using the three-dimensional anisotropy contrast (3DAC) technique, but its precision has not been fully validated. Hence, we attempted to determine whether 3DAC is comparable to a diffusion tensor imaging (DTI) color map. We examined 15 healthy individuals and generated color-coded maps using 3DAC as well as using primary eigenvector (e1) and fractional anisotropy (FA) from identical DTI datasets. The difference in the direction of the 3DAC vector from e1 (θ) in cerebral white matter was evaluated. Correlations between θ and FA or obliqueness of e1 were also examined. In cerebral white matter, θ had significantly negative and positive correlations with FA values and e1 obliqueness, respectively. Among white matter tracts, the pyramidal tract, cingulum, and corpus callosum, which had significantly high FA and/or low obliqueness, exhibited similar coloration and significantly smaller θ (4.4° ± 1.6°, 9.3° ± 2.8°, and 11.2° ± 1.1°, respectively) than the entire white matter (13.9° ± 1.1°). The 3DAC could visualize directional information of white matter tracts as precisely DTI-based color maps did, particularly when FA was large and/or e1 directions were orthogonal. Copyright © 2012 by the American Society of Neuroimaging.

  14. A dual-modal magnetic nanoparticle probe for preoperative and intraoperative mapping of sentinel lymph nodes by magnetic resonance and near infrared fluorescence imaging.

    Science.gov (United States)

    Zhou, Zhengyang; Chen, Hongwei; Lipowska, Malgorzata; Wang, Liya; Yu, Qiqi; Yang, Xiaofeng; Tiwari, Diana; Yang, Lily; Mao, Hui

    2013-07-01

    The ability to reliably detect sentinel lymph nodes for sentinel lymph node biopsy and lymphadenectomy is important in clinical management of patients with metastatic cancers. However, the traditional sentinel lymph node mapping with visible dyes is limited by the penetration depth of light and fast clearance of the dyes. On the other hand, sentinel lymph node mapping with radionucleotide technique has intrinsically low spatial resolution and does not provide anatomic details in the sentinel lymph node mapping procedure. This work reports the development of a dual modality imaging probe with magnetic resonance and near infrared imaging capabilities for sentinel lymph node mapping using magnetic iron oxide nanoparticles (10 nm core size) conjugated with a near infrared molecule with emission at 830 nm. Accumulation of magnetic iron oxide nanoparticles in sentinel lymph nodes leads to strong T2 weighted magnetic resonance imaging contrast that can be potentially used for preoperative localization of sentinel lymph nodes, while conjugated near infrared molecules provide optical imaging tracking of lymph nodes with a high signal to background ratio. The new magnetic nanoparticle based dual imaging probe exhibits a significant longer lymph node retention time. Near infrared signals from nanoparticle conjugated near infrared dyes last up to 60 min in sentinel lymph node compared to that of 25 min for the free near infrared dyes in a mouse model. Furthermore, axillary lymph nodes, in addition to sentinel lymph nodes, can be also visualized with this probe, given its slow clearance and sufficient sensitivity. Therefore, this new dual modality imaging probe with the tissue penetration and sensitive detection of sentinel lymph nodes can be applied for preoperative survey of lymph nodes with magnetic resonance imaging and allows intraoperative sentinel lymph node mapping using near infrared optical devices.

  15. Multiplexed color-coded probe-based gene expression assessment for clinical molecular diagnostics in formalin-fixed paraffin-embedded human renal allograft tissue.

    Science.gov (United States)

    Adam, Benjamin; Afzali, Bahman; Dominy, Katherine M; Chapman, Erin; Gill, Reeda; Hidalgo, Luis G; Roufosse, Candice; Sis, Banu; Mengel, Michael

    2016-03-01

    Histopathologic diagnoses in transplantation can be improved with molecular testing. Preferably, molecular diagnostics should fit into standard-of-care workflows for transplant biopsies, that is, formalin-fixed paraffin-embedded (FFPE) processing. The NanoString(®) gene expression platform has recently been shown to work with FFPE samples. We aimed to evaluate its methodological robustness and feasibility for gene expression studies in human FFPE renal allograft samples. A literature-derived antibody-mediated rejection (ABMR) 34-gene set, comprised of endothelial, NK cell, and inflammation transcripts, was analyzed in different retrospective biopsy cohorts and showed potential to molecularly discriminate ABMR cases, including FFPE samples. NanoString(®) results were reproducible across a range of RNA input quantities (r = 0.998), with different operators (r = 0.998), and between different reagent lots (r = 0.983). There was moderate correlation between NanoString(®) with FFPE tissue and quantitative reverse transcription polymerase chain reaction (qRT-PCR) with corresponding dedicated fresh-stabilized tissue (r = 0.487). Better overall correlation with histology was observed with NanoString(®) (r = 0.354) than with qRT-PCR (r = 0.146). Our results demonstrate the feasibility of multiplexed gene expression quantification from FFPE renal allograft tissue. This represents a method for prospective and retrospective validation of molecular diagnostics and its adoption in clinical transplantation pathology. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Water adsorption on TiO2 surfaces probed by soft X-ray spectroscopies: bulk materials vs. isolated nanoparticles

    Science.gov (United States)

    Benkoula, Safia; Sublemontier, Olivier; Patanen, Minna; Nicolas, Christophe; Sirotti, Fausto; Naitabdi, Ahmed; Gaie-Levrel, François; Antonsson, Egill; Aureau, Damien; Ouf, François-Xavier; Wada, Shin-Ichi; Etcheberry, Arnaud; Ueda, Kiyoshi; Miron, Catalin

    2015-01-01

    We describe an experimental method to probe the adsorption of water at the surface of isolated, substrate-free TiO2 nanoparticles (NPs) based on soft X-ray spectroscopy in the gas phase using synchrotron radiation. To understand the interfacial properties between water and TiO2 surface, a water shell was adsorbed at the surface of TiO2 NPs. We used two different ways to control the hydration level of the NPs: in the first scheme, initially solvated NPs were dried and in the second one, dry NPs generated thanks to a commercial aerosol generator were exposed to water vapor. XPS was used to identify the signature of the water layer shell on the surface of the free TiO2 NPs and made it possible to follow the evolution of their hydration state. The results obtained allow the establishment of a qualitative determination of isolated NPs’ surface states, as well as to unravel water adsorption mechanisms. This method appears to be a unique approach to investigate the interface between an isolated nano-object and a solvent over-layer, paving the way towards new investigation methods in heterogeneous catalysis on nanomaterials. PMID:26462615

  17. A Conjugated Aptamer-Gold Nanoparticle Fluorescent Probe for Highly Sensitive Detection of rHuEPO-α

    Directory of Open Access Journals (Sweden)

    Zhaoyang Zhang

    2011-11-01

    Full Text Available We present here a novel conjugated aptamer-gold nanoparticle (Apt-AuNPs fluorescent probe and its application for specific detection of recombinant human erythropoietin-α (rHuEPO-α. In this nanobiosensor, 12 nm AuNPs function as both a nano-scaffold and a nano-quencher (fluorescent energy acceptor, on the surface of which the complementary sequences are linked (as cODN-AuNPs and pre-hybridized with carboxymethylfluorescein (FAM-labeled anti-rHuEPO-α aptamers. Upon target protein binding, the aptamers can be released from the AuNP surface and the fluorescence signal is restored. Key variables such as the length of linker, the hybridization site and length have been designed and optimized. Full performance evaluation including sensitivity, linear range and interference substances are also described. This nanobiosensor provides a promising approach for a simple and direct quantification of rHuEPO-α concentrations as low as 0.92 nM within a few hours.

  18. Curcumin as fluorescent probe for directly monitoring in vitro uptake of curcumin combined paclitaxel loaded PLA-TPGS nanoparticles

    International Nuclear Information System (INIS)

    Nguyen, Hoai Nam; Ha, Phuong Thu; Do, Hai Doan; Nguyen, Anh Sao; Nguyen, Dac Tu; Thi, Quy Nguyen; Thi, My Nhung Hoang

    2016-01-01

    Theranostics, which is the combination of both therapeutic and diagnostic capacities in one dose, is a promising tool for both clinical application and research. Although there are many chromophores available for optical imaging, their applications are limited due to the photobleaching property or intrinsic toxicity. Curcumin, a natural compound extracted from the rhizome of curcuma longa, is well known thanks to its bio-pharmaceutical activities and strong fluorescence as biocompatible probe for bio-imaging. In this study, we aimed to fabricate a system with dual functions: diagnostic and therapeutic, based on poly(lactide)-tocopheryl polyethylene glycol succinate (PLA-TPGS) micelles co-loaded curcumin (Cur) and paclitaxel (PTX). Two kinds of curcumin nanoparticle (NP) were fabricated and characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy and dynamic light scattering methods. The cellular uptake and fluorescent activities of curcumin in these systems were also tested by bioassay studies, and were compared with paclitaxe-oregon. The results showed that (Cur + PTX)-PLA-TPGS NPs is a potential system for cancer theranostics. (paper)

  19. Curcumin as fluorescent probe for directly monitoring in vitro uptake of curcumin combined paclitaxel loaded PLA-TPGS nanoparticles

    Science.gov (United States)

    Nguyen, Hoai Nam; Thu Ha, Phuong; Sao Nguyen, Anh; Nguyen, Dac Tu; Doan Do, Hai; Nguyen Thi, Quy; Nhung Hoang Thi, My

    2016-06-01

    Theranostics, which is the combination of both therapeutic and diagnostic capacities in one dose, is a promising tool for both clinical application and research. Although there are many chromophores available for optical imaging, their applications are limited due to the photobleaching property or intrinsic toxicity. Curcumin, a natural compound extracted from the rhizome of curcuma longa, is well known thanks to its bio-pharmaceutical activities and strong fluorescence as biocompatible probe for bio-imaging. In this study, we aimed to fabricate a system with dual functions: diagnostic and therapeutic, based on poly(lactide)-tocopheryl polyethylene glycol succinate (PLA-TPGS) micelles co-loaded curcumin (Cur) and paclitaxel (PTX). Two kinds of curcumin nanoparticle (NP) were fabricated and characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy and dynamic light scattering methods. The cellular uptake and fluorescent activities of curcumin in these systems were also tested by bioassay studies, and were compared with paclitaxe-oregon. The results showed that (Cur + PTX)-PLA-TPGS NPs is a potential system for cancer theranostics.

  20. Enhanced MRI T 2 Relaxivity in Contrast-Probed Anchor-Free PEGylated Iron Oxide Nanoparticles

    Science.gov (United States)

    Thapa, Bibek; Diaz-Diestra, Daysi; Beltran-Huarac, Juan; Weiner, Brad R.; Morell, Gerardo

    2017-04-01

    Superparamagnetic iron oxide nanoparticles (SPIONs, 11-nm cores) were PEGylated without anchoring groups and studied as efficient MRI T 2 contrast agents (CAs). The ether group of PEG is efficiently and directly linked to the positively charged surface of SPIONs, and mediated through a dipole-cation covalent interaction. Anchor-free PEG-SPIONs exhibit a spin-spin relaxivity of 123 ± 6 mM-1s-1, which is higher than those of PEG-SPIONs anchored with intermediate biomolecules, iron oxide nanoworms, or Feridex. They do not induce a toxic response for Fe concentrations below 2.5 mM, as tested on four different cell lines with and without an external magnetic field. Magnetic resonance phantom imaging studies show that anchor-free PEG-SPIONs produce a significant contrast in the range of 0.1-0.4 [Fe] mM. Our findings reveal that the PEG molecules attached to the cores immobilize water molecules in large regions of 85 nm, which would lead to blood half-life of a few tens of minutes. This piece of research represents a step forward in the development of next-generation CAs for nascent-stage cancer detection.

  1. Disposable Electrochemical Immunosensor Diagnosis Device Based on Nanoparticle Probe and Immunochromatographic Strip

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guodong; Lin, Ying-Ying; Wang, Jun; Wu, Hong; Wai, Chien M.; Lin, Yuehe

    2007-10-15

    We describe a disposable electrochemical immunosensor diagnosis device that is based on the immunochromatographic strip technique and an electrochemical immunoassay based on quantum dot (QD, CdS@ZnS) labels. The device takes advantage of the speed and low-cost of the conventional immunochromatographic strip test and the high-sensitivity of the nanoparticle-based electrochemical immunoassay. A sandwich immunoreaction was performed on the immunochromatographic strip, and the captured QD labels in the test zone were determined by highly sensitive stripping voltammetric measurement of the dissolved metallic component (cadmium) with a disposable-screen-printed electrode, which is embedded underneath the membrane on the test zone. The new device coupled with a portable electrochemical analyzer shows great promise for in-field and point-of-care quantitative testing of disease-related protein biomarkers. The parameters (e.g., voltammetric measurement of QD labels, antibody immobilization, the loading amount of QD-antibody, and the immunoreaction time) that govern the sensitivity and reproducibility of the device were optimized with IgG model analyte. The voltammetric response of the optimized device is highly linear over the range of 0.1 to 10 ng mL-1 IgG, and the limit of detection is estimated to be 30 pg mL-1 in association with a 7-min immunoreaction time. The detection limit was improved to 10 pg mL-1 using a 20-min immunoreaction time. The new disposable electrochemical diagnosis device thus provides a more user-friendly, rapid, clinically accurate, less expensive, and quantitative tool for protein detection.

  2. Understanding Atom Probe Tomography of Oxide-Supported Metal Nanoparticles by Correlation with Atomic-Resolution Electron Microscopy and Field Evaporation Simulation.

    Science.gov (United States)

    Devaraj, Arun; Colby, Robert; Vurpillot, François; Thevuthasan, Suntharampillai

    2014-04-17

    Oxide-supported metal nanoparticles are widely used in heterogeneous catalysis. The increasingly detailed design of such catalysts necessitates three-dimensional characterization with high spatial resolution and elemental selectivity. Laser-assisted atom probe tomography (APT) is uniquely suited to the task but faces challenges with the evaporation of metal/insulator systems. Correlation of APT with aberration-corrected scanning transmission electron microscopy (STEM), for Au nanoparticles embedded in MgO, reveals preferential evaporation of the MgO and an inaccurate assessment of nanoparticle composition. Finite element field evaporation modeling is used to illustrate the evolution of the evaporation front. Nanoparticle composition is most accurately predicted when the MgO is treated as having a locally variable evaporation field, indicating the importance of considering laser-oxide interactions and the evaporation of various molecular oxide ions. These results demonstrate the viability of APT for analysis of oxide-supported metal nanoparticles, highlighting the need for developing a theoretical framework for the evaporation of heterogeneous materials.

  3. The Use of Color-Coded Duplex Scanning in the Selection of Patients with Lower Extremity Arterial Disease for Percutaneous Transluminal Angioplasty: A Prospective Study

    International Nuclear Information System (INIS)

    Elsman, Bernard H.P.; Legemate, Dink A.; Heyden, Frank W.H.M. van der; Vos, Henk de; Mali, Willem P.T.M.; Eikelboom, Bert C.

    1996-01-01

    Purpose: To exploit the potential benefits of percutaneous transluminal angioplasty (PTA) in patients with short obstructive lesions in the lower extremity, it is preferable to select patients suitable for PTA before proceeding to hospital admission and angiography. The aim of this prospective study was to evaluate the role of color-coded duplex scanning in the correct selection of patients for PTA and its influence on planning the approach to the lesion. Methods: On the basis of clinical history, physical examination, pressure indices, and ultrasound duplex scanning, 109 patients were scheduled for PTA. Results: The indication for PTA was correct in 103 patients (94%), while the procedure was performed successfully in 98 patients (90%). The approach to the lesion was planned successfully in the majority of patients. Conclusion: This study shows that it is justifiable to plan PTA on the basis of information obtained by duplex scanning. Results of the duplex scan may guide the catheterization route

  4. Tumor-targeting Salmonella typhimurium A1-R Inhibits Osteosarcoma Angiogenesis in the In Vivo Gelfoam® Assay Visualized by Color-coded Imaging.

    Science.gov (United States)

    Kiyuna, Tasuku; Tome, Yasunori; Uehara, Fuminari; Murakami, Takashi; Zhang, Yong; Zhao, Ming; Kanaya, Fuminori; Hoffman, Robert M

    2018-01-01

    We previously developed a color-coded imaging model that can quantify the length of nascent blood vessels using Gelfoam® implanted in nestin-driven green fluorescent protein (ND-GFP) nude mice. In this model, nascent blood vessels selectively express GFP. We also previously showed that osteosarcoma cells promote angiogenesis in this assay. We have also previously demonstrated the tumor-targeting bacteria Salmonella typhimurium A1-R (S. typhimurium A1-R) can inhibit or regress all tested tumor types in mouse models. The aim of the present study was to determine if S. typhimurium A1-R could inhibit osteosarcoma angiogenesis in the in vivo Gelfoam® color-coded imaging assay. Gelfoam® was implanted subcutaneously in ND-GFP nude mice. Skin flaps were made 7 days after implantation and 143B-RFP human osteosarcoma cells expressing red fluorescent protein (RFP) were injected into the implanted Gelfoam. After establishment of tumors in the Gelfoam®, control-group mice were treated with phosphate buffered saline via tail-vein injection (iv) and the experimental group was treated with S. typhimurium A1-R iv Skin flaps were made at day 7, 14, 21, and 28 after implantation of the Gelfoam® to allow imaging of vascularization in the Gelfoam® using a variable-magnification small-animal imaging system and confocal fluorescence microscopy. Nascent blood vessels expressing ND-GFP extended into the Gelfoam® over time in both groups. However, the extent of nascent blood-vessel growth was significantly inhibited by S. typhimurium A1-R treatment by day 28. The present results indicate S. typhimurium A1-R has potential for anti-angiogenic targeted therapy of osteosarcoma. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  5. High-Temperature Magnetism as a Probe for Structural and Compositional Uniformity in Ligand-Capped Magnetite Nanoparticles.

    Science.gov (United States)

    Kolen'ko, Yury V; Bañobre-López, Manuel; Rodríguez-Abreu, Carlos; Carbó-Argibay, Enrique; Deepak, Francis Leonard; Petrovykh, Dmitri Y; Cerqueira, M Fátima; Kamali, Saeed; Kovnir, Kirill; Shtansky, Dmitry V; Lebedev, Oleg I; Rivas, Jose

    2014-12-04

    To investigate magnetostructural relationships in colloidal magnetite (Fe 3 O 4 ) nanoparticles (NPs) at high temperature (300-900 K), we measured the temperature dependence of magnetization ( M ) of oleate-capped magnetite NPs ca. 20 nm in size. Magnetometry revealed an unusual irreversible high-temperature dependence of M for these NPs, with dip and loop features observed during heating-cooling cycles. Detailed characterizations of as-synthesized and annealed Fe 3 O 4 NPs as well as reference ligand-free Fe 3 O 4 NPs indicate that both types of features in M ( T ) are related to thermal decomposition of the capping ligands. The ligand decomposition upon the initial heating induces a reduction of Fe 3+ to Fe 2+ and the associated dip in M , leading to more structurally and compositionally uniform magnetite NPs. Having lost the protective ligands, the NPs continually sinter during subsequent heating cycles, resulting in divergent M curves featuring loops. The increase in M with sintering proceeds not only through elimination of a magnetically dead layer on the particle surface, as a result of a decrease in specific surface area with increasing size, but also through an uncommonly invoked effect resulting from a significant change in Fe 3+ /Fe 2+ ratio with heat treatment. The interpretation of irreversible features in M ( T ) indicates that reversible M ( T ) behavior, conversely, can be expected only for ligand-free, structurally and compositionally uniform magnetite NPs, suggesting a general applicability of high-temperature M ( T ) measurements as an analytical method for probing the structure and composition of magnetic nanomaterials.

  6. Andromede project: Surface analysis and modification with probes from hydrogen to nano-particles in the MeV energy range

    Energy Technology Data Exchange (ETDEWEB)

    Eller, Michael J.; Cottereau, Evelyne [Institut de Physique Nucléaire d’Orsay, UMR8608, CNRS/IN2P3, Université Paris-Sud 11, F-91406 Orsay (France); Rasser, Bernard; Verzeroli, Elodie [Orsay Physics, ZAC Saint Charles, 95 Av des Monts Auréliens, 13710 Fuveau (France); Agnus, Benoit; Gaubert, Gabriel; Donzel, Xavier [Pantechnik SA, 13 rue de la Résistance, 14400 Bayeux (France); Delobbe, Anne [Orsay Physics, ZAC Saint Charles, 95 Av des Monts Auréliens, 13710 Fuveau (France); Della-Negra, Serge, E-mail: dellaneg@ipno.in2p3.fr [Institut de Physique Nucléaire d’Orsay, UMR8608, CNRS/IN2P3, Université Paris-Sud 11, F-91406 Orsay (France)

    2015-12-15

    The Andromede project is the center of a multi-disciplinary team which will build a new instrument for surface modification and analysis using the impact of probes from hydrogen to nano-particles (Au{sub 400}{sup +4}) in the MeV range. For this new instrument a series of atomic, polyatomic, molecular and nano-particle ion beams will be delivered using two ion sources in tandem, a liquid metal ion source and an electron cyclotron resonance source. The delivered ion beams will be accelerated to high energy with a 4 MeV van de Graaff type accelerator. By using a suite of probes in the MeV energy range, ion beam analysis techniques, MeV atomic and cluster secondary ion mass spectrometry can all be performed in one location. A key feature of the instrument is its ability to produce an intense beam for injection into the accelerator. The commissioning of the two sources shows that intense beams from atomic ions to nano-particles can be delivered for subsequent acceleration. The calculations and measurements for the two sources are presented.

  7. Determination of lysozyme at the nanogram level in food sample using Resonance Rayleigh-scattering method with Au nanoparticles as probe

    Science.gov (United States)

    Cai, Zhaoxia; Yu, Haifen; Ma, Meihu

    2011-04-01

    A new method for determination of lysozyme with high sensitivity based on Resonance Rayleigh scattering (RRS) by using Au nanoparticles as a probe was proposed in this experiment. The RRS spectrum, nonlinear scattering (second-order scattering (SOS), frequency doubling scattering (FDS)) spectra and absorption spectrum of the Au nanoparticles-lysozyme system have been analyzed. In addition, the effects of several factors on scattering intensities were investigated, including pH value of solution, amount of Au nanoparticles, mixing sequence of each reagent and the coexisting substances. The results showed that the coexisting substances have little influence on the RRS intensities of the systems. Moreover, the possible mechanism for the RRS enhancement of Au nanoparticles-lysozyme system was preliminary discussed. The RRS method for determination of lysozyme has good sensitivity and selectivity with the detection limits 30.1 ng/ml. The contents of lysozyme were determined with recoveries of 98.2-105.4% and relativity relative standard deviation (RSD) of 0.3-3.7%, respectively. It proved that the method established in our study is suitable for the determination of lysozyme in synthetic sample and natural chicken egg white sample.

  8. Folic acid-targeted magnetic Tb-doped CeF3 fluorescent nanoparticles as bimodal probes for cellular fluorescence and magnetic resonance imaging.

    Science.gov (United States)

    Ma, Zhi-Ya; Liu, Yu-Ping; Bai, Ling-Yu; An, Jie; Zhang, Lin; Xuan, Yang; Zhang, Xiao-Shuai; Zhao, Yuan-Di

    2015-10-07

    Magnetic fluorescent nanoparticles (NPs) have great potential applications for diagnostics, imaging and therapy. We developed a facile polyol method to synthesize multifunctional Fe3O4@CeF3:Tb@CeF3 NPs with small size (imaging agents for simultaneous in vitro targeted fluorescence imaging and magnetic resonance imaging (MRI) of HeLa cells with overexpressed folate receptors (FR). The results indicated that these NPs had strong luminescence and enhanced T2-weighted MR contrast and would be promising candidates as multimodal probes for both fluorescence and MRI imaging.

  9. Transluminal color-coded three-dimensional magnetic resonance angiography for visualization of signal Intensity distribution pattern within an unruptured cerebral aneurysm: preliminarily assessment with anterior communicating artery aneurysms

    International Nuclear Information System (INIS)

    Satoh, T.; Ekino, C.; Ohsako, C.

    2004-01-01

    The natural history of unruptured cerebral aneurysm is not known; also unknown is the potential growth and rupture in any individual aneurysm. The authors have developed transluminal color-coded three-dimensional magnetic resonance angiography (MRA) obtained by a time-of-flight sequence to investigate the interaction between the intra-aneurysmal signal intensity distribution patterns and configuration of unruptured cerebral aneurysms. Transluminal color-coded images were reconstructed from volume data of source magnetic resonance angiography by using a parallel volume-rendering algorithm with transluminal imaging technique. By selecting a numerical threshold range from a signal intensity opacity chart of the three-dimensional volume-rendering dataset several areas of signal intensity were depicted, assigned different colors, and visualized transparently through the walls of parent arteries and an aneurysm. Patterns of signal intensity distribution were analyzed with three operated cases of an unruptured anterior communicating artery aneurysm and compared with the actual configurations observed at microneurosurgery. A little difference in marginal features of an aneurysm was observed; however, transluminal color-coded images visualized the complex signal intensity distribution within an aneurysm in conjunction with aneurysmal geometry. Transluminal color-coded three-dimensional magnetic resonance angiography can thus provide numerical analysis of the interaction between spatial signal intensity distribution patterns and aneurysmal configurations and may offer an alternative and practical method to investigate the patient-specific natural history of individual unruptured cerebral aneurysms. (orig.)

  10. An in vitro and in vivo validation of a novel color-coded syringe device for measuring the intracuff pressure in cuffed endotracheal tubes.

    Science.gov (United States)

    Kamata, Mineto; Kako, Hiromi; Ramesh, Archana S; Krishna, Senthil G; Tobias, Joseph D

    2015-01-01

    The clinical practice of pediatric anesthesiology has changed with a transition to the use of cuffed endotracheal tubes (ETTs) in infants and children. The monitoring of intracuff pressure has been suggested as one means to limit the potential for damage to the tracheal mucosa. The current study evaluates the accuracy of a novel, color-coded syringe device which provides three zones (green, clear, and red) to estimate the intracuff pressure. The study was conducted in two phases. Phase 1 was an in vitro study where cuffed ETTs of sizes 4.0 mm, 5.0 mm and 6.0 mm ID were placed into polyvinylchloride tubing of appropriate sizes. A manometer and the syringe device were simultaneously attached to measure the intracuff pressure at the middle of the 3 different zones on the device (red, clear, and green). Phase 2 was an in vivo study where the syringe device and the manometer were simultaneously attached to the pilot balloon to measure the intracuff pressure and the corresponding zone on the color-coded syringe following endotracheal intubation. Statistical analysis included a descriptive reporting of the mean ± SD, median, range, and 95% confidence intervals (CI) of the actual intracuff pressure readings at the three zones of the syringe device during both its in vitro and in vivo use. For phase 1 of the study, the 95% CI for the green, clear, and red zones were 21.5-21.8, 29.2-29.5, and 46.5-47.4 cmH2O respectively. This correlated well with the manufacturer reported values of 20-30, 30-40, and 40-60 cmH2O for the 3 zones (green, clear, and red respectively). Phase 2 of the study included 200 patients ranging in age from 0.1 to 21.8 years (6.7 ± 5.1 years) and in weight from 4.0 to 129.1 kilograms (29.4 ± 23.3 kgs). The size of the ETTs ranged from 3.0 to 7.0 mm ID. The intracuff pressure measured by the manometer ranged from 4 to 65 cmH2O (27.6 ± 9.7 cmH2O). The 95% CI for the green, clear, and red zones were 20.5-21.7, 27.7-29.1, and 41.2-46.5 cmH2O respectively

  11. Feasibility of iFlow color-coding technique in quantitative real-time measurement of hemodynamic changes after transarterial chemoembolization for hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    WANG Yuzhe

    2018-01-01

    Full Text Available Objective To investigate the value of iFlow color-coding technique in quantitative real-time analysis of hemodynamic changes after transarterial chemoembolization (TACE for hepatocellular carcinoma (HCC. Methods A total of 31 patients who were diagnosed with HCC in Shanghai Fifth People′s Hospital from December 2015 to January 2017 were enrolled. No patient underwent surgical operation or ablation. All patients underwent TACE with the same contrast agent, high-pressure injector parameters, and place of angiographic catheter. The iFlow technique was used to generate two-dimensional color-coded images and time-density curve (TDC before and after surgery and measure the opening of the angiographic catheter and the time to peak (TTP of the starting and ending points of the major tumor feeding arteries, as well as the ratio of the areas under the curve (AUC of TDC of tumor tissue and the opening of the angiographic catheter. The paired t-test was used for comparison of continuous data between groups. Results TTP of the major tumor feeding arteries was 4.64±0.49 s before TACE and 5.97±0.84 s after TACE (t=11.57, P<0.01, and there was a significant difference in AUC between the tumor tissue and the opening of the angiographic catheter (0.53±0.15 vs 0.16±0.12, t=25.85, P<0.01. There was no significant difference in TTP between the opening of the angiographic catheter and the major tumor feeding arteries before and after TACE (P>0.05. Before TACE, the TDC of tumor feeding arteries had a shape of “rapid increase-rapid reduction” with relatively high slope and peak value, while after TACE, the TDC had a shape of “increase-flat-reduction” with reductions in slope and peak value. Conclusion The iFlow technique can perform real-time measurement of TTP and TDC of the region of interest and helps with quantitative evaluation of hemodynamic changes in HCC. Therefore, it can provide objective quantitative indices for evaluating the degree of

  12. Bioinspired systems for metal-ion sensing: new emissive peptide probes based on benzo[d]oxazole derivatives and their gold and silica nanoparticles.

    Science.gov (United States)

    Oliveira, Elisabete; Genovese, Damiano; Juris, Riccardo; Zaccheroni, Nelsi; Capelo, José Luis; Raposo, M Manuela M; Costa, Susana P G; Prodi, Luca; Lodeiro, Carlos

    2011-09-19

    Seven new bioinspired chemosensors (2-4 and 7-10) based on fluorescent peptides were synthesized and characterized by elemental analysis, (1)H and (13)C NMR, melting point, matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and IR and UV-vis absorption and emission spectroscopy. The interaction with transition- and post-transition-metal ions (Cu(2+), Ni(2+), Ag(+), Zn(2+), Cd(2+), Hg(2+), Pb(2+), and Fe(3+)) has been explored by absorption and fluorescence emission spectroscopy and MALDI-TOF-MS. The reported fluorescent peptide systems, introducing biological molecules in the skeleton of the probes, enhance their sensitivity and confer them strong potential for applications in biological fields. Gold and silica nanoparticles functionalized with these peptides were also obtained. All nanoparticles were characterized by dynamic light scattering, transmission electron microscopy, and UV-vis absorption and fluorescence spectroscopy. Stable gold nanoparticles (diameter 2-10 nm) bearing ligands 1 and 4 were obtained by common reductive synthesis. Commercial silica nanoparticles were decorated at their surface using compounds 8-10, linked through a silane spacer. The same chemosensors were also taken into aqueous solutions through their dispersion in the outer layer of silica core/poly(ethylene glycol) shell nanoparticles. In both cases, these complex nanoarchitectures behaved as new sensitive materials for Ag(+) and Hg(2+) in water. The possibility of using these species in this solvent is particularly valuable because the impact on human health of heavy- and transition-metal-ion pollution is very severe, and all analytical and diagnostics investigations involve a water environment.

  13. Probing colloidal forces between a Si3N4 AFM tip and single nanoparticles of silica and alumina.

    Science.gov (United States)

    Drelich, J; Long, J; Xu, Z; Masliyah, J; White, C L

    2006-11-15

    The atomic force microscope (AFM) has been used to measure surface forces between silicon nitride AFM tips and individual nanoparticles deposited on substrates in 10(-4) and 10(-2) M KCl solutions. Silica nanoparticles (10 nm diameter) were deposited on an alumina substrate and alumina particles (5 to 80 nm diameter) were deposited on a mica substrate using aqueous suspensions. Ionic concentrations and pH were used to manage attractive substrate-particle electrostatic forces. The AFM tip was located on deposited nanoparticles using an operator controlled offset to achieve stepwise tip movements. Nanoparticles were found to have a negligible effect on long-range tip-substrate interactions, however, the forces between the tip and nanoparticle were detectable at small separations. Exponentially increasing short-range repulsive forces, attributed to the hydration forces, were observed for silica nanoparticles. The effective range of hydration forces was found to be 2-3 nm with the decay length of 0.8-1.3 nm. These parameters are in a good agreement with the results reported for macroscopic surfaces of silica obtained using the surface force apparatus suggesting that hydration forces for the silica nanoparticles are similar to those for flat silica surfaces. Hydration forces were not observed for either alumina substrates or alumina nanoparticles in both 10(-4) M KCl solution at pH 6.5 and 10(-2) M KCl at pH 10.2. Instead, strong attractive forces between the silicon nitride tip and the alumina (nanoparticles and substrate) were observed.

  14. Time-Resolved 2PPE and Time-Resolved PEEM as a Probe of LSP's in Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    D. Bayer

    2008-01-01

    Full Text Available The time-resolved two-photon photoemission technique (TR-2PPE has been applied to study static and dynamic properties of localized surface plasmons (LSP in silver nanoparticles. Laterally, integrated measurements show the difference between LSP excitation and nonresonant single electron-hole pair creation. Studies below the optical diffraction limit were performed with the detection method of time-resolved photoemission electron microscopy (TR-PEEM. This microscopy technique with a resolution down to 40 nm enables a systematic study of retardation effects across single nanoparticles. In addition, as will be shown in this paper, it is a highly sensitive sensor for coupling effects between nanoparticles.

  15. Radioactive probe studies of coordination modes of heavy metal ions from natural waters to functionalized magnetic nanoparticles

    CERN Multimedia

    Carvalho Soares, J; Lopes, C; Araujo, J

    We propose to use PAC, Perturbed Angular Correlations, to study the local environment of ionic species (Hg$^{2+}$, Cd$^{2+}$) coordinated on functionalized magnetic nanoparticles. Studies include the analysis of different nanoparticle sizes (30-100nm), and the monitoring of time/steps dependence of the coordination of those cations at the nanoparticle surfaces. Combined with theoretical calculations, the obtained data will support the understanding of local coordination modes, which is essential to help to improve methods of magnetically assisted separation of such hazardous contaminants from water.

  16. Visual discrimination among patients with depression and schizophrenia and healthy individuals using semiquantitative color-coded fast spin-echo T1-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Makoto; Kudo, Kohsuke; Narumi, Shinsuke [Iwate Medical University, Advanced Medical Research Center, Morioka (Japan); Shibata, Eri; Ohtsuka, Kotaro; Endoh, Jin; Sakai, Akio [Iwate Medical University, Department of Neuropsychiatry, Morioka (Japan)

    2010-02-15

    Fast spin-echo (FSE) T1-weighted (T1W) magnetic resonance imaging (MRI) at 3T, which is sensitive to neuromelanin-related contrast, can quantitatively detect signal alterations in the locus ceruleus (LC) and the substantia nigra pars compacta (SNc) of depressive and schizophrenic patients; however, its qualitative diagnostic performance remains unknown. We investigated whether visual interpretation of semiquantitative color maps can be used for discriminating between depressive and schizophrenic patients and healthy individuals. We retrospectively examined 23 patients with major depression, 23 patients with schizophrenia, and 23 age-matched healthy controls by using a FSE-T1W MRI technique. Semiquantitative color maps of sections through the LC and SNc were visually interpreted by nine raters using a continuous confidence rating scale for receiver operating characteristic (ROC) analysis. The area under the ROC curve (Az), which reflects the performance in differentiating between depressive patients and controls, was 0.88, and the sensitivity and specificity at the maximum likelihood were 76% and 83%, respectively. In contrast, the Az value, sensitivity, and specificity values between schizophrenics and controls and between depressives and schizophrenics were 0.66 and 0.69, 42% and 48%, and 82% and 84%, respectively. Semiquantitative, color-coded FSE-T1W MRI at 3T can be used for visually differentiating depressive patients from healthy individuals with a substantially high likelihood, but this technique cannot be applied to distinguish schizophrenic patients from the other two groups. (orig.)

  17. Visual discrimination among patients with depression and schizophrenia and healthy individuals using semiquantitative color-coded fast spin-echo T1-weighted magnetic resonance imaging

    International Nuclear Information System (INIS)

    Sasaki, Makoto; Kudo, Kohsuke; Narumi, Shinsuke; Shibata, Eri; Ohtsuka, Kotaro; Endoh, Jin; Sakai, Akio

    2010-01-01

    Fast spin-echo (FSE) T1-weighted (T1W) magnetic resonance imaging (MRI) at 3T, which is sensitive to neuromelanin-related contrast, can quantitatively detect signal alterations in the locus ceruleus (LC) and the substantia nigra pars compacta (SNc) of depressive and schizophrenic patients; however, its qualitative diagnostic performance remains unknown. We investigated whether visual interpretation of semiquantitative color maps can be used for discriminating between depressive and schizophrenic patients and healthy individuals. We retrospectively examined 23 patients with major depression, 23 patients with schizophrenia, and 23 age-matched healthy controls by using a FSE-T1W MRI technique. Semiquantitative color maps of sections through the LC and SNc were visually interpreted by nine raters using a continuous confidence rating scale for receiver operating characteristic (ROC) analysis. The area under the ROC curve (Az), which reflects the performance in differentiating between depressive patients and controls, was 0.88, and the sensitivity and specificity at the maximum likelihood were 76% and 83%, respectively. In contrast, the Az value, sensitivity, and specificity values between schizophrenics and controls and between depressives and schizophrenics were 0.66 and 0.69, 42% and 48%, and 82% and 84%, respectively. Semiquantitative, color-coded FSE-T1W MRI at 3T can be used for visually differentiating depressive patients from healthy individuals with a substantially high likelihood, but this technique cannot be applied to distinguish schizophrenic patients from the other two groups. (orig.)

  18. Extraction of Dysprosium Ions with DTPA Functionalized Superparamagnetic Nanoparticles Probed by Energy Dispersive X-ray Fluorescence and TEM/High-Angle Annular Dark Field Imaging.

    Science.gov (United States)

    Melo, Fernando Menegatti de; Almeida, Sabrina da Nobrega; Uezu, Noemi Saori; Ramirez, Carlos Alberto Ospina; Santos, Antonio Domingues Dos; Toma, Henrique Eisi

    2018-06-01

    The extraction of dysprosium (Dy3+) ions from aqueous solution was carried out successfully, using magnetite (Fe3O4) nanoparticles functionalized with diethylenetriaminepentaacetic acid (MagNP@DTPA). The process was monitored by energy dispersive X-ray fluorescence spectroscopy, as a function of concentration, proceeding according to a Langmuir isotherm with an equilibrium constant of 2.57 × 10-3 g(MagNP) L-1 and a saturation limit of 63.2 mgDy/gMagNP. The presence of paramagnetic Dy3+ ions attached to the superparamagnetic nanoparticles led to an overall decrease of magnetization. By imaging the nanoparticles surface using scanning transmission electron microscopy equipped with high resolution elemental analysis, it was possible to probe the binding of the Dy3+ ions to DTPA, and to show their distribution in a region of negative magnetic field gradients. This finding is coherent with the observed decrease of magnetization, associated with the antiferromagnetic coupling between the lanthanide ions and the Fe3O4 core.

  19. Dynamic Probing of Nanoparticle Stability In Vivo: A Liposomal Model Assessed Using In Situ Microdialysis and Optical Imaging

    OpenAIRE

    Jeng, Chien-Chung; Cheng, Shih-Hsun; Ho, Ja-an Annie; Huang, Sam Hong-Yi; Chang, Jerry C.; Tsai, Pi-Ju; Yang, Chung-Shi; Lo, Leu-Wei

    2011-01-01

    Nanoparticle-mediated drug delivery and controlled release has been a vigorous research area in contemporary nanomedicine. The in vivo stability of nanoparticle delivered on site is a prerequisite for the design of drug-controlled release by any means. In this study, the first methodology comprised of microdialysis and optical imaging to assess the liposome stability in vivo is reported. Macroscopically, we demonstrated the DPPG liposomes with negative surface charge fast accumulated in the ...

  20. Probing Hot Electron Flow Generated on Pt Nanoparticles with Au/TiO2 Schottky Diodes during Catalytic CO Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeong Y.; Lee, Hyunjoo; Renzas, J. Russell; Zhang, Yawen; Somorjai, G.A.

    2008-05-01

    Hot electron flow generated on colloid platinum nanoparticles during exothermic catalytic carbon monoxide oxidation was directly detected with Au/TiO{sub 2} diodes. Although Au/TiO{sub 2} diodes are not catalytically active, platinum nanoparticles on Au/TiO{sub 2} exhibit both chemicurrent and catalytic turnover rate. Hot electrons are generated on the surface of the metal nanoparticles and go over the Schottky energy barrier between Au and TiO{sub 2}. The continuous Au layer ensures that the metal nanoparticles are electrically connected to the device. The overall thickness of the metal assembly (nanoparticles and Au thin film) is comparable to the mean free path of hot electrons, resulting in ballistic transport through the metal. The chemicurrent and chemical reactivity of nanoparticles with citrate, hexadecylamine, hexadecylthiol, and TTAB (Tetradecyltrimethylammonium Bromide) capping agents were measured during catalytic CO oxidation at pressures of 100 Torr O{sub 2} and 40 Torr CO at 373-513 K. We found that chemicurrent yield varies with each capping agent, but always decreases with increasing temperature. We suggest that this inverse temperature dependence is associated with the influence of charging effects due to the organic capping layer during hot electron transport through the metal-oxide interface.

  1. Rapid colorimetric assay for detection of Listeria monocytogenes in food samples using LAMP formation of DNA concatemers and gold nanoparticle-DNA probe complex

    Science.gov (United States)

    Wachiralurpan, Sirirat; Sriyapai, Thayat; Areekit, Supatra; Sriyapai, Pichapak; Augkarawaritsawong, Suphitcha; Santiwatanakul, Somchai; Chansiri, Kosum

    2018-04-01

    ABSTRACT Listeria monocytogenes is a major foodborne pathogen of global health concern. Herein, the rapid diagnosis of L. monocytogenes has been achieved using loop-mediated isothermal amplification (LAMP) based on the phosphatidylcholine-phospholipase C gene (plcB). Colorimetric detection was then performed through the formation of DNA concatemers and a gold nanoparticle/DNA probe complex (GNP/DNA probe). The overall detection process was accomplished within approximately 1 h with no need for complicated equipment. The limits of detection for L. monocytogenes in the forms of purified genomic DNA and pure culture were 800 fg and 2.82 CFU mL-1, respectively. No cross reactions were observed from closely related bacteria species. The LAMP-GNP/DNA probe assay was applied to the detection of 200 raw chicken meat samples and compared to routine standard methods. The data revealed that the specificity, sensitivity and accuracy were 100%, 90.20% and 97.50%, respectively. The present assay was 100% in conformity with LAMP-agarose gel electrophoresis assay. Five samples that were negative by both assays appeared to have the pathogen at below the level of detection. The assay can be applied as a rapid direct screening method for L. monocytogenes.

  2. Antibody tagged gold nanoparticles as scattering probes for the pico molar detection of the proteins in blood serum using nanoparticle tracking analyzer.

    Science.gov (United States)

    Kashid, Sahebrao Balaso; Tak, Rajesh D; Raut, Rajesh Warluji

    2015-09-01

    We report a rapid one-step immunoassay to detect protein using antibody conjugated gold nanoparticles (AbGNPs) where the targeted protein concentration was determined by analyzing the gold nanoparticle aggregation caused by antibody-antigen interactions using nanoparticles tracking analysis (NTA) technique. The sandwich structure constituting the binding of the targeted human IgG to the gold nanoparticle conjugates with goat anti human monoclonal IgG (AbGNPs) was confirmed by transmission electron microscopy. The binding of human IgG (antigen, mentioned hence forth as AT) induce AbGNPs to form dimers or trimers through a typical antibody-antigen-antibody sandwich structure that can be analyzed for the sensitive determination on the basis of change in hydrodynamic diameter of AbGNPs. By this method the minimum detectable concentration of AT is found to be below 2pg/ml. We expect that a significant change in the hydrodynamic diameter of AbGNP could form the basis for the rapid one-step immunoassay development. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales.

    Science.gov (United States)

    Burke, Kerry B; Stapleton, Andrew J; Vaughan, Ben; Zhou, Xiaojing; Kilcoyne, A L David; Belcher, Warwick J; Dastoor, Paul C

    2011-07-01

    Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N'-(4-butylphenyl)-bis-N, N'-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

  4. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

    Science.gov (United States)

    Burke, Kerry B.; Stapleton, Andrew J.; Vaughan, Ben; Zhou, Xiaojing; Kilcoyne, A. L. David; Belcher, Warwick J.; Dastoor, Paul C.

    2011-07-01

    Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N'-(4-butylphenyl)-bis-N, N'-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

  5. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

    International Nuclear Information System (INIS)

    Burke, Kerry B; Stapleton, Andrew J; Vaughan, Ben; Zhou Xiaojing; Belcher, Warwick J; Dastoor, Paul C; Kilcoyne, A L David

    2011-01-01

    Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N ' -(4-butylphenyl)-bis-N, N ' -phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

  6. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

    Energy Technology Data Exchange (ETDEWEB)

    Burke, Kerry B; Stapleton, Andrew J; Vaughan, Ben; Zhou Xiaojing; Belcher, Warwick J; Dastoor, Paul C [Centre for Organic Electronics, University of Newcastle, Callaghan, NSW 2308 (Australia); Kilcoyne, A L David, E-mail: Paul.Dastoor@newcastle.edu.au [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2011-07-01

    Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N{sup '}-(4-butylphenyl)-bis-N, N{sup '}-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

  7. Distinct local structure of nanoparticles and nanowires of V2O5 probed by x-ray absorption spectroscopy

    Science.gov (United States)

    Joseph, B.; Iadecola, A.; Maugeri, L.; Bendele, M.; Okubo, M.; Li, H.; Zhou, H.; Mizokawa, T.; Saini, N. L.

    2013-12-01

    We have used V K-edge x-ray absorption spectroscopy to study local structures of bulk, nanoparticles and nanowires of V2O5. The extended x-ray absorption fine structure measurements show different local displacements in the three morphologically different V2O5 samples. It is found that the nanowires have a significantly ordered chain structure in comparison to the V2O5 bulk. In contrast, nanoparticles have larger interlayer disorder. The x-ray absorption near-edge structure spectra show different electronic structure that appears to be related with the local atomic disorder in the three V2O5 samples.

  8. Growth of block copolymer stabilized metal nanoparticles probed simultaneously by in situ XAS and UV-Vis spectroscopy.

    Science.gov (United States)

    Nayak, C; Bhattacharyya, D; Jha, S N; Sahoo, N K

    2016-01-01

    The growth of Au and Pt nanoparticles from their respective chloride precursors using block copolymer-based reducers has been studied by simultaneous in situ measurement of XAS and UV-Vis spectroscopy at the energy-dispersive EXAFS beamline (BL-08) at INDUS-2 SRS at RRCAT, Indore, India. While the XANES spectra of the precursor give real-time information on the reduction process, the EXAFS spectra reveal the structure of the clusters formed at the intermediate stages of growth. The growth kinetics of both types of nanoparticles are found to be almost similar and are found to follow three stages, though the first stage of nucleation takes place earlier in the case of Au than in the case of Pt nanoparticles due to the difference in the reduction potential of the respective precursors. The first two stages of the growth of Au and Pt nanoparticles as obtained by in situ XAS measurements could be corroborated by simultaneous in situ measurement of UV-Vis spectroscopy also.

  9. Ultrasmall Superparamagnetic Iron Oxide Nanoparticles with Europium(III) DO3A as a Bimodal Imaging Probe.

    Science.gov (United States)

    Carron, Sophie; Bloemen, Maarten; Vander Elst, Luce; Laurent, Sophie; Verbiest, Thierry; Parac-Vogt, Tatjana N

    2016-03-18

    A new prototype consisting of ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles decorated with europium(III) ions encapsulated in a DO3A organic scaffold was designed as a platform for further development of bimodal contrast agents for MRI and optical imaging. The USPIO nanoparticles act as negative MRI contrast agents, whereas the europium(III) ion is a luminophore that is suitable for use in optical imaging detection. The functionalized USPIO nanoparticles were characterized by TEM, DLS, XRD, FTIR, and TXRF analysis, and a full investigation of the relaxometric and optical properties was conducted. The typical luminescence emission of europium(III) was observed and the main red emission wavelength was found at 614 nm. The relaxometric study of these ultrasmall nanoparticles showed r2 values of 114.8 mM(-1) Fes(-1) at 60 MHz, which is nearly double the r2 relaxivity of Sinerem(®). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Insights into post-annealing and silver doping effects on the internal microstructure of ZnO nanoparticles through X-ray diffraction probe

    Science.gov (United States)

    Obeydavi, Ali; Dastafkan, Kamran; Rahimi, Mohammad; Ghadam Dezfouli, Mohammad Amin

    2017-07-01

    ZnO nanoparticles were synthesized via Pechini method at various post-annealing temperatures (400°, 500°, and 600 °C) and silver doping concentrations (Zn:Ag molar ratios of 30, 20, and 10). Multifarious microstructural features including crystallite size, size-strain based broadening, residual stress, preferential orientation, crystallinity degree, lattice parameters, unit cell variation, and stacking fault probability were surveyed through phase analysis, Williamson-Hall plot, texture coefficient and unit cell calculations. X-ray probing verified good crystallinity with a hexagonal close pack Wurtzite morphology. Williamson-Hall analysis exhibited distributions of crystallite size and microstrain as well as their contributions on the line broadening of the host ZnO and guest Ag phases upon annealing-doping treatments. Textural analysis revealed the alteration in anisotropic crystallinity of the host phase and transformation of the preferred directions, (100) and (101), as function of annealing-doping processes. Besides, while guest Ag phase was shown to be polycrystalline with randomly orientated crystals at moderate concentration with respect to thermal treatment, preferential orientation went through a major change, (220) to (111), with increment in Ag loadings. Under identical synthetic conditions, the distinction in the lattice constants and unit cell variation between pure and doped ZnO nanoparticles was enforced and results verified major impressionability via annealing and doping factors.

  11. Magnetofluorescent probe of superparamagnetic iron oxide nanoparticles modified with poly(TMSMA-r-PEGMA-r-Eu(NTA)3(MMA)(TOPO)3).

    Science.gov (United States)

    Kim, Min Cheol; Kang, Bo-Sun; Sohn, Youngjoo; Tae, Ki-Sik; Lee, Hyun-Ju; Kim, Do Kyung; Chang, Yun Seung

    2014-11-01

    In this study, hybrid magnetofluorescent structures composed of organic moiety of poly(TMSMA-r-PEGMA) for biomolecules-resistant surfaces and methyl methacrylate for conjugation of europium complex inorganic moiety of magnetic nanoparticles are reported. Lanthanide complex of europium ion with 4,4,4-Trifluoro-1-(2-naphthyl)-1,3-butanedione (NTA) and trioctylphosphine oxide (TOPO)[Eu(NTA)3(TOPO)3] were incorporated into poly(TMSMA-r-PEGMA-r-MMA) matrix. Afterward, superparamagnetic iron oxide nanoparticles (SPIONs) were coated with as prepared polymeric europium complex (PEC) to construct hierarchical structure of magnetofluorescent probe. The PL spectra of the PEC@SPIONs excited by UV light showed characteristic emission behavior with a hypersensitive transition 5D0 --> 7F2 at 621 nm. About a 20% quenching in the intensity of the emission peak at 621 nm was found after the addition of SPIONs. Interestingly, when the concentration of PEC against SPIONs is increased, the hypersensitive transition 5D0 --> 7F2 at 621 nm is linearly increased, while 5D1 --> 7F6 at 700 nm is linearly decreased. The cytotoxic effect of PEC@SPIONs was evaluated with U373MG cell by the MTT assay of PEC@SPIONs in cell proliferation. The cell viability in the range of 10-200 ug/ml was more than 80%. No significant difference in cell proliferation until the concentration of 300 ug/ml (77.61 ± 3.33%). The cellular uptake of PEC@SPIONs evaluated by confocal microscopy showed that the magnetofluorescent nanoparticles were internalized extensively in the cytoplasmic region.

  12. Electrochemical aptamer/antibody based sandwich immunosensor for the detection of EGFR, a cancer biomarker, using gold nanoparticles as a signaling probe.

    Science.gov (United States)

    Ilkhani, Hoda; Sarparast, Morteza; Noori, Abolhassan; Zahra Bathaie, S; Mousavi, Mir F

    2015-12-15

    Detection of epidermal growth factor receptor (EGFR) in biological fluids is of paramount importance, since it has significant application in cancer diagnosis, drug development, and therapy monitoring. EGFR is a cancer biomarker, and its overexpression is associated with the development of some types of cancer. Herein, we report on the development of a sensitive and selective electrochemical aptamer/antibody (Apt/Ab) sandwich immunosensor for detection of EGFR. In this study, a biotinylated anti-human EGFR Apt was immobilized on streptavidin-coated magnetic beads (MB) and served as a capture probe. A polyclonal anti-human EGFR Ab was conjugated to citrate-coated gold nanoparticles (AuNPs) and used as a signaling probe. In the presence of EGFR, an Apt-EGFR-Ab sandwich was formed on the MB surface. The extent of the complexation was evaluated by differential pulse voltammetry of AuNPs after their dissolution in HCl. Under optimal conditions, the dynamic concentration range of the immunosensor for EGFR spanned from 1 to 40 ng/mL, with a low detection limit of 50 pg/mL, and RSD percent of less than 4.2%. The proposed approach takes advantage of sandwich assay for high specificity, MBs for fast separation, and electrochemical method for cost-effective and sensitive detection. In this proof-of-principle study, we demonstrate the potential clinical efficacy of the immunosensor for monitoring of chemotherapy effectiveness in breast cancer samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Horseradish peroxidase and antibody labeled gold nanoparticle probe for amplified immunoassay of ciguatoxin in fish samples based on capillary electrophoresis with electrochemical detection.

    Science.gov (United States)

    Zhang, Zhaoxiang; Liu, Ying; Zhang, Chaoying; Luan, Wenxiu

    2015-03-01

    This paper describes a new amplified immunoassay with horseradish peroxidase (HRP) and antibody (Ab) labeled gold nanoparticles (AuNPs) probe hyphenated to capillary electrophoresis (CE) with electrochemical (EC) detection for ultrasensitive determination of ciguatoxin CTX1B. AuNPs were conjugated with HRP and Ab, and then incubated with limited amount of CTX1B to produce immunocomplex. The immunoreactive sample was injected into capillary for CE separation and EC detection. Enhanced sensitivity was obtained by adopting the AuNPs as carriers of HRP and Ab at high HRP/Ab molar ratio. The calibration curve of CTX1B was in the range of 0.06-90 ng/mL. The detection limit was 0.045 ng/mL, which is 38-fold lower than that of HPLC-MS method for CTX1B analysis. The proposed method was successfully applied for the quantification of CTX1B in contamined fish samples by simultaneously labeling Ab and HRP on AuNPs. The amplified IA with HRP and Ab labeled AuNPs probe hyphenated to CE and EC detection provides a sensitive analytical approach for the determination of trace ciguatoxin in complex samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Identification of human DNA in forensic evidence by loop-mediated isothermal amplification combined with a colorimetric gold nanoparticle hybridization probe.

    Science.gov (United States)

    Watthanapanpituck, Khanistha; Kiatpathomchai, Wansika; Chu, Eric; Panvisavas, Nathinee

    2014-11-01

    A DNA test based on loop-mediated isothermal amplification (LAMP) and colorimetric gold nanoparticle (AuNP) hybridization probe to detect the presence of human DNA in forensic evidence was developed. The LAMP primer set targeted eight regions of the human cytochrome b, and its specificity was verified against the DNA of 11 animal species, which included animals closely related to humans, such as chimpanzee and orangutan. By using the AuNP probe, sequence-specific LAMP product could be detected and the test result could be visualized through the change in color. The limit of detection was demonstrated with reproducibility to be as low as 718 fg of genomic DNA, which is equivalent to approximately 100 plasmid DNA copies containing the cytochrome b DNA target region. A simple DNA extraction method for the commonly found forensic biological samples was also devised to streamline the test process. This LAMP-AuNP human DNA test showed to be a robust, specific, and cost-effective tool for the forensic identification of human specimens without requiring sophisticated laboratory instruments.

  15. nanoparticles

    Science.gov (United States)

    Andreu-Cabedo, Patricia; Mondragon, Rosa; Hernandez, Leonor; Martinez-Cuenca, Raul; Cabedo, Luis; Julia, J. Enrique

    2014-10-01

    Thermal energy storage (TES) is extremely important in concentrated solar power (CSP) plants since it represents the main difference and advantage of CSP plants with respect to other renewable energy sources such as wind, photovoltaic, etc. CSP represents a low-carbon emission renewable source of energy, and TES allows CSP plants to have energy availability and dispatchability using available industrial technologies. Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 500°C. Their main drawbacks are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve thermal properties of fluids is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. In this work, solar salt used in CSP plants (60% NaNO3 + 40% KNO3) was doped with silica nanoparticles at different solid mass concentrations (from 0.5% to 2%). Specific heat was measured by means of differential scanning calorimetry (DSC). A maximum increase of 25.03% was found at an optimal concentration of 1 wt.% of nanoparticles. The size distribution of nanoparticle clusters present in the salt at each concentration was evaluated by means of scanning electron microscopy (SEM) and image processing, as well as by means of dynamic light scattering (DLS). The cluster size and the specific surface available depended on the solid content, and a relationship between the specific heat increment and the available particle surface area was obtained. It was proved that the mechanism involved in the specific heat increment is based on a surface phenomenon. Stability of samples was tested for several thermal cycles and thermogravimetric analysis at high temperature was carried out, the samples being stable.

  16. Simultaneous Expression of GUS and Actin Genes by Using the Multiplex RT-PCR and Multiplex Gold Nanoparticle Probes.

    Science.gov (United States)

    Ghazi, Yaser; Vaseghi, Akbar; Ahmadi, Sepideh; Haddadi, Fatemeh

    2018-04-23

    Gene expression analysis is considered to be extremely important in many different biological researches. DNA-based diagnostic test, which contributes to DNA identification, has higher specificity, cost, and speed than some biochemical and molecular methods. In this study, we try to use the novel nano technology approach with Multiplex RT-PCR and Gold nano particular probes (GNPs-probes) in order to get gene expression in Curcumas melons. We used Agrobacterium tumefactions for gene transfer and GUS reporter gene as a reporter. After cDNA synthesis, Multiplex PCR and Multiplex RT-PCR techniques were used. Finally, probes were designed for RNA of GUS and Actin genes, and then the analysis of the gene expression using the probes attached to GNPs was carried out and the color changes in the GNPs were applied. In the following, probes hybridization was checked with DNA between 400 to 700 nm wavelengths and the highest rate was observed in the 550 to 650 nm. The results show that the simultaneous use of GNP-attached detectors and Multiplex RT-PCRcan reduce time and costmore considerably than somelaboratory methods for gene expiration investigation. Additionally, it can be seen thatthere is an increase in sensitivity and specificity of our investigation. Based on our findings, this can bea novel study doneusingMultiplex RT-PCRand unmodified AuNPs for gene transfer and expression detection to plants. We can claim that this assay has a remarkable advantage including rapid, cost-effectiveness, specificity and accuracy to detect transfer and expression genes in plants. Also,we can use this technique from other gene expressionsin many different biology samples.

  17. A color-coded reporter model to study the effect of immunosuppressants on CD8+ T-cell memory in antitumor and alloimmune responses.

    Science.gov (United States)

    Rovira, Jordi; Sabet-Baktach, Manije; Eggenhofer, Elke; Lantow, Margareta; Koehl, Gudrun E; Schlitt, Hans J; Campistol, Josep M; Geissler, Edward K; Kroemer, Alexander

    2013-01-15

    Mammalian target of rapamycin (mTOR) inhibitors possess anticancer properties potentially useful in reducing posttransplantation malignancy. Besides controlling tumor-sensitive proliferative and angiogenic effects, mTOR influences transcription factors T-bet and Eomesodermin (Eomes) in CD8 cytotoxic T cells (Tc), which are key in rejecting tumors, and allografts. To study the role of mTOR in tumor and transplant immunity in an antigen-specific way, we used T-cell receptor transgenic B6.OTI recipients, B6.OVA.TG donors, and OVA-B16F10 melanoma cells. For tracking color-coded OTI-Tc cells associated with antitumor and alloimmunity in vivo, CD8-OTI transgenic reporter mice were created by crossbreeding DsRed-expressing B6.Nagy mice with B6.OTI mice. The role of mTOR in regulating the differentiation and function of alloreactive Tc cells in vitro was explored by stimulating OTI-Tc cells with ovalbumin-transgenic antigen-presenting cells in the presence of rapamycin or tacrolimus. Rapamycin, but not tacrolimus, induced a pro-antitumor phenotypic shift from CD62LCD44 effector memory Tc cells to CD62LCD44 central memory Tc cells, which featured up-regulated levels of T-bet and Eomes and preserved levels of interferon-γ and perforin. For future investigations, an in vivo model was established whereby DsRedOTI-Tc cells adoptively transferred into B6 mice bearing either a ovalbumin-transgenic mouse skin transplant or OVA-B16F10 tumor could be traced by fluorescence-activated cell sorting analysis as effector or memory Tc cells in transplant and tumor tissues. mTOR, but not calcineurin, inhibition spares antitumoral memory Tc cells by distinctively regulating T-bet and Eomes. This finding is now testable in a new tumor transplant model, which incorporates DsRedOTI-Tc cell tracing, opening the way to study the differential effects of immunosuppressants in posttransplantation malignancy.

  18. In situ probing of temperature in radio frequency thermal plasma using Yttrium ion emission lines during synthesis of yttria nanoparticles

    Science.gov (United States)

    Dhamale, G. D.; Tiwari, N.; Mathe, V. L.; Bhoraskar, S. V.; Ghorui, S.

    2017-07-01

    Particle feeding is used in the most important applications of radio frequency (r.f.) thermal plasmas like synthesis of nanoparticles and particle spheroidization. The study reports an in-situ investigation of radial distribution of temperature in such devices using yttrium ion emission lines under different rates of particle loading during synthesis of yttria nanoparticles. A number of interesting facts about the response of r.f. plasma to the rate of particle loading, hitherto unknown, are revealed. Observed phenomena are supported with experimental data from fast photographic experiments and actual synthesis results. The use of the Abel inversion technique together with simultaneous multi-track acquisition of emission spectra from different spatial locations using a CCD based spectrometer allowed us to extract accurate distribution of temperature inside the plasma in the presence of inherent instabilities. The temperature profiles of this type of plasma have been measured possibly for the first time while particles are being fed into the plasma. Observed changes in the temperature profiles as the particle feed rate increases are very significant. Reaction forces resulting from particle evaporation, and increased skin depth owing to the decrease in electrical conductivity in the edge region are proposed as the two different mechanisms to account for the observed changes in the temperature profile as the powder feed rate is increased. Quantitative analyses supporting the proposed mechanisms are presented.

  19. Synthesis and characterization of Nd3+: Yb3+ co-doped near infrared sensitive fluorapatite nanoparticles as a bioimaging probe

    Science.gov (United States)

    Karthi, S.; Kumar, G. A.; Sardar, D. K.; Santhosh, C.; Girija, E. K.

    2018-03-01

    Trivalent Nd and Yb co-doped rod shaped hexagonal phase fluorapatite (FAP) nanoparticles of length and width about 32 and 13 nm, respectively were prepared by hydrothermal method and investigated the ability for 980 nm emission via Nd3+ → Yb3+ energy transfer with the objective of utilizing them in biomedical imaging. Nd3+ → Yb3+ energy transfer in FAP was studied as a function of both Nd3+ and Yb3+ concentrations and found that when Yb3+ concentration was 10 mol% the FAP phase has partially turned in to YbPO4 phase. The Yb3+ emission intensity at 980 nm significantly increased up to 5 mol% Yb3+ doping and then reduced drastically for further increase in its concentration. Nd3+ →Yb3+ energy transfer rates were evaluated from the decay curves and found that a transfer rate of 71% for 2 mol% Nd3+ co-doped with 5 mol% Yb3+. The cytocompatibility test with fibroblast like cells using MTT assay revealed that the nanoparticles are compatible with the cells.

  20. Colloidal gold nanoparticle probe-based immunochromatographic assay for the rapid detection of chromium ions in water and serum samples

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xi; Xiang, Jun-Jian; Tang, Yong; Zhang, Xiao-Li; Fu, Qiang-Qiang; Zou, Jun-Hui; Lin, Yuehe

    2012-09-01

    An immunochromatographic assay (ICA) using gold nanoparticles coated with monoclonal antibody (McAb) for the detection of chromium ions (Cr) in water and serum samples was developed, optimized, and validated. Gold nanoparticles coated with affinity- purified monoclonal antibodies against isothiocyanobenzyl-EDTA (iEDTA)-chelated Cr3+ were used as the detecting reagent in this completive immunoassay-based one- step test strip. The ICA was investigated to measure chromium speciation in water samples. Chromium standard samples of 0-80 ng/mL in water were determined by the test strips. The results showed that the visual lowest detection limit (LDL) of the test strip was 50.0 ng/mL. A portable colorimetric lateral flow reader was used for the quantification of Cr. The results indicated that the linear range of the ICA with colorimetric detection was 5-80 ng/mL. The ICA was also validated for the detection of chromium ions in serum samples. The test trips showed high stability in that they could be stored at at 37 C for at least 12 weeks without significant loss of activity. The test strip also showed good selectivity for Cr detection with negligible interference from other heavy metals. Because of its low cost and short testing time (within 5 min), the test strip is especially suitable for on-site large- scale screening of Cr-polluted water samples, biomonitoring of Cr exposure, and many other field applications.

  1. Au@Ag/Au nanoparticles assembled with activatable aptamer probes as smart ``nano-doctors'' for image-guided cancer thermotherapy

    Science.gov (United States)

    Shi, Hui; Ye, Xiaosheng; He, Xiaoxiao; Wang, Kemin; Cui, Wensi; He, Dinggeng; Li, Duo; Jia, Xuekun

    2014-07-01

    Although nanomaterial-based theranostics have increased positive expectations from cancer treatment, it remains challenging to develop in vivo ``nano-doctors'' that provide high-contrast image-guided site-specific therapy. Here we designed an activatable theranostic nanoprobe (ATNP) via self-assembly of activatable aptamer probes (AAPs) on Au@Ag/Au nanoparticles (NPs). As both quenchers and heaters, novel Au@Ag/Au NPs were prepared, showing excellent fluorescence quenching and more effective near-infrared photothermal therapy than Au nanorods. The AAP comprised a thiolated aptamer and a fluorophore-labeled complementary DNA; thus, the ATNP with quenched fluorescence in the free state could realize signal activation through target binding-induced conformational change of the AAP, and then achieve on-demand treatment under image-guided irradiation. By using S6 aptamer as the model, in vitro and in vivo studies of A549 lung cancer verified that the ATNP greatly improved imaging contrast and specific destruction, suggesting a robust and versatile theranostic strategy for personalized medicine in future.Although nanomaterial-based theranostics have increased positive expectations from cancer treatment, it remains challenging to develop in vivo ``nano-doctors'' that provide high-contrast image-guided site-specific therapy. Here we designed an activatable theranostic nanoprobe (ATNP) via self-assembly of activatable aptamer probes (AAPs) on Au@Ag/Au nanoparticles (NPs). As both quenchers and heaters, novel Au@Ag/Au NPs were prepared, showing excellent fluorescence quenching and more effective near-infrared photothermal therapy than Au nanorods. The AAP comprised a thiolated aptamer and a fluorophore-labeled complementary DNA; thus, the ATNP with quenched fluorescence in the free state could realize signal activation through target binding-induced conformational change of the AAP, and then achieve on-demand treatment under image-guided irradiation. By using S6 aptamer as

  2. Multifunctional molecular imaging probes for estrogen receptors. 99mTc labeled diethylstilbestrol (DES) conjugated, cuinp quantum dot nanoparticles (DESCIP)

    International Nuclear Information System (INIS)

    Payam Moharrami; Perihan Unak; Ozge Kozgus Guldu; Medine, E.I.; Gul Gumuser; Elvan Sayit Bilgin; Omer Aras

    2017-01-01

    A theranostic nanoparticle was synthesized based on diethylstilbestrol conjugated with phosphate, copper, and indium (DESCIP) and labelled with 99m Tc which can be used for SPECT imaging of ER-enriched cancers. In vitro biological activity of 99m Tc-DESCIP was examined in breast adenocarcinoma cells (MCF-7), prostatic carcinoma cells (PC-3), and pulmonary epithelial cells (A-549). In vivo lymph node imaging was performed in normal and receptor blocked female New Zealand rabbits. Results demonstrated that 99m Tc-DESCIP and DESCIP has potential for imaging ER-enriched tumors such as breast and prostate tumors, and their metastases in the lung, as well as improving management for their therapies. (author)

  3. Color-coded intravital imaging demonstrates a transforming growth factor-β (TGF-β) antagonist selectively targets stromal cells in a human pancreatic-cancer orthotopic mouse model.

    Science.gov (United States)

    Murakami, Takashi; Hiroshima, Yukihiko; Miyake, Kentaro; Hwang, Ho Kyoung; Kiyuna, Tasuku; DeLong, Jonathan C; Lwin, Thinzar M; Matsuyama, Ryusei; Mori, Ryutaro; Kumamoto, Takafumi; Chishima, Takashi; Tanaka, Kuniya; Ichikawa, Yasushi; Bouvet, Michael; Endo, Itaru; Hoffman, Robert M

    2017-05-19

    Pancreatic cancer is a recalcitrant malignancy, partly due to desmoplastic stroma which stimulates tumor growth, invasion, and metastasis, and inhibits chemotherapeutic drug delivery. Transforming growth factor-β (TGF-β) has an important role in the formation of stromal desmoplasia. The present study describes the ability of color-coded intravital imaging to demonstrate the efficacy of a TGF-β inhibitor to target stroma in an orthotopic mouse model of pancreatic cancer. The BxPC-3 human pancreatic adenocarcinoma cell line expressing green fluorescent protein (GFP), which also has a high TGF-β expression level, was used in an orthotopic model in transgenic nude mice ubiquitously expressing red fluorescent protein (RFP). Fourteen mice were randomized into a control group (n = 7, vehicle, i.p., weekly, for 3 weeks) and a treated group (n = 7, SB431542 [TGF-β receptor type I inhibitor] 0.3 mg, i.p., weekly, for 3 weeks). Stromal cells expressing RFP and cancer cells expressing GFP were observed weekly for 3 weeks by real-time color-coded intravital imaging. The RFP fluorescence area from the stromal cells, relative to the GFP fluorescence area of the cancer cells, was significantly decreased in the TGF-β-inhibitor-treatment group compared to the control group. The present study demonstrated color-coded imaging in an orthotopic pancreatic-cancer cell-line mouse model can readily detect the selective anti-stromal-cell targeting of a TGF-β inhibitor.

  4. Highly-controllable imprinted polymer nanoshell at the surface of silica nanoparticles based room-temperature phosphorescence probe for detection of 2,4-dichlorophenol

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Xiao; Zhou, Zhiping; Hao, Tongfan [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Li, Hongji; Xu, Yeqing [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Lu, Kai [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Wu, Yilin [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Dai, Jiangdong [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Pan, Jianming [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Yan, Yongsheng, E-mail: jdwxtx@126.com [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2015-04-22

    Highlights: • Highly-controllable core–shell MIPs@SiO{sub 2}–ZnS:Mn QDs were prepared. • The MIPs@SiO{sub 2}–ZnS:Mn QDs integrated the advantages of molecular imprinting and QDs. • We used MIPs@SiO{sub 2}–ZnS:Mn QDs as phosphorescence probes for detection of 2,4-DCP. • MIPs@SiO{sub 2}–ZnS:Mn QDs were successfully applied to detect 2,4-DCP in real samples. - Abstract: This paper reports a facile and general method for preparing an imprinted polymer thin shell with Mn-doped ZnS quantum dots (QDs) at the surface of silica nanoparticles by stepwise precipitation polymerization to form the highly-controllable core–shell nanoparticles (MIPs@SiO{sub 2}–ZnS:Mn QDs) and sensitively recognize the target 2,4-dichlorophenol (2,4-DCP). Acrylamide (AM) and ethyl glycol dimethacrylate (EGDMA) were used as the functional monomer and the cross-linker, respectively. The MIPs@SiO{sub 2}–ZnS:Mn QDs had a controllable shell thickness and a high density of effective recognition sites, and the thickness of uniform core–shell 2,4-DCP-imprinted nanoparticles was controlled by the total amounts of monomers. The MIPs@SiO{sub 2}–ZnS:Mn QDs with a shell thickness of 45 nm exhibited the largest quenching efficiency to 2,4-DCP by using the spectrofluorometer. After the experimental conditions were optimized, a linear relationship was obtained covering the linear range of 1.0–84 μmol L{sup −1} with a correlation coefficient of 0.9981 and the detection limit (3σ/k) was 0.15 μmol L{sup −1}. The feasibility of the developed method was successfully evaluated through the determination of 2,4-DCP in real samples. This study provides a general strategy to fabricate highly-controllable core–shell imprinted polymer-contained QDs with highly selective recognition ability.

  5. An aptasensor for voltammetric and impedimetric determination of cocaine based on a glassy carbon electrode modified with platinum nanoparticles and using rutin as a redox probe

    International Nuclear Information System (INIS)

    Roushani, Mahmoud; Shahdost-fard, Faezeh

    2016-01-01

    We describe a method for the determination of cocaine that is based on a glassy carbon electrode modified with a nanocomposite consisting of multiwalled carbon nanotubes, an ionic liquid, and chitosan. The electrode was made cocaine-responsive by immobilizing a cocaine-specific aptamer and platinum nanoparticles (PtNPs) on the modified electrode. The use of PtNPs resulted in the acceleration of the electron transfer kinetics of the reduction of the redox probe rutin and enhances sensitivity. The sensor, best operated at a working voltage of 260 mV vs. Ag/AgCl, has a linear response to cocaine in the 1 nM to 11 μM concentration range, and the detection limit is 100 pM (at an S/N ratio of 3). We think this strategy to represent a promising platform for the sensitive and selective determination of cocaine. The sensor is adequately stable and was successfully applied to the determination of cocaine in spiked serum. (author)

  6. Electrospun nanofibers decorated with bio-sonochemically synthesized gold nanoparticles as an ultrasensitive probe in amalgam-based mercury (II) detection system.

    Science.gov (United States)

    Parsaee, Zohreh

    2018-06-01

    In this study, bio-ultrasound-assisted synthesized gold nanoparticles using Gracilaria canaliculata algae have been immobilized on a polymeric support and used as a glassy probe chemosensor for detection and rapid removal of Hg 2+ ions. The function of the suggested chemosensor has been explained based on gold-amalgam formation and its catalytic role on the reaction of sodium borohydride and rhodamine B (RhB) with fluorescent and colorimetric sensing function. The catalyzed reduction of RhB by the gold amalgam led to a distinguished color change from red and yellow florescence to colorless by converting the amount of Hg 2+ deposited on Au-NPs. The detection limit of the colorimetric and fluorescence assays for Hg 2+ was 2.21 nM and 1.10 nM respectively. By exposing the mentioned colorless solution to air for at least 2 h, unexpectedly it was observed that the color and fluorescence of RhB were restored. Have the benefit of the above phenomenon a recyclable and portable glass-based sensor has been provided by immobilizing the Au-NPs and RB on the glass slide using electrospinning. Moreover, the introduced combinatorial membrane has facilitated the detection and removal of Hg 2+ ions in various Hg (II)-contaminated real water samples with efficiency of up to 99%. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Simple, Fast and Selective Detection of Adenosine Triphosphate at Physiological pH Using Unmodified Gold Nanoparticles as Colorimetric Probes and Metal Ions as Cross-Linkers

    Directory of Open Access Journals (Sweden)

    Huan Pang

    2012-11-01

    Full Text Available We report a simple, fast and selective colorimetric assay of adenosine triphosphate (ATP using unmodified gold nanoparticles (AuNPs as probes and metal ions as cross-linkers. ATP can be assembled onto the surface of AuNPs through interaction between the electron-rich nitrogen atoms and the electron-deficient surface of AuNPs. Accordingly, Cu2+ ions induce a change in the color and UV/Vis absorbance of AuNPs by coordinating to the triphosphate groups and a ring nitrogen of ATP. A detection limit of 50 nM was achieved, which is comparable to or lower than that achievable by the currently used electrochemical, spectroscopic or chromatographic methods. The theoretical simplicity and high selectivity reported herein demonstrated that AuNPs-based colorimetric assay could be applied in a wide variety of fields by rationally designing the surface chemistry of AuNPs. In addition, our results indicate that ATP-modified AuNPs are less stable in Cu2+, Cd2+ or Zn2+-containing solutions due to the formation of the corresponding dimeric metal-ATP complexes.

  8. Gold Nanoparticle Aggregation as a Probe of Antifreeze (Glyco) Protein-Inspired Ice Recrystallization Inhibition and Identification of New IRI Active Macromolecules.

    Science.gov (United States)

    Mitchell, Daniel E; Congdon, Thomas; Rodger, Alison; Gibson, Matthew I

    2015-10-26

    Antifreeze (glyco)proteins are found in polar fish species and act to slow the rate of growth of ice crystals; a property known as ice recrystallization inhibition. The ability to slow ice growth is of huge technological importance especially in the cryopreservation of donor cells and tissue, but native antifreeze proteins are often not suitable, nor easily available. Therefore, the search for new materials that mimic this function is important, but currently limited by the low-throughout assays associated with the antifreeze properties. Here 30 nm gold nanoparticles are demonstrated to be useful colorimetric probes for ice recrystallization inhibition, giving a visible optical response and is compatible with 96 well plates for high-throughout studies. This method is faster, requires less infrastructure, and has easier interpretation than the currently used 'splat' methods. Using this method, a series of serum proteins were identified to have weak, but specific ice recrystallization inhibition activity, which was removed upon denaturation. It is hoped that high-throughput tools such as this will accelerate the discovery of new antifreeze mimics.

  9. Probing the interaction of Rh, Co and bimetallic Rh-Co nanoparticles with the CeO2 support: catalytic materials for alternative energy generation.

    Science.gov (United States)

    Varga, E; Pusztai, P; Óvári, L; Oszkó, A; Erdőhelyi, A; Papp, C; Steinrück, H-P; Kónya, Z; Kiss, J

    2015-10-28

    The interaction of CeO2-supported Rh, Co and bimetallic Rh-Co nanoparticles, which are active catalysts in hydrogen production via steam reforming of ethanol, a process related to renewable energy generation, was studied by X-ray diffraction (XRD), high resolution electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and low energy ion scattering (LEIS). Furthermore, diffuse reflectance infrared spectroscopy (DRIFTS) of adsorbed CO as a probe molecule was used to characterize the morphology of metal particles. At small loadings (0.1%), Rh is in a much dispersed state on ceria, while at higher contents (1-5%), Rh forms 2-8 nm particles. Between 473-673 K pronounced oxygen transfer from ceria to Rh is observed and at 773 K significant agglomeration of Rh occurs. On reduced ceria, XPS indicates a possible electron transfer from Rh to ceria. The formation of smaller ceria crystallites upon loading with Co was concluded from XRD and HRTEM; for 10% Co, the CeO2 particle size decreased from 27.6 to 10.7 nm. A strong dissolution of Co into ceria and a certain extent of encapsulation by ceria were deduced by XRD, XPS and LEIS. In the bimetallic system, the presence of Rh enhances the reduction of cobalt and ceria. During thermal treatments, reoxidation of Co occurs, and Rh agglomeration as well as oxygen migration from ceria to Rh are hindered in the presence of cobalt.

  10. Cyclen dithiocarbamate-functionalized silver nanoparticles as a probe for colorimetric sensing of thiram and paraquat pesticides via host-guest chemistry

    Science.gov (United States)

    Rohit, Jigneshkumar V.; Kailasa, Suresh Kumar

    2014-11-01

    We have developed a simple and rapid colorimetric method for on-site analysis of thiram and paraquat using cyclen dithiocarbamate-functionalized silver nanoparticles (CN-DTC-Ag NPs) as a colorimetric probe. The synthesized CN-DTC-Ag NPs were characterized by UV-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy, dynamic light scattering, and transmission electron microscopic techniques. The CN-DTC molecules provide good supramolecular self assembly on the surfaces of Ag NPs to encapsulate thiram and paraquat selectively via "host-guest" chemistry, resulting in red-shift in surface plasmon resonance peak of CN-DTC-Ag NPs from 396 to 530 nm and 510 nm and color change from yellow to pink for thiram and to orange for paraquat, which can be naked-eye detected. The present method shows good linearity in the range of 10.0-20.0 µM and of 50.0-250 µM with limits of detection 2.81 × 10-6 M and 7.21 × 10-6 M for thiram and paraquat, respectively. This method was proved as a promising tool for on-site and real-time monitoring of thiram and paraquat in environmental water, potato, and wheat samples.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-08-15

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  13. Determination of nickel(II) at nanomolar levels using iodide-responsive gold-copper nanoparticles as colorimetric probes.

    Science.gov (United States)

    Xi, Hongyan; Liu, Qingyun; Chen, Zhengbo

    2018-01-08

    The authors present a colorimetric method for the quantification of Ni(II) at nanomolar levels. It is based on the use of iodide-responsive copper-gold nanoparticles (Cu-Au NPs) combined with the Ni(II)-catalyzed glutathione (GSH)-oxygen reaction system. In the presence of Ni(II), the catalytic reaction between GSH and oxygen is can triggered. This leads to the formation of GSSG which is bulky and hinders the access of iodide to the surface of the Cu-Au NPs. Concomitantly, the color of the solution containing the Cu-Au NPs changes from gray to red. Based on these findings, a method was developed for the quantitation of Ni(II) that has a detection limit as low as 0.54 nM. This is 1-3 orders of magnitude lower than that of previously reported optical methods. The assay has excellent selectivity for Ni(II), is rapid, cost-effective, portable, and allows for bare eye observation. Conceivably the method is suitable for field detection of Ni(II) in biological, food, and environmental samples. Graphical Abstract A sensitive colorimetric strategy for Ni(II) through the combination of iodide-responsive Cu-Au NPs with Ni(II)-catalyzed the oxidation of GSH by oxygen was presented.

  14. Probing the Sulfur-Modified Capping Layer of Gold Nanoparticles Using Surface Enhanced Raman Spectroscopy (SERS) Effects.

    Science.gov (United States)

    Prado, Adilson R; Souza, Danilo Oliveira de; Oliveira, Jairo P; Pereira, Rayssa H A; Guimarães, Marco C C; Nogueira, Breno V; Dixini, Pedro V; Ribeiro, Moisés R N; Pontes, Maria J

    2017-12-01

    Gold nanoparticles (AuNP) exhibit particular plasmonic properties when stimulated by visible light, which makes them a promising tool to many applications in sensor technology and biomedical applications, especially when associated to sulfur-based compounds. Sulfur species form a great variety of self-assembled structures that cap AuNP and this interaction rules the optical and plasmonic properties of the system. Here, we report the behavior of citrate-stabilized gold nanospheres in two distinct sulfur colloidal solutions, namely, thiocyanate and sulfide ionic solutions. Citrate-capped gold nanospheres were characterized using ultraviolet-visible (UV-Vis) absorption, transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and atomic force microscopy (AFM). In the presence of sulfur species, we have observed the formation of NP clusters and chain-like structures, giving rise to surface-enhanced effects. Surface-enhanced Raman spectroscopy (SERS) pointed to a modification in citrate vibrational modes, which suggests substitution of citrate by either thiocyanate or sulfide ions with distinct dynamics, as showed by in situ fluorescence. Moreover, we report the emergence of surface-enhanced infrared absorption (SEIRA) effect, which corroborates SERS conclusions. Further, SEIRA shows a great potential as a tool for specification of sulfur compounds in colloidal solutions, which is particularly useful when dealing with sensor technology.

  15. Gap controlled plasmon-dielectric coupling effects investigated with single nanoparticle-terminated atomic force microscope probes.

    Science.gov (United States)

    Huang, Qian; Teran Arce, Fernando; Lee, Joon; Yoon, Ilsun; Villanueva, Joshua; Lal, Ratnesh; Sirbuly, Donald J

    2016-10-06

    Precise positioning of a plasmonic nanoparticle (NP) near a small dielectric surface is not only necessary for understanding gap-dependent interactions between a metal and dielectric but it is also a critical component in building ultrasensitive molecular rulers and force sensing devices. In this study we investigate the gap-dependent scattering of gold and silver NPs by controllably depositing them on an atomic force microscope (AFM) tip and monitoring their scattering within the evanescent field of a tin dioxide nanofiber waveguide. The enhanced distance-dependent scattering profiles due to plasmon-dielectric coupling effects show similar decays for both gold and silver NPs given the strong dependence of the coupling on the decaying power in the near-field. Experiments and simulations also demonstrate that the NPs attached to the AFM tips act as free NPs, eliminating optical interference typically observed from secondary dielectric substrates. With the ability to reproducibly place individual plasmonic NPs on an AFM tip, and optically monitor near-field plasmon-dielectric coupling effects, this approach allows a wide-variety of light-matter interactions studies to be carried out on other low-dimensional nanomaterials.

  16. Sensitive Pb(2+) probe based on the fluorescence quenching by graphene oxide and enhancement of the leaching of gold nanoparticles.

    Science.gov (United States)

    Shi, Xinhao; Gu, Wei; Peng, Weidong; Li, Bingyu; Chen, Ningning; Zhao, Kai; Xian, Yuezhong

    2014-02-26

    A novel strategy was developed for fluorescent detection of Pb(2+) in aqueous solution based on the fact that graphene oxide (GO) could quench the fluorescence of amino pyrene (AP)-grafted gold nanoparticles (AP-AuNPs) and Pb(2+) could accelerate the leaching rate of AuNPs in the presence of S2O3(2-). In this system, fluorescence reporter AP was grafted on AuNPs through the Au-N bond. In the presence of GO, the system shows fluorescence quenching because of π-π stacking between AP and GO. With the addition of Pb(2+) and S2O3(2-), the system displays fluorescence recovery, which is attributed to the fact that Pb(2+) could accelerate the leaching of the AuNPs from GO surfaces and release of AP into aqueous solution. Interestingly, the concentration of GO could control the fluorescence "turn-off" or "turn-on" for Pb(2+) detection. In addition, GO is also an excellent promoter for the acceleration of the leaching of AuNPs and shortening the analytical time to ∼15 min. Under the optimal conditions, the fluorescence Pb(2+) sensor shows a linear range from 2.0 × 10(-9) to 2.3 × 10(-7) mol/L, with a detection limit of 1.0 × 10(-10) mol/L.

  17. Breast cancer cell targeted MR molecular imaging probe: Anti-MUC1 antibody-based magnetic nanoparticles

    Science.gov (United States)

    Moradi Khaniabadi, P.; S. A Majid, A. M.; Asif, M.; Moradi Khaniabadi, B.; Shahbazi-Gahrouei, D.; Jaafar, M. S.

    2017-05-01

    Effective and specific diagnostic imaging techniques are important in early-stage breast cancer treatment. The objective of this study was to develop a specific breast cancer contrast agent for magnetic resonance imaging (MRI). In so doing, superparamagnetic iron oxide nanoparticles (SPIONs) were conjugated to C595 monoclonal antibody using EDC chemistry to produce nanoprobe with high relaxivity and narrow size (87.4±0.7 nm). To test the developed nanoprobe in vitro, assessments including Cell toxicity, targeting efficacy, cellular binding, and MR imaging were carried out. The results indicated that after 6 hrs incubation with MCF-7 cells at 200 to 25 µg Fe/ml doses, 76% to 16% T2 reduction was obtained. The presence of iron localised in MCF-7 cells measured by atomic absorption spectroscopy (AAS) was about 9.95±0.09 ppm iron/cell at higher doses of nanoprobe. Moreover, a linear relationship between iron concentration of nontoxic SPION-C595 and T2 relaxation times was observed. This study also revealed that developed nanoprobe might be used as a specific negative contrast agent for detecting breast cancer.

  18. Microwave assisted one-step green synthesis of fluorescent carbon nanoparticles from ionic liquids and their application as novel fluorescence probe for quercetin determination

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Deli; Yuan, Danhua [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China); He, Hua, E-mail: dochehua@163.com [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China); Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, Nanjing 210009 (China); Gao, Mengmeng [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China)

    2013-08-15

    In this study, a new sensitive and convenient method for the determination of quercetin based on the fluorescence quenching of fluorescent carbon nanoparticles (CNPs) was developed. The CNPs derived from ionic liquids were prepared using a green and rapid microwave-assisted synthetic approach for the first time. The one-step green preparation process is simple and effective, neither a strong acid solvent nor surface modification reagent is needed, which makes this approach very suitable for large-scale production. The prepared CNPs were characterized by high-resolution transmission electron microscopy, Fourier transform infrared spectrometry, elemental analysis and spectrofluorometry. In NH{sub 3}–NH{sub 4}Cl buffer solution (pH 9.47), the fluorescence signals of CNPs decreased obviously with increase of the quercetin concentration. The effect of other coexisting foreign substances on the intensity of CNPs showed a low interference response. Under the optimum conditions, the fluorescence intensity presented a linear response versus quercetin concentration according to the Stern–Volmer equation with an excellent 0.9989 correlation coefficient. The linearity ranged from 2.87×10{sup −6} to 31.57×10{sup −6} mol L{sup −1} with the detection limit (3σ) of 9.88×10{sup −8} mol L{sup −1}. The recovery of this method was in the range of 93.3–105.1%. Therefore, the CNPs could to be a promising candidate as a fluorescence probe for the detection of trace levels of quercetin due to their advantages in low-cost production, low cytotoxicity, strong fluorescence and excellent biocompatibility. -- Highlights: ► Fluorescent CNPs were synthesized with microwave pyrolysis approach. ► Ionic liquids were used as sources of carbon and nitrogen for the first time. ► The formation and functionalization of CNPs were accomplished simultaneously. ► CNPs were used as fluorescent probes for the determination of quercetin. ► A sensitive and convenient method based

  19. Paper-based magnetic nanoparticle-peptide probe for rapid and quantitative colorimetric detection of Escherichia coli O157:H7.

    Science.gov (United States)

    Suaifan, Ghadeer A R Y; Alhogail, Sahar; Zourob, Mohammed

    2017-06-15

    There is a critical and urgent demand for a simple, rapid and specific qualitative and quantitative colorimetric biosensor for the detection of the food contaminant Escherichia coli O157:H7 (E. coli O157:H7) in complex food products due to the recent outbreaks of food-borne diseases. Traditional detection techniques are time-consuming, require expensive instrumentation and are labour-intensive. To overcome these limitations, a novel, ultra-rapid visual biosensor was developed based on the ability of E. coli O157:H7 proteases to change the optical response of a surface-modified, magnetic nanoparticle-specific (MNP-specific) peptide probe. Upon proteolysis, a gradual increase in the golden color of the sensor surface was visually observed. The intensification of color was correlated with the E. coli O157:H7 concentration. The color change resulting from the dissociation of the self-assembled monolayer (SAM) was detected by the naked eye and analysed using an image analysis software (ImageJ) for the purpose of quantitative detection. This biosensor demonstrated high sensitivity and applicability, with lower limits of detection of 12CFUmL -1 in broth samples and 30-300CFUmL -1 in spiked complex food matrices. In conclusion, this approach permits the use of a disposable biosensor chip that can be mass-produced at low cost and can be used not only by food manufacturers but also by regulatory agencies for better control of potential health risks associated with the consumption of contaminated foods. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Gold nanoclusters as switch-off fluorescent probe for detection of uric acid based on the inner filter effect of hydrogen peroxide-mediated enlargement of gold nanoparticles.

    Science.gov (United States)

    Liu, Yanyan; Li, Hongchang; Guo, Bin; Wei, Lijuan; Chen, Bo; Zhang, Youyu

    2017-05-15

    Herein we report a novel switch-off fluorescent probe for highly selective determination of uric acid (UA) based on the inner filter effect (IFE), by using poly-(vinylpyrrolidone)-protected gold nanoparticles (PVP-AuNPs) and chondroitin sulfate-stabilized gold nanoclusters (CS-AuNCs) as the IFE absorber/fluorophore pair. In this IFE-based fluorometric assay, the newly designed CS-AuNCs were explored as an original fluorophore and the hydrogen peroxide (H 2 O 2 ) -driven formed PVP-AuNPs can be a powerful absorber to influence the excitation of the fluorophore, due to the complementary overlap between the absorption band of PVP-AuNPs and the emission band of CS-AuNCs. Under the optimized conditions, the extent of the signal quenching depends linearly on the H 2 O 2 concentration in the range of 1-100μM (R 2 =0.995) with a detection limit down to 0.3μM. Based on the H 2 O 2 -dependent fluorescence IFE principle, we further developed a new assay strategy to enable selective sensing of UA by using a specific uricase-catalyzed UA oxidation as the in situ H 2 O 2 generator. The proposed uricase-linked IFE-based assay exhibited excellent analytical performance for measuring UA over the concentration ranging from 5 to 100μM (R 2 =0.991), and can be successfully applied to detection of UA as low as 1.7μM (3σ) in diluted human serum samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    Duvaa, Uffe; Ørngreen, Rikke; Weinkouff, Anne-Gitte

    2012-01-01

    Mobile probing is a method, which has been developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time...... and space). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings...... point to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face...

  2. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    Duvaa, Uffe; Ørngreen, Rikke; Weinkouff Mathiasen, Anne-Gitte

    2013-01-01

    Mobile probing is a method, developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time and space......). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings point...... to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face). The development...

  3. Ce (III) - Porphyrin Sandwich Complex Ce2(TPP)3: A Rod-Like Nanoparticle as a Fluorescence Turn-Off Probe for Detection of Hg (II) and Cu (II).

    Science.gov (United States)

    Boroujerdi, Ramin

    2016-05-01

    In this study the researcher reports a novel, one step synthesized rod-like nanoparticles of cerium (III)-tetraphenylporphyrin sandwich complex as a spectrofluorometric sensor to measure trace amount of Hg (II) and Cu (II) metal ions. Moreover, the synthesized fluorescent probe was able to detect higher amounts (>10(-4) M) of Hg (II) in aqueous media by changing the color which can also be used as a selective mercury naked-eye sensor. The selectivity and sensitivity of the sensor based on its fluorescence quenching in the presence of Hg (II) and Cu (II) were studied according to the Stern-Volmer equation. The detection limit of the sensor was 16 nM for Hg (II) and about 2.34 μM for Cu (II) ions. Graphical Abstract Ce2(TPP)3 sandwich complex application as a fluorescent probe for measuring trace amounts of mercury and copper in real samples.

  4. Design and synthesis of biofunctional magnetic/fluorescent glyco-nanoparticles and quantum dots and their application as specific molecular imaging probes

    OpenAIRE

    Gallo Páramo, Juan

    2014-01-01

    206 p. [EN]Nanotechnology presents very promising characteristics for its application in the biomedicine area. By now the most advanced application of nanoparticles in medicine is the use of iron oxide nanoparticles embedded in biocompatible polymers as magnetic resonance imaging (MRI) contrast agents. Nowadays MRI application relies either on inherent tissue contrast differences or on the unspecific accumulation of contrast agents in certain tissues. This status can be exte...

  5. An ultrasensitive electrochemiluminescence immunoassay for carbohydrate antigen 19-9 in serum based on antibody labeled Fe3O4 nanoparticles as capture probes and graphene/CdTe quantum dot bionanoconjugates as signal amplifiers.

    Science.gov (United States)

    Gan, Ning; Zhou, Jing; Xiong, Ping; Li, Tianhua; Jiang, Shan; Cao, Yuting; Jiang, Qianli

    2013-05-17

    The CdTe quantum dots (QDs), graphene nanocomposite (CdTe-G) and dextran-Fe3O4 magnetic nanoparticles have been synthesized for developing an ultrasensitive electrochemiluminescence (ECL) immunoassay for Carcinoembryonic antigen 19-9 (CA 19-9) in serums. Firstly, the capture probes (CA 19-9 Ab1/Fe3O4) for enriching CA 19-9 were synthesized by immobilizing the CA 19-9's first antibody (CA 19-9 Ab1) on magnetic nanoparticles (dextran-Fe3O4). Secondly, the signal probes (CA 19-9 Ab2/CdTe-G), which can emit an ECL signal, were formed by attaching the secondary CA 19-9 antibody (CA 19-9 Ab2) to the surface of the CdTe-G. Thirdly, the above two probes were used for conjugating with a serial of CA 19-9 concentrations. Graphene can immobilize dozens of CdTe QDs on their surface, which can emit stronger ECL intensity than CdTe QDs. Based on the amplified signal, ultrasensitive antigen detection can be realized. Under the optimal conditions, the ECL signal depended linearly on the logarithm of CA 19-9 concentration from 0.005 to 100 pg/mL, and the detection limit was 0.002 pg/mL. Finally, five samples of human serum were tested, and the results were compared with a time-resolved fluorescence assay (TRFA). The novel immunoassay provides a stable, specific and highly sensitive immunoassay protocol for tumor marker detection at very low levels, which can be applied in early diagnosis of tumor.

  6. An Ultrasensitive Electrochemiluminescence Immunoassay for Carbohydrate Antigen 19-9 in Serum Based on Antibody Labeled Fe3O4 Nanoparticles as Capture Probes and Graphene/CdTe Quantum Dot Bionanoconjugates as Signal Amplifiers

    Science.gov (United States)

    Gan, Ning; Zhou, Jing; Xiong, Ping; Li, Tianhua; Jiang, Shan; Cao, Yuting; Jiang, Qianli

    2013-01-01

    The CdTe quantum dots (QDs), graphene nanocomposite (CdTe-G) and dextran–Fe3O4 magnetic nanoparticles have been synthesized for developing an ultrasensitive electrochemiluminescence (ECL) immunoassay for Carcinoembryonic antigen 19-9 (CA 19-9) in serums. Firstly, the capture probes (CA 19-9 Ab1/Fe3O4) for enriching CA 19-9 were synthesized by immobilizing the CA 19-9’s first antibody (CA 19-9 Ab1) on magnetic nanoparticles (dextran-Fe3O4). Secondly, the signal probes (CA 19-9 Ab2/CdTe-G), which can emit an ECL signal, were formed by attaching the secondary CA 19-9 antibody (CA 19-9 Ab2) to the surface of the CdTe-G. Thirdly, the above two probes were used for conjugating with a serial of CA 19-9 concentrations. Graphene can immobilize dozens of CdTe QDs on their surface, which can emit stronger ECL intensity than CdTe QDs. Based on the amplified signal, ultrasensitive antigen detection can be realized. Under the optimal conditions, the ECL signal depended linearly on the logarithm of CA 19-9 concentration from 0.005 to 100 pg/mL, and the detection limit was 0.002 pg/mL. Finally, five samples of human serum were tested, and the results were compared with a time-resolved fluorescence assay (TRFA). The novel immunoassay provides a stable, specific and highly sensitive immunoassay protocol for tumor marker detection at very low levels, which can be applied in early diagnosis of tumor. PMID:23685872

  7. The sandwich-type electrochemiluminescence immunosensor for {alpha}-fetoprotein based on enrichment by Fe{sub 3}O{sub 4}-Au magnetic nano probes and signal amplification by CdS-Au composite nanoparticles labeled anti-AFP

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Hankun [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo 315211 (China); Gan Ning, E-mail: ganning@nbu.edu.cn [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo 315211 (China); Li Tianhua; Cao Yuting; Zeng Saolin [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo 315211 (China); Zheng Lei, E-mail: nfyyzl@163.com [Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515 (China); Guo Zhiyong [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo 315211 (China)

    2012-10-09

    Highlights: Black-Right-Pointing-Pointer Sandwich immunoreaction, testing a large number of samples simultaneously. Black-Right-Pointing-Pointer The magnetic separation and enrichment by Fe{sub 3}O{sub 4}-Au magnetic nano probes. Black-Right-Pointing-Pointer The amplification of detection signal by CdS-Au composite nanoparticles labeled anti-AFP. Black-Right-Pointing-Pointer Almost no background signal, which greatly improve the sensitivity of detection. - Abstract: A novel and sensitive sandwich-type electrochemiluminescence (ECL) immunosensor was fabricated on a glassy carbon electrode (GCE) for ultra trace levels of {alpha}-fetoprotein (AFP) based on sandwich immunoreaction strategy by enrichment using magnetic capture probes and quantum dots coated with Au shell (CdS-Au) as the signal tag. The capture probe was prepared by immobilizing the primary antibody of AFP (Ab1) on the core/shell Fe{sub 3}O{sub 4}-Au nanoparticles, which was first employed to capture AFP antigens to form Fe{sub 3}O{sub 4}-Au/Ab1/AFP complex from the serum after incubation. The product can be separated from the background solution through the magnetic separation. Then the CdS-Au labeled secondary antibody (Ab2) as signal tag (CdS-Au/Ab2) was conjugated successfully with Fe{sub 3}O{sub 4}-Au/Ab1/AFP complex to form a sandwich-type immunocomplex (Fe{sub 3}O{sub 4}-Au/Ab1/AFP/Ab2/CdS-Au), which can be further separated by an external magnetic field and produce ECL signals at a fixed voltage. The signal was proportional to a certain concentration range of AFP for quantification. Thus, an easy-to-use immunosensor with magnetic probes and a quantum dots signal tag was obtained. The immunosensor performed at a level of high sensitivity and a broad concentration range for AFP between 0.0005 and 5.0 ng mL{sup -1} with a detection limit of 0.2 pg mL{sup -1}. The use of magnetic probes was combined with pre-concentration and separation for trace levels of tumor markers in the serum. Due to the

  8. Voltammetric immunosensor for human chorionic gonadotropin using a glassy carbon electrode modified with silver nanoparticles and a nanocomposite composed of graphene, chitosan and ionic liquid, and using riboflavin as a redox probe

    International Nuclear Information System (INIS)

    Roushani, Mahmoud; Valipour, Akram

    2016-01-01

    The aim of this study was to develop an electrochemical immunoassay system to detect of human chorionic gonadotropin (hCG). The immunosensor was constructed by covalent immobilization of silver nanoparticles (AgNPs) onto a nanocomposite containing graphene, chitosan (Chit) and 1-methyl-3-octylimidazolium tetrafluoroborate as ionic liquid (IL). Silver nanoparticles were used as a linker to immobilize hCG antibody onto the modified electrode. The amino groups of the antibody were covalently attached to an AgNP/g-IL-Chit nanocomposite. Cyclic voltammetry and electrochemical impedance spectroscopy were employed to characterize the assembly process of the immunosensor. Riboflavin was used as the redox probe. Differential pulse voltammetry demonstrated that the formation of antibody–antigen complexes decreases the peak current of redox pair at the AgNP/Gr-IL-Chit/GCE (at a working potential of −0.38 V). The signal changes of riboflavin are used to detect hCG with broad response ranges from 0.0212 to 530 mIU.mL −1 and a low detection limit of 0.0066 ± 0.02 mIU.mL −1 . (author)

  9. Distinct local structure of nanoparticles and nanowires of V{sub 2}O{sub 5} probed by x-ray absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, B.; Maugeri, L.; Bendele, M.; Saini, N. L., E-mail: Naurang.Saini@roma1.infn.it [Dipartimento di Fisica, Universitá di Roma “La Sapienza” - P. le Aldo Moro 2, 00185 Roma (Italy); Iadecola, A. [Dipartimento di Fisica, Universitá di Roma “La Sapienza” - P. le Aldo Moro 2, 00185 Roma (Italy); Elettra, Sincrotrone Trieste, Strada Statale 14, Km 163.5, Basovizza, Trieste (Italy); Okubo, M.; Li, H.; Zhou, H. [National Institute of Advanced Industrial Science and Technology (AIST), Umezono 1-1-1, Tsukuba 305-8568 (Japan); Mizokawa, T. [Department of Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Department of Complexity Science and Engineering, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan)

    2013-12-16

    We have used V K-edge x-ray absorption spectroscopy to study local structures of bulk, nanoparticles and nanowires of V{sub 2}O{sub 5}. The extended x-ray absorption fine structure measurements show different local displacements in the three morphologically different V{sub 2}O{sub 5} samples. It is found that the nanowires have a significantly ordered chain structure in comparison to the V{sub 2}O{sub 5} bulk. In contrast, nanoparticles have larger interlayer disorder. The x-ray absorption near-edge structure spectra show different electronic structure that appears to be related with the local atomic disorder in the three V{sub 2}O{sub 5} samples.

  10. An imprinted Ag@CdS core shell nanoparticle based optical-electrochemical dual probe for trace level recognition of ferritin.

    Science.gov (United States)

    Patra, Santanu; Roy, Ekta; Madhuri, Rashmi; Sharma, Prashant K

    2015-01-15

    In this work, we present a new approach to prepare the Ag@CdS core-shell fluorescent nanoparticles wrapped with molecularly imprinted polymer for ferritin macromolecule by capping with vinyl derivative of cysteine. The imprinted Ag@CdS nanoparticle was prepared via activator regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP) method onto the surface of vinyl silane modified pencil graphite electrode. Combination of Ag and CdS in a single motif causes the dual behavior of core shell nanoparticle, which shows enhanced fluorescence as well as electrochemical properties. The performance of the obtained imprinted sensor was investigated by cyclic voltammetry, electrochemical impedance spectroscopy, chronocoulometry, differential pulse voltammetry and fluorescence spectrophotometry. Under the optimal experimental conditions, the current response of the electrochemical sensor was linear to ferritin concentrations in the range from 1.99 to 23.43 µg L⁻¹, with the detection limit of 0.65 µg L⁻¹. Similarly, a linear response was obtained between fluorescence quenching of imprinted Ag@CdS and concentration of ferritin in the range from 4.0 to 91.0 µg L⁻¹, with limit of detection (LOD) of 1.3 µg L⁻¹. The method was successfully applied to the analysis of blood serum samples of five different men and women with acceptable recoveries of 99.7% and 100.3% (RSD in %=1.0-2.0).

  11. Thermal and optical characterization of biologically synthesized ZnS nanoparticles synthesized from an endophytic fungus Aspergillus flavus: A colorimetric probe in metal detection

    Science.gov (United States)

    Uddandarao, Priyanka; Balakrishnan, Raj Mohan

    2017-03-01

    Nanostructured semiconductor materials are of great importance for several technological applications due to their optical and thermal properties. The design and fabrication of metal sulfide nanoparticles with tunable properties for advanced applications have drawn a great deal of attention in the field of nanotechnology. ZnS is a potential II-IV group material which is used in hetero-junction solar cells, light emitting diodes, optoelectronic devices, electro luminescent devices and photovoltaic cells. Due to their multiple applications, there is a need to elucidate their thermal and optical properties. In the present study, thermal and optical properties of biologically synthesized ZnS nanoparticles are determined in detail with Thermal Gravimetric Analysis (TGA), Derivative Thermogravimetric Analysis (DTG), Differential Scanning Calorimeter (DSC), Diffuse Reflectance Spectroscopy (DRS), Photoluminescence (PL) and Raman spectroscopy. The results reveal that ZnS NPs exhibit a very strong quantum confinement with a significant increase in their optical band gap energy. These biologically synthesized ZnS NPs contain protein residues that can selectively bind with metal ions in aqueous solutions and can exhibit an aggregation-induced color change. This phenomenon is utilized to quantitatively measure the metal concentrations of Cu2 + and Mn2 + in this study. Further the stability of nanoparticles for the metal sensing process is accessed by UV-Vis spectrometer, zeta potential and cyclic voltammeter. The selectivity and sensitivity of ZnS NPs indicate its potential use as a sensor for metal detection in the ecosystem.

  12. Thermal and optical characterization of biologically synthesized ZnS nanoparticles synthesized from an endophytic fungus Aspergillus flavus: A colorimetric probe in metal detection.

    Science.gov (United States)

    Uddandarao, Priyanka; Balakrishnan, Raj Mohan

    2017-03-15

    Nanostructured semiconductor materials are of great importance for several technological applications due to their optical and thermal properties. The design and fabrication of metal sulfide nanoparticles with tunable properties for advanced applications have drawn a great deal of attention in the field of nanotechnology. ZnS is a potential II-IV group material which is used in hetero-junction solar cells, light emitting diodes, optoelectronic devices, electro luminescent devices and photovoltaic cells. Due to their multiple applications, there is a need to elucidate their thermal and optical properties. In the present study, thermal and optical properties of biologically synthesized ZnS nanoparticles are determined in detail with Thermal Gravimetric Analysis (TGA), Derivative Thermogravimetric Analysis (DTG), Differential Scanning Calorimeter (DSC), Diffuse Reflectance Spectroscopy (DRS), Photoluminescence (PL) and Raman spectroscopy. The results reveal that ZnS NPs exhibit a very strong quantum confinement with a significant increase in their optical band gap energy. These biologically synthesized ZnS NPs contain protein residues that can selectively bind with metal ions in aqueous solutions and can exhibit an aggregation-induced color change. This phenomenon is utilized to quantitatively measure the metal concentrations of Cu 2+ and Mn 2+ in this study. Further the stability of nanoparticles for the metal sensing process is accessed by UV-Vis spectrometer, zeta potential and cyclic voltammeter. The selectivity and sensitivity of ZnS NPs indicate its potential use as a sensor for metal detection in the ecosystem. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Cultural probes

    DEFF Research Database (Denmark)

    Madsen, Jacob Østergaard

    The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation.......The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation....

  14. A rapid and universal bacteria-counting approach using CdSe/ZnS/SiO2 composite nanoparticles as fluorescence probe.

    Science.gov (United States)

    Fu, Xin; Huang, Kelong; Liu, Suqin

    2010-02-01

    In this paper, a rapid, simple, and sensitive method was described for detection of the total bacterial count using SiO(2)-coated CdSe/ZnS quantum dots (QDs) as a fluorescence marker that covalently coupled with bacteria using glutaraldehyde as the crosslinker. Highly luminescent CdSe/ZnS were prepared by applying cadmium oxide and zinc stearate as precursors instead of pyrophoric organometallic precursors. A reverse-microemulsion technique was used to synthesize CdSe/ZnS/SiO(2) composite nanoparticles with a SiO(2) surface coating. Our results showed that CdSe/ZnS/SiO(2) composite nanoparticles prepared with this method possessed highly luminescent, biologically functional, and monodispersive characteristics, and could successfully be covalently conjugated with the bacteria. As a demonstration, it was found that the method had higher sensitivity and could count bacteria in 3 x 10(2) CFU/mL, lower than the conventional plate counting and organic dye-based method. A linear relationship of the fluorescence peak intensity (Y) and the total bacterial count (X) was established in the range of 3 x 10(2)-10(7) CFU/mL using the equation Y = 374.82X-938.27 (R = 0.99574). The results of the determination for the total count of bacteria in seven real samples were identical with the conventional plate count method, and the standard deviation was satisfactory.

  15. NanoDLSay: a new platform technology for biomolecular detection and analysis using gold nanoparticle probes coupled with dynamic light scattering

    Science.gov (United States)

    Bogdanovic, Jelena; Huo, Qun

    2010-04-01

    Most analytical techniques that are routinely used in biomedical research for detection and quantification of biomolecules are time-consuming, expensive and labor-intensive, and there is always a need for rapid, affordable and convenient methods. Recently we have developed a new platform technology for biomolecular detection and analysis: NanoDLSay. NanoDLSay employs antibody-coated gold nanoparticles (GNPs) and dynamic light scattering, and correlates the specific increase in particle size after antigen-antibody interaction to the target antigen concentration. We applied this technology to develop an assay for rapid detection of actin, a protein widely used as a loading control in Western Blot analysis. GNPs were coated with two types of polyclonal anti-actin antibodies, and used in the assay to detect two types of actin: β- and bovine skeletal muscle actin in RIPA buffer. The results of our study revealed some complex aspects of actin binding characteristics, which depended on the type of actin reagent and anti-actin antibody used. A surprising finding was a reverse dose-response relationship between the actin concentration and the average particle size in the assay solution, which we attributed to the effect of RIPA buffer. Our results indicate that RIPA may also interfere in other types of nanoparticle-based assays, and that this interference deserves further study.

  16. Mobile probes

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Jørgensen, Anna Neustrup; Noesgaard, Signe Schack

    2016-01-01

    to in an interview. This method provided valuable insight into the contextual use, i.e. how did the online resource transfer to the work practice. However, the research team also found that mobile probes may provide the scaffolding necessary for individual and peer learning at a very local (intra-school) community...... level. This paper is an initial investigation of how the mobile probes process proved to engage teachers in their efforts to improve teaching. It also highlights some of the barriers emerging when applying mobile probes as a scaffold for learning.......A project investigating the effectiveness of a collection of online resources for teachers' professional development used mobile probes as a data collection method. Teachers received questions and tasks on their mobile in a dialogic manner while in their everyday context as opposed...

  17. Counting probe

    International Nuclear Information System (INIS)

    Matsumoto, Haruya; Kaya, Nobuyuki; Yuasa, Kazuhiro; Hayashi, Tomoaki

    1976-01-01

    Electron counting method has been devised and experimented for the purpose of measuring electron temperature and density, the most fundamental quantities to represent plasma conditions. Electron counting is a method to count the electrons in plasma directly by equipping a probe with the secondary electron multiplier. It has three advantages of adjustable sensitivity, high sensitivity of the secondary electron multiplier, and directional property. Sensitivity adjustment is performed by changing the size of collecting hole (pin hole) on the incident front of the multiplier. The probe is usable as a direct reading thermometer of electron temperature because it requires to collect very small amount of electrons, thus it doesn't disturb the surrounding plasma, and the narrow sweep width of the probe voltage is enough. Therefore it can measure anisotropy more sensitively than a Langmuir probe, and it can be used for very low density plasma. Though many problems remain on anisotropy, computer simulation has been carried out. Also it is planned to provide a Helmholtz coil in the vacuum chamber to eliminate the effect of earth magnetic field. In practical experiments, the measurement with a Langmuir probe and an emission probe mounted to the movable structure, the comparison with the results obtained in reverse magnetic field by using a Helmholtz coil, and the measurement of ionic sound wave are scheduled. (Wakatsuki, Y.)

  18. Size dependent reactivity of metal nanoparticles and alloys supported on HOPG, probed by the H-D exchange and the NH3 decomposition reactions

    DEFF Research Database (Denmark)

    Fiordaliso, Elisabetta Maria

    This thesis presents the results obtained from experiments performed in an Ultra High Vacuum (UHV) apparatus, named Parallel Screening, consisting of a preparation chamber combined to a High Pressure Cell (HPC) for testing catalytic activity at 1 bar. Two catalytic reactions have been carried out...... on different transition metals and metal alloys supported on sputtered Highly Ordered Pyrolytic Graphite (HOPG). The first is the H-D exchange reaction, used as probe reaction for H2 dissociation, which is relevant for Proton Exchange Membrane (PEM) fuel cells. Experiments have been performed on Pt, Ru, and Rh...... for Ru and Rh is due to the formation of compressed hydrogen adlayers on the terraces of the larger particles. In the case of the Pt/Ru alloys, it is found that the activity exceeds the values measured on the individual metals and have a maximum on alloys with surface composition ratio of Pt:Ru equal...

  19. Visual detection of telomerase activity with a tunable dynamic range by using a gold nanoparticle probe-based hybridization protection strategy

    Science.gov (United States)

    Wang, Jiasi; Wu, Li; Ren, Jinsong; Qu, Xiaogang

    2014-01-01

    We developed a novel telomere complementary (TC) oligonucleotide modified AuNP probe (TC-AuNPs) for colorimetric analysis of telomerase activity. The mechanism of this method is that the telomerase reaction products (TRP), which can hybridize with the TC-AuNPs, are able to protect the AuNPs from the aggregation induced by salt. It is demonstrated that the colorimetric method enabled the analysis of the telomerase activity in 1000 HeLa cells with the naked eye, and down to 100 HeLa cells with the aid of UV-Vis spectroscopy. This strategy is not only convenient and sensitive, but also has a tunable dynamic range. The platform is also applicable for the initial screening of a telomerase inhibitor to discover new anticancer drugs.We developed a novel telomere complementary (TC) oligonucleotide modified AuNP probe (TC-AuNPs) for colorimetric analysis of telomerase activity. The mechanism of this method is that the telomerase reaction products (TRP), which can hybridize with the TC-AuNPs, are able to protect the AuNPs from the aggregation induced by salt. It is demonstrated that the colorimetric method enabled the analysis of the telomerase activity in 1000 HeLa cells with the naked eye, and down to 100 HeLa cells with the aid of UV-Vis spectroscopy. This strategy is not only convenient and sensitive, but also has a tunable dynamic range. The platform is also applicable for the initial screening of a telomerase inhibitor to discover new anticancer drugs. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr05185d

  20. Paper-based assay of antioxidant activity using analyte-mediated on-paper nucleation of gold nanoparticles as colorimetric probes.

    Science.gov (United States)

    Choleva, Tatiana G; Kappi, Foteini A; Giokas, Dimosthenis L; Vlessidis, Athanasios G

    2015-02-20

    With the increasing interest in the health benefits arising from the consumption of dietary products rich in antioxidants, there exists a clear demand for easy-to-use and cost-effective tests that can be used for the identification of the antioxidant power of food products. Paper-based analytical devices constitute a remarkable platform for such expedient and low-cost assays with minimal external resources but efforts in this direction are still scarce. In this work we introduce a new paper-based device in the form of a sensor patch that enables the determination of antioxidant activity through analyte-driven on-paper formation of gold nanoparticles. The principle of detection capitalizes, for the first time, on the on-paper nucleation of gold ions to its respective nanoparticles, upon reduction by antioxidant compounds present in an aqueous sample. The ensuing chromatic transitions, induced on the paper surface, are used as an optical "signature" of the antioxidant strength of the solution. The response of the paper-based sensor was evaluated against a large variety of antioxidant species and the respective dose response curves were constructed. On the basis of these data, the contribution of each species according to its chemical structure was elucidated. For the analysis of real samples, a concentration-dependent colorimetric response was established against Gallic acid equivalents over a linear range of 10 μM-1.0 mM, with detection limits at the low and ultra-low μM levels (i.e. <1.0 μM) and satisfactory precision (RSD=3.6-12.6%). The sensor has been tested for the assessment of antioxidant activity in real samples (teas and wines) and the results correlated well with commonly used antioxidant detection methods. Importantly, the sensor performed favorably for long periods of time when stored at moisture-free and low temperature conditions without losing its activity thus posing as an attractive alternative to the assessment of antioxidant activity without

  1. Microwave-assisted synthesis of BSA-modified silver nanoparticles as a selective fluorescent probe for detection and cellular imaging of cadmium(II)

    International Nuclear Information System (INIS)

    Gu, Yu; Li, Nan; Gao, Mengmeng; Wang, Zilu; Xiao, Deli; Li, Yun; Jia, Huning; He, Hua

    2015-01-01

    We have developed a microwave-assisted method for the synthesis of silver nanoparticles (AgNPs) whose surface is modified with bovine serum albumin (BSA). The reaction involves reduction of the BSA-Ag(I) complex by tyrosine in strongly alkaline solution to form BSA-AgNPs. The reaction takes a few minutes only owing to rapid and uniform microwave heating. The modified AgNPs were characterized by UV–vis and fluorescence spectroscopy, transmission electron microscopy and X- ray photoelectron spectroscopy. The BSA-AgNPs are yellow and display luminescence with a maximum at 521 nm if excited at 465 nm. They have a hydrodynamic diameter of 3–5 nm and possess good colloidal stability in the pH 4.6 to 12.0 range. The fluorescence of the BSA-AgNPs is enhanced by Cd(II) ion due to the formation of a stable hybrid conjugate referred to as Cd-BSA-AgNPs. The effect was exploited to quantify Cd(II) in spiked real water samples with a 4.7 nM detection limit, and also to fluorescently image Cd(II) in Hepatoma cells. (author)

  2. A Simple Fluorescence Quenching Method for the Determination of Vanillin Using TGA-capped CdTe/ZnS Nanoparticles as Probes.

    Science.gov (United States)

    Li, Li; Zhang, Qiaolin; Ding, Yaping; Lu, Yaxiang; Cai, Xiaoyong; Yu, Lurong

    2015-07-01

    Based on the quenching of the fluorescence intensity of thioglycolic acid (TGA)-capped core-shell CdTe/ZnS nanoparticles (NPs) by vanillin, a novel, simple and rapid method for the determination of vanillin was proposed. In aqueous medium, the functionalized core-shell CdTe/ZnS NPs were successfully synthesized with TGA as the capping ligand. TGA-capped core-shell CdTe/ZnS NPs were characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. Factors affecting the vanillin detection were investigated, and the optimum conditions were also determined. Under the optimum conditions, the relative fluorescence intensity of CdTe/ZnS NPs was linearly proportional to vanillin over a concentration range from 9.4 × 10(-7) to 5.2 × 10(-4) M with a correlation coefficient of 0.998 and a detection limit of 2.6 × 10(-7) M. The proposed method was also employed to detect trace vanillin in cookies with satisfactory results.

  3. Probing the effects of cysteine residues on protein adsorption onto gold nanoparticles using wild-type and mutated GB3 proteins.

    Science.gov (United States)

    Siriwardana, Kumudu; Wang, Ailin; Vangala, Karthikeshwar; Fitzkee, Nicholas; Zhang, Dongmao

    2013-09-03

    The role of cysteine residues in the protein binding kinetics and stability on gold nanoparticles (AuNP) was studied using AuNP localized surface plasmon resonance (LSPR) in combination with an organothiol (OT) displacement method. GB3, the third IgG-binding domain of protein G, was used to model protein-AuNP adsorption. While wild-type GB3 (GB30) contains no cysteine residues, bioengineered GB3 variants containing one (GB31) and two (GB32) cysteine residues were also tested. The cysteine content has no significant effect on GB3 binding kinetics with AuNPs, and most protein adsorption occurs within the first few seconds upon protein/AuNP mixing. However, the stability of GB3 on the AuNP surface against OT displacement depends strongly on the cysteine content and the age of the AuNP/GB3 mixture. The GB30 covered AuNPs can be completely destabilized and aggregated by OTs, regardless of the age of the GB30/AuNP mixtures. Long-time incubation of GB31 or GB32 with AuNPs can stabilize AuNPs against the OT adsorption inducted aggregation. This study indicates that multiple forces involved in the GB3/AuNP interaction, and covalent binding between cysteine and AuNP is essential for a stable protein/AuNP complex.

  4. DNA probes

    International Nuclear Information System (INIS)

    Castelino, J.

    1992-01-01

    The creation of DNA probes for detection of specific nucleotide segments differs from ligand detection in that it is a chemical rather than an immunological reaction. Complementary DNA or RNA is used in place of the antibody and is labelled with 32 P. So far, DNA probes have been successfully employed in the diagnosis of inherited disorders, infectious diseases, and for identification of human oncogenes. The latest approach to the diagnosis of communicable and parasitic infections is based on the use of deoxyribonucleic acid (DNA) probes. The genetic information of all cells is encoded by DNA and DNA probe approach to identification of pathogens is unique because the focus of the method is the nucleic acid content of the organism rather than the products that the nucleic acid encodes. Since every properly classified species has some unique nucleotide sequences that distinguish it from every other species, each organism's genetic composition is in essence a finger print that can be used for its identification. In addition to this specificity, DNA probes offer other advantages in that pathogens may be identified directly in clinical specimens

  5. Targeting Cells With MR Imaging Probes: Cellular Interaction And Intracellular Magnetic Iron Oxide Nanoparticles Uptake In Brain Capillary Endothelial and Choroidal Plexus Epithelial Cells

    Science.gov (United States)

    Cambianica, I.; Bossi, M.; Gasco, P.; Gonzalez, W.; Idee, J. M.; Miserocchi, G.; Rigolio, R.; Chanana, M.; Morjan, I.; Wang, D.; Sancini, G.

    2010-10-01

    Magnetic iron oxide nanoparticles (NPs) are considered for various diagnostic and therapeutic applications in brain including their use as contrast agent for magnetic resonance imaging. In delivery application, the critical step is the transport across cell layers and the internalization of NPs into specific cells, a process often limited by poor targeting specificity and low internalization efficiency. The development of the models of brain endothelial cells and choroidal plexus epithelial cells in culture has allowed us to investigate into these mechanisms. Our strategy is aimed at exploring different routes to the entrapment of iron oxide NPs in these brain related cells. Here we demonstrated that not only cells endowed with a good phagocytic activity like activated macrophages but also endothelial brain capillary and choroidal plexus epithelial cells do internalize iron oxide NPs. Our study of the intracellular trafficking of NPs by TEM, and confocal microscopy revealed that NPs are mainly internalized by the endocytic pathway. Iron oxide NPs were dispersed in water and coated with 3,4-dihydroxyl-L-phenylalanine (L-DOPA) using standard procedures. Magnetic lipid NPs were prepared by NANOVECTOR: water in oil in water (W/O/W) microemulsion process has been applied to directly coat different iron based NPs by lipid layer or to encapsulate them into Solid Lipid Nanoparticles (SLNs). By these coating/loading the colloidal stability was improved without strong alteration of the particle size distribution. Magnetic lipid NPs could be reconstituted after freeze drying without appreciable changes in stability. L-DOPA coated NPs are stable in PBS and in MEM (Modified Eagle Medium) medium. The magnetic properties of these NPs were not altered by the coating processes. We investigated the cellular uptake, cytotoxicity, and interaction of these NPs with rat brain capillary endothelial (REB4) and choroidal plexus epithelial (Z310) cells. By means of widefield, confocal

  6. Conductivity Probe

    Science.gov (United States)

    2008-01-01

    The Thermal and Electrical Conductivity Probe (TECP) for NASA's Phoenix Mars Lander took measurements in Martian soil and in the air. The needles on the end of the instrument were inserted into the Martian soil, allowing TECP to measure the propagation of both thermal and electrical energy. TECP also measured the humidity in the surrounding air. The needles on the probe are 15 millimeters (0.6 inch) long. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  7. Pollution Probe.

    Science.gov (United States)

    Chant, Donald A.

    This book is written as a statement of concern about pollution by members of Pollution Probe, a citizens' anti-pollution group in Canada. Its purpose is to create public awareness and pressure for the eventual solution to pollution problems. The need for effective government policies to control the population explosion, conserve natural resources,…

  8. Probe specificity

    International Nuclear Information System (INIS)

    Laget, J.M.

    1986-11-01

    Specificity and complementarity of hadron and electron probes must be systematically developed to answer three questions currently asked in intermediate energy nuclear physics: what is nucleus structure at short distances, what is nature of short range correlations, what is three body force nature [fr

  9. Determination of DNA by solid substrate room temperature phosphorescence enhancing method based on the Morin.SiO{sub 2} luminescent nanoparticles-Pd system as a phosphorescence probe

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jiaming [Department of Chemistry, Zhangzhou Normal College, Zhangzhou 363000 (China)]. E-mail: zzsyliujiaming@163.com; Yang Tianlong [Department of Chemistry, Zhangzhou Normal College, Zhangzhou 363000 (China); Gao Fei [Department of Chemistry, Zhangzhou Normal College, Zhangzhou 363000 (China); Hu Lixiang [Department of Chemistry, Zhangzhou Normal College, Zhangzhou 363000 (China); He Hangxia [Department of Chemistry, Zhangzhou Normal College, Zhangzhou 363000 (China); Liu Qinying [Department of Chemistry, Zhangzhou Normal College, Zhangzhou 363000 (China); Liu Zhenbo [Department of Orthopedics and Traumatology, Fujian College of Chinese Medicine, Fuzhou 350003 (China); Huang Xiaomei [Department of Food and Chemical Engineering, Zhangzhou Institute of Technology, Zhangzhou 363000 (China); Zhu Guohui [Department of Food and Chemical Engineering, Zhangzhou Institute of Technology, Zhangzhou 363000 (China)

    2006-03-02

    Sodium carbonate (Na{sub 2}SiO{sub 3}) as the precursor, was mixed with Morin organic dye to synthesize silicon dioxide luminescent nanoparticles containing Morin (Morin.SiO{sub 2}) by sol-gel method. The particle sizes of SiO{sub 2}.nH{sub 2}O and Morin.SiO{sub 2} were both 50 nm, measured with TEM (transmission electron microscope). Morin.SiO{sub 2} modified by HS-CH{sub 2}COOH could be dissolved by water. In the HMTA (hexamethylenetetramine)-HCl buffer solution, Pd{sup 2+} could coordinate with Morin in Morin.SiO{sub 2} to form complex Pd{sup 2+}-Morin.SiO{sub 2}, which could emit phosphorescence on polyamide membrane. And DNA (deoxyribonucleic acid) could cause a sharp enhancement of the room temperature phosphorescence (RTP) intensity of complex Pd{sup 2+}-Morin.SiO{sub 2}. Thus a new method of solid substrate room temperature phosphorescence (SS-RTP) enhancing for the determination of DNA was established based on the Morin.SiO{sub 2} luminescent nanoparticles-Pd system as a phosphorescence probe. The {delta}Ip is directly proportional to the content of DNA in the range of 4.00-1000.0 fg spot{sup -1} (corresponding concentration: 0.010-2.50 ng ml{sup -1}). The regression equation of working curve was {delta}Ip = 21.13 + 0.2076m{sub DNA} (fg spot{sup -1}) (r = 0.9990) and the detection limit was 0.61 fg spot{sup -1} (corresponding concentration: 1.5 pg ml{sup -1}). This method had a wide linear range, high sensitivity, convenience, rapidity and only a little sample was needed. Samples containing 0.10 and 25.0 ng ml{sup -1} DNA were measured repeatedly for 11 times and RSDs were 3.2 and 4.1% (n = 11), respectively, which indicated that the method had a good repeatability. Disturbance of common ions, such as Mg{sup 2+}, K{sup +}, and Ca{sup 2+}, was small, and there was no disturbance in the presence of protein and RNA. This method has been applied to the determination of DNA in nectar successfully.

  10. Probing the crossover in CO desorption from single crystal to nanoparticulate Ru model catalysts

    DEFF Research Database (Denmark)

    Murphy, Shane; Strebel, Christian Ejersbo; Vendelbo, Søren Bastholm

    2011-01-01

    Crossover in CO desorption behavior and nanoscale structure probed with STM from ruthenium single crystals to PVD and mass-selected nanoparticles.......Crossover in CO desorption behavior and nanoscale structure probed with STM from ruthenium single crystals to PVD and mass-selected nanoparticles....

  11. Inorganic Nanoparticles for Multimodal Molecular Imaging

    Directory of Open Access Journals (Sweden)

    Magdalena Swierczewska

    2011-01-01

    Full Text Available Multimodal molecular imaging can offer a synergistic improvement of diagnostic ability over a single imaging modality. Recent development of hybrid imaging systems has profoundly impacted the pool of available multimodal imaging probes. In particular, much interest has been focused on biocompatible, inorganic nanoparticle-based multimodal probes. Inorganic nanoparticles offer exceptional advantages to the field of multimodal imaging owing to their unique characteristics, such as nanometer dimensions, tunable imaging properties, and multifunctionality. Nanoparticles mainly based on iron oxide, quantum dots, gold, and silica have been applied to various imaging modalities to characterize and image specific biologic processes on a molecular level. A combination of nanoparticles and other materials such as biomolecules, polymers, and radiometals continue to increase functionality for in vivo multimodal imaging and therapeutic agents. In this review, we discuss the unique concepts, characteristics, and applications of the various multimodal imaging probes based on inorganic nanoparticles.

  12. Quantifying Nanoparticle Internalization Using a High Throughput Internalization Assay.

    Science.gov (United States)

    Mann, Sarah K; Czuba, Ewa; Selby, Laura I; Such, Georgina K; Johnston, Angus P R

    2016-10-01

    The internalization of nanoparticles into cells is critical for effective nanoparticle mediated drug delivery. To investigate the kinetics and mechanism of internalization of nanoparticles into cells we have developed a DNA molecular sensor, termed the Specific Hybridization Internalization Probe - SHIP. Self-assembling polymeric 'pHlexi' nanoparticles were functionalized with a Fluorescent Internalization Probe (FIP) and the interactions with two different cell lines (3T3 and CEM cells) were studied. The kinetics of internalization were quantified and chemical inhibitors that inhibited energy dependent endocytosis (sodium azide), dynamin dependent endocytosis (Dyngo-4a) and macropinocytosis (5-(N-ethyl-N-isopropyl) amiloride (EIPA)) were used to study the mechanism of internalization. Nanoparticle internalization kinetics were significantly faster in 3T3 cells than CEM cells. We have shown that ~90% of the nanoparticles associated with 3T3 cells were internalized, compared to only 20% of the nanoparticles associated with CEM cells. Nanoparticle uptake was via a dynamin-dependent pathway, and the nanoparticles were trafficked to lysosomal compartments once internalized. SHIP is able to distinguish between nanoparticles that are associated on the outer cell membrane from nanoparticles that are internalized. This study demonstrates the assay can be used to probe the kinetics of nanoparticle internalization and the mechanisms by which the nanoparticles are taken up by cells. This information is fundamental for engineering more effective nanoparticle delivery systems. The SHIP assay is a simple and a high-throughput technique that could have wide application in therapeutic delivery research.

  13. Magnetic nanoparticles for biomedical applications

    International Nuclear Information System (INIS)

    Krustev, P.; Ruskov, T.

    2007-01-01

    In this paper we describe different biomedical application using magnetic nanoparticles. Over the past decade, a number of biomedical applications have begun to emerge for magnetic nanoparticles of differing sizes, shapes, and compositions. Areas under investigation include targeted drug delivery, ultra-sensitive disease detection, gene therapy, high throughput genetic screening, biochemical sensing, and rapid toxicity cleansing. Magnetic nanoparticles exhibit ferromagnetic or superparamagnetic behavior, magnetizing strongly under an applied field. In the second case (superparamagnetic nanoparticles) there is no permanent magnetism once the field is removed. The superparamagnetic nanoparticles are highly attractive as in vivo probes or in vitro tools to extract information on biochemical systems. The optical properties of magnetic metal nanoparticles are spectacular and, therefore, have promoted a great deal of excitement during the last few decades. Many applications as MRI imaging and hyperthermia rely on the use of iron oxide particles. Moreover magnetic nanoparticles conjugated with antibodies are also applied to hyperthermia and have enabled tumor specific contrast enhancement in MRI. Other promising biomedical applications are connected with tumor cells treated with magnetic nanoparticles with X-ray ionizing radiation, which employs magnetic nanoparticles as a complementary radiate source inside the tumor. (authors)

  14. Proximal Probes Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Proximal Probes Facility consists of laboratories for microscopy, spectroscopy, and probing of nanostructured materials and their functional properties. At the...

  15. Absence of Structural Impact of Noble Nanoparticles on P3HT:PCBM Blends for Plasmon-Enhanced Bulk-Heterojunction Organic Solar Cells Probed by Synchrotron GI-XRD.

    Science.gov (United States)

    Lilliu, Samuele; Alsari, Mejd; Bikondoa, Oier; Emyr Macdonald, J; Dahlem, Marcus S

    2015-06-01

    The incorporation of noble metal nanoparticles, displaying localized surface plasmon resonance, in the active area of donor-acceptor bulk-heterojunction organic photovoltaic devices is an industrially compatible light trapping strategy, able to guarantee better absorption of the incident photons and give an efficiency improvement between 12% and 38%. In the present work, we investigate the effect of Au and Ag nanoparticles blended with P3HT: PCBM on the P3HT crystallization dynamics by synchrotron grazing incidence X-ray diffraction. We conclude that the presence of (1) 80 nm Au, (2) mix of 5 nm, 50 nm, 80 nm Au, (3) 40 nm Ag, and (4) 10 nm, 40 nm, 60 nm Ag colloidal nanoparticles, at different concentrations below 0.3 wt% for Au and below 0.1% for Ag in P3HT: PCBM blends, does not affect the behaviour of the blends themselves.

  16. THE ORNL ATOM PROBE

    OpenAIRE

    Miller, M.

    1986-01-01

    The ORNL Atom Probe is a microanalytical tool for studies in materials science. The instrument is a combination of a customized version of the vacuum system of the VG FIM-100 atom probe, an ORNL-designed microcomputer-controlled digital timing system, and a double curved CEMA Imaging Atom Probe detector. The atom probe combines four instruments into one - namely a field ion microscope, an energy compensated time-of-flight mass spectrometer, an imaging atom probe, and a pulsed laser atom probe.

  17. Mobile Game Probes

    DEFF Research Database (Denmark)

    Borup Lynggaard, Aviaja

    2006-01-01

    This paper will examine how probes can be useful for game designers in the preliminary phases of a design process. The work is based upon a case study concerning pervasive mobile phone games where Mobile Game Probes have emerged from the project. The new probes are aimed towards a specific target...... group and the goal is to specify the probes so they will cover the most relevant areas for our project. The Mobile Game Probes generated many interesting results and new issues occurred, since the probes came to be dynamic and favorable for the process in new ways....

  18. Mismatch discrimination of lipidated DNA and LNA-probes (LiNAs) in hybridization-controlled liposome assembly

    DEFF Research Database (Denmark)

    Jakobsen, Ulla; Vogel, Stefan

    2016-01-01

    nucleic acids) probe designs, including membrane-anchoring requirements, studies on different probes and target lengths (including overhangs), DNA and RNA targets (including sequences associated with pathogens) for lipidated nucleic acids (LiNAs). Advantages and limitations of the liposome assembly based...... assay in the context of mismatch discrimination and SNP detection are presented. The advantages of membrane-anchored LiNA-probes compared to chemically attached probes on solid nanoparticles (e.g. gold nanoparticles) are described. Key functionalities such as non-covalent attachment of LiNA probes...

  19. Liquid-liquid interfacial nanoparticle assemblies

    Science.gov (United States)

    Emrick, Todd S [South Deerfield, MA; Russell, Thomas P [Amherst, MA; Dinsmore, Anthony [Amherst, MA; Skaff, Habib [Amherst, MA; Lin, Yao [Amherst, MA

    2008-12-30

    Self-assembly of nanoparticles at the interface between two fluids, and methods to control such self-assembly process, e.g., the surface density of particles assembling at the interface; to utilize the assembled nanoparticles and their ligands in fabrication of capsules, where the elastic properties of the capsules can be varied from soft to tough; to develop capsules with well-defined porosities for ultimate use as delivery systems; and to develop chemistries whereby multiple ligands or ligands with multiple functionalities can be attached to the nanoparticles to promote the interfacial segregation and assembly of the nanoparticles. Certain embodiments use cadmium selenide (CdSe) nanoparticles, since the photoluminescence of the particles provides a convenient means by which the spatial location and organization of the particles can be probed. However, the systems and methodologies presented here are general and can, with suitable modification of the chemistries, be adapted to any type of nanoparticle.

  20. From Color Code to Color Cue: Remembering Graphic Information.

    Science.gov (United States)

    Pruisner, Peggy A. P.

    This paper reports on a study which was conducted to determine the impact of color on learning. The entire seventh-grade class from a Midwest junior high school was used in the study. Each student was randomly assigned into one of four treatment groups: (1) color-cued presentation, color-cued assessment; (2) color-cued presentation, black/white…

  1. Electrical resistivity probes

    Science.gov (United States)

    Lee, Ki Ha; Becker, Alex; Faybishenko, Boris A.; Solbau, Ray D.

    2003-10-21

    A miniaturized electrical resistivity (ER) probe based on a known current-voltage (I-V) electrode structure, the Wenner array, is designed for local (point) measurement. A pair of voltage measuring electrodes are positioned between a pair of current carrying electrodes. The electrodes are typically about 1 cm long, separated by 1 cm, so the probe is only about 1 inch long. The electrodes are mounted to a rigid tube with electrical wires in the tube and a sand bag may be placed around the electrodes to protect the electrodes. The probes can be positioned in a borehole or on the surface. The electrodes make contact with the surrounding medium. In a dual mode system, individual probes of a plurality of spaced probes can be used to measure local resistance, i.e. point measurements, but the system can select different probes to make interval measurements between probes and between boreholes.

  2. Magnetic moment measurement of magnetic nanoparticles using atomic force microscopy

    International Nuclear Information System (INIS)

    Park, J-W; Lee, E-C; Ju, H; Yoo, I S; Chang, W-S; Chung, B H; Kim, B S

    2008-01-01

    Magnetic moment per unit mass of magnetic nanoparticles was found by using the atomic force microscope (AFM). The mass of the nanoparticles was acquired from the resonance frequency shift of the particle-attached AFM probe and magnetic force measurement was also carried out with the AFM. Combining with magnetic field strength, the magnetic moment per unit mass of the nanoparticles was determined as a function of magnetic field strength. (technical design note)

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  4. High temperature probe

    Science.gov (United States)

    Swan, Raymond A.

    1994-01-01

    A high temperature probe for sampling, for example, smokestack fumes, and is able to withstand temperatures of 3000.degree. F. The probe is constructed so as to prevent leakage via the seal by placing the seal inside the water jacket whereby the seal is not exposed to high temperature, which destroys the seal. The sample inlet of the probe is also provided with cooling fins about the area of the seal to provide additional cooling to prevent the seal from being destroyed. Also, a heated jacket is provided for maintaining the temperature of the gas being tested as it passes through the probe. The probe includes pressure sensing means for determining the flow velocity of an efficient being sampled. In addition, thermocouples are located in various places on the probe to monitor the temperature of the gas passing there through.

  5. Microneurosurgical water probe.

    Science.gov (United States)

    Pogády, P; Wurm, G

    2005-04-01

    When constructing the micro-neurosurgical water ball probe, the authors have simply combined the properties of a ball probe with an irrigational function and the supportive role of water current to form a new irrigating ball dissector. The micro-instrument has an outlet mechanism with which the surgeon can regulate the flow of physiological solution into the operational field. Its point has the properties of a ball probe, and the overall bayonet shape facilitates surgical interventions in deep tissues under microscopic control. The water probe therefore enables the surgeon to perform precise mechanical preparation supported by a regulated current of water and a targeted irrigation in the operational field. The physiological solution in the pressure infusion cuff is under minimal pressure and directly connected to the probe. Due to the fact that one device can be used for various purposes the water ball probe represents an advantageous alternative to conventional micro-neurosurgical preparation.

  6. Refining the statistical model for quantitative immunostaining of surface-functionalized nanoparticles by AFM.

    Science.gov (United States)

    MacCuspie, Robert I; Gorka, Danielle E

    2013-10-01

    Recently, an atomic force microscopy (AFM)-based approach for quantifying the number of biological molecules conjugated to a nanoparticle surface at low number densities was reported. The number of target molecules conjugated to the analyte nanoparticle can be determined with single nanoparticle fidelity using antibody-mediated self-assembly to decorate the analyte nanoparticles with probe nanoparticles (i.e., quantitative immunostaining). This work refines the statistical models used to quantitatively interpret the observations when AFM is used to image the resulting structures. The refinements add terms to the previous statistical models to account for the physical sizes of the analyte nanoparticles, conjugated molecules, antibodies, and probe nanoparticles. Thus, a more physically realistic statistical computation can be implemented for a given sample of known qualitative composition, using the software scripts provided. Example AFM data sets, using horseradish peroxidase conjugated to gold nanoparticles, are presented to illustrate how to implement this method successfully.

  7. Silver Nanoparticles

    Science.gov (United States)

    Khaydarov, R. R.; Khaydarov, R. A.; Estrin, Y.; Evgrafova, S.; Scheper, T.; Endres, C.; Cho, S. Y.

    The bactericidal effect of silver nanoparticles obtained by a novel electrochemical method on Escherichia coli, Staphylococcus aureus, Aspergillus niger and Penicillium phoeniceum cultures has been studied. The tests conducted have demonstrated that synthesized silver nanoparticles — when added to water paints or cotton fabrics — show a pronounced antibacterial/antifungal effect. It was shown that smaller silver nanoparticles have a greater antibacterial/antifungal efficacy. The paper also provides a review of scientific literature with regard to recent developments in the field of toxicity of silver nanoparticles and its effect on environment and human health.

  8. Tunable synthetic control of soft polymeric nanoparticle morphology.

    Science.gov (United States)

    Martin, Halie J; White, B Tyler; Scanlon, Christopher J; Saito, Tomonori; Dadmun, Mark D

    2017-11-29

    With a growing variety of nanoparticles available, research probing the influence of particle deformability, morphology, and topology on the behavior of all polymer nanocomposites is also increasing. In particular, the behavior of soft polymeric nanoparticles in polymer nanocomposites has displayed unique behavior, but their precise performance depends intimately on the internal structure and morphology of the nanoparticle. With the goal of providing guidelines to control the structure and morphology of soft polymeric nanoparticles, we have examined monomer starved semi-batch nano-emulsion polymerizations that form organic, soft nanoparticles, to correlate the precise structure of the nanoparticle to the rate of monomer addition and crosslinking density. The synthesis method produces 5-20 nm radii polystyrene nanoparticles with tunable morphologies. We report small angle neutron scattering (SANS) results that correlate synthetic conditions to the structural characteristics of soft polystyrene nanoparticles. These results show that the measured molecular weight of the nanoparticles is controlled by the monomer addition rate, the total nanoparticle radius is controlled by the excess surfactant concentration, and the crosslinking density has a direct effect on the topology of each nanoparticle. These studies thus provide pathways to control these 3 structural characteristics of the nanoparticle. This research, therefore provides a conduit to thoroughly investigate the effect of structural features of soft nanoparticles on their individual properties and those of their polymer nanocomposites.

  9. Protease-activated quantum dot probes

    International Nuclear Information System (INIS)

    Chang, Emmanuel; Miller, Jordan S.; Sun, Jiantang; Yu, William W.; Colvin, Vicki L.; Drezek, Rebekah; West, Jennifer L.

    2005-01-01

    We have developed a novel nanoparticulate luminescent probe with inherent signal amplification upon interaction with a targeted proteolytic enzyme. This construct may be useful for imaging in cancer detection and diagnosis. In this system, quantum dots (QDs) are bound to gold nanoparticles (AuNPs) via a proteolytically degradable peptide sequence to non-radiatively suppress luminescence. A 71% reduction in luminescence was achieved with conjugation of AuNPs to QDs. Release of AuNPs by peptide cleavage restores radiative QD photoluminescence. Initial studies observed a 52% rise in luminescence over 47 h of exposure to 0.2 mg/mL collagenase. These probes can be customized for targeted degradation simply by changing the sequence of the peptide linker

  10. Probe tests microweld strength

    Science.gov (United States)

    1965-01-01

    Probe is developed to test strength of soldered, brazed or microwelded joints. It consists of a spring which may be adjusted to the desired test pressure by means of a threaded probe head, and an indicator lamp. Device may be used for electronic equipment testing.

  11. (BDMCA) Nanoparticles

    African Journals Online (AJOL)

    Methods: Nanoparticle formulations were fabricated by a double emulsion solvent evaporation technique using polycaprolactone as the polymer. The nanoparticles were characterised for drug content, particles size, in vitro drug release and the drug-polymer interaction. The in vivo properties of the formulations in male ...

  12. Electrical impedance map (EIM) for margin assessment during robot-assisted laparoscopic prostatectomy (RALP) using a microendoscopic probe

    Science.gov (United States)

    Mahara, Aditya; Khan, Shadab; Schned, Alan R.; Hyams, Elias S.; Halter, Ryan J.

    2015-03-01

    Positive surgical margins (PSMs) found following prostate cancer surgery are a significant risk factor for post-operative disease recurrence. Noxious adjuvant radiation and chemical-based therapies are typically offered to men with PSMs. Unfortunately, no real-time intraoperative technology is currently available to guide surgeons to regions of suspicion during the initial prostatectomy where immediate surgical excisions could be used to reduce the chance of PSMs. A microendoscopic electrical impedance sensing probe was developed with the intention of providing real-time feedback regarding margin status to surgeons during robot-assisted laparoscopic prostatectomy (RALP) procedures. A radially configured 17-electrode microendoscopic probe was designed, constructed, and initially evaluated through use of gelatin-based phantoms and an ex vivo human prostate specimen. Impedance measurements are recorded at 10 frequencies (10 kHz - 100 kHz) using a high-speed FPGA-based electrical impedance tomography (EIT) system. Tetrapolar impedances are recorded from a number of different electrode configurations strategically chosen to sense tissue in a pre-defined sector underlying the probe face. A circular electrical impedance map (EIM) with several color-coded pie-shaped sectors is created to represent the impedance values of the probed tissue. Gelatin phantom experiments show an obvious distinction in the impedance maps between high and low impedance regions. Similarly, the EIM generated from the ex vivo prostate case shows distinguishing features between cancerous and benign regions. Based on successful development of this probe and these promising initial results, EIMs of additional prostate specimens are being collected to further evaluate this approach for intraoperative surgical margin assessment during RALP procedures.

  13. Intermetallic nanoparticles

    Science.gov (United States)

    Singh, Dileep; Yusufoglu, Yusuf; Timofeeva, Elena; Routbort, Jules

    2015-07-14

    A process for preparing intermetallic nanoparticles of two or more metals is provided. In particular, the process includes the steps: a) dispersing nanoparticles of a first metal in a solvent to prepare a first metal solution, b) forming a reaction mixture with the first metal solution and a reducing agent, c) heating the reaction mixture to a reaction temperature; and d) adding a second metal solution containing a salt of a second metal to the reaction mixture. During this process, intermetallic nanoparticles, which contain a compound with the first and second metals are formed. The intermetallic nanoparticles with uniform size and a narrow size distribution is also provided. An electrochemical device such as a battery with the intermetallic nanoparticles is also provided.

  14. Multi-color magnetic nanoparticle imaging using magnetorelaxometry.

    Science.gov (United States)

    Coene, A; Leliaert, J; Liebl, M; Löwa, N; Steinhoff, U; Crevecoeur, G; Dupré, L; Wiekhorst, F

    2017-04-21

    Magnetorelaxometry (MRX) is a well-known measurement technique which allows the retrieval of magnetic nanoparticle (MNP) characteristics such as size distribution and clustering behavior. This technique also enables the non-invasive reconstruction of the spatial MNP distribution by solving an inverse problem, referred to as MRX imaging. Although MRX allows the imaging of a broad range of MNP types, little research has been done on imaging different MNP types simultaneously. Biomedical applications can benefit significantly from a measurement technique that allows the separation of the resulting measurement signal into its components originating from different MNP types. In this paper, we present a theoretical procedure and experimental validation to show the feasibility of MRX imaging in reconstructing multiple MNP types simultaneously. Because each particle type has its own characteristic MRX signal, it is possible to take this a priori information into account while solving the inverse problem. This way each particle type's signal can be separated and its spatial distribution reconstructed. By assigning a unique color code and intensity to each particle type's signal, an image can be obtained in which each spatial distribution is depicted in the resulting color and with the intensity measuring the amount of particles of that type, hence the name multi-color MNP imaging. The theoretical procedure is validated by reconstructing six phantoms, with different spatial arrangements of multiple MNP types, using MRX imaging. It is observed that MRX imaging easily allows up to four particle types to be separated simultaneously, meaning their quantitative spatial distributions can be obtained.

  15. Recent Advances in Nanoparticle-Based Förster Resonance Energy Transfer for Biosensing, Molecular Imaging and Drug Release Profiling

    Directory of Open Access Journals (Sweden)

    Nai-Tzu Chen

    2012-12-01

    Full Text Available Förster resonance energy transfer (FRET may be regarded as a “smart” technology in the design of fluorescence probes for biological sensing and imaging. Recently, a variety of nanoparticles that include quantum dots, gold nanoparticles, polymer, mesoporous silica nanoparticles and upconversion nanoparticles have been employed to modulate FRET. Researchers have developed a number of “visible” and “activatable” FRET probes sensitive to specific changes in the biological environment that are especially attractive from the biomedical point of view. This article reviews recent progress in bringing these nanoparticle-modulated energy transfer schemes to fruition for applications in biosensing, molecular imaging and drug delivery.

  16. Neutrons as a probe

    International Nuclear Information System (INIS)

    Iizumi, Masashi

    1993-01-01

    As an introduction to the symposium a brief overview will be given about the features of neutrons as a probe. First it will be pointed out that the utilization of neutrons as a probe for investigating the structural and dynamical properties of condensed matters is a benign gift eventuated from the release of atomic energy initiated by Enrico Fermi exactly half century ago. Features of neutrons as a probe are discussed in accordance with the four basic physical properties of neutrons as an elementary particle; (1) no electric charge (the interaction with matter is nuclear), (2) the mass of neutron is 1 amu, (3) spin is 1/2 and (4) neutrons have magnetic dipole moment. Overview will be given on the uniqueness of neutrons as a probe and on the variety in the way they are used in the wide research area from the pure science to the industrial applications. (author)

  17. Noninvasive ultrasonic probes

    International Nuclear Information System (INIS)

    Barnes, S.R.; Galer, D.R.; Leard, R.S.

    1987-01-01

    An ultrasonic probe is described for insonifying the ascending aorta of a supine or reclining human patient from a location within the suprasternal notch of the patient. The probe comprises: a transducer head and an elongated handle; housing propagates ultrasonic energy and for intercept-frequency-shifted, reflected radiant energy; the handle has a proximate portion and a distal portion and a non-circular cross-sectional configuration with at least one longitudinal edge which furnishes a gripping surface; this facilitates tactile positioning of the probe; the transducer head is integral with the handle of the probe at the exposed end of the proximate portion; the transducer head has a generally arcuate cross-sectional configuration and a generally trapezoidal profile; the transducer head is oriented at right angles to the proximate portion of the handle and has an exposed, patient contacting end in which the transducer means are located; this facilitates the orientation of the transducer means housed in the head relative to the ascending aorta of the patient; and the distal end portion of the elongated probe handle is integral with and immovably oriented at a severe angle relative to the proximate end of that handle, and lies in the same plane as the proximate end of the handle; the transducer head of the probe is placed with facility within the suprasternal notch of the patient by an operator positioned behind the head of the patient

  18. Lipid nanoparticle interactions and assemblies

    Science.gov (United States)

    Preiss, Matthew Ryan

    Novel liposome-nanoparticle assemblies (LNAs) provide a biologically inspired route for designing multifunctional bionanotheranostics. LNAs combine the benefits of lipids and liposomes to encapsulate, transport, and protect hydrophilic and hydrophobic therapeutics with functional nanoparticles. Functional nanoparticles endow LNAs with additional capabilities, including the ability to target diseases, triggered drug release, controlled therapeutic output, and diagnostic capabilities to produce a drug delivery system that can effectively and efficiently deliver therapeutics while reducing side effects. Not only could LNAs make existing drugs better, they could also provide an avenue to allow once promising non-approved drugs (rejected due to harmful side effects, inadequate pharmacokinetics, and poor efficacy) to be safely used through targeted and controlled delivery directly to the diseased site. LNAs have the potential to be stimuli responsive, delivering drugs on command by external (ultrasound, RF heating, etc.) or internal (pH, blood sugar, heart rate, etc.) stimuli. Individually, lipids and nanoparticles have been clinically approved for therapy, such as Doxil (a liposomal doxorubicin for cancer treatment), and diagnosis, such as Feridex (an iron oxide nanoparticle an MRI contrast enhancement agent for liver tumors). In order to engineer these multifunctional LNAs for theranostic applications, the interactions between nanoparticles and lipids must be better understood. This research sought to explore the formation, design, structures, characteristics, and functions of LNAs. To achieve this goal, different types of LNAs were formed, specifically magnetoliposomes, bilayer decorated LNAs (DLNAs), and lipid-coated magnetic nanoparticles (LMNPs). A fluorescent probe was embedded in the lipid bilayer of magnetoliposomes allowing the local temperature and membrane fluidity to be observed. When subjected to an electromagnetic field that heated the encapsulated iron

  19. and Au nanoparticles for SERS applications

    Directory of Open Access Journals (Sweden)

    Fazio Enza

    2018-01-01

    Full Text Available The morphological and optical properties of noble metal nanoparticles prepared by picosecond laser generated plasmas in water were investigated. First, the ablation efficiency was maximized searching the optimal focusing conditions. The nanoparticle size, measured by Scanning Transmission Electron Microscopy, strongly depends on the laser fluence, keeping fixed the other deposition parameters such as the target to scanner objective distance and laser repetition frequency. STEM images indicate narrow gradients of NP sizes. Hence the optimization of ablation parameters favours a fine tuning of nanoparticles. UV-Visible spectroscopy helped to determine the appropriate laser wavelength to resonantly excite the localized surface plasmon to carry out Surface Enhanced Raman Scattering (SERS measurements. The SERS activity of Ag and Au substrates, obtained spraying the colloids synthesized in water, was tested using crystal violet as a probe molecule. The good SERS performance, observed at excitation wavelength 785 nm, is attributed to aggregation phenomena of nanoparticles sprayed on the support.

  20. Characterization of Polystyrene Soft Nanoparticles Using Small Angle Neutron Scattering

    Science.gov (United States)

    Martin, Halie; White, Tyler; Saito, Tomonori; Dadmun, Mark

    Polymer nanocomposites have become a prominent area of research recently. With a growing variety of nanoparticles available, research probing the influence of particle morphology on the overall nanocomposite properties is also increasing. Nanoparticle dispersion is controlled by both the chemical nature and morphology of the nanoparticle where a crosslinked, fuzzy organic nanoparticle is anticipated to enhance the overall miscibility and create a homogenous dispersion within a like-polymer matrix. A semi-batch microemulsion polymerization forms organic, soft nanoparticles where the precise structure of the nanoparticle is controlled by monomer rate of addition and crosslinking density. We will report small angle neutron scattering results that correlate synthetic conditions to the structural characteristics of soft nanoparticles. This analysis provides characterization of the individual nanoparticle molecular weight, the radius of the crosslinked core, the thickness of the fuzzy interfacial layer, and provides insight into the overall topography of the soft nanoparticle. This research provides a pathway to investigate the effect of nanoscale structural features of the nanoparticle on their individual properties and those of nanocomposites that contain these soft nanoparticles. DOE-BES, Division of Materials Sciences and Engineering.

  1. Model for resonant plasma probe.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Johnson, William Arthur; Hebner, Gregory Albert; Jorgenson, Roy E.; Coats, Rebecca Sue

    2007-04-01

    This report constructs simple circuit models for a hairpin shaped resonant plasma probe. Effects of the plasma sheath region surrounding the wires making up the probe are determined. Electromagnetic simulations of the probe are compared to the circuit model results. The perturbing effects of the disc cavity in which the probe operates are also found.

  2. Convective heat flow probe

    Science.gov (United States)

    Dunn, James C.; Hardee, Harry C.; Striker, Richard P.

    1985-01-01

    A convective heat flow probe device is provided which measures heat flow and fluid flow magnitude in the formation surrounding a borehole. The probe comprises an elongate housing adapted to be lowered down into the borehole; a plurality of heaters extending along the probe for heating the formation surrounding the borehole; a plurality of temperature sensors arranged around the periphery of the probe for measuring the temperature of the surrounding formation after heating thereof by the heater elements. The temperature sensors and heater elements are mounted in a plurality of separate heater pads which are supported by the housing and which are adapted to be radially expanded into firm engagement with the walls of the borehole. The heat supplied by the heater elements and the temperatures measured by the temperature sensors are monitored and used in providing the desired measurements. The outer peripheral surfaces of the heater pads are configured as segments of a cylinder and form a full cylinder when taken together. A plurality of temperature sensors are located on each pad so as to extend along the length and across the width thereof, with a heating element being located in each pad beneath the temperature sensors. An expansion mechanism driven by a clamping motor provides expansion and retraction of the heater pads and expandable packer-type seals are provided along the probe above and below the heater pads.

  3. Tuning structure of oppositely charged nanoparticle and protein complexes

    Science.gov (United States)

    Kumar, Sugam; Aswal, V. K.; Callow, P.

    2014-04-01

    Small-angle neutron scattering (SANS) has been used to probe the structures of anionic silica nanoparticles (LS30) and cationic lyszyme protein (M.W. 14.7kD, I.P. ˜ 11.4) by tuning their interaction through the pH variation. The protein adsorption on nanoparticles is found to be increasing with pH and determined by the electrostatic attraction between two components as well as repulsion between protein molecules. We show the strong electrostatic attraction between nanoparticles and protein molecules leads to protein-mediated aggregation of nanoparticles which are characterized by fractal structures. At pH 5, the protein adsorption gives rise to nanoparticle aggregation having surface fractal morphology with close packing of nanoparticles. The surface fractals transform to open structures of mass fractal morphology at higher pH (7 and 9) on approaching isoelectric point (I.P.).

  4. Tuning structure of oppositely charged nanoparticle and protein complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sugam, E-mail: sugam@barc.gov.in; Aswal, V. K., E-mail: sugam@barc.gov.in [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Callow, P. [Institut Laue Langevin, DS/LSS, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2014-04-24

    Small-angle neutron scattering (SANS) has been used to probe the structures of anionic silica nanoparticles (LS30) and cationic lyszyme protein (M.W. 14.7kD, I.P. ∼ 11.4) by tuning their interaction through the pH variation. The protein adsorption on nanoparticles is found to be increasing with pH and determined by the electrostatic attraction between two components as well as repulsion between protein molecules. We show the strong electrostatic attraction between nanoparticles and protein molecules leads to protein-mediated aggregation of nanoparticles which are characterized by fractal structures. At pH 5, the protein adsorption gives rise to nanoparticle aggregation having surface fractal morphology with close packing of nanoparticles. The surface fractals transform to open structures of mass fractal morphology at higher pH (7 and 9) on approaching isoelectric point (I.P.)

  5. Tuning structure of oppositely charged nanoparticle and protein complexes

    International Nuclear Information System (INIS)

    Kumar, Sugam; Aswal, V. K.; Callow, P.

    2014-01-01

    Small-angle neutron scattering (SANS) has been used to probe the structures of anionic silica nanoparticles (LS30) and cationic lyszyme protein (M.W. 14.7kD, I.P. ∼ 11.4) by tuning their interaction through the pH variation. The protein adsorption on nanoparticles is found to be increasing with pH and determined by the electrostatic attraction between two components as well as repulsion between protein molecules. We show the strong electrostatic attraction between nanoparticles and protein molecules leads to protein-mediated aggregation of nanoparticles which are characterized by fractal structures. At pH 5, the protein adsorption gives rise to nanoparticle aggregation having surface fractal morphology with close packing of nanoparticles. The surface fractals transform to open structures of mass fractal morphology at higher pH (7 and 9) on approaching isoelectric point (I.P.)

  6. Multispectral imaging probe

    Science.gov (United States)

    Sandison, David R.; Platzbecker, Mark R.; Descour, Michael R.; Armour, David L.; Craig, Marcus J.; Richards-Kortum, Rebecca

    1999-01-01

    A multispectral imaging probe delivers a range of wavelengths of excitation light to a target and collects a range of expressed light wavelengths. The multispectral imaging probe is adapted for mobile use and use in confined spaces, and is sealed against the effects of hostile environments. The multispectral imaging probe comprises a housing that defines a sealed volume that is substantially sealed from the surrounding environment. A beam splitting device mounts within the sealed volume. Excitation light is directed to the beam splitting device, which directs the excitation light to a target. Expressed light from the target reaches the beam splitting device along a path coaxial with the path traveled by the excitation light from the beam splitting device to the target. The beam splitting device directs expressed light to a collection subsystem for delivery to a detector.

  7. Cytotoxicity of surface-functionalized silicon and germanium nanoparticles: the dominant role of surface charges

    NARCIS (Netherlands)

    Bhattacharjee, S.; Rietjens, I.M.C.M.; Singh, M.P.; Atkins, T.M.; Purkait, T.K.; Xu, Z.; Regli, S.; Shukaliak, A.; Clark, R.J.; Mitchell, B.S.; Alink, G.M.; Marcelis, A.T.M.; Fink, M.J.; Veinot, J.G.C.; Kauzlarich, S.M.; Zuilhof, H.

    2013-01-01

    Although it is frequently hypothesized that surface (like surface charge) and physical characteristics (like particle size) play important roles in cellular interactions of nanoparticles (NPs), a systematic study probing this issue is missing. Hence, a comparative cytotoxicity study, quantifying

  8. DNA nanoparticles with core-shell morphology.

    Science.gov (United States)

    Chandran, Preethi L; Dimitriadis, Emilios K; Lisziewicz, Julianna; Speransky, Vlad; Horkay, Ferenc

    2014-10-14

    Mannobiose-modified polyethylenimines (PEI) are used in gene therapy to generate nanoparticles of DNA that can be targeted to the antigen-presenting cells of the immune system. We report that the sugar modification alters the DNA organization within the nanoparticles from homogenous to shell-like packing. The depth-dependent packing of DNA within the nanoparticles was probed using AFM nano-indentation. Unmodified PEI-DNA nanoparticles display linear elastic properties and depth-independent mechanics, characteristic of homogenous materials. Mannobiose-modified nanoparticles, however, showed distinct force regimes that were dependent on indentation depth, with 'buckling'-like response that is reproducible and not due to particle failure. By comparison with theoretical studies of spherical shell mechanics, the structure of mannobiosylated particles was deduced to be a thin shell with wall thickness in the order of few nanometers, and a fluid-filled core. The shell-core structure is also consistent with observations of nanoparticle denting in altered solution conditions, with measurements of nanoparticle water content from AFM images, and with images of DNA distribution in Transmission Electron Microscopy.

  9. Optical sensors and their applications for probing biological systems

    DEFF Research Database (Denmark)

    Palanco, Marta Espina

    biological sample to provide a SERS-template where silver nanoparticles can grow, thus providing a new insight into SERS-based sensors for chemically sensing in-situ plant constituents. Optical manipulation techniques have been used to investigate mechanical properties of soft membrane cells, i.e. mammalian......There is a great interest in exploring and developing new optical sensitive methodologies for probing complex biological systems. In this project we developed non-invasive and sensitive biosensor strategies for studying physiologically relevant chemical and physical properties of plant...... parts of the fresh tissues. The location of the nanoparticles inside some of the tissues was examined via SERS images, collected from Raman signatures of the constituents of the tissues as well as from Raman signatures of a specific pH-sensitive reporter molecule attached to the nanoparticles...

  10. Interaction of Colloidal Gold Nanoparticles with Model Serum Proteins: The Nanoparticle-Protein 'Corona' from a PhysicoChemical Viewpoint

    Science.gov (United States)

    Dominguez Medina, Sergio

    When nanoparticles come in contact with biological fluids they become coated with a mixture of proteins present in the media, forming what is known as the nanoparticle-protein 'corona'. This corona changes the nanoparticles' original surface properties and plays a central role in how these get screened by cellular receptors. In the context of biomedical research, this presents a bottleneck for the transition of nanoparticles from research laboratories to clinical settings. It is therefore fundamental to probe these nanoparticle-protein interactions in order to understand the different physico-chemical mechanisms involved. This thesis is aimed to investigate the exposure of colloidal gold nanoparticles to model serum proteins, particularly serum albumin, the main transporter of molecular compounds in the bloodstream of mammals. A set of experimental tools based on optical microscopy and spectroscopy were developed in order to probe these interactions in situ. First, the intrinsic photoluminescence and elastic scattering of individual gold nanoparticles were investigated in order to understand its physical origin. These optical signals were then used to measure the size of the nanoparticles while in Brownian diffusion using fluctuation correlation spectroscopy. This spectroscopic tool was then applied to detect the binding of serum albumin onto the nanoparticle surface, increasing its hydrodynamic size. By performing a binding isotherm as a function of protein concentration, it was determined that serum albumin follows an anti-cooperative binding mechanism on negatively charged gold nanoparticles. This protein monolayer substantially enhanced the stability of the colloid, preventing their aggregation in saline solutions with ionic strength higher than biological media. Cationic gold nanoparticles in contrast, aggregated when serum albumin was present at a low protein-to-nanoparticle ratio, but prevented aggregation if exposed in excess. Single-molecule fluorescence

  11. Probing the Solar Interior

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 3. Probing the Solar Interior Hearing the Heartbeats of the Sun. Ashok Ambastha. General ... Author Affiliations. Ashok Ambastha1. Joint In-Charge Udaipur Solar Observatory Physical Research laboratory P.O. Box No. 198 Udaipur 313 001, India ...

  12. Probing the Solar Interior

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 3. Probing the Solar Interior Hearing the Heartbeats of the Sun. Ashok Ambastha. General Article Volume 3 Issue 3 March 1998 pp 18-31. Fulltext. Click here to view fulltext PDF. Permanent link:

  13. Terahertz scanning probe microscope

    NARCIS (Netherlands)

    Klapwijk, T.M.

    2014-01-01

    The invention provides aterahertz scanning probe microscope setup comprising (i) a terahertz radiation source configured to generate terahertz radiation; (ii) a terahertz lens configured to receive at least part of the terahertz radiation from the terahertz radiation source; (iii) a cantilever unit

  14. One-Probe Search

    DEFF Research Database (Denmark)

    Östlin, Anna; Pagh, Rasmus

    2002-01-01

    We consider dictionaries that perform lookups by probing a single word of memory, knowing only the size of the data structure. We describe a randomized dictionary where a lookup returns the correct answer with probability 1 - e, and otherwise returns don't know. The lookup procedure uses an expan...

  15. Probing the Solar System

    Science.gov (United States)

    Wilkinson, John

    2013-01-01

    Humans have always had the vision to one day live on other planets. This vision existed even before the first person was put into orbit. Since the early space missions of putting humans into orbit around Earth, many advances have been made in space technology. We have now sent many space probes deep into the Solar system to explore the planets and…

  16. Thermal conductivity probe

    Science.gov (United States)

    Navickas, J.

    1969-01-01

    Low-mass probe accurately measures the thermal conductivity of polyurethane foam /and other thermal insulating materials/ while exposed to either hydrogen of helium permeation in temperature ranges from ambient to cryogenic. The thermal conductivity of a specimen is determined from an experimentally determined increase in temperature.

  17. Nanoparticle standards

    Energy Technology Data Exchange (ETDEWEB)

    Havrilla, George Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-08

    We will purchase a COTS materials printer and adapt it for solution printing of known elemental concentration solutions. A methodology will be developed to create deposits of known mass in known locations on selected substrates. The deposits will be characterized for deposited mass, physical morphology, thickness and uniformity. Once an acceptable methodology has been developed and validated, we will create round robin samples to be characterized by LGSIMS instruments at LANL, PNNL and NIST. We will demonstrate the feasibility of depositing nanoparticles in known masses with the goal of creating separated nanoparticles in known locations.

  18. Structure and function of nanoparticle-protein conjugates

    International Nuclear Information System (INIS)

    Aubin-Tam, M-E; Hamad-Schifferli, K

    2008-01-01

    Conjugation of proteins to nanoparticles has numerous applications in sensing, imaging, delivery, catalysis, therapy and control of protein structure and activity. Therefore, characterizing the nanoparticle-protein interface is of great importance. A variety of covalent and non-covalent linking chemistries have been reported for nanoparticle attachment. Site-specific labeling is desirable in order to control the protein orientation on the nanoparticle, which is crucial in many applications such as fluorescence resonance energy transfer. We evaluate methods for successful site-specific attachment. Typically, a specific protein residue is linked directly to the nanoparticle core or to the ligand. As conjugation often affects the protein structure and function, techniques to probe structure and activity are assessed. We also examine how molecular dynamics simulations of conjugates would complete those experimental techniques in order to provide atomistic details on the effect of nanoparticle attachment. Characterization studies of nanoparticle-protein complexes show that the structure and function are influenced by the chemistry of the nanoparticle ligand, the nanoparticle size, the nanoparticle material, the stoichiometry of the conjugates, the labeling site on the protein and the nature of the linkage (covalent versus non-covalent)

  19. PSMA-Targeted Nano-Conjugates as Dual-Modality (MRI/PET) Imaging Probes for the Non-Invasive Detection of Prostate Cancer

    National Research Council Canada - National Science Library

    Sun, Xiankai

    2008-01-01

    The goal of this project is to develop dual modality imaging probes for the detection of prostate cancer by doping radioisotopes to iron oxide nanoparticles, so that the sensitivity and specificity...

  20. Stabilization and controlled association of superparamagnetic nanoparticles using block copolymers

    International Nuclear Information System (INIS)

    Frka-Petesic, Bruno; Fresnais, Jerome; Berret, Jean-Francois; Dupuis, Vincent; Perzynski, Regine; Sandre, Olivier

    2009-01-01

    Mixing in aqueous solutions polyelectrolyte-neutral block copolymers with oppositely charged species, spontaneously forms stable core-shell complexes, which are electrostatically driven. We report here on the structural and orientational properties of such mixed magnetic nanoclusters made of magnetic iron oxide nanoparticles (MNPs) and polyelectrolyte-neutral block copolymers. Small angle neutron scattering and transmission electron microscopy experiments allows to probe the inner-core nanoparticle organization, leading to an average interparticle distance and confirming the hierarchical internal structure of the clusters. Thanks to the MNP optical anisotropy, we also probe the under-magnetic field orientational properties of the core-shell clusters and their dynamical rotational relaxation

  1. Influence of nanoparticle-ion and nanoparticle-polymer interactions on ion transport and viscoelastic properties of polymer electrolytes

    International Nuclear Information System (INIS)

    Mogurampelly, Santosh; Sethuraman, Vaidyanathan; Pryamitsyn, Victor; Ganesan, Venkat

    2016-01-01

    We use atomistic simulations to probe the ion conductivities and mechanical properties of polyethylene oxide electrolytes containing Al 2 O 3 nanoparticles. We specifically study the influence of repulsive polymer-nanoparticle and ion-nanoparticle interactions and compare the results with those reported for electrolytes containing the polymorph β-Al 2 O 3 nanoparticles. We observe that incorporating repulsive nanoparticle interactions generally results in increased ionic mobilities and decreased elastic moduli for the electrolyte. Our results indicate that both ion transport and mechanical properties are influenced by the polymer segmental dynamics in the interfacial zones of the nanoparticle in the ion-doped systems. Such effects were seen to be determined by an interplay between the nanoparticle-polymer, nanoparticle-ion, and ion-polymer interactions. In addition, such interactions were also observed to influence the number of dissociated ions and the resulting conductivities. Within the perspective of the influence of nanoparticles on the polymer relaxation times in ion-doped systems, our results in the context of viscoelastic properties were consistent with the ionic mobilities. Overall, our results serve to highlight some issues that confront the efforts to use nanoparticle dispersions to simultaneously enhance the conductivity and the mechanical strength of polymer electrolyte.

  2. Is there evidence for man-made nanoparticles in the Dutch environment?

    NARCIS (Netherlands)

    Bäuerlein, Patrick S; Emke, Erik; Tromp, Peter; Hofman, Jan A M H; Carboni, Andrea; Schooneman, Ferry; de Voogt, Pim; van Wezel, Annemarie P

    2016-01-01

    Only very limited information is available on measured environmental concentrations of nanoparticles. In this study, several environmental compartments in The Netherlands were probed for the presence of nanoparticles. Different types of water were screened for the presence of inorganic (Ag, Au,

  3. (shell) nanoparticles

    Indian Academy of Sciences (India)

    nanoparticles the quasistatic approximation is not appropriate and Mie theory illustrates SPR due to dipole and quadrupole in extinction ... The time-dependent local density approximation (TDLDA) [19] .... satile technique for determining the optical properties of nanoshells or any other spherical particles of any dimension.

  4. Calibration Fixture For Anemometer Probes

    Science.gov (United States)

    Lewis, Charles R.; Nagel, Robert T.

    1993-01-01

    Fixture facilitates calibration of three-dimensional sideflow thermal anemometer probes. With fixture, probe oriented at number of angles throughout its design range. Readings calibrated as function of orientation in airflow. Calibration repeatable and verifiable.

  5. Small angle neutron scattering study of disordered and crystalline iron nanoparticle assemblies

    International Nuclear Information System (INIS)

    Farrell, D.F.; Ijiri, Y.; Kelly, C.V.; Borchers, J.A.; Rhyne, J.J.; Ding, Y.; Majetich, S.A.

    2006-01-01

    Monodisperse surfactant-coated iron nanoparticles are used to form both disordered nanoparticle assemblies and ordered face-centered cubic nanoparticle crystals. The structural order is probed by small angle X-ray scattering, and the magnetic scattering is studied using small angle neutron scattering. The magnetic scattering corresponding to different length scales is interpreted in terms of collective correlations among the particles within the assemblies

  6. Photosensitization of Colloidal SnO2 Semiconductor Nanoparticles with Xanthene Dyes

    OpenAIRE

    Nagarajan, N.; Paramaguru, G.; Vanitha, G.; Renganathan, R.

    2013-01-01

    The photochemical behavior of xanthene dyes (fluorescein, erythrosine, and eosin) with colloidal SnO2 nanoparticles was probed by UV-visible, steady state, and time resolved fluorescence measurements. The prepared SnO2 nanoparticles were characterized by using UV-visible and powder XRD measurements. The xanthene dyes were adsorbed on the surface of colloidal SnO2 nanoparticles through electrostatic interaction. Apparent association constant (Kapp) was calculated from the relevant fluorescence...

  7. Heavy ion beam probing

    Energy Technology Data Exchange (ETDEWEB)

    Hickok, R L

    1980-07-01

    This report consists of the notes distributed to the participants at the IEEE Mini-Course on Modern Plasma Diagnostics that was held in Madison, Wisconsin in May 1980. It presents an overview of Heavy Ion Beam Probing that briefly describes the principles and discuss the types of measurements that can be made. The problems associated with implementing beam probes are noted, possible variations are described, estimated costs of present day systems, and the scaling requirements for large plasma devices are presented. The final chapter illustrates typical results that have been obtained on a variety of plasma devices. No detailed calculations are included in the report, but a list of references that will provide more detailed information is included.

  8. Heavy ion beam probing

    International Nuclear Information System (INIS)

    Hickok, R.L.

    1980-07-01

    This report consists of the notes distributed to the participants at the IEEE Mini-Course on Modern Plasma Diagnostics that was held in Madison, Wisconsin in May 1980. It presents an overview of Heavy Ion Beam Probing that briefly describes the principles and discuss the types of measurements that can be made. The problems associated with implementing beam probes are noted, possible variations are described, estimated costs of present day systems, and the scaling requirements for large plasma devices are presented. The final chapter illustrates typical results that have been obtained on a variety of plasma devices. No detailed calculations are included in the report, but a list of references that will provide more detailed information is included

  9. Gravity Probe B Inspection

    Science.gov (United States)

    2000-01-01

    The space vehicle Gravity Probe B (GP-B) is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. In this photograph, engineer Gary Reynolds is inspecting the inside of the probe neck during probe thermal repairs. GP-B is scheduled for launch in April 2004 and managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Russ Leese, Gravity Probe B, Stanford University)

  10. Novel Eddycurrent Probe Development.

    Science.gov (United States)

    1981-12-01

    oVCut MVc AVu inc F C -- -(1)(-jlOOO AZC (23)0 --2--M F1 (23) If the Thevenin source voltages, V0, are adjusted so that Vinc is the same for both the...as small as 1.2 cm. The differential probe assembly was spring loaded about a pivot post (see Figure 12) so it could scan noncircular or eccentric

  11. Induced current heating probe

    International Nuclear Information System (INIS)

    Thatcher, G.; Ferguson, B.G.; Winstanley, J.P.

    1984-01-01

    An induced current heating probe is of thimble form and has an outer conducting sheath and a water flooded flux-generating unit formed from a stack of ferrite rings coaxially disposed in the sheath. The energising coil is made of solid wire which connects at one end with a coaxial water current tube and at the other end with the sheath. The stack of ferrite rings may include non-magnetic insulating rings which help to shape the flux. (author)

  12. Atom probe crystallography

    OpenAIRE

    Gault, Baptiste; Moody, Michael P.; Cairney, Julie M.; Ringer, Simon P.

    2012-01-01

    This review addresses new developments in the emerging area of “atom probe crystallography”, a materials characterization tool with the unique capacity to reveal both composition and crystallographic structure at the atomic scale. This information is crucial for the manipulation of microstructure for the design of both structural and functional materials with optimized mechanical, electric, optoelectronic, magnetic, or superconducting properties that will find application in, for example, nan...

  13. Probing gravitation with pulsars

    Science.gov (United States)

    Kramer, Michael

    2013-03-01

    Radio pulsars are fascinating and extremely useful objects. Despite our on-going difficulties in understanding the details of their emission physics, they can be used as precise cosmic clocks in a wide-range of experiments - in particular for probing gravitational physics. While the reader should consult the contributions to these proceedings to learn more about this exciting field of discovering, exploiting and understanding pulsars, we will concentrate here on on the usage of pulsars as gravity labs.

  14. Nanoscale thermal probing

    Directory of Open Access Journals (Sweden)

    Yanan Yue

    2012-03-01

    Full Text Available Nanoscale novel devices have raised the demand for nanoscale thermal characterization that is critical for evaluating the device performance and durability. Achieving nanoscale spatial resolution and high accuracy in temperature measurement is very challenging due to the limitation of measurement pathways. In this review, we discuss four methodologies currently developed in nanoscale surface imaging and temperature measurement. To overcome the restriction of the conventional methods, the scanning thermal microscopy technique is widely used. From the perspective of measuring target, the optical feature size method can be applied by using either Raman or fluorescence thermometry. The near-field optical method that measures nanoscale temperature by focusing the optical field to a nano-sized region provides a non-contact and non-destructive way for nanoscale thermal probing. Although the resistance thermometry based on nano-sized thermal sensors is possible for nanoscale thermal probing, significant effort is still needed to reduce the size of the current sensors by using advanced fabrication techniques. At the same time, the development of nanoscale imaging techniques, such as fluorescence imaging, provides a great potential solution to resolve the nanoscale thermal probing problem.

  15. Einstein Inflationary Probe (EIP)

    Science.gov (United States)

    Hinshaw, Gary

    2004-01-01

    I will discuss plans to develop a concept for the Einstein Inflation Probe: a mission to detect gravity waves from inflation via the unique signature they impart to the cosmic microwave background (CMB) polarization. A sensitive CMB polarization satellite may be the only way to probe physics at the grand-unified theory (GUT) scale, exceeding by 12 orders of magnitude the energies studied at the Large Hadron Collider. A detection of gravity waves would represent a remarkable confirmation of the inflationary paradigm and set the energy scale at which inflation occurred when the universe was a fraction of a second old. Even a strong upper limit to the gravity wave amplitude would be significant, ruling out many common models of inflation, and pointing to inflation occurring at much lower energy, if at all. Measuring gravity waves via the CMB polarization will be challenging. We will undertake a comprehensive study to identify the critical scientific requirements for the mission and their derived instrumental performance requirements. At the core of the study will be an assessment of what is scientifically and experimentally optimal within the scope and purpose of the Einstein Inflation Probe.

  16. Multifunctional Silica Nanoparticles Modified via Silylated-Decaborate Precursors

    Directory of Open Access Journals (Sweden)

    Fatima Abi-Ghaida

    2015-01-01

    Full Text Available A new class of multifunctional silica nanoparticles carrying boron clusters (10-vertex closo-decaborate and incorporating luminescent centers (fluorescein has been developed as potential probes/carriers for potential application in boron neutron capture therapy (BNCT. These silica nanoparticles were charged in situ with silylated-fluorescein fluorophores via the Stöber method and their surface was further functionalized with decaborate-triethoxysilane precursors. The resulting decaborate dye-doped silica nanoparticles were characterized by TEM, solid state NMR, DLS, nitrogen sorption, elemental analysis, and fluorescence spectroscopy.

  17. Fungus-mediated synthesis of gold nanoparticles: a novel biological approach to nanoparticle synthesis.

    Science.gov (United States)

    Honary, Soheyla; Gharaei-Fathabad, Eshrat; Barabadi, Hamed; Naghibi, Farzaneh

    2013-02-01

    The biological effects of nanoparticles and their uses as molecular probes are research areas of growing interest. The present study demonstrates an eco-friendly biosynthesis of gold nanoparticles. The pure colonies of penicillium aurantiogriseum, penicillium citrinum, and penicillium waksmanii were cultured in fluid czapek dox broth. Then, their supernatants were examined for the ability to produce gold nanoparticles. In this step, 1 mM solution of AuCl added to the reaction matrixes separately. The reactions were performed in a dark environment at 28 degrees C. After 24 hours, it was observed that the color of the solutions turned to dark purple from light yellow. Synthesized gold nanoparticles were characterized by using UV-Visible Spectroscopy, Nano Zeta Sizer, Scanning Electron Microscopy and Fourier transformed infrared spectroscopy. The results showed that the gold nanoparticles were formed fairly uniform with spherical shape with the Z-average diameter of 153.3 nm, 172 nm and 160.1 nm for penicillium aurantiogriseum, penicillium citrinum, and penicillium waksmanii, respectively. The Fourier transformed infrared spectra revealed the presence of different functional groups to gold nanoparticles which were present in the fungal extract. The current approach suggests that the rapid synthesis of nanoparticles would be proper for developing a biological process for mass scale production.

  18. Nine New Fluorescent Probes

    Science.gov (United States)

    Lin, Tsung-I.; Jovanovic, Misa V.; Dowben, Robert M.

    1989-06-01

    Absorption and fluorescence spectroscopic studies are reported here for nine new fluorescent probes recently synthesized in our laboratories: four pyrene derivatives with substituents of (i) 1,3-diacetoxy-6,8-dichlorosulfonyl, (ii) 1,3-dihydroxy-6,8-disodiumsulfonate, (iii) 1,3-disodiumsulfonate, and (iv) l-ethoxy-3,6,8-trisodiumsulfonate groups, and five [7-julolidino] coumarin derivatives with substituents of (v) 3-carboxylate-4-methyl, (vi) 3- methylcarboxylate, (vii) 3-acetate-4-methyl, (viii) 3-propionate-4-methyl, and (ix) 3-sulfonate-4-methyl groups. Pyrene compounds i and ii and coumarin compounds v and vi exhibit interesting absorbance and fluorescence properties: their absorption maxima are red shifted compared to the parent compound to the blue-green region, and the band width broadens considerably. All four blue-absorbing dyes fluoresce intensely in the green region, and the two pyrene compounds emit at such long wavelengths without formation of excimers. The fluorescence properties of these compounds are quite environment-sensitive: considerable spectral shifts and fluorescence intensity changes have been observed in the pH range from 3 to 10 and in a wide variety of polar and hydrophobic solvents with vastly different dielectric constants. The high extinction and fluorescence quantum yield of these probes make them ideal fluorescent labeling reagents for proteins, antibodies, nucleic acids, and cellular organelles. The pH and hydrophobicity-dependent fluorescence changes can be utilized as optical pH and/or hydrophobicity indicators for mapping environmental difference in various cellular components in a single cell. Since all nine probes absorb in the UV, but emit at different wavelengths in the visible, these two groups of compounds offer an advantage of utilizing a single monochromatic light source (e.g., a nitrogen laser) to achieve multi-wavelength detection for flow cytometry application. As a first step to explore potential application in

  19. Development of Mackintosh Probe Extractor

    Science.gov (United States)

    Rahman, Noor Khazanah A.; Kaamin, Masiri; Suwandi, Amir Khan; Sahat, Suhaila; Jahaya Kesot, Mohd

    2016-11-01

    Dynamic probing is a continuous soil investigation technique, which is one of the simplest soil penetration test. It basically consist of repeatedly driving a metal tipped probe into the ground using a drop weight of fixed mass and travel. Testing was carried out continuously from ground level to the final penetration depth. Once the soil investigation work done, it is difficult to pull out the probe rod from the ground, due to strong soil structure grip against probe cone and prevent the probe rod out from the ground. Thus, in this case, a tool named Extracting Probe was created to assist in the process of retracting the probe rod from the ground. In addition, Extracting Probe also can reduce the time to extract the probe rod from the ground compare with the conventional method. At the same time, it also can reduce manpower cost because only one worker involve to handle this tool compare with conventional method used two or more workers. From experiment that have been done we found that the time difference between conventional tools and extracting probe is significant, average time difference is 155 minutes. In addition the extracting probe can reduce manpower usage, and also labour cost for operating the tool. With all these advantages makes this tool has the potential to be marketed.

  20. Preparation and characterization of graphene oxide encapsulated gold nanoparticles.

    Science.gov (United States)

    Yun, Yong Ju; Song, Ki-Bong

    2013-11-01

    We present a simple approach for the fabrication of graphene oxide-encapsulated gold nanoparticles using graphene oxide sheet-wrapping via electrostatic self-assembly. By mixing bovine serum albumin molecule-functionalized gold nanoparticles with graphene oxide dispersion, positively charged bovine serum albumin/gold nanoparticles easily assembled with negatively charged graphene oxide sheets through electrostatic interaction. Transmittance electron microscopy, scanning electron microscopy, atomic force microscopy, and Raman spectroscopy were used to confirm the encapsulation of graphene oxide on gold nanoparticles. Interestingly, graphene oxide sheets wrapping mainly occurs along the main body of single or a few gold nanoparticles. Additionally, by measuring the ultraviolet-visible spectroscopy spectrum, we found that the surface plasmon resonances band of the graphene oxide-encapsulated gold nanoparticles was found to become red-shifted compared to that of pristine gold nanoparticles, whereas similar to that of bovine serum albumin-coated gold nanoparticles. These results indicating that most of graphene oxide-encapsulated gold nanoparticles have good monodispersity and spherical shape. These resulting materials may potentially serve as a platform for plasmon resonance electron transfer spectroscopy or a probe for low level biosensing.

  1. A colorimetric probe for the detection of Ni2+ in water based on Ag ...

    African Journals Online (AJOL)

    A Ni2+ based colorimetric probe based on glutathione-stabilized silver/copper nanoparticles (GSH-Ag-Cu alloy NPs) in an electrospun polymer matrix is reported. Glutathione-Ag-Cu alloy NPs were characterized by ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM) and transmission electron ...

  2. Electrospun fibre colorimetric probe based on gold nanoparticles for ...

    African Journals Online (AJOL)

    Upon exposure to cholesterol and a series of compounds known to induce oestrogenic activity, p,p'-DDE, deltamethrin, 4-tert-octylphenol and nonylphenol, only 17β-estradiol could induce a pink colour observable by the naked eye, which is indicative that the proposed gold nanoparticles–incorporated electrospun ...

  3. Mobile Probing Kit

    DEFF Research Database (Denmark)

    Larsen, Jakob Eg; Sørensen, Lene Tolstrup; Sørensen, J.K.

    2007-01-01

    Mobile Probing Kit is a low tech and low cost methodology for obtaining inspiration and insights into user needs, requirements and ideas in the early phases of a system's development process. The methodology is developed to identify user needs, requirements and ideas among knowledge workers...... characterized as being highly nomadic and thus potential users of mobile and ubiquitous technologies. The methodology has been applied in the 1ST MAGNET Beyond project in order to obtain user needs and requirements in the process of developing pilot services. We report on the initial findings from applying...... this methodology in the early phases of this large scale research and development process....

  4. High spatial resolution Kelvin probe force microscopy with coaxial probes

    International Nuclear Information System (INIS)

    Brown, Keith A; Westervelt, Robert M; Satzinger, Kevin J

    2012-01-01

    Kelvin probe force microscopy (KPFM) is a widely used technique to measure the local contact potential difference (CPD) between an AFM probe and the sample surface via the electrostatic force. The spatial resolution of KPFM is intrinsically limited by the long range of the electrostatic interaction, which includes contributions from the macroscopic cantilever and the conical tip. Here, we present coaxial AFM probes in which the cantilever and cone are shielded by a conducting shell, confining the tip–sample electrostatic interaction to a small region near the end of the tip. We have developed a technique to measure the true CPD despite the presence of the shell electrode. We find that the behavior of these probes agrees with an electrostatic model of the force, and we observe a factor of five improvement in spatial resolution relative to unshielded probes. Our discussion centers on KPFM, but the field confinement offered by these probes may improve any variant of electrostatic force microscopy. (paper)

  5. Surface plasmon enhancement in gold nanoparticles in the presence of an optical gain medium: an analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sathiyamoorthy, K; Sreekanth, K V; Sidharthan, R; Murukeshan, V M [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Xing Bengang, E-mail: mmurukeshan@ntu.edu.sg [Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371 (Singapore)

    2011-10-26

    The localized surface plasmon (LSP) enhancement in a gold nanoparticle is demonstrated in this paper. The enhancement of LSP is influenced by both size and the dielectric gain medium surrounding the nanoparticles. The nanoparticle is found to induce plasmonic enhancement of varying degrees depending on its size, and it is inferred that a gold nanoparticle of size 60 nm exhibits the maximum LSP for 532 nm excitation. Singularity due to cancellation of SP loss by an infinite gain medium and LSP enhancement are studied using a pump-probe Rayleigh scattering experiment. Gold nanoparticles of average size 60 nm exhibit the lowest threshold power to observe Rayleigh scattering. Furthermore, compared with the bare nanoparticles, a 12.5 fold enhancement of LSP is observed when the nanoparticle of average size 60 nm is kept in the gain medium.

  6. Thermal Plasma Synthesis of Superparamagnetic Iron Oxide Nanoparticles

    NARCIS (Netherlands)

    Lei, P.Y.; Boies, A.M.; Calder, S.A.; Girshick, S.L.

    2012-01-01

    Superparamagnetic iron oxide nanoparticles were synthesized by injecting ferrocene vapor and oxygen into an argon/helium DC thermal plasma. Size distributions of particles in the reactor exhaust were measured online using an aerosol extraction probe interfaced to a scanning mobility particle sizer,

  7. The Galaxy Evolution Probe

    Science.gov (United States)

    Glenn, Jason; Galaxy Evolution Probe Team

    2018-01-01

    The Galaxy Evolution Probe (GEP) is a concept for a far-infrared observatory to survey large regions of sky for star-forming galaxies from z = 0 to beyond z = 3. Our knowledge of galaxy formation is incomplete and requires uniform surveys over a large range of redshifts and environments to accurately describe mass assembly, star formation, supermassive black hole growth, interactions between these processes, and what led to their decline from z ~ 2 to the present day. Infrared observations are sensitive to dusty, star-forming galaxies, which have bright polycyclic aromatic hydrocarbon (PAH) emission features and warm dust continuum in the rest-frame mid infrared and cooler thermal dust emission in the far infrared. Unlike previous far-infrared continuum surveys, the GEP will measure photometric redshifts commensurate with galaxy detections from PAH emission and Si absorption features, without the need for obtaining spectroscopic redshifts of faint counterparts at other wavelengths.The GEP design includes a 2 m diameter telescope actively cooled to 4 K and two instruments: (1) An imager covering 10 to 300 um with 25 spectral resolution R ~ 8 bands (with lower R at the longest wavelengths) to detect star-forming galaxies and measure their redshifts photometrically. (2) A 23 – 190 um, R ~ 250 dispersive spectrometer for redshift confirmation and identification of obscured AGN using atomic fine-structure lines. Lines including [Ne V], [O IV], [O III], [O I], and [C II] will probe gas physical conditions, radiation field hardness, and metallicity. Notionally, the GEP will have a two-year mission: galaxy surveys with photometric redshifts in the first year and a second year devoted to follow-up spectroscopy. A comprehensive picture of star formation in galaxies over the last 10 billion years will be assembled from cosmologically relevant volumes, spanning environments from field galaxies and groups, to protoclusters, to dense galaxy clusters.Commissioned by NASA, the

  8. Poly(amino acid) functionalized maghemite and gold nanoparticles

    International Nuclear Information System (INIS)

    Perego, Davide; Manuel Domínguez-Vera, José; Gálvez, Natividad; Masciocchi, Norberto; Guagliardi, Antonietta

    2013-01-01

    Bimodal MRI/OI imaging probes are of great interest in nanomedicine. Although many organic polymers have been studied thoroughly for in vivo applications, reports on the use of poly(amino acid)s as coating polymers are scarce. In this paper, poly-(d-glutamic acid, d-lysine) (PGL) has been used for coating maghemite and gold nanoparticles. An advantage of this flexible and biocompatible polymer is that, once anchored to the nanoparticle surface, dangling lysine amino groups are available for the incorporation of new functionalities. As an example, Alexa Fluor derivatives have been attached to PGL-coated maghemite nanoparticles to obtain magnetic/fluorescent materials. These dual-property materials could be used as bimodal MRI/OI probes for in vivo imaging. (paper)

  9. Cosmological Probes for Supersymmetry

    Directory of Open Access Journals (Sweden)

    Maxim Khlopov

    2015-05-01

    Full Text Available The multi-parameter character of supersymmetric dark-matter models implies the combination of their experimental studies with astrophysical and cosmological probes. The physics of the early Universe provides nontrivial effects of non-equilibrium particles and primordial cosmological structures. Primordial black holes (PBHs are a profound signature of such structures that may arise as a cosmological consequence of supersymmetric (SUSY models. SUSY-based mechanisms of baryosynthesis can lead to the possibility of antimatter domains in a baryon asymmetric Universe. In the context of cosmoparticle physics, which studies the fundamental relationship of the micro- and macro-worlds, the development of SUSY illustrates the main principles of this approach, as the physical basis of the modern cosmology provides cross-disciplinary tests in physical and astronomical studies.

  10. Convex probe endobronchial ultrasound.

    Science.gov (United States)

    Bade, Brett; Furukawa, Brian; Tanner, Nichole T

    2014-12-01

    Convex probe endobronchial ultrasound (EBUS) is a minimally invasive diagnostic technique that allows real-time sampling of mediastinal and hilar lymph nodes and central pulmonary lesions. Its utility in diagnosing both malignant and nonmalignant diseases has led to an increased uptake and use by pulmonologists over the past decade. Because of the robust evidence supporting its safety and diagnostic yield, EBUS is now the first guideline recommended test for staging in non-small cell lung cancer (NSCLC). It has also a role in providing tissue for molecular analysis, thereby guiding in the selection of agents in the new era of personalized chemotherapies in the treatment of NSCLC. The following review highlights the evidence for EBUS in diagnosing mediastinal pathology and addresses technique, training, and competency and future directions for this technology. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  11. One-Step Protein Conjugation to Upconversion Nanoparticles.

    Science.gov (United States)

    Lu, Jie; Chen, Yinghui; Liu, Deming; Ren, Wei; Lu, Yiqing; Shi, Yu; Piper, James; Paulsen, Ian; Jin, Dayong

    2015-10-20

    The emerging upconversion nanoparticles offer a fascinating library of ultrasensitive luminescent probes for a range of biotechnology applications from biomarker discovery to single molecule tracking, early disease diagnosis, deep tissue imaging, and drug delivery and therapies. The effective bioconjugation of inorganic nanoparticles to the molecule-specific proteins, free of agglomeration, nonspecific binding, or biomolecule deactivation, is crucial for molecular recognition of target molecules or cells. The current available protocols require multiple steps which can lead to low probe stability, specificity, and reproducibility. Here we report a simple and rapid protein bioconjugation method based on a one-step ligand exchange using the DNAs as the linker. Our method benefits from the robust DNA-protein conjugates as well as from multiple ions binding capability. Protein can be preconjugated via an amino group at the 3' end of a synthetic DNA molecule, so that the 5' end phosphoric acid group and multiple phosphate oxygen atoms in the phosphodiester bonds are exposed to replace the oleic acid ligands on the surface of upconversion nanoparticles due to their stronger chelating capability to lanthanides. We demonstrated that our method can efficiently pull out the upconversion nanoparticles from organic solvent into an aqueous phase. The upconversion nanoparticles then become hydrophilic, stable, and specific biomolecules recognition. This allows us to successfully functionalize the upconversion nanoparticles with horseradish peroxidise (HRP) for catalytic colorimetric assay and for streptavidin (SA)-biotin immunoassays.

  12. Probing Interfacial Water on Nanodiamonds in Colloidal Dispersion.

    Science.gov (United States)

    Petit, Tristan; Yuzawa, Hayato; Nagasaka, Masanari; Yamanoi, Ryoko; Osawa, Eiji; Kosugi, Nobuhiro; Aziz, Emad F

    2015-08-06

    The structure of interfacial water layers around nanoparticles dispersed in an aqueous environment may have a significant impact on their reactivity and on their interaction with biological species. Using transmission soft X-ray absorption spectroscopy in liquid, we demonstrate that the unoccupied electronic states of oxygen atoms from water molecules in aqueous colloidal dispersions of nanodiamonds have a different signature than bulk water. X-ray absorption spectroscopy can thus probe interfacial water molecules in colloidal dispersions. The impacts of nanodiamond surface chemistry and concentration on interfacial water electronic signature are discussed.

  13. Local magnetism in palladium bionanomaterials probed by muon spectroscopy.

    Science.gov (United States)

    Creamer, Neil J; Mikheenko, Iryna P; Johnson, Clive; Cottrell, Stephen P; Macaskie, Lynne E

    2011-05-01

    Palladium bionanomaterial was manufactured using the sulfate-reducing bacterium, Desulfovibrio desulfuricansm, to reduce soluble Pd(II) ions to cell-bound Pd(0) in the presence of hydrogen. The biomaterial was examined using a Superconducting Quantum Interference Device (SQUID) to measure bulk magnetisation and by Muon Spin Rotation Spectroscopy (µSR) which is uniquely able to probe the local magnetic environment inside the sample. Results showed behaviour attributable to interaction of muons both with palladium electrons and the nuclei of hydrogen trapped in the particles during manufacture. Electronic magnetism, also suggested by SQUID, is not characteristic of bulk palladium and is consistent with the presence of nanoparticles previously seen in electron micrographs. We show the first use of μSR as a tool to probe the internal magnetic environment of a biologically-derived nanocatalyst material. © Springer Science+Business Media B.V. 2011

  14. Near-infrared Molecular Probes for In Vivo Imaging

    Science.gov (United States)

    Zhang, Xuan; Bloch, Sharon; Akers, Walter; Achilefu, Samuel

    2012-01-01

    Cellular and tissue imaging in the near-infrared (NIR) wavelengths between 700 and 900 nm is advantageous for in vivo because of the low absorption of biological molecules in this region. This Unit presents protocols for small animal imaging using planar and fluorescence lifetime imaging techniques. Included is an overview of NIR fluorescence imaging of cells and small animals using NIR organic fluorophores, nanoparticles, and multimodal imaging probes. The development, advantages, and application of NIR fluorescent probes that have been used for in vivo imaging are also summarized. The use of NIR agents in conjunction with visible dyes and considerations in selecting imaging agents are discussed. We conclude with practical considerations for the use of these dyes in cell and small animal imaging applications. PMID:22470154

  15. Non-inductive current probe

    DEFF Research Database (Denmark)

    Bak, Christen Kjeldahl

    1977-01-01

    The current probe described is a low-cost, shunt resistor for monitoring current pulses in e.g., pulsed lasers. Rise time is......The current probe described is a low-cost, shunt resistor for monitoring current pulses in e.g., pulsed lasers. Rise time is...

  16. Gene probes: principles and protocols

    National Research Council Canada - National Science Library

    Aquino de Muro, Marilena; Rapley, Ralph

    2002-01-01

    ... of labeled DNA has allowed genes to be mapped to single chromosomes and in many cases to a single chromosome band, promoting significant advance in human genome mapping. Gene Probes: Principles and Protocols presents the principles for gene probe design, labeling, detection, target format, and hybridization conditions together with detailed protocols, accom...

  17. Nanobits: customizable scanning probe tips

    DEFF Research Database (Denmark)

    Kumar, Rajendra; Shaik, Hassan Uddin; Sardan Sukas, Özlem

    2009-01-01

    We present here a proof-of-principle study of scanning probe tips defined by planar nanolithography and integrated with AFM probes using nanomanipulation. The so-called 'nanobits' are 2-4 mu m long and 120-150 nm thin flakes of Si3N4 or SiO2, fabricated by electron beam lithography and standard...... or dislocation of the tips of the nanobit after several scans. This approach allows an unprecedented freedom in adapting the shape and size of scanning probe tips to the surface topology or to the specific application....... silicon processing. Using a microgripper they were detached from an array and fixed to a standard pyramidal AFM probe or alternatively inserted into a tipless cantilever equipped with a narrow slit. The nanobit-enhanced probes were used for imaging of deep trenches, without visible deformation, wear...

  18. Water cooled static pressure probe

    Science.gov (United States)

    Lagen, Nicholas T. (Inventor); Eves, John W. (Inventor); Reece, Garland D. (Inventor); Geissinger, Steve L. (Inventor)

    1991-01-01

    An improved static pressure probe containing a water cooling mechanism is disclosed. This probe has a hollow interior containing a central coolant tube and multiple individual pressure measurement tubes connected to holes placed on the exterior. Coolant from the central tube symmetrically immerses the interior of the probe, allowing it to sustain high temperature (in the region of 2500 F) supersonic jet flow indefinitely, while still recording accurate pressure data. The coolant exits the probe body by way of a reservoir attached to the aft of the probe. The pressure measurement tubes are joined to a single, larger manifold in the reservoir. This manifold is attached to a pressure transducer that records the average static pressure.

  19. Electrophoresis-mass spectrometry probe

    Science.gov (United States)

    Andresen, Brian D.; Fought, Eric R.

    1987-01-01

    The invention involves a new technique for the separation of complex mixtures of chemicals, which utilizes a unique interface probe for conventional mass spectrometers which allows the electrophoretically separated compounds to be analyzed in real-time by a mass spectrometer. This new chemical analysis interface, which couples electrophoresis with mass spectrometry, allows complex mixtures to be analyzed very rapidly, with much greater specificity, and with greater sensitivity. The interface or probe provides a means whereby large and/or polar molecules in complex mixtures to be completely characterized. The preferred embodiment of the probe utilizes a double capillary tip which allows the probe tip to be continually wetted by the buffer, which provides for increased heat dissipation, and results in a continually operating interface which is more durable and electronically stable than the illustrated single capillary tip probe interface.

  20. Mobile Probes in Mobile Learning

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Blomhøj, Ulla; Duvaa, Uffe

    In this paper experiences from using mobile probes in educational design of a mobile learning application is presented. The probing process stems from the cultural probe method, and was influenced by qualitative interview and inquiry approaches. In the project, the mobile phone was not only acting...... as an agent for acquiring empirical data (as the situation in hitherto mobile probe settings) but was also the technological medium for which data should say something about (mobile learning). Consequently, not only the content of the data but also the ways in which data was delivered and handled, provided...... a valuable dimension for investigating mobile use. The data was collected at the same time as design activities took place and the collective data was analysed based on user experience goals and cognitive processes from interaction design and mobile learning. The mobile probe increased the knowledge base...

  1. Wearable probes for service design

    DEFF Research Database (Denmark)

    Mullane, Aaron; Laaksolahti, Jarmo Matti; Svanæs, Dag

    2014-01-01

    by service employees in reflecting on the delivery of a service. In this paper, we present the ‘wearable probe’, a probe concept that captures sensor data without distracting service employees. Data captured by the probe can be used by the service employees to reflect and co-reflect on the service journey......Probes are used as a design method in user-centred design to allow end-users to inform design by collecting data from their lives. Probes are potentially useful in service innovation, but current probing methods require users to interrupt their activity and are consequently not ideal for use......, helping to identify opportunities for service evolution and innovation....

  2. Transient Astrophysics Probe

    Science.gov (United States)

    Camp, Jordan; Transient Astrophysics Probe Team

    2018-01-01

    The Transient Astrophysics Probe (TAP) is a wide-field multi-wavelength transient mission proposed for flight starting in the late 2020s. The mission instruments include unique “Lobster-eye” imaging soft X-ray optics that allow a ~1600 deg2 FoV; a high sensitivity, 1 deg2 FoV soft X-ray telescope; a 1 deg2 FoV Infrared telescope with bandpass 0.6-3 micron; and a set of 8 NaI gamma-ray detectors. TAP’s most exciting capability will be the observation of tens per year of X-ray and IR counterparts of GWs involving stellar mass black holes and neutron stars detected by LIGO/Virgo/KAGRA/LIGO-India, and possibly several per year X-ray counterparts of GWs from supermassive black holes, detected by LISA and Pulsar Timing Arrays. TAP will also discover hundreds of X-ray transients related to compact objects, including tidal disruption events, supernova shock breakouts, and Gamma-Ray Bursts from the epoch of reionization.

  3. Steerable Doppler transducer probes

    International Nuclear Information System (INIS)

    Fidel, H.F.; Greenwood, D.L.

    1986-01-01

    An ultrasonic diagnostic probe is described which is capable of performing ultrasonic imaging and Doppler measurement consisting of: a hollow case having an acoustic window which passes ultrasonic energy and including chamber means for containing fluid located within the hollow case and adjacent to a portion of the acoustic window; imaging transducer means, located in the hollow case and outside the fluid chamber means, and oriented to direct ultrasonic energy through the acoustic window toward an area which is to be imaged; Doppler transducer means, located in the hollow case within the fluid chamber means, and movably oriented to direct Doppler signals through the acoustic window toward the imaged area; means located within the fluid chamber means and externally controlled for controllably moving the Doppler transducer means to select one of a plurality of axes in the imaged area along which the Doppler signals are to be directed; and means, located external to the fluid chamber means and responsive to the means for moving, for providing an indication signal for identifying the selected axis

  4. Drug delivery into microneedle-porated nails from nanoparticle reservoirs.

    Science.gov (United States)

    Chiu, Wing Sin; Belsey, Natalie A; Garrett, Natalie L; Moger, Julian; Price, Gareth J; Delgado-Charro, M Begoña; Guy, Richard H

    2015-12-28

    This study demonstrates the potential of polymeric nanoparticles as drug reservoirs for sustained topical drug delivery into microneedle-treated human nail. Laser scanning confocal microscopy was used to image the delivery of a fluorescent model compound from nanoparticles into the nail. A label-free imaging technique, stimulated Raman scattering microscopy, was applied, in conjunction with two-photon fluorescence imaging, to probe the disposition of nanoparticles and an associated lipophilic 'active' in a microneedle-porated nail. The results provide clear evidence that the nanoparticles function as immobile reservoirs, sequestered on the nail surface and in the microneedle-generated pores, from which the active payload can be released and diffuse laterally into the nail over an extended period of time. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Nanoparticles for multimodal in vivo imaging in nanomedicine

    Directory of Open Access Journals (Sweden)

    Key J

    2014-01-01

    Full Text Available Jaehong Key,1–3 James F Leary1–41Weldon School of Biomedical Engineering, 2Birck Nanotechnology Center, 3Bindley Bioscience Center, 4College of Veterinary Medicine, Purdue University, West Lafayette, IN, USAAbstract: While nanoparticles are usually designed for targeted drug delivery, they can also simultaneously provide diagnostic information by a variety of in vivo imaging methods. These diagnostic capabilities make use of specific properties of nanoparticle core materials. Near-infrared fluorescent probes provide optical detection of cells targeted by real-time nanoparticle-distribution studies within the organ compartments of live, anesthetized animals. By combining different imaging modalities, we can start with deep-body imaging by magnetic resonance imaging or computed tomography, and by using optical imaging, get down to the resolution required for real-time fluorescence-guided surgery.Keywords: nanomedicine, nanoparticles, multimodal imaging, CT, MRI, NIRF, PET, cancer

  6. Magnetization reversal of ferromagnetic nanoparticles under inhomogeneous magnetic field

    International Nuclear Information System (INIS)

    Chang, Joonyeon; Yi, Hyunjung; Cheol Koo, Hyun; Mironov, V.L.; Gribkov, B.A.; Fraerman, A.A.; Gusev, S.A.; Vdovichev, S.N.

    2007-01-01

    We investigated remagnetization processes in ferromagnetic nanoparticles under inhomogeneous magnetic field induced by the tip of magnetic force microscope (MFM) in both theoretical and empirical ways. Systematic MFM observations were carried out on arrays of submicron-sized elliptical ferromagnetic particles of Co and FeCr with different sizes and periods. It clearly reveals the distribution of remanent magnetization and processes of local remagnetization of individual ferromagnetic particles. Modeling of remagnetization processes in ferromagnetic nanoparticles under magnetic field induced by MFM probe was performed on the base of Landau-Lifshitz-Gilbert equation for magnetization. MFM-induced inhomogeneous magnetic field is very effective to control the magnetic state of individual ferromagnetic nanoparticles as well as to create different distribution of magnetic field in array of ferromagnetic nanoparticles

  7. Selective porous gates made from colloidal silica nanoparticles

    Directory of Open Access Journals (Sweden)

    Roberto Nisticò

    2015-11-01

    Full Text Available Highly selective porous films were prepared by spin-coating deposition of colloidal silica nanoparticles on an appropriate macroporous substrate. Silica nanoparticles very homogenous in size were obtained by sol–gel reaction of a metal oxide silica precursor, tetraethyl orthosilicate (TEOS, and using polystyrene-block-poly(ethylene oxide (PS-b-PEO copolymers as soft-templating agents. Nanoparticles synthesis was carried out in a mixed solvent system. After spin-coating onto a macroporous silicon nitride support, silica nanoparticles were calcined under controlled conditions. An organized nanoporous layer was obtained characterized by a depth filter-like structure with internal porosity due to interparticle voids. Permeability and size-selectivity were studied by monitoring the diffusion of probe molecules under standard conditions and under the application of an external stimulus (i.e., electric field. Promising results were obtained, suggesting possible applications of these nanoporous films as selective gates for controlled transport of chemical species in solution.

  8. Construction of PSCA-specific MR molecular probe and its immunological activity examination

    International Nuclear Information System (INIS)

    Ren Jing; Yang Yong; Wang Fang; Wei Guangquan; Zhang Rui; Yang Angang; Huan Yi

    2011-01-01

    Objective: To construct the PSCA-specific MR molecular probe 7F5@GoldMag, and to reveal its biochemical characteristics. Methods: The PSCA -specific MR molecular probe 7F5@GoldMag was constructed by noncovalent bond conjugating anti-human PSCA monoclonal antibody (mAb) 7F5 with ColdMag TM -CS nanoparticles, and the coupling efficiency was calculated. The specific binding capability for 7F5@GoldMag to prostate cancer cells was defined by using laser confocal microscopy, transmission electron microscope, and flow cytometry. Results: The PSCA-specific MR molecular probe (7F5@GoldMag) was successfully constructed. Flow cytometry results have shown that the positive rate of the binding was 92.1% at the mAb 7F5@GoldMag + PC-3 cells. Red fluorescence was observed in the membrane at the group of mAb 7F5@GoldMag + PC-3 cells by laser confocal microscopy. The results of transmission electron microscope showed that GoldMag nanoparticles were observed as punctuate black spots, which located near the membrane at mAb 7F5@GoldMag + PC-3 cells. Conclusion: The PSCA-specific MR molecular probe (7F5@GoldMag) constructed by conjugating anti-human PSCA mAb 7F5 with GoldMag TM -CS nanoparticles can specifically bind with PSCA-positive prostate cancer cells. (authors)

  9. Plectin-1 Targeted Dual-modality Nanoparticles for Pancreatic Cancer Imaging

    Directory of Open Access Journals (Sweden)

    Xiao Chen

    2018-04-01

    Full Text Available Background: Biomarker-targeted molecular imaging holds promise for early detection of pancreatic cancer. The aim of this study was to design and evaluate a plectin-1 targeted multi-functional nanoparticle probe for pancreatic cancer imaging. Methods: 1,2-Distearoyl-sn-glycero-3-phosphoethanolamine-N-amino(polyethylene glycol (DSPE-PEG-NH2-modified superparamagnetic iron oxide (Fe3O4 nanoparticles (SPION were conjugated with plectin-1 antibody and/or Cy7 to create the multi-functional targeted nanoparticle targeted probe (Plectin-SPION-Cy7 or non-targeted probe (SPION-Cy7. Pancreatic carcinoma cell lines expressing plectin-1 were cultured with the targeted or control probes and then were imaged using confocal laser scanning microscopy and magnetic resonance imaging (MRI. Accumulations of the nanoparticles in pancreatic tumor xenografted mice were determined by MRI and fluorescence imaging. Results: In vitro optical imaging and MRI showed that the targeted nanoparticles were highly accumulated in MIAPaCa2 and XPA-1 carcinoma cells but not in non-carcinoma MIN6 cells, which was further confirmed by Prussian blue staining. In vivo MRI showed a significant T2 signal reduction. Prussian blue staining further confirmed that the plectin-1 targeted nanoparticles were highly accumulated in the tumor mass but not in normal pancreatic tissues, or in the liver and kidney, and few nanoparticles were observed in the tumors of mice injected with SPION-Cy7. Conclusions: Our data demonstrate that plectin-1 targeted fluorescence and MR dual-functional nanoparticle can visualize pancreatic cancer, and it has great potential to be used with various imaging devices for pancreatic cancer detection. Keywords: Pancreatic cancer, Plectin-1, Magnetic resonance imaging, Optical imaging, Nanoparticle

  10. PREFACE: Quantum dots as probes in biology

    Science.gov (United States)

    Cieplak, Marek

    2013-05-01

    photosynthetic systems. The next paper, by Olejnik et al, discussed metallic QDs which enhance photosynthetic function in light-harvesting biomolecular complexes. Such hybrid structures with gold QDs are shown to exhibit a strong increase in the fluorescence quantum yield. The next two papers, by Sikora et al and Kaminska et al deal with the ZnO nanoparticles passivated by MgO. In the first of these two papers, the authors describe the behavior of ZnO/MgO when introduced to human cancer cells. In the second, the authors describe the QDs with an extra outer layer of Fe2O3 which makes the nanoparticles superparamagnetic and also capable of generation of reactive oxygen species which could be applied to form localized centers of toxicity for cancer treatment. Finally, in the last paper by Yatsunenko et al, the authors discuss several semiconducting QDs like ZnO with various rare-earth dopands. They propose a microwave-driven hydrothermal technology to make them, characterize their luminescence and demonstrate their usefulness in the early recognition of cancer tissues. Quantum dots as probes in biology contents Quantum dots as probes in biologyMarek Cieplak Luminescent nanoparticles and their applications in the life sciencesVarun K A Sreenivasan, Andrei V Zvyagin and Ewa M Goldys Ferredoxin:NADP+ oxidoreductase in junction with CdSe/ZnS quantum dots: characteristics of an enzymatically active nanohybrid Krzysztof Szczepaniak, Remigiusz Worch and Joanna Grzyb Spectroscopic studies of plasmon coupling between photosynthetic complexes and metallic quantum dotsMaria Olejnik, Bartosz Krajnik, Dorota Kowalska, Guanhua Lin and Sebastian Mackowski Luminescence of colloidal ZnO nanoparticles synthesized in alcohols and biological application of ZnO passivated by MgOBożena Sikora, Krzysztof Fronc, Izabela Kamińska, Kamil Koper, Piotr Stępień and Danek Elbaum Novel ZnO/MgO/Fe2O3 composite optomagnetic nanoparticles I Kamińska, B Sikora, K Fronc, P Dziawa, K Sobczak, R Minikayev, W

  11. Probing the Probes: Fitness Factors For Small Molecule Tools

    OpenAIRE

    Workman, Paul; Collins, Ian

    2010-01-01

    Chemical probes for interrogating biological processes are of considerable current interest. Cell permeable small molecule tools have a major role in facilitating the functional annotation of the human genome, understanding both physiological and pathological processes, and validating new molecular targets. To be valuable, chemical tools must satisfy necessary criteria and recent publications have suggested objective guidelines for what makes a useful chemical probe. Although recognizing that...

  12. Hybrid gold nanoparticles in molecular imaging and radiotherapy

    International Nuclear Information System (INIS)

    Katti, K.V.; Kannan, R.; Katti, K.; Kattumuri, V.; Pandrapragada, R.; Rahing, V.; Cutler, C.; Boote, E.; Casteel, S.W.; Smith, C.J.; Robertson, J.D.; Jurrison, S.

    2006-01-01

    Metallic nanoparticles, because of their size, chemical and physical properties, are particularly attractive as therapeutic probes in treating cancer. Central to any clinical advances in nanoparticulate based therapy will be to produce hybrid nanoparticles that can be targeted to vascular, extracellular or cell surface receptors. Development of hybrid nanoparticles that specifically target cancer vasculature has received considerable attention. Most cancers have leaky vasculature and the defective vascular architecture, created due to the rapid vascularisation necessary to serve fast growing cancers, in combination with poor lymphatic drainage allows increased permeation and retention effects. The leaky vasculature, because of higher porosity and permeability, serve as natural high affinity targets to metallic nanoparticles. Another attractive approach toward the application of nanotechnology to nanomedicine is the utility of nanoparticles that display inherent therapeutic properties. For example radioactive gold nanoparticles present attractive prospects in therapy of cancer. The radioactive properties of Au-198 (β(max) = 0.96 MeV; t(1/2) = 2.7 d) and Au-199 (β(max) 0.46 MeV; t(1/2) = 3.14 d) make them ideal candidates for use in radiotherapeutic applications. In addition, they both have imageable gamma emissions for dosimetry and pharmacokinetic studies and Au-199 can be made carrier-free by indirect methods. Gold nanoparticles are of interest for treatment of disease as they can deliver agents directly into cells and cellular components with a higher concentration of radioactivity, e.g. higher dose of radioactivity, to cancerous tumor cells

  13. O3 Nanoparticles

    KAUST Repository

    Wang, Juan

    2016-11-16

    Ti2O3 nanoparticles with high performance of photothermal conversion are demonstrated for the first time. Benefiting from the nanosize and narrow-bandgap features, the Ti2O3 nanoparticles possess strong light absorption and nearly 100% internal solar–thermal conversion efficiency. Furthermore, Ti2O3 nanoparticle-based thin film shows potential use in seawater desalination and purification.

  14. Biosynthesis of silver nanoparticles.

    Science.gov (United States)

    Poulose, Subin; Panda, Tapobrata; Nair, Praseetha P; Théodore, Thomas

    2014-02-01

    Metal nanoparticles have unique optical, electronic, and catalytic properties. There exist well-defined physical and chemical processes for their preparation. Those processes often yield small quantities of nanoparticles having undesired morphology, and involve high temperatures for the reaction and the use of hazardous chemicals. Relatively, the older technique of bioremediation of metals uses either microorganisms or their components for the production of nanoparticles. The nanoparticles obtained from bacteria, fungi, algae, plants and their components, etc. appear environment-friendly, as toxic chemicals are not used in the processes. In addition to this, the formation of nanoparticles takes place at almost normal temperature and pressure. Control of the shape and size of the nanoparticles is possible by appropriate selection of the pH and temperature. Three important steps are the bioconversion of Ag+ ions, conversion of desired crystals to nanoparticles, and nanoparticle stability. Generally, nanoparticles are characterized by the UV-visible spectroscopy and use of the electron microscope. Silver nanoparticles are used as antimicrobial agents and they possess antifungal, anti-inflammatory, and anti-angiogenic properties. This review highlights the biosynthesis of silver nanoparticles by various organisms, possible mechanisms of their synthesis, their characterization, and applications of silver nanoparticles.

  15. Monitoring probe for groundwater flow

    Science.gov (United States)

    Looney, B.B.; Ballard, S.

    1994-08-23

    A monitoring probe for detecting groundwater migration is disclosed. The monitor features a cylinder made of a permeable membrane carrying an array of electrical conductivity sensors on its outer surface. The cylinder is filled with a fluid that has a conductivity different than the groundwater. The probe is placed in the ground at an area of interest to be monitored. The fluid, typically saltwater, diffuses through the permeable membrane into the groundwater. The flow of groundwater passing around the permeable membrane walls of the cylinder carries the conductive fluid in the same general direction and distorts the conductivity field measured by the sensors. The degree of distortion from top to bottom and around the probe is precisely related to the vertical and horizontal flow rates, respectively. The electrical conductivities measured by the sensors about the outer surface of the probe are analyzed to determine the rate and direction of the groundwater flow. 4 figs.

  16. A three dimensional probe positioner

    International Nuclear Information System (INIS)

    Intrator, T.; Sun, X.; Furno, I.; Dorf, L.; Lapenta, G.

    2008-01-01

    In order to sort out the physics that is important in many plasma experiments, data in three dimensions (3D) are becoming necessary. Access to the usual cylindrical vacuum vessel is typically restricted to radially or axially insertable probes that can pivot. The space that can be explored usually has significant restrictions either because probe travel must be along a travel path, or a 'wobbly' probe positioner requires one to map between a moveable coordinate system and a preferred laboratory coordinate system. This could for example introduce errors in measurements of vector quantities such as magnetic field or flow. We describe the design and implementation of a 3D probe positioner that slides in two dimensions on a double O-ring seal and radially inserts along the third dimension. The net result is that a 3D space can be explored in a laboratory Cartesian reference frame.

  17. Pneumatic probe with laser interferometer

    International Nuclear Information System (INIS)

    Wilkens, P.H.

    1978-01-01

    Improvements to upgrade the accuracy of Rotacon probes by a complete redesign of probe to include a Michelson interferometer to replace the existing long-range capacity transducer are described. This has resulted in a compact and interchangeable probe cartridge with a 3 μin. resolution and accuracy; the cartridge can be installed and replaced in the Rotacon gauge with the minimum of realignment, which should reduce our dependence on operator skill. In addition, the stylus contact force can be reduced to 750 mg for the contacting types, but an alternative feature, which we are still developing, will use a gas jet cushion in place of the stylus to provide a noncontacting version of the same basic probe cartridge. This device is very sensitive to external vibration effects because it is virtually frictionless

  18. DNA probe for lactobacillus delbrueckii

    Energy Technology Data Exchange (ETDEWEB)

    Delley, M.; Mollet, B.; Hottinger, H. (Nestle Research Centre, Lausanne (Switzerland))

    1990-06-01

    From a genomic DNA library of Lactobacillus delbrueckii subsp. bulgaricus, a clone was isolated which complements a leucine auxotrophy of an Escherichia coli strain (GE891). Subsequent analysis of the clone indicated that it could serve as a specific DNA probe. Dot-blot hybridizations with over 40 different Lactobacillus strains showed that this clone specifically recognized L. delbrueckii subsp. delbrueckii, bulgaricus, and lactis. The sensitivity of the method was tested by using an {alpha}-{sup 32}P-labeled probe.

  19. DNA probe for lactobacillus delbrueckii

    International Nuclear Information System (INIS)

    Delley, M.; Mollet, B.; Hottinger, H.

    1990-01-01

    From a genomic DNA library of Lactobacillus delbrueckii subsp. bulgaricus, a clone was isolated which complements a leucine auxotrophy of an Escherichia coli strain (GE891). Subsequent analysis of the clone indicated that it could serve as a specific DNA probe. Dot-blot hybridizations with over 40 different Lactobacillus strains showed that this clone specifically recognized L. delbrueckii subsp. delbrueckii, bulgaricus, and lactis. The sensitivity of the method was tested by using an α- 32 P-labeled probe

  20. DIGITAL CONTACT POTENTIAL DIFFERENCE PROBE

    Directory of Open Access Journals (Sweden)

    K. U. Pantsialeyeu

    2016-01-01

    Full Text Available Nowadays the technique of analog contact potential difference probes well developed. Due to the influence of various parasitic factors, analog probes has substantial errors. The integration time for automatic CPD compensation should be at least several seconds to achieve high accuracy measurements. The speed and the accuracy are essential, for example, for Scanning Kelvin Probes. The purpose of this paper is to develop a digital contact potential difference probe, with a higher accuracy and speed of measurements as compared to analog probe. The digital probe made on base of 32-bit microprocessor with a Cortex M4 core. Measuring cycle consists of at least two successive determinations of the output signal amplitude at different compensation voltage generated by the microcontroller. It allows synchronizing of the generated oscillations and reading of the measuring signals. Data arrays processed in real time of the Digital Signal Processing by microprocessor. In this case is possible computation of the root mean square value or determination of the desired spectral line of the signal after fast Fourier transformation. Both methods permit eliminate of random noise and spurious harmonics. The method provides the digital contact potential difference probe operation in large signal mode and with a large signal/noise ratio. This eliminates the error associated with the zero signal finding. Also the integration time for automatic CPD compensation of the measured value is not necessary, which significantly reduces the measurement time and eliminates errors of compensation and DAC. In addition, the microcontroller could control the movement of the probe during scanning and transfer data to the host computer on interface USB, etc.

  1. Recent development of nanoparticles for molecular imaging

    Science.gov (United States)

    Kim, Jonghoon; Lee, Nohyun; Hyeon, Taeghwan

    2017-10-01

    Molecular imaging enables us to non-invasively visualize cellular functions and biological processes in living subjects, allowing accurate diagnosis of diseases at early stages. For successful molecular imaging, a suitable contrast agent with high sensitivity is required. To date, various nanoparticles have been developed as contrast agents for medical imaging modalities. In comparison with conventional probes, nanoparticles offer several advantages, including controllable physical properties, facile surface modification and long circulation time. In addition, they can be integrated with various combinations for multimodal imaging and therapy. In this opinion piece, we highlight recent advances and future perspectives of nanomaterials for molecular imaging. This article is part of the themed issue 'Challenges for chemistry in molecular imaging'.

  2. Green Chemistry Techniques for Gold Nanoparticles Synthesis

    Science.gov (United States)

    Cannavino, Sarah A.; King, Christy A.; Ferrara, Davon W.

    Gold nanoparticles (AuNPs) are often utilized in many technological and research applications ranging from the detection of tumors, molecular and biological sensors, and as nanoantennas to probe physical processes. As these applications move from the research laboratory to industrial settings, there is a need to develop efficient and sustainable synthesis techniques. Recent research has shown that several food products and beverages containing polyphenols, a common antioxidant, can be used as reducing agents in the synthesis of AuNPs in solution. In this study, we explore a variety of products to determine which allow for the most reproducible solution of nanoparticles based on the size and shapes of particles present. We analyzed the AuNPs solutions using extinction spectroscopy and atomic force microscopy. We also develop a laboratory activity to introduce introductory chemistry and physics students to AuNP synthesis techniques and analysis.

  3. Novel magnetic heating probe for multimodal cancer treatment.

    Science.gov (United States)

    Kan-Dapaah, Kwabena; Rahbar, Nima; Soboyejo, Wole

    2015-05-01

    Multifunctional materials consisting of polymers and magnetic nanoparticles (MNPs) are highly sought after in the field of biomedical engineering. These materials offer new opportunities for the development of novel cancer treatment modalities that can increase the efficacy of cancer therapy. In this paper, a novel probe for multimodal cancer treatment is proposed and analyzed. The probe is essentially a cannula with two main parts: a distal heat generating tip made of a magnetic nanocomposite and a proximal insulated shaft. A description of the concept and functional operations of the probe is presented. In an effort to assess its feasibility, the authors evaluated the ability of probe tip (made of PMMA-Fe3O4 nanocomposite) to generate heat in biological tissue using alternating magnetic field (AMF) parameters (field strength and frequency) that are acceptable for human use. Heat generation by MNPs was determined using the linear response theory. The effects of Fe3O4 volume fraction on heat generation as well as treatment time on the thermal dose were studied. The finite element method model was tested for its validity using an analytical model. Lesions were revealed to have an ellipsoidal shape and their sizes were affected by treatment time. However, their shapes remained unchanged. The comparison with the analytical model showed reasonably a good agreement to within 2%. Furthermore, the authors' numerical predictions also showed reasonable agreement with the experimental results previously reported in the literature. The authors' predictions demonstrate the feasibility of their novel probe to achieve reasonable lesion sizes, during hyperthermic or ablative heating using AMF parameters (field strength and frequency) that are acceptable for human use.

  4. Molecular Imaging Probes for Positron Emission Tomography and Optical Imaging of Sentinel Lymph Node and Tumor

    Science.gov (United States)

    Qin, Zhengtao

    Molecular imaging is visualizations and measurements of in vivo biological processes at the molecular or cellular level using specific imaging probes. As an emerging technology, biocompatible macromolecular or nanoparticle based targeted imaging probes have gained increasing popularities. Those complexes consist of a carrier, an imaging reporter, and a targeting ligand. The active targeting ability dramatically increases the specificity. And the multivalency effect may further reduce the dose while providing a decent signal. In this thesis, sentinel lymph node (SLN) mapping and cancer imaging are two research topics. The focus is to develop molecular imaging probes with high specificity and sensitivity, for Positron Emission Tomography (PET) and optical imaging. The objective of this thesis is to explore dextran radiopharmaceuticals and porous silicon nanoparticles based molecular imaging agents. Dextran polymers are excellent carriers to deliver imaging reporters or therapeutic agents due to its well established safety profile and oligosaccharide conjugation chemistry. There is also a wide selection of dextran polymers with different lengths. On the other hand, Silicon nanoparticles represent another class of biodegradable materials for imaging and drug delivery. The success in fluorescence lifetime imaging and enhancements of the immune activation potency was briefly discussed. Chapter 1 begins with an overview on current molecular imaging techniques and imaging probes. Chapter 2 presents a near-IR dye conjugated probe, IRDye 800CW-tilmanocept. Fluorophore density was optimized to generate the maximum brightness. It was labeled with 68Ga and 99mTc and in vivo SLN mapping was successfully performed in different animals, such as mice, rabbits, dogs and pigs. With 99mTc labeled IRDye 800CW-tilmanocept, chapter 3 introduces a two-day imaging protocol with a hand-held imager. Chapter 4 proposed a method to dual radiolabel the IRDye 800CW-tilmanocept with both 68Ga and

  5. Assessing Nanoparticle Toxicity

    Science.gov (United States)

    Love, Sara A.; Maurer-Jones, Melissa A.; Thompson, John W.; Lin, Yu-Shen; Haynes, Christy L.

    2012-07-01

    Nanoparticle toxicology, an emergent field, works toward establishing the hazard of nanoparticles, and therefore their potential risk, in light of the increased use and likelihood of exposure. Analytical chemists can provide an essential tool kit for the advancement of this field by exploiting expertise in sample complexity and preparation as well as method and technology development. Herein, we discuss experimental considerations for performing in vitro nanoparticle toxicity studies, with a focus on nanoparticle characterization, relevant model cell systems, and toxicity assay choices. Additionally, we present three case studies (of silver, titanium dioxide, and carbon nanotube toxicity) to highlight the important toxicological considerations of these commonly used nanoparticles.

  6. Novel biocompatible hydrogel nanoparticles: generation and size-tuning of nanoparticles by the formation of micelle templates obtained from thermo-responsive monomers mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Khandadash, Raz; Machtey, Victoria [Bar Ilan University, Department of Chemistry (Israel); Shainer, Inbal [Tel-Aviv University, Department of Neurobiology, The George S. Wise Faculty of Life Sciences (Israel); Gottlieb, Hugo E. [Bar Ilan University, Department of Chemistry (Israel); Gothilf, Yoav [Tel-Aviv University, Department of Neurobiology, The George S. Wise Faculty of Life Sciences, and Sagol School of Neuroscience (Israel); Ebenstein, Yuval [Tel Aviv University, Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry (Israel); Weiss, Aryeh [Bar Ilan University, School of Engineering (Israel); Byk, Gerardo, E-mail: gerardo.byk@biu.ac.il [Bar Ilan University, Department of Chemistry (Israel)

    2014-12-15

    Biocompatible hydrogel nanoparticles are prepared by polymerization and cross-linking of N-isopropyl acrylamide in a micelle template formed by block copolymers macro-monomers at high temperature. Different monomer ratios form, at high temperature, well-defined micelles of different sizes which are further polymerized leading to nanoparticles with varied sizes from 20 to 390 nm. Physico-chemical characterization of the nanoparticles demonstrates their composition and homogeneity. The NPs were tested in vitro and in vivo biocompatibility assays, and their lack of toxicity was proven. The NPs can be labeled with fluorescent probes, and their intracellular fate can be visualized and quantified using confocal microscopy. Their uptake by live stem cells and distribution in whole developing animals is reported. On the basis of our results, a mechanism of nanoparticle formation is suggested. The lack of toxicity makes these nanoparticles especially attractive for biological applications such as screening and bio-sensing.

  7. Influence of synthesis parameters on iron nanoparticle size and zeta potential

    Science.gov (United States)

    Goldstein, Nikki; Greenlee, Lauren F.

    2012-03-01

    Zero valent iron nanoparticles are of increasing interest in clean water treatment applications due to their reactivity toward organic contaminants and their potential to degrade a variety of compounds. This study focuses on the effect of organophosphate stabilizers on nanoparticle characteristics, including particle size distribution and zeta potential, when the stabilizer is present during nanoparticle synthesis. Particle size distributions from DLS were obtained as a function of stabilizer type and iron precursor (FeSO4·7H2O or FeCl3), and nanoparticles from 2 to 200 nm were produced. Three different organophosphate stabilizer compounds were compared in their ability to control nanoparticle size, and the size distributions obtained for particle volume demonstrated differences caused by the three stabilizers. A range of stabilizer-to-iron (0.05-0.9) and borohydride-to-iron (0.5-8) molar ratios were tested to determine the effect of concentration on nanoparticle size distribution and zeta potential. The combination of ferrous sulfate and ATMP or DTPMP phosphonate stabilizer produced stabilized nanoparticle suspensions, and the stabilizers tested resulted in varying particle size distributions. In general, higher stabilizer concentrations resulted in smaller nanoparticles, and excess borohydride did not decrease nanoparticle size. Zeta potential measurements were largely consistent with particle size distribution data and indicated the stability of the suspensions. Probe sonication, as a nanoparticle resuspension method, was minimally successful in several different organic solvents.

  8. Influence of synthesis parameters on iron nanoparticle size and zeta potential

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, Nikki; Greenlee, Lauren F., E-mail: lauren.greenlee@nist.gov [National Institute of Standards and Technology, Materials Reliability Division (United States)

    2012-03-15

    Zero valent iron nanoparticles are of increasing interest in clean water treatment applications due to their reactivity toward organic contaminants and their potential to degrade a variety of compounds. This study focuses on the effect of organophosphate stabilizers on nanoparticle characteristics, including particle size distribution and zeta potential, when the stabilizer is present during nanoparticle synthesis. Particle size distributions from DLS were obtained as a function of stabilizer type and iron precursor (FeSO{sub 4}{center_dot}7H{sub 2}O or FeCl{sub 3}), and nanoparticles from 2 to 200 nm were produced. Three different organophosphate stabilizer compounds were compared in their ability to control nanoparticle size, and the size distributions obtained for particle volume demonstrated differences caused by the three stabilizers. A range of stabilizer-to-iron (0.05-0.9) and borohydride-to-iron (0.5-8) molar ratios were tested to determine the effect of concentration on nanoparticle size distribution and zeta potential. The combination of ferrous sulfate and ATMP or DTPMP phosphonate stabilizer produced stabilized nanoparticle suspensions, and the stabilizers tested resulted in varying particle size distributions. In general, higher stabilizer concentrations resulted in smaller nanoparticles, and excess borohydride did not decrease nanoparticle size. Zeta potential measurements were largely consistent with particle size distribution data and indicated the stability of the suspensions. Probe sonication, as a nanoparticle resuspension method, was minimally successful in several different organic solvents.

  9. Influence of synthesis parameters on iron nanoparticle size and zeta potential

    International Nuclear Information System (INIS)

    Goldstein, Nikki; Greenlee, Lauren F.

    2012-01-01

    Zero valent iron nanoparticles are of increasing interest in clean water treatment applications due to their reactivity toward organic contaminants and their potential to degrade a variety of compounds. This study focuses on the effect of organophosphate stabilizers on nanoparticle characteristics, including particle size distribution and zeta potential, when the stabilizer is present during nanoparticle synthesis. Particle size distributions from DLS were obtained as a function of stabilizer type and iron precursor (FeSO 4 ·7H 2 O or FeCl 3 ), and nanoparticles from 2 to 200 nm were produced. Three different organophosphate stabilizer compounds were compared in their ability to control nanoparticle size, and the size distributions obtained for particle volume demonstrated differences caused by the three stabilizers. A range of stabilizer-to-iron (0.05–0.9) and borohydride-to-iron (0.5–8) molar ratios were tested to determine the effect of concentration on nanoparticle size distribution and zeta potential. The combination of ferrous sulfate and ATMP or DTPMP phosphonate stabilizer produced stabilized nanoparticle suspensions, and the stabilizers tested resulted in varying particle size distributions. In general, higher stabilizer concentrations resulted in smaller nanoparticles, and excess borohydride did not decrease nanoparticle size. Zeta potential measurements were largely consistent with particle size distribution data and indicated the stability of the suspensions. Probe sonication, as a nanoparticle resuspension method, was minimally successful in several different organic solvents.

  10. Fluorescence resonance energy transfer in a binary organic nanoparticle system and its application.

    Science.gov (United States)

    Wu, Meng; Xu, Xinjun; Wang, Jinshan; Li, Lidong

    2015-04-22

    Fluorescent organic nanoparticles have a much better photostability than molecule-based probes. Here, we report a simple strategy to detect chemicals and biomolecules by a binary nanoparticle system based on fluorescence resonance energy transfer (FRET). Poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO, energy donor) and poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV, energy acceptor) are utilized to prepare the binary nanoparticle system through a reprecipitation method. Since the FRET process is strongly distance-dependent, a change in the interparticle distance between the two kinds of nanoparticles after introduction of analytes will alter the FRET efficiency. The response of the binary nanoparticle system to cationic polyelectrolytes was investigated by monitoring the FRET efficiency from PFO to MEH-PPV nanoparticles and the fluorescence color of the nanoparticle solutions. Furthermore, the cationic polyelectrolyte pretreated binary nanoparticle system can be used to detect DNA by desorption of nanoparticles from the polyelectrolyte's chains and the detection concentration can go down to 10(-14) M. Thus, the binary nanoparticle system shows great promise for applications in chemical sensing or biosensing.

  11. Epoxy based photoresist/carbon nanoparticle composites

    DEFF Research Database (Denmark)

    Lillemose, Michael; Gammelgaard, Lauge; Richter, Jacob

    2008-01-01

    We have fabricated composites of SU-8 polymer and three different types of carbon nanoparticles (NPs) using ultrasonic mixing. Structures of composite thin films have been patterned on a characterization chip with standard UV photolithography. Using a four-point bending probe, a well defined stress...... is applied to the composite thin film and we have demonstrated that the composites are piezoresistive. Stable gauge factors of 5-9 have been measured, but we have also observed piezoresistive responses with gauge factors as high as 50. As SU-8 is much softer than silicon and the gauge factor of the composite...

  12. Analytical performance of molecular beacons on surface immobilized gold nanoparticles of varying size and density.

    Science.gov (United States)

    Uddayasankar, Uvaraj; Krull, Ulrich J

    2013-11-25

    The high quenching efficiency of metal nanoparticles has facilitated its use as quenchers in molecular beacons. To optimize this system, a good understanding of the many factors that influence molecular beacon performance is required. In this study, molecular beacon performance was evaluated as a function of gold nanoparticle size and its immobilization characteristics. Gold nanoparticles of 4 nm, 15 nm and 87 nm diameter, were immobilized onto glass slides. Each size regime offered distinctive optical properties for fluorescence quenching of molecular dyes that were conjugated to oligonucleotides that were immobilized to the gold nanoparticles. Rigid double stranded DNA was used as a model to place fluorophores at different distances from the gold nanoparticles. The effect of particle size and also the immobilization density of nanoparticles was evaluated. The 4 nm and 87 nm gold nanoparticles offered the highest sensitivity in terms of the change in fluorescence intensity as a function of distance (3-fold improvement for Cy5). The optical properties of the molecular fluorophore was of significance, with Cy5 offering higher contrast ratios than Cy3 due to the red-shifted emission spectrum relative to the plasmon peak. A high density of gold nanoparticles reduced contrast ratios, indicating preference for a monolayer of immobilized nanoparticles when considering analytical performance. Molecular beacon probes were then used in place of the double stranded oligonucleotides. There was a strong dependence of molecular beacon performance on the length of a linker used for attachment to the nanoparticle surface. The optimal optical performance was obtained with 4 nm gold nanoparticles that were immobilized as monolayers of low density (5.7×10(11)particles cm(-2)) on glass surfaces. These nanoparticle surfaces offered a 2-fold improvement in analytical performance of the molecular beacons when compared to other nanoparticle sizes investigated. The principles developed

  13. IVVS probe mechanical concept design

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Paolo, E-mail: paolo.rossi@enea.it; Neri, Carlo; De Collibus, Mario Ferri; Mugnaini, Giampiero; Pollastrone, Fabio; Crescenzi, Fabio

    2015-10-15

    Highlights: • ENEA designed, developed and tested a laser based In Vessel Viewing System (IVVS). • IVVS mechanical design has been revised from 2011 to 2013 to meet ITER requirements. • Main improvements are piezoceramic actuators and a step focus system. • Successful qualification activities validated the concept design for ITER environment. - Abstract: ENEA has been deeply involved in the design, development and testing of a laser based In Vessel Viewing System (IVVS) required for the inspection of ITER plasma-facing components. The IVVS probe shall be deployed into the vacuum vessel, providing high resolution images and metrology measurements to detect damages and possible erosion. ENEA already designed and manufactured an IVVS probe prototype based on a rad-hard concept and driven by commercial micro-step motors, which demonstrated satisfying viewing and metrology performances at room conditions. The probe sends a laser beam through a reflective rotating prism. By rotating the axes of the prism, the probe can scan all the environment points except those present in a shadow cone and the backscattered light signal is then processed to measure the intensity level (viewing) and the distance from the probe (metrology). During the last years, in order to meet all the ITER environmental conditions, such as high vacuum, gamma radiation lifetime dose up to 5 MGy, cumulative neutron fluence of about 2.3 × 10{sup 17} n/cm{sup 2}, temperature of 120 °C and magnetic field of 8 T, the probe mechanical design was significantly revised introducing a new actuating system based on piezo-ceramic actuators and improved with a new step focus system. The optical and mechanical schemes have been then modified and refined to meet also the geometrical constraints. The paper describes the mechanical concept design solutions adopted in order to fulfill IVVS probe functional performance requirements considering ITER working environment and geometrical constraints.

  14. Optogenetic probing and manipulation of the calyx-type presynaptic terminal in the embryonic chick ciliary ganglion.

    Science.gov (United States)

    Egawa, Ryo; Hososhima, Shoko; Hou, Xubin; Katow, Hidetaka; Ishizuka, Toru; Nakamura, Harukazu; Yawo, Hiromu

    2013-01-01

    The calyx-type synapse of chick ciliary ganglion (CG) has been intensively studied for decades as a model system for the synaptic development, morphology and physiology. Despite recent advances in optogenetics probing and/or manipulation of the elementary steps of the transmitter release such as membrane depolarization and Ca(2+) elevation, the current gene-manipulating methods are not suitable for targeting specifically the calyx-type presynaptic terminals. Here, we evaluated a method for manipulating the molecular and functional organization of the presynaptic terminals of this model synapse. We transfected progenitors of the Edinger-Westphal (EW) nucleus neurons with an EGFP expression vector by in ovo electroporation at embryonic day 2 (E2) and examined the CG at E8-14. We found that dozens of the calyx-type presynaptic terminals and axons were selectively labeled with EGFP fluorescence. When a Brainbow construct containing the membrane-tethered fluorescent proteins m-CFP, m-YFP and m-RFP, was introduced together with a Cre expression construct, the color coding of each presynaptic axon facilitated discrimination among inter-tangled projections, particularly during the developmental re-organization period of synaptic connections. With the simultaneous expression of one of the chimeric variants of channelrhodopsins, channelrhodopsin-fast receiver (ChRFR), and R-GECO1, a red-shifted fluorescent Ca(2+)-sensor, the Ca(2+) elevation was optically measured under direct photostimulation of the presynaptic terminal. Although this optically evoked Ca(2+) elevation was mostly dependent on the action potential, a significant component remained even in the absence of extracellular Ca(2+). It is suggested that the photo-activation of ChRFR facilitated the release of Ca(2+) from intracellular Ca(2+) stores directly or indirectly. The above system, by facilitating the molecular study of the calyx-type presynaptic terminal, would provide an experimental platform for unveiling

  15. Optogenetic probing and manipulation of the calyx-type presynaptic terminal in the embryonic chick ciliary ganglion.

    Directory of Open Access Journals (Sweden)

    Ryo Egawa

    Full Text Available The calyx-type synapse of chick ciliary ganglion (CG has been intensively studied for decades as a model system for the synaptic development, morphology and physiology. Despite recent advances in optogenetics probing and/or manipulation of the elementary steps of the transmitter release such as membrane depolarization and Ca(2+ elevation, the current gene-manipulating methods are not suitable for targeting specifically the calyx-type presynaptic terminals. Here, we evaluated a method for manipulating the molecular and functional organization of the presynaptic terminals of this model synapse. We transfected progenitors of the Edinger-Westphal (EW nucleus neurons with an EGFP expression vector by in ovo electroporation at embryonic day 2 (E2 and examined the CG at E8-14. We found that dozens of the calyx-type presynaptic terminals and axons were selectively labeled with EGFP fluorescence. When a Brainbow construct containing the membrane-tethered fluorescent proteins m-CFP, m-YFP and m-RFP, was introduced together with a Cre expression construct, the color coding of each presynaptic axon facilitated discrimination among inter-tangled projections, particularly during the developmental re-organization period of synaptic connections. With the simultaneous expression of one of the chimeric variants of channelrhodopsins, channelrhodopsin-fast receiver (ChRFR, and R-GECO1, a red-shifted fluorescent Ca(2+-sensor, the Ca(2+ elevation was optically measured under direct photostimulation of the presynaptic terminal. Although this optically evoked Ca(2+ elevation was mostly dependent on the action potential, a significant component remained even in the absence of extracellular Ca(2+. It is suggested that the photo-activation of ChRFR facilitated the release of Ca(2+ from intracellular Ca(2+ stores directly or indirectly. The above system, by facilitating the molecular study of the calyx-type presynaptic terminal, would provide an experimental platform for

  16. Trimetallic nanostructures: the case of AgPd/Pt multiply twinned nanoparticles

    OpenAIRE

    Khanal, Subarna; Bhattarai, Nabraj; Velázquez-Salazar, J. Jesús; Bahena, Daniel; Soldano, German; Ponce, Arturo; Mariscal, Marcelo M.; Mejía-Rosales, Sergio; José-Yacamán, Miguel

    2013-01-01

    We report the synthesis, structural characterization, and atomistic simulations of AgPd/Pt trimetallic (TM) nanoparticles. Two types of structure were synthesized using a relatively facile chemical method: multiply twinned core-shell, and hollow particles. The nanoparticles were small in size, with an average diameter of 11 nm and a narrow distribution, and their characterization by aberration corrected scanning transmission electron microscopy allowed us to probe the structure of the particl...

  17. Annealing effect on the ultrafast dynamics of Ag nanoparticles embedded in soda-lime silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Dong Zhiwei [Surface Physics Laboratory (National Key Laboratory) and Department of Physics, Fudan University, Shanghai 200433 (China); National Key Laboratory of Tunable Lasers, Institute of Optical-Electronics, Harbin Institute of Technology, Harbin 150001 (China); Yang Xiucun; Li Zhihui [School of Materials Science and Engineering, Tongji University, Shanghai 200433 (China); You Guanjun; Yan Yongli [Surface Physics Laboratory (National Key Laboratory) and Department of Physics, Fudan University, Shanghai 200433 (China); Qian Shixiong, E-mail: sxqian@fudan.ac.c [Surface Physics Laboratory (National Key Laboratory) and Department of Physics, Fudan University, Shanghai 200433 (China)

    2009-08-01

    Ag nanoparticles embedded in soda-lime silicate glasses were fabricated by the ion-exchange technique. Effects of thermal treatment on the optical nonlinearity and ultrafast dynamics of Ag nanoparticles were investigated by applying time-resolved optical Kerr effect and pump-probe techniques. The results indicate that thermal treatment is an efficient method to improve the nonlinear optical performance of this kind of material.

  18. De-alloyed platinum nanoparticles

    Science.gov (United States)

    Strasser, Peter [Houston, TX; Koh, Shirlaine [Houston, TX; Mani, Prasanna [Houston, TX; Ratndeep, Srivastava [Houston, TX

    2011-08-09

    A method of producing de-alloyed nanoparticles. In an embodiment, the method comprises admixing metal precursors, freeze-drying, annealing, and de-alloying the nanoparticles in situ. Further, in an embodiment de-alloyed nanoparticle formed by the method, wherein the nanoparticle further comprises a core-shell arrangement. The nanoparticle is suitable for electrocatalytic processes and devices.

  19. MR imaging of Her-2/neu protein using magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hilger, Ingrid [Department of Experimental Radiology, Institute for Diagnostic and Interventional Radiology, Friedrich Schiller University, FZL, Erlanger Allee 101, 07747, Jena (Germany); Trost, Rene [Department of Experimental Radiology, Institute for Diagnostic and Interventional Radiology, Friedrich Schiller University, FZL, Erlanger Allee 101, 07747, Jena (Germany); Reichenbach, Juergen R [Medical Physics Group, Institute for Diagnostic and Interventional Radiology, Friedrich Schiller University, Philosophenweg 3, 07743, Jena (Germany); Linss, Werner [Institute of Anatomy, Friedrich Schiller University, Teichgraben 7, 07740, Jena (Germany); Lisy, Marcus-Rene [Department of Experimental Radiology, Institute for Diagnostic and Interventional Radiology, Friedrich Schiller University, FZL, Erlanger Allee 101, 07747, Jena (Germany); Berndt, Alexander [Institute of Pathology, Friedrich Schiller University, Ziegelmuehlenweg 1, 07740, Jena (Germany); Kaiser, Werner A [Department of Experimental Radiology, Institute for Diagnostic and Interventional Radiology, Friedrich Schiller University, FZL, Erlanger Allee 101, 07747, Jena (Germany)

    2007-04-04

    The aim of this study was to assess whether Her-2/neu expressing tumour cells can be detected in vitro as well as in animal tumour models with magnetic resonance imaging at 1.5 T. Magnetic nanoparticles (with relaxivities R 1, R 2 of 3.7 {+-} 0.4 (mM s){sup -1}, 277 {+-} 32 (mM s){sup -1} at 21 deg. C, respectively) coupled to anti-Her-2/neu antibodies or gamma globulin IgG (high or non-affinity probe, respectively) were used. After incubation of Her-2/neu expressing cells (SKBR3) with high or non-affinity probes (20 min), values of R 1 = 0.34 {+-} 0.02 (mM s){sup -1} and R 2 = 63.02 {+-} 30 (mM s){sup -1} were obtained. Electron microscopy and atomic absorption spectrometry examinations verified the presence of relatively high iron levels in cells incubated with the high affinity probe compared to controls. For in vivo MRI, high or non-affinity probes ({approx}1.7 mg Fe/animal) were injected into the tail vein of mice (n = 16) bearing SKBR3 tumours. A distinct decrease in the normalized MR signal ratio between tumour and reference area (approximately -17 {+-} 2%) after application of the high affinity probe was observed. In conclusion, in vivo detection of Her-2/neu expressing tumours is feasible in a clinical MR scanner by using immunoconjugated magnetic nanoparticles.

  20. Measuring binding kinetics of aromatic thiolated molecules with nanoparticles via surface-enhanced Raman spectroscopy

    Science.gov (United States)

    Devetter, Brent M.; Mukherjee, Prabuddha; Murphy, Catherine J.; Bhargava, Rohit

    2015-05-01

    Colloidal plasmonic nanomaterials, consisting of metals such as gold and silver, are excellent candidates for advanced optical probes and devices, but precise control over surface chemistry is essential for realizing their full potential. Coupling thiolated (R-SH) molecules to nanoprobe surfaces is a convenient and established route to tailor surface properties. The ability to dynamically probe and monitor the surface chemistry of nanoparticles in solution is essential for rapidly manufacturing spectroscopically tunable nanoparticles. In this study, we report the development of surface-enhanced Raman spectroscopy (SERS) as a method to monitor the kinetics of gold-thiolate bond formation on colloidal gold nanoparticles. A theoretical model combining SERS enhancement with the Beer-Lambert law is proposed to explain ensemble scattering and absorption effects in colloids during chemisorption. In order to maximize biological relevance and signal reproducibility, experiments used to validate the model focused on maintaining nanoparticle stability after the addition of water-soluble aromatic thiolated molecules. Our results indicate that ligand exchange on gold nanoparticles follow a first-order Langmuir adsorption model with rate constants on the order of 0.01 min-1. This study demonstrates an experimental spectroscopic method and theoretical model for monitoring binding kinetics that may prove useful for designing novel probes.Colloidal plasmonic nanomaterials, consisting of metals such as gold and silver, are excellent candidates for advanced optical probes and devices, but precise control over surface chemistry is essential for realizing their full potential. Coupling thiolated (R-SH) molecules to nanoprobe surfaces is a convenient and established route to tailor surface properties. The ability to dynamically probe and monitor the surface chemistry of nanoparticles in solution is essential for rapidly manufacturing spectroscopically tunable nanoparticles. In this

  1. In-situ small-angle x-ray scattering study of nanoparticles in the plasma plume induced by pulsed laser irradiation of metallic targets

    Energy Technology Data Exchange (ETDEWEB)

    Lavisse, L.; Jouvard, J.-M.; Girault, M.; Potin, V.; Andrzejewski, H.; Marco de Lucas, M. C.; Bourgeois, S. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Universite de Bourgogne, 9 Avenue A. Savary, BP 47870-21078 Dijon Cedex (France); Le Garrec, J.-L.; Carles, S.; Mitchell, J. B. A. [Institut de Physique de Rennes, UMR 6251 CNRS-Universite de Rennes 1, 35042 Rennes Cedex (France); Hallo, L. [CEA CESTA, 15 Avenue des Sablieres CS 60001, 33116 Le Barp Cedex (France); Perez, J. [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex (France); Decloux, J. [Kaluti System, Optique et Laser, Centre Scientifique d' Orsay, 91400 Orsay (France)

    2012-04-16

    Small angle x-ray scattering was used to probe in-situ the formation of nanoparticles in the plasma plume generated by pulsed laser irradiation of a titanium metal surface under atmospheric conditions. The size and morphology of the nanoparticles were characterized as function of laser irradiance. Two families of nanoparticles were identified with sizes on the order of 10 and 70 nm, respectively. These results were confirmed by ex-situ transmission electron microscopy experiments.

  2. Composite nanoparticle of Au and quantum dots for X-ray computed tomography and fluorescence dual-mode imaging in vivo

    International Nuclear Information System (INIS)

    Song, Ji-Tao; Yang, Xiao-Quan; Zhang, Xiao-Shuai; Yan, Dong-Mei; Yao, Ming-Hao; Qin, Meng-Yao; Zhao, Yuan-Di

    2015-01-01

    In this study, composite nanoparticles comprising Au nanoparticle and quantum dots were built and used for contrast-enhanced computed tomography imaging (CT) and fluorescence dual-mode imaging in vivo. The nanoparticle exhibited good monodispersity and good biocompatibility, and had excellent CT contrast-enhancement effect and fluorescence imaging capability. They were appropriate for being used as dual-mode imaging probe in vivo

  3. All-Fiber Raman Probe

    DEFF Research Database (Denmark)

    Brunetti, Anna Chiara

    to perform real-time measurements with little or no sample preparation, Raman spectroscopy is now considered an invaluable analytical tool, finding application in several fields including medicine, defense and process control. When combined with fiber optics technology, Raman spectroscopy allows......The design and development of an all-in-fiber probe for Raman spectroscopy are presented in this Thesis. Raman spectroscopy is an optical technique able to probe a sample based on the inelastic scattering of monochromatic light. Due to its high specificity and reliability and to the possibility...... for the realization of flexible and minimally-invasive devices, able to reach remote or hardly accessible samples, and to perform in-situ analyses in hazardous environments. The work behind this Thesis focuses on the proof-of-principle demonstration of a truly in-fiber Raman probe, where all parts are realized...

  4. Gamma-ray imaging probes

    International Nuclear Information System (INIS)

    Wild, W.J.

    1988-01-01

    External nuclear medicine diagnostic imaging of early primary and metastatic lung cancer tumors is difficult due to the poor sensitivity and resolution of existing gamma cameras. Nonimaging counting detectors used for internal tumor detection give ambiguous results because distant background variations are difficult to discriminate from neighboring tumor sites. This suggests that an internal imaging nuclear medicine probe, particularly an esophageal probe, may be advantageously used to detect small tumors because of the ability to discriminate against background variations and the capability to get close to sites neighboring the esophagus. The design, theory of operation, preliminary bench tests, characterization of noise behavior and optimization of such an imaging probe is the central theme of this work

  5. Spaser as a biological probe

    Science.gov (United States)

    Galanzha, Ekaterina I.; Weingold, Robert; Nedosekin, Dmitry A.; Sarimollaoglu, Mustafa; Nolan, Jacqueline; Harrington, Walter; Kuchyanov, Alexander S.; Parkhomenko, Roman G.; Watanabe, Fumiya; Nima, Zeid; Biris, Alexandru S.; Plekhanov, Alexander I.; Stockman, Mark I.; Zharov, Vladimir P.

    2017-06-01

    Understanding cell biology greatly benefits from the development of advanced diagnostic probes. Here we introduce a 22-nm spaser (plasmonic nanolaser) with the ability to serve as a super-bright, water-soluble, biocompatible probe capable of generating stimulated emission directly inside living cells and animal tissues. We have demonstrated a lasing regime associated with the formation of a dynamic vapour nanobubble around the spaser that leads to giant spasing with emission intensity and spectral width >100 times brighter and 30-fold narrower, respectively, than for quantum dots. The absorption losses in the spaser enhance its multifunctionality, allowing for nanobubble-amplified photothermal and photoacoustic imaging and therapy. Furthermore, the silica spaser surface has been covalently functionalized with folic acid for molecular targeting of cancer cells. All these properties make a nanobubble spaser a promising multimodal, super-contrast, ultrafast cellular probe with a single-pulse nanosecond excitation for a variety of in vitro and in vivo biomedical applications.

  6. Radioactive Probes on Ferromagnetic Surfaces

    CERN Multimedia

    2002-01-01

    On the (broad) basis of our studies of nonmagnetic radioactive probe atoms on magnetic surfaces and at interfaces, we propose to investigate the magnetic interaction of magnetic probe atoms with their immediate environment, in particular of rare earth (RE) elements positioned on and in ferromagnetic surfaces. The preparation and analysis of the structural properties of such samples will be performed in the UHV chamber HYDRA at the HMI/Berlin. For the investigations of the magnetic properties of RE atoms on surfaces Perturbed Angular Correlation (PAC) measurements and Mössbauer Spectroscopy (MS) in the UHV chamber ASPIC (Apparatus for Surface Physics and Interfaces at CERN) are proposed.

  7. Probing nuclear matter with dileptons

    International Nuclear Information System (INIS)

    Schroeder, L.S.

    1986-06-01

    Dileptons are shown to be of interest in helping probe extreme conditions of temperature and density in nuclear matter. The current state of experimental knowledge about dileptons is briefly described, and their use in upcoming experiments with light ions at CERN SPS are reviewed, including possible signatures of quark matter formation. Use of dileptons in an upcoming experiment with a new spectrometer at Berkeley is also discussed. This experiment will probe the nuclear matter equation of state at high temperature and density. 16 refs., 8 figs

  8. Asphaltene nanoparticle aggregation in mixtures of incompatible crude oils

    International Nuclear Information System (INIS)

    Mason, T.G.; Lin, M.Y.

    2003-01-01

    We study the structure and phase behavior of asphaltenes comprised of large polyaromatic molecules in blends of naturally occurring crude oils using small angle neutron scattering (SANS). When two compatible oils are blended together, the asphaltenes remain dispersed as colloidal nanoparticles; however, when two incompatible oils are blended together, these asphaltene nanoparticles can aggregate to form microscale structures. We show that SANS directly probes asphaltene aggregation in unmodified (i.e., nondeuterated) crude oil mixtures due to a significant neutron scattering length density difference between the hydrogen-poor asphaltenes and the surrounding oil. Moreover, the small length scales probed by SANS are ideally suited for studying asphaltene aggregation: SANS simultaneously provides the average size and concentration of nanoscale asphaltene particles and also the volume fraction of microscale asphaltene aggregates. These discoveries yield a practical means for directly assessing the compatibility of crude oils and for diagnosing refinery fouling problems resulting from blending incompatible oils

  9. Improving proton therapy by metal-containing nanoparticles: nanoscale insights

    Science.gov (United States)

    Schlathölter, Thomas; Eustache, Pierre; Porcel, Erika; Salado, Daniela; Stefancikova, Lenka; Tillement, Olivier; Lux, Francois; Mowat, Pierre; Biegun, Aleksandra K; van Goethem, Marc-Jan; Remita, Hynd; Lacombe, Sandrine

    2016-01-01

    The use of nanoparticles to enhance the effect of radiation-based cancer treatments is a growing field of study and recently, even nanoparticle-induced improvement of proton therapy performance has been investigated. Aiming at a clinical implementation of this approach, it is essential to characterize the mechanisms underlying the synergistic effects of nanoparticles combined with proton irradiation. In this study, we investigated the effect of platinum- and gadolinium-based nanoparticles on the nanoscale damage induced by a proton beam of therapeutically relevant energy (150 MeV) using plasmid DNA molecular probe. Two conditions of irradiation (0.44 and 3.6 keV/μm) were considered to mimic the beam properties at the entrance and at the end of the proton track. We demonstrate that the two metal-containing nanoparticles amplify, in particular, the induction of nanosize damages (>2 nm) which are most lethal for cells. More importantly, this effect is even more pronounced at the end of the proton track. This work gives a new insight into the underlying mechanisms on the nanoscale and indicates that the addition of metal-based nanoparticles is a promising strategy not only to increase the cell killing action of fast protons, but also to improve tumor targeting. PMID:27143877

  10. Challenges in nanoelectrochemical and nanomechanical studies of individual anisotropic gold nanoparticles.

    Science.gov (United States)

    Knittel, P; Bibikova, O; Kranz, C

    2016-11-01

    The characterization of nanoparticles and the correlation of physical properties such as size and shape to their (electro)chemical properties is an emerging field, which may facilitate future optimization and tuning of devices involving nanoparticles. This requires the investigation of individual particles rather than obtaining averaged information on large ensembles. Here, we present atomic force - scanning electrochemical microscopy (AFM-SECM) measurements of soft conductive PDMS substrates modified with gold nanostars (i.e., multibranched Au nanoparticles) in peak force tapping mode, which next to the electrochemical characterization provides information on the adhesion, deformation properties, and Young's modulus of the sample. AFM-SECM probes with integrated nanodisc electrodes (radii nanostars.

  11. The Application of Nanoparticles in Gene Therapy and Magnetic Resonance Imaging

    Science.gov (United States)

    HERRANZ, FERNANDO; ALMARZA, ELENA; RODRÍGUEZ, IGNACIO; SALINAS, BEATRIZ; ROSELL, YAMILKA; DESCO, MANUEL; BULTE, JEFF W.; RUIZ-CABELLO, JESÚS

    2012-01-01

    The combination of nanoparticles, gene therapy, and medical imaging has given rise to a new field known as gene theranostics, in which a nanobioconjugate is used to diagnose and treat the disease. The process generally involves binding between a vector carrying the genetic information and a nanoparticle, which provides the signal for imaging. The synthesis of this probe generates a synergic effect, enhancing the efficiency of gene transduction and imaging contrast. We discuss the latest approaches in the synthesis of nanoparticles for magnetic resonance imaging, gene therapy strategies, and their conjugation and in vivo application. PMID:21484943

  12. Gold-coated iron nanoparticles in transparent Si3N4 matrix thin films

    Science.gov (United States)

    Sánchez-Marcos, J.; Céspedes, E.; Jiménez-Villacorta, F.; Muñoz-Martín, A.; Prieto, C.

    2013-06-01

    A new method to prepare thin films containing gold-coated iron nanoparticles is presented. The ternary Fe-Au-Si3N4 system prepared by sequential sputtering has revealed a progressive variation of microstructures from Au/Fe/Au/Si3N4 multilayers to iron nanoparticles. Microstructural characterization by transmission electron microscopy, analysis of the magnetic properties and probing of the iron short-range order by X-ray absorption spectroscopy confirm the existence of a gold-coated iron nanoparticles of 1-2 nm typical size for a specific range of iron and gold contents per layer in the transparent silicon nitride ceramic matrix.

  13. Disulfide-induced self-assembled targets : A novel strategy for the label free colorimetric detection of DNAs/RNAs via unmodified gold nanoparticles

    NARCIS (Netherlands)

    Shokri, Ehsan; Hosseini, Morteza; Davari, Mehdi D.; Ganjali, Mohammad R.; Peppelenbosch, Maikel P.; Rezaee, Farhad

    2017-01-01

    A modified non-cross-linking gold-nanoparticles (Au-NPs) aggregation strategy has been developed for the label free colorimetric detection of DNAs/RNAs based on self-assembling target species in the presence of thiolated probes. Two complementary thiol-modified probes, each of which specifically

  14. Disulfide-induced self-assembled targets: A novel strategy for the label free colorimetric detection of DNAs/RNAs via unmodified gold nanoparticles

    NARCIS (Netherlands)

    Shokri, E. (Ehsan); M. Hosseini (Morteza); Davari, M.D. (Mehdi D.); Ganjali, M.R. (Mohammad R.); M.P. Peppelenbosch (Maikel); F. Rezaee (Farhad)

    2017-01-01

    textabstractA modified non-cross-linking gold-nanoparticles (Au-NPs) aggregation strategy has been developed for the label free colorimetric detection of DNAs/RNAs based on self-assembling target species in the presence of thiolated probes. Two complementary thiol- modified probes, each of which

  15. Nanoparticle agglomerates in magnetoliposomes

    Science.gov (United States)

    Cintra, E. R.; Ferreira, F. S.; Santos Junior, J. L.; Campello, J. C.; Socolovsky, L. M.; Lima, E. M.; Bakuzis, A. F.

    2009-01-01

    Magnetoliposomes consist of vesicles composed of a phospholipid membrane encapsulating magnetic nanoparticles. These systems have several important applications, such as in MRI contrast agents, drug and gene carriers, and cancer treatment devices. For all of these applications, controlling the number of encapsulated magnetic nanoparticles is a key issue. In this work, we used a magneto-optical technique to obtain information about the efficiency of encapsulation, the number of nanoparticles encapsulated per liposome and also about the formation of the nanoparticle structures. The parameters studied included the effect of the duration of sonication, the presence of cholesterol in the liposome membrane, as well as time-related stability. For the liposomal vesicles prepared in this work, we found between 35 and 300 nanoparticles encapsulated per liposome, depending on the experimental conditions, consisting of small linear chains of nanoparticles, basically trimers and tetramers. The methodology developed might be useful for the investigation and improvement of the properties of several magnetic nanocarrier systems.

  16. Multifunctional nanoparticles: Analytical prospects

    International Nuclear Information System (INIS)

    Dios, Alejandro Simon de; Diaz-Garcia, Marta Elena

    2010-01-01

    Multifunctional nanoparticles are among the most exciting nanomaterials with promising applications in analytical chemistry. These applications include (bio)sensing, (bio)assays, catalysis and separations. Although most of these applications are based on the magnetic, optical and electrochemical properties of multifunctional nanoparticles, other aspects such as the synergistic effect of the functional groups and the amplification effect associated with the nanoscale dimension have also been observed. Considering not only the nature of the raw material but also the shape, there is a huge variety of nanoparticles. In this review only magnetic, quantum dots, gold nanoparticles, carbon and inorganic nanotubes as well as silica, titania and gadolinium oxide nanoparticles are addressed. This review presents a narrative summary on the use of multifuncional nanoparticles for analytical applications, along with a discussion on some critical challenges existing in the field and possible solutions that have been or are being developed to overcome these challenges.

  17. Nanoparticles and direct immunosuppression

    Science.gov (United States)

    Ngobili, Terrika A

    2016-01-01

    Targeting the immune system with nanomaterials is an intensely active area of research. Specifically, the capability to induce immunosuppression is a promising complement for drug delivery and regenerative medicine therapies. Many novel strategies for immunosuppression rely on nanoparticles as delivery vehicles for small-molecule immunosuppressive compounds. As a consequence, efforts in understanding the mechanisms in which nanoparticles directly interact with the immune system have been overshadowed. The immunological activity of nanoparticles is dependent on the physiochemical properties of the nanoparticles and its subsequent cellular internalization. As the underlying factors for these reactions are elucidated, more nanoparticles may be engineered and evaluated for inducing immunosuppression and complementing immunosuppressive drugs. This review will briefly summarize the state-of-the-art and developments in understanding how nanoparticles induce immunosuppressive responses, compare the inherent properties of nanomaterials which induce these immunological reactions, and comment on the potential for using nanomaterials to modulate and control the immune system. PMID:27229901

  18. Multifunctional nanoparticles: analytical prospects.

    Science.gov (United States)

    de Dios, Alejandro Simón; Díaz-García, Marta Elena

    2010-05-07

    Multifunctional nanoparticles are among the most exciting nanomaterials with promising applications in analytical chemistry. These applications include (bio)sensing, (bio)assays, catalysis and separations. Although most of these applications are based on the magnetic, optical and electrochemical properties of multifunctional nanoparticles, other aspects such as the synergistic effect of the functional groups and the amplification effect associated with the nanoscale dimension have also been observed. Considering not only the nature of the raw material but also the shape, there is a huge variety of nanoparticles. In this review only magnetic, quantum dots, gold nanoparticles, carbon and inorganic nanotubes as well as silica, titania and gadolinium oxide nanoparticles are addressed. This review presents a narrative summary on the use of multifunctional nanoparticles for analytical applications, along with a discussion on some critical challenges existing in the field and possible solutions that have been or are being developed to overcome these challenges. 2010 Elsevier B.V. All rights reserved.

  19. The reactivity of phenylethanethiolated gold nanoparticles with acetic acid.

    Science.gov (United States)

    Xia, Nan; Gan, Zibao; Liao, Lingwen; Zhuang, Shengli; Wu, Zhikun

    2017-10-24

    We report the size-dependent reactivity of phenylethanethiolated gold nanoparticles with acetic acid. Employing this reactivity, we synthesize a novel nanocluster Au 38 (PET) 26 (PET: phenylethanethiolate), which is otherwise difficult to obtain and exhibits remarkably different photoluminescence and electrochemical properties compared with the well-known Au 38 (PET) 24 nanoclusters. And the reaction process between Au 38 (PET) 26 and acetic acid was probed by matrix-assisted laser desorption/ionization time of flight mass spectrometry.

  20. Photovoltaic properties of graphene oxide sheets beaded with ZnO nanoparticles

    Science.gov (United States)

    Wang, Huan; Wang, Li; Qu, Chaoqun; Su, Yadong; Yu, Shansheng; Zheng, Weitao; Liu, Yichun

    2011-04-01

    A hybrid material of graphene oxide (GO) sheets beaded with ZnO nanoparticles was prepared. The material extends over a few hundred square nanometers, in which the ZnO nanoparticles (average diameter (˜5 nm)) are dispersed evenly on the GO sheet. Both the surface photovoltage or surface photocurrent intensity for the material are much stronger than for pure ZnO nanoparticles, meaning that the free charge carriers can effectively be transferred from ZnO nanoparticles to GO sheets, which can serve as a probe to monitor the electron transfer from excited ZnO to GO. Anchoring ZnO nanoparticles on two dimensional carbon nanostructures such as GO can pave a way towards the design of ordered nanostructure assemblies that can harvest light energy efficiently.

  1. Surface-enhanced Raman scattering from magneto-metal nanoparticle assemblies.

    Science.gov (United States)

    Qu, Hua; Lai, Yuming; Niu, Dongzi; Sun, Shuqing

    2013-02-06

    Binary nanoparticles composed of a superparamagnetic Fe(3)O(4) core and an Au nanoshell (Fe(3)O(4)@Au) were prepared via a simple co-precipitation method followed by seed-mediated growth process. The nanoparticles exhibited functions of both fast magnetic response and local surface plasmon resonance. The Fe(3)O(4)@Au nanoparticles were used as probes for surface-enhanced Raman scattering (SERS) using p-thiocresol (p-TC) as reporter molecule. With the ability of analyte capture and concentration magnetically, the Fe(3)O(4)@Au nanoparticles showed significant SERS properties with excellent reproducibility. Under non-optimized conditions, detection limit as low as 4.55 pM of analyte can be reached using Fe(3)O(4)@Au nanoparticle assemblies, which excel remarkably the cases with traditional Au nanoprobes. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. [How safe are nanoparticles?].

    Science.gov (United States)

    Lademann, J; Meinke, M; Sterry, W; Patzelt, A

    2009-04-01

    Nanoparticles are experiencing an increasing application in dermatology and cosmetics. In both application areas, the requirements of nanoparticles are in most cases widely different. As a component of sunscreens, the nanoparticles are supposed to remain on the skin surface or in the upper most layers of the stratum corneum to protect the skin against UV-radiation of the sun. Whereas, on the other hand, when particulate substances are used as carrier systems for drugs, they have to cross the skin barrier to reach the target sites within the living tissue. We discuss the perspectives and risks of the topical application of nanoparticles.

  3. SUB-SLAB PROBE INSTALLATION

    Science.gov (United States)

    Sub-slab sampling has become an integral part of vapor intrusion investigations. It is now recommended in guidance documents developed by EPA and most states. A method for sub-slab probe installation was devised in 2002, presented at conferences through 2005, and finally docume...

  4. Resolution analysis by random probing

    NARCIS (Netherlands)

    Fichtner, Andreas; van Leeuwen, T.

    2015-01-01

    We develop and apply methods for resolution analysis in tomography, based on stochastic probing of the Hessian or resolution operators. Key properties of our methods are (i) low algorithmic complexity and easy implementation, (ii) applicability to any tomographic technique, including full‐waveform

  5. Seismic probing of Fennoscandian lithosphere

    Czech Academy of Sciences Publication Activity Database

    Bock, G.; Achauer, U.; Alinaghi, A.; Ansorge, J.; Bruneton, M.; Friederich, W.; Grad, M.; Guterch, A.; Hjelt, S. E.; Plomerová, Jaroslava

    2001-01-01

    Roč. 82, č. 50 (2001), s. 621, 628-629 ISSN 0096-3941 R&D Projects: GA AV ČR IAA3012908 Institutional research plan: CEZ:AV0Z3012916 Keywords : seismic probing * lithosphere * Fennoscandia * SVEKALAPKO * Europrobe Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  6. Gold nanoparticles and films produced by a laser ablation/gas deposition (LAGD) method

    International Nuclear Information System (INIS)

    Kawakami, Yuji; Seto, Takafumi; Yoshida, Toshinobu; Ozawa, Eiichi

    2002-01-01

    Gold nanoparticles have great potential for various nanoelectronic applications such as single electron transistors, an infrared absorption sensor and so on. It is very important to understand and control the size distribution of the particles for such a variety of applications. In this paper, we report the size distribution of gold nanoparticles and the relationship between the nanoparticle-films and the electrical property produced by a laser ablation method. Gold nanoparticle-films were prepared by a technique, which sprays nanoparticles on the substrate through a nozzle. We call it a gas deposition method. The nanoparticles were generated by the nanosecond pulsed Nd:YAG laser ablation of a gold substrate under a low-pressure inert gas atmosphere. The ambient pressure was changed to control the average size and their distribution. The particles produced in the generation chamber were transported by a helium carrier gas to the deposition chamber and deposited on a substrate to form the films composed of gold nanoparticles. The electrical resistivity of the generated gold nanoparticle-films on the glass substrates was measured using a four-probe method. The size distribution of the nanoparticles was examined using transmission electron microscopy (TEM) and a low-pressure differential mobility analyzer (LP-DMA). The relationship between the particle size and the electrical properties of each film made by the different synthesis conditions were analyzed. The electrical resistivity changed from the order of 10 -5 to 10 -1 Ω cm depending on the ambient pressure and the size distribution

  7. The characteristics of laser welded magnesium alloy using silver nanoparticles as insert material

    International Nuclear Information System (INIS)

    Ishak, M.; Maekawa, K.; Yamasaki, K.

    2012-01-01

    Highlights: ► Ag nanoparticles are used as insert material for welding Mg alloy with laser. ► We examine the microstructure and mechanical properties of welded Mg alloys. ► Nananoparticle promote grain refinement to the weld structure. ► Finer nanoparticle produces high weld efficiency and mechanical properties. - Abstract: This paper describes the characteristics of the laser welding of thin-sheet magnesium alloys using silver (Ag) nanoparticles as an insert material. The experiment was conducted using nanoparticles with 5 nm and 100 nm diameters that were welded with a Nd:YAG laser. The microstructure and mechanical properties of the specimens welded using inserts with different sizes of nanoparticles and without an insert material, were examined. Electron probe micro-analyzer (EPMA) analysis was conducted to confirm the existence of Ag in the welded area. The introduction of the Ag nanoparticle insert promoted large area of fine grain and broadened the acceptable range of scanning speed parameters compared to welds without an insert. Welds with 5 nm nanoparticles yielded the highest fracture load of up to 818 N while the lowest fracture load was found for weld specimens with 100 nm nanoparticles. This lower fracture load was due to larger voids and a smaller throat length, which contributed to a lower fracture load when using larger nanoparticles.

  8. DNA-based MRI probes for specific detection of chronic exposure to amphetamine in living brains.

    Science.gov (United States)

    Liu, Christina H; Ren, Jia Q; Yang, Jinsheng; Liu, Charng-ming; Mandeville, Joseph B; Rosen, Bruce R; Bhide, Pradeep G; Yanagawa, Yuchio; Liu, Philip K

    2009-08-26

    We designed phosphorothioate-modified DNA probes linked to superparamagnetic iron oxide nanoparticles (SPION) for in vivo magnetic resonance imaging (MRI) of fosB and Delta fosB mRNA after amphetamine (AMPH) exposure in mice. Specificity of both the fosB and Delta fosB probes was verified by in vitro reverse transcriptase-PCR amplification to a single fragment of total cDNA obtained from acutely AMPH-exposed mouse brains. We confirmed time-dependent uptake and retention profiles of both probes in neurons of GAD67-green fluorescent protein knock-in mice. MRI signal of SPION-labeled fosB probe delivered via intracerebroventricular route was elevated in both acutely and chronically AMPH-exposed mice; the signal was suppressed by dopaminergic receptor antagonist pretreatment. SPION-labeled Delta fosB probe signal elevation occurred only in chronically AMPH-exposed mice. The in vivo target specificity of these probes permits reliable MRI visualization of AMPH-induced differential elevations of fosB and Delta fosB mRNA in living brains.

  9. Sum Frequency Generation Studies of Hydrogenation Reactions on Platinum Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Krier, James M. [Univ. of California, Berkeley, CA (United States)

    2013-08-31

    Sum Frequency Generation (SFG) vibrational spectroscopy is used to characterize intermediate species of hydrogenation reactions on the surface of platinum nanoparticle catalysts. In contrast to other spectroscopy techniques which operate in ultra-high vacuum or probe surface species after reaction, SFG collects information under normal conditions as the reaction is taking place. Several systems have been studied previously using SFG on single crystals, notably alkene hydrogenation on Pt(111). In this thesis, many aspects of SFG experiments on colloidal nanoparticles are explored for the first time. To address spectral interference by the capping agent (PVP), three procedures are proposed: UV cleaning, H2 induced disordering and calcination (core-shell nanoparticles). UV cleaning and calcination physically destroy organic capping while disordering reduces SFG signal through a reversible structural change by PVP.

  10. Nonviral gene transfection nanoparticles: function and applications in the brain.

    Science.gov (United States)

    Roy, Indrajit; Stachowiak, Michal K; Bergey, Earl J

    2008-06-01

    In vivo transfer and expression of foreign genes allows for the elucidation of functions of genes in living organisms and generation of disease models in animals that more closely resemble the etiology of human diseases. Gene therapy holds promise for the cure of a number of diseases at the fundamental level. Synthetic "nonviral" materials are fast gaining popularity as safe and efficient vectors for delivering genes to target organs. Not only can nanoparticles function as efficient gene carriers, they also can simultaneously carry diagnostic probes for direct "real-time" visualization of gene transfer and downstream processes. This review has focused on the central nervous system (CNS) as the target for nonviral gene transfer, with special emphasis on organically modified silica (ORMOSIL) nanoparticles developed in our laboratory. These nanoparticles have shown robust gene transfer efficiency in brain cells in vivo and allowed to investigate mechanisms that control neurogenesis as well as neurodegenerative disorders.

  11. Mapping and Quantifying Surface Charges on Clay Nanoparticles.

    Science.gov (United States)

    Liu, Jun; Gaikwad, Ravi; Hande, Aharnish; Das, Siddhartha; Thundat, Thomas

    2015-09-29

    Understanding the electrical properties of clay nanoparticles is very important since they play a crucial role in every aspect of oil sands processing, from bitumen extraction to sedimentation in mature fine tailings (MFT). Here, we report the direct mapping and quantification of surface charges on clay nanoparticles using Kelvin probe force microscopy (KPFM) and electrostatic force microscopy (EFM). The morphology of clean kaolinite clay nanoparticles shows a layered structure, while the corresponding surface potential map shows a layer-dependent charge distribution. More importantly, a surface charge density of 25 nC/cm(2) was estimated for clean kaolinite layers by using EFM measurements. On the other hand, the EFM measurements show that the clay particles obtained from the tailings demonstrate a reduced surface charge density of 7 nC/cm(2), which may be possibly attributed to the presence of various bituminous compounds residing on the clay surfaces.

  12. Magnetic nanoparticles as contrast agents for molecular imaging in medicine

    Science.gov (United States)

    O'Donnell, Matthew

    2018-05-01

    For over twenty years, superparamagnetic nanoparticles have been developed for a number of medical applications ranging from bioseparations, magnetic drug targeting, hyperthermia and imaging. Recent studies have shown that they can be functionalized for in vivo biological targeting, potentially enabling nanoagents for molecular imaging and site-localized drug delivery. Here we review several imaging technologies developed using functionalized superparamagnetic iron oxide nanoparticles (SPIONs) as targeted molecular agents. Several imaging modalities have exploited the large induced magnetic moment of SPIONs to create local mechanical force. Magnetic force microscopy can probe nanoparticle uptake in single cells. For in vivo applications, magnetomotive modulation of primary images in ultrasound (US), photoacoustics (PA), and optical coherence tomography (OCT) can help identify very small concentrations of nanoagents while simultaneously suppressing intrinsic background signals from tissue.

  13. Detection of Salmonella typhi utilizing bioconjugated fluorescent polymeric nanoparticles

    International Nuclear Information System (INIS)

    Jain, Swati; Chattopadhyay, Sruti; Jackeray, Richa; Abid, Zainul; Singh, Harpal

    2016-01-01

    Present work demonstrates effective utilization of functionalized polymeric fluorescent nanoparticles as biosensing probe for the detection of Salmonella typhi bacteria on modified polycarbonate (PC) filters in about 3 h. Antibody modified-PC membranes were incubated with contaminated bacterial water for selective capturing which were detected by synthesized novel bioconjugate probe. Core–shell architecture of polymeric nanoparticles endows them with aqueous stabilization and keto-enolic functionalities making them usable for covalently linking S. typhi antibodies without any crosslinker or activator. Bradford analysis revealed that one nanoparticle has an average of 3.51 × 10 −19  g or 21 × 10 4 bound S. typhi Ab molecules. Analysis of the regions of interest (ROI) in fluorescent micrographs of modified fluoroimmunoassay showed higher detection sensitivity of 5 × 10 2  cells/mL due to signal amplification unlike conventional naked dye FITC-Ab conjugate. Fluorescence of pyrene dye remained same on immobilization of biomolecules and nanoparticles showed stable fluorescent intensity under prolong exposure to laser owing to protective polymeric layer allowing accurate identification of bacteria. Surface-functionalized PC matrix and fluorescent label NPs permit covalent interactions among biomolecules enhancing signal acquisitions showing higher detection efficiency as compared to conventional microtiter plate-based system. Our novel immunoassay has the potential to be explored as rapid detection method for identifying S. typhi contaminations in water.Graphical Abstract

  14. Detection of Salmonella typhi utilizing bioconjugated fluorescent polymeric nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Swati, E-mail: swatijain.iitd@gmail.com; Chattopadhyay, Sruti, E-mail: sruticiitd@gmail.com; Jackeray, Richa; Abid, Zainul; Singh, Harpal, E-mail: harpal2000@yahoo.com [Centre for Biomedical Engineering, Indian Institute of Technology-Delhi (India)

    2016-05-15

    Present work demonstrates effective utilization of functionalized polymeric fluorescent nanoparticles as biosensing probe for the detection of Salmonella typhi bacteria on modified polycarbonate (PC) filters in about 3 h. Antibody modified-PC membranes were incubated with contaminated bacterial water for selective capturing which were detected by synthesized novel bioconjugate probe. Core–shell architecture of polymeric nanoparticles endows them with aqueous stabilization and keto-enolic functionalities making them usable for covalently linking S. typhi antibodies without any crosslinker or activator. Bradford analysis revealed that one nanoparticle has an average of 3.51 × 10{sup −19} g or 21 × 10{sup 4} bound S. typhi Ab molecules. Analysis of the regions of interest (ROI) in fluorescent micrographs of modified fluoroimmunoassay showed higher detection sensitivity of 5 × 10{sup 2} cells/mL due to signal amplification unlike conventional naked dye FITC-Ab conjugate. Fluorescence of pyrene dye remained same on immobilization of biomolecules and nanoparticles showed stable fluorescent intensity under prolong exposure to laser owing to protective polymeric layer allowing accurate identification of bacteria. Surface-functionalized PC matrix and fluorescent label NPs permit covalent interactions among biomolecules enhancing signal acquisitions showing higher detection efficiency as compared to conventional microtiter plate-based system. Our novel immunoassay has the potential to be explored as rapid detection method for identifying S. typhi contaminations in water.Graphical Abstract.

  15. Elution of labile fluorescent dye from nanoparticles during biological use.

    Directory of Open Access Journals (Sweden)

    Tiziana Tenuta

    Full Text Available Cells act as extremely efficient filters for elution of unbound fluorescent tags or impurities associated with nanoparticles, including those that cannot be removed by extensive cleaning. This has consequences for quantification of nanoparticle uptake and sub-cellular localization in vitro and in vivo as a result of the presence of significant amount of labile dye even following extensive cleaning by dialysis. Polyacrylamide gel electrophoresis (PAGE can be used to monitor the elution of unbound fluorescent probes from nanoparticles, either commercially available or synthesized in-house, and to ensure their complete purification for biological studies, including cellular uptake and sub-cellular localisation. Very different fluorescence distribution within cells is observed after short dialysis times versus following extensive dialysis against a solvent in which the free dye is more soluble, due to the contribution from free dye. In the absence of an understanding of the presence of residual free dye in (most labeled nanoparticle solutions, the total fluorescence intensity in cells following exposure to nanoparticle solutions could be mis-ascribed to the presence of nanoparticles through the cell, rather than correctly assigned to either a combination of free-dye and nanoparticle-bound dye, or even entirely to free dye depending on the exposure conditions (i.e. aggregation of the particles etc. Where all of the dye is nanoparticle-bound, the particles are highly localized in sub-cellular organelles, likely lysosomes, whereas in a system containing significant amounts of free dye, the fluorescence is distributed through the cell due to the free diffusion of the molecule dye across all cellular barriers and into the cytoplasm.

  16. Encapsulation of gold nanoparticles into self-assembling protein nanoparticles

    OpenAIRE

    Yang Yongkun; Burkhard Peter

    2012-01-01

    Abstract Background Gold nanoparticles are useful tools for biological applications due to their attractive physical and chemical properties. Their applications can be further expanded when they are functionalized with biological molecules. The biological molecules not only provide the interfaces for interactions between nanoparticles and biological environment, but also contribute their biological functions to the nanoparticles. Therefore, we used self-assembling protein nanoparticles (SAPNs...

  17. Bioconjugation of quantum dot luminescent probes for Western blot analysis.

    Science.gov (United States)

    Makrides, Savvas C; Gasbarro, Christina; Bello, Job M

    2005-10-01

    Western blot analysis is a widely used technique for protein immunodetection. Its current format, however is unsuitable for multiplex detection of proteins, primarily due to intrinsic limitations of standard organic dyes employed as probes. Quantum dot (QD) semiconductor nanoparticles exhibit significant advantages over organic dyes, including their broad absorption bands, narrow, tunable, and symmetric emission spectra, large Stokes shifts, and excellent photostability. Here we describe a novel method for the functionalization of streptavidin-coated QDs with an in vivo biotinylated peptide (head-to-tail dimerized Z domain derived from protein A) that permits the facile conjugation of antibodies to QDs. In this study, we demonstrate the simultaneous detection of two different types of protein in a Western blot. The bioconjugation of QDs described here makes it possible to achieve multiplex detection of proteins in Western blot analysis in a more straightforward manner.

  18. Cantilevered probe detector with piezoelectric element

    Science.gov (United States)

    Adams, Jesse D; Sulchek, Todd A; Feigin, Stuart C

    2013-04-30

    A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

  19. Cantilevered probe detector with piezoelectric element

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Jesse D; Sulchek, Todd A; Feigin, Stuart C

    2014-04-29

    A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

  20. Optical properties of nanoparticles

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    At the NBI I am involved in projects relating to optical properties of metallic nanoparticles in particular with respect to plasmonic heating with direct applications to photothermal cancer therapy. For this purpose we have developed heating assays that can be used to measure the heating of any...... nanoscopic heat source like an irradiated nanoparticle...

  1. Visualisation of distribution of gold nanoparticles in liver tissues ex vivo and in vitro using the method of optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Genina, Elina A; Terentyuk, G S; Khlebtsov, B N; Bashkatov, A N; Tuchin, Valerii V

    2012-06-30

    The possibility of visualising the distribution of gold nanoparticles in liver by means of the method of optical coherence tomography is studied experimentally in model samples of beef liver in vitro and rat liver ex vivo. In the experiments we used the gold nanoparticles in the form of nanocages with resonance absorption in the near-IR spectral region. In the model studies the suspension of nanoparticles was applied to the surface of the sample, which then was treated with ultrasound. In the ex vivo studies the suspension of nanoparticles was injected to the laboratory rats intravenously. The image contrast and the optical depth of detection of blood vessels and liver structure components are calculated, as well as the depth of liver optical probing before and after the injection of nanoparticles. It was shown that the administration of the nanoparticle increases significantly the imaging contrast of liver blood vessels owing to the localisation of the nanoparticles therein.

  2. Visualisation of distribution of gold nanoparticles in liver tissues ex vivo and in vitro using the method of optical coherence tomography

    International Nuclear Information System (INIS)

    Genina, Elina A; Terentyuk, G S; Khlebtsov, B N; Bashkatov, A N; Tuchin, Valerii V

    2012-01-01

    The possibility of visualising the distribution of gold nanoparticles in liver by means of the method of optical coherence tomography is studied experimentally in model samples of beef liver in vitro and rat liver ex vivo. In the experiments we used the gold nanoparticles in the form of nanocages with resonance absorption in the near-IR spectral region. In the model studies the suspension of nanoparticles was applied to the surface of the sample, which then was treated with ultrasound. In the ex vivo studies the suspension of nanoparticles was injected to the laboratory rats intravenously. The image contrast and the optical depth of detection of blood vessels and liver structure components are calculated, as well as the depth of liver optical probing before and after the injection of nanoparticles. It was shown that the administration of the nanoparticle increases significantly the imaging contrast of liver blood vessels owing to the localisation of the nanoparticles therein.

  3. Probing Photocatalytic Characteristics of Sb-Doped TiO2 under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Lingjing Luo

    2014-01-01

    Full Text Available Sb-doped TiO2 nanoparticle with varied dopant concentrations was synthesized using titanium tetrachloride (TiCl4 and antimony chloride (SbCl3 as the precursors. The properties of Sb-doped TiO2 nanoparticles were characterized by X-ray diffraction (XRD, scanning electron microscope (SEM, fluorescence spectrophotometer, and Uv-vis spectrophotometer. The absorption edge of TiO2 nanoparticles could be extended to visible region after doping with antimony, in contrast to the UV absorption of pure TiO2. The results showed that the photocatalytic activity of Sb-doped TiO2 nanoparticles was much more active than pure TiO2. The 0.1% Sb-doped TiO2 nanoparticles demonstrated the best photocatalytic activity which was better than that of the Degussa P25 under visible light irradiation using terephthalic acid as fluorescent probe. The effects of Sb dopant on the photocatalytic activity and the involved mechanism were extensively investigated in this work as well.

  4. Where do pulse oximeter probes break?

    Science.gov (United States)

    Crede, S; Van der Merwe, G; Hutchinson, J; Woods, D; Karlen, W; Lawn, J

    2014-06-01

    Pulse oximetry, a non-invasive method for accurate assessment of blood oxygen saturation (SPO2), is an important monitoring tool in health care facilities. However, it is often not available in many low-resource settings, due to expense, overly sophisticated design, a lack of organised procurement systems and inadequate medical device management and maintenance structures. Furthermore medical devices are often fragile and not designed to withstand the conditions of low-resource settings. In order to design a probe, better suited to the needs of health care facilities in low-resource settings this study aimed to document the site and nature of pulse oximeter probe breakages in a range of different probe designs in a low to middle income country. A retrospective review of job cards relating to the assessment and repair of damaged or faulty pulse oximeter probes was conducted at a medical device repair company based in Cape Town, South Africa, specializing in pulse oximeter probe repairs. 1,840 job cards relating to the assessment and repair of pulse oximeter probes were reviewed. 60.2 % of probes sent for assessment were finger-clip probes. For all probes, excluding the neonatal wrap probes, the most common point of failure was the probe wiring (>50 %). The neonatal wrap most commonly failed at the strap (51.5 %). The total cost for quoting on the broken pulse oximeter probes and for the subsequent repair of devices, excluding replacement components, amounted to an estimated ZAR 738,810 (USD $98,508). Improving the probe wiring would increase the life span of pulse oximeter probes. Increasing the life span of probes will make pulse oximetry more affordable and accessible. This is of high priority in low-resource settings where frequent repair or replacement of probes is unaffordable or impossible.

  5. Single Nanoparticle Plasmonic Sensors

    Directory of Open Access Journals (Sweden)

    Manish Sriram

    2015-10-01

    Full Text Available The adoption of plasmonic nanomaterials in optical sensors, coupled with the advances in detection techniques, has opened the way for biosensing with single plasmonic particles. Single nanoparticle sensors offer the potential to analyse biochemical interactions at a single-molecule level, thereby allowing us to capture even more information than ensemble measurements. We introduce the concepts behind single nanoparticle sensing and how the localised surface plasmon resonances of these nanoparticles are dependent upon their materials, shape and size. Then we outline the different synthetic approaches, like citrate reduction, seed-mediated and seedless growth, that enable the synthesis of gold and silver nanospheres, nanorods, nanostars, nanoprisms and other nanostructures with tunable sizes. Further, we go into the aspects related to purification and functionalisation of nanoparticles, prior to the fabrication of sensing surfaces. Finally, the recent developments in single nanoparticle detection, spectroscopy and sensing applications are discussed.

  6. Magnetic interactions between nanoparticles

    DEFF Research Database (Denmark)

    Mørup, Steen; Hansen, Mikkel Fougt; Frandsen, Cathrine

    2010-01-01

    We present a short overview of the influence of inter-particle interactions on the properties of magnetic nanoparticles. Strong magnetic dipole interactions between ferromagnetic or ferrimagnetic particles, that would be superparamagnetic if isolated, can result in a collective state...... of nanoparticles. This collective state has many similarities to spin-glasses. In samples of aggregated magnetic nanoparticles, exchange interactions are often important and this can also lead to a strong suppression of superparamagnetic relaxation. The temperature dependence of the order parameter in samples...... of strongly interacting hematite nanoparticles or goethite grains is well described by a simple mean field model. Exchange interactions between nanoparticles with different orientations of the easy axes can also result in a rotation of the sub-lattice magnetization directions....

  7. Probe-based recording technology

    International Nuclear Information System (INIS)

    Naberhuis, Steve

    2002-01-01

    The invention of the scanning tunneling microscope (STM) prompted researchers to contemplate whether such technology could be used as the basis for the storage and retrieval of information. With magnetic data storage technology facing limits in storage density due to the thermal instability of magnetic bits, the super-paramagnetic limit, the heir-apparent for information storage at higher densities appeared to be variants of the STM or similar probe-based storage techniques such as atomic force microscopy (AFM). Among these other techniques that could provide replacement technology for magnetic storage, near-field optical scanning optical microscopy (NSOM or SNOM) has also been investigated. Another alternative probe-based storage technology called atomic resolution storage (ARS) is also currently under development. An overview of these various technologies is herein presented, with an analysis of the advantages and disadvantages inherent in each particularly with respect to reduced device dimensions. The role of micro electro mechanical systems (MEMS) is emphasized

  8. Surface and bulk dissolution properties, and selectivity of DNA-linked nanoparticle assemblies

    NARCIS (Netherlands)

    Lukatsky, D.B.; Frenkel, D.

    2005-01-01

    Using a simple mean-field model, we analyze the surface and bulk dissolution properties of DNA-linked nanoparticle assemblies. We find that the dissolution temperature and the sharpness of the dissolution profiles increase with the grafting density of the single-stranded DNA "probes" on the surface

  9. Gold Nanoparticles-Coated SU-8 for Sensitive Fluorescence-Based Detections of DNA

    DEFF Research Database (Denmark)

    Cao, Cuong; Birtwell, Sam W.; Høgberg, Jonas

    2012-01-01

    that use fluorescence as the predominant detection workhorse. Here, we show that deposition of a thin gold nanoparticles layer onto the SU-8 surface significantly reduces the autofluorescence of the coated SU-8 surface by as much as 81% compared to bare SU-8. Furthermore, DNA probes can easily...

  10. Distance probes of dark energy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, A. G.; Padmanabhan, N.; Aldering, G.; Allen, S. W.; Baltay, C.; Cahn, R. N.; D’Andrea, C. B.; Dalal, N.; Dawson, K. S.; Denney, K. D.; Eisenstein, D. J.; Finley, D. A.; Freedman, W. L.; Ho, S.; Holz, D. E.; Kasen, D.; Kent, S. M.; Kessler, R.; Kuhlmann, S.; Linder, E. V.; Martini, P.; Nugent, P. E.; Perlmutter, S.; Peterson, B. M.; Riess, A. G.; Rubin, D.; Sako, M.; Suntzeff, N. V.; Suzuki, N.; Thomas, R. C.; Wood-Vasey, W. M.; Woosley, S. E.

    2015-03-01

    This document presents the results from the Distances subgroup of the Cosmic Frontier Community Planning Study (Snowmass 2013). We summarize the current state of the field as well as future prospects and challenges. In addition to the established probes using Type Ia supernovae and baryon acoustic oscillations, we also consider prospective methods based on clusters, active galactic nuclei, gravitational wave sirens and strong lensing time delays.

  11. Functional Magnetic Nanoparticles

    Science.gov (United States)

    Gass, James

    Nanoparticle system research and characterization is the focal point of this research and dissertation. In the research presented here, magnetite, cobalt, and ferrite nanoparticle systems have been explored in regard to their magnetocaloric effect (MCE) properties, as well as for use in polymer composites. Both areas of study have potential applications across a wide variety of interdisciplinary fields. Magnetite nanoparticles have been successfully dispersed in a polymer. The surface chemistry of the magnetic nanoparticle proves critical to obtaining a homogenous and well separated high density dispersion in PMMA. Theoretical studies found in the literature have indicated that surface interface energy is a critical component in dispersion. Oleic acid is used to alter the surface of magnetite nanoparticles and successfully achieve good dispersion in a PMMA thin film. Polypyrrole is then coated onto the PMMA composite layer. The bilayer is characterized using cross-sectional TEM, cross-sectional SEM, magnetic characterization, and low frequency conductivity. The results show that the superparmagnetic properties of the as synthesized particles are maintained in the composite. With further study of the properties of these nanoparticles for real and functional uses, MCE is studied on a variety of magnetic nanoparticle systems. Magnetite, manganese zinc ferrite, and cobalt ferrite systems show significant broadening of the MCE and the ability to tune the peak temperature of MCE by varying the size of the nanoparticles. Four distinct systems are studied including cobalt, cobalt core silver shell nanoparticles, nickel ferrite, and ball milled zinc ferrite. The results demonstrate the importance of surface characteristics on MCE. Surface spin disorder appears to have a large influence on the low temperature magnetic and magnetocalorie characteristics of these nanoparticle systems.

  12. The Van Allen Probes mission

    CERN Document Server

    Burch, James

    2014-01-01

    This collection of articles provides broad and detailed information about NASA’s Van Allen Probes (formerly known as the Radiation Belt Storm Probes) twin-spacecraft Earth-orbiting mission. The mission has the objective of achieving predictive understanding of the dynamic, intense, energetic, dangerous, and presently unpredictable belts of energetic particles that are magnetically trapped in Earth’s space environment above the atmosphere. It documents the science of the radiation belts and the societal benefits of achieving predictive understanding. Detailed information is provided about the Van Allen Probes mission design, the spacecraft, the science investigations, and the onboard instrumentation that must all work together to make unprecedented measurements within a most unforgiving environment, the core of Earth’s most intense radiation regions.
 This volume is aimed at graduate students and researchers active in space science, solar-terrestrial interactions and studies of the up...

  13. A computerized Langmuir probe system

    Science.gov (United States)

    Pilling, L. S.; Bydder, E. L.; Carnegie, D. A.

    2003-07-01

    For low pressure plasmas it is important to record entire single or double Langmuir probe characteristics accurately. For plasmas with a depleted high energy tail, the accuracy of the recorded ion current plays a critical role in determining the electron temperature. Even for high density Maxwellian distributions, it is necessary to accurately model the ion current to obtain the correct electron density. Since the electron and ion current saturation values are, at best, orders of magnitude apart, a single current sensing resistor cannot provide the required resolution to accurately record these values. We present an automated, personal computer based data acquisition system for the determination of fundamental plasma properties in low pressure plasmas. The system is designed for single and double Langmuir probes, whose characteristics can be recorded over a bias voltage range of ±70 V with 12 bit resolution. The current flowing through the probes can be recorded within the range of 5 nA-100 mA. The use of a transimpedance amplifier for current sensing eliminates the requirement for traditional current sensing resistors and hence the need to correct the raw data. The large current recording range is realized through the use of a real time gain switching system in the negative feedback loop of the transimpedance amplifier.

  14. Bacteriophage T4 Nanoparticles as Materials in Sensor Applications: Variables That Influence Their Organization and Assembly on Surfaces

    Directory of Open Access Journals (Sweden)

    Jinny L. Liu

    2009-08-01

    Full Text Available Bacteriophage T4 nanoparticles possess characteristics that make them ideal candidates as materials for sensors, particularly as sensor probes. Their surface can be modified, either through genetic engineering or direct chemical conjugation to display functional moieties such as antibodies or other proteins to recognize a specific target. However, in order for T4 nanoparticles to be utilized as a sensor probe, it is necessary to understand and control the variables that determine their assembly and organization on a surface. The aim of this work is to discuss some of variables that we have identified as influencing the behavior of T4 nanoparticles on surfaces. The effect of pH, ionic strength, substrate characteristics, nanoparticle concentration and charge was addressed qualitatively using atomic force microscopy (AFM.

  15. Graphene oxide and shape-controlled silver nanoparticle hybrids for ultrasensitive single-particle surface-enhanced Raman scattering (SERS) sensing.

    Science.gov (United States)

    Fan, Wei; Lee, Yih Hong; Pedireddy, Srikanth; Zhang, Qi; Liu, Tianxi; Ling, Xing Yi

    2014-05-07

    Graphene oxide (GO) is an emerging material for surface-enhanced Raman scattering (SERS) due to its strong chemical enhancement. Studying the SERS performance of plasmonic nanoparticle/GO hybrid materials at the single particle level is crucial for direct probing of the chemical effect of GO on plasmonic nanoparticles. In this work, we integrate GO and shape-controlled Ag nanoparticles to create hybrid nanomaterials, and the chemical enhancement arising from GO is investigated using single-particle SERS measurements. Ag nanoparticle@GO hybrid nanostructures are prepared by assembling Ag nanoparticles, including spheres, cubes and octahedra with GO sheets. The SERS behaviors of the hybrid nanostructures are characterized, and 2-3 times enhanced SERS intensities are detected from the Ag nanoparticle@GO hybrid nanostructures as compared to pure Ag nanoparticles. Furthermore, we probe the mechanism of SERS enhancement in the hybrid nanostructures by changing the surface coverage of GO on Ag octahedra, by using reduced GO in place of GO as well as by using probe molecules of different electronegativities. This hybrid system is an excellent candidate for single-particle SERS sensors. Sub-nanomolar levels of aromatic molecules are detected using a single Ag/GO hybrid nanomaterial. This as-prepared GO and shape-controlled Ag nanoparticle hybrid is capable of serving as a high performance SERS platform, providing new opportunities for efficient chemical and biological sensing applications.

  16. Influence of probe geometry on the response of an electrostatic probe

    DEFF Research Database (Denmark)

    Johansson, Torben; Crichton, George C; McAllister, Iain Wilson

    1999-01-01

    The response of an electrostatic probe is examined with reference to the probe geometry. The study involves the evaluation of the probe lambda function, from which response-related characteristic parameters can be derived. These parameters enable the probe detection sensitivity Se and spatial...

  17. Long-term thermal stability of nanoclusters in ODS-Eurofer steel: An atom probe tomography study

    Science.gov (United States)

    Zilnyk, K. D.; Pradeep, K. G.; Choi, P.; Sandim, H. R. Z.; Raabe, D.

    2017-08-01

    Oxide-dispersion strengthened materials are important candidates for several high-temperature structural applications in advanced nuclear power plants. Most of the desirable mechanical properties presented by these materials are due to the dispersion of stable nanoparticles in the matrix. Samples of ODS-Eurofer steel were annealed for 4320 h (6 months) at 800 °C. The material was characterized using atom probe tomography in both conditions (prior and after heat treatment). The particles number density, size distribution, and chemical compositions were determined. No significant changes were observed between the two conditions indicating a high thermal stability of the Y-rich nanoparticles at 800 °C.

  18. Microemulsion Synthesis of Nanoparticles

    Directory of Open Access Journals (Sweden)

    Gotić, M.

    2013-11-01

    Full Text Available Nanoparticles and nanomaterials have wide applications in electronics, physics, material design, being also utilized as sensors, catalysts, and more and more in biomedicine. Microemulsions are an exceptionally suitable medium for the synthesis of nanoparticles due to their thermodynamical stability, great solubility of both polar and nonpolar components, as well as their ability to control the size, dispersity and shape of the particles. This review presents microemulsion techniques for the synthesis of inorganic nanoparticles. It takes place in water-in-oil microemulsions by mixing one microemulsion with a cationic precursor, and the other with a precipitating or reducing agent, or by direct addition of reducing agents or gas (O2, NH3 ili CO2 into microemul sion (Fig. 1. Metal nanoparticles are used as catalysts, sensors, ferrofluids etc. They are produced by reducing the metal cation with a suitable reducing agent. In a similar way, one can prepare nanoparticles of alloys from the metal salts, provided that the metals are mutually soluble. The microemulsion technique is also suitable for depositing nanoparticles onto various surfaces. Highly active catalysts made from nanoparticles of Pt, Pd, Rh and other noble metals may be obtained in this way. Metal oxides and hydroxides may be prepared by hydrolysis or precipitation in the water core of microemulsion. Precipitation can be initiated by adding the base or precipitating agent into the microemulsion with water solution of metal ions. Similarly, nanoparticles may be prepared of sulphides, halogenides, cyanides, carbonates, sulphates and other insoluble metal salts. To prevent oxidation of nanoparticles, especially Fe, the particles are coated with inert metals, oxides, various polymers etc. Coating may provide additional functionality; e.g. coating with gold allows subsequent functionalization with organic compounds containing sulphur, due to the strong Au–S bond. Polymer coatings decrease

  19. Electroanalytical Evaluation of Nanoparticles by Nano-impact Electrochemistry

    Science.gov (United States)

    Karimi, Anahita

    Applications of engineered nanoparticles in electronics, catalysis, solid oxide fuel cells, medicine and sensing continue to increase. Traditionally, nanoparticle systems are characterized by spectroscopic and microscopic techniques. These methods are cumbersome and expensive, which limit their routine use for screening purposes. Electrochemistry is a powerful, yet underutilized tool, for the detection and classification of nanoparticles. The first part of this dissertation investigates a recently developed electrochemical method -- nanoparticle collision electrochemistry -- for detection and characterization of nanoparticles. Three independent projects have been described to evaluate the use of this technique for characterizing nanoparticle based systems including: conjugation with biomolecules, interaction with environmental contaminants and fundamental investigation of conformational changes of nanoparticle capping ligands. The thesis reports the first use of nano-impact electrochemistry to quantitatively investigate bioconjugation and biomolecular recognition at conductive nanoparticles. Furthermore, we also demonstrate the potential of this method as a single step, reagentless and label-free technique for the ultra-sensitive detection of biomolecular targets. A fundamental study of biorecognition is important for the development of therapeutics and molecular diagnosis probes in the biomedical, biosensing and biotechnology fields. The second project describes the use of this method as a screening tool of particle reactivity. We study the interaction and adsorption of a toxic environmental metalloid (Arsenic) with metal oxide nanoparticles to extract mechanistic, speciation and loading information. We discuss the potential of this approach to complement or replace costly characterization techniques and enable routine study of nanoparticles and their reactivity. In the third project, we use the nano-impact method to study the pH-dependent conformational changes

  20. A simple method for large scale synthesis of highly monodisperse gold nanoparticles at room temperature and their electron relaxation properties

    International Nuclear Information System (INIS)

    Polavarapu, Lakshminarayana; Xu Qinghua

    2009-01-01

    Here we demonstrate a simple method for large scale preparation of monodisperse gold nanoparticles by simple mixing of chloroauricacid (HAuCl 4 ) with oleylamine (OA) at room temperature. The as-prepared gold nanoparticles have high monodispersity with an average diameter of 13 nm and can self-organize into two-dimensional (2D) hexagonal close-packed arrays. The size of the gold nanoparticles can be experimentally controlled. The capping agent, oleylamine, can be easily replaced with other capping agents such as thiol groups for further functionalization. The electron relaxation dynamics of these gold nanoparticles in toluene was studied by femtosecond pump-probe measurements, in comparison with the citrate-stabilized gold nanoparticles in water. The phonon-phonon relaxation time of gold nanoparticles in toluene is slower than that of citrate-capped gold nanoparticles in water, due to the lower thermal conductivity of toluene than water. The electron-phonon relaxation of the gold nanoparticles in toluene was found to display weaker pump energy dependence, compared to that of citrate-capped gold nanoparticles in water. The different electron-phonon relaxation dynamics is ascribed to the extra vibrational states provided by gold- NH 2 , which serves as an extra nonradiative relaxation pathway for the e-ph relaxation in oleylamine-capped gold nanoparticles in toluene.

  1. Spatial Manipulation and Assembly of Nanoparticles by Atomic Force Microscopy Tip-Induced Dielectrophoresis.

    Science.gov (United States)

    Zhou, Peilin; Yu, Haibo; Yang, Wenguang; Wen, Yangdong; Wang, Zhidong; Li, Wen Jung; Liu, Lianqing

    2017-05-17

    In this article, we present a novel method of spatial manipulation and assembly of nanoparticles via atomic force microscopy tip-induced dielectrophoresis (AFM-DEP). This method combines the high-accuracy positioning of AFM with the parallel manipulation of DEP. A spatially nonuniform electric field is induced by applying an alternating current (AC) voltage between the conductive AFM probe and an indium tin oxide glass substrate. The AFM probe acted as a movable DEP tweezer for nanomanipulation and assembly of nanoparticles. The mechanism of AFM-DEP was analyzed by numerical simulation. The effects of solution depth, gap distance, AC voltage, solution concentration, and duration time were experimentally studied and optimized. Arrays of 200 nm polystyrene nanoparticles were assembled into various nanostructures, including lines, ellipsoids, and arrays of dots. The sizes and shapes of the assembled structures were controllable. It was thus demonstrated that AFM-DEP is a flexible and powerful tool for nanomanipulation.

  2. Project Prometheus and Future Entry Probe Missions

    Science.gov (United States)

    Spilker, Thomas R.

    2005-01-01

    A viewgraph presentation on project Prometheus and future entry probe missions is shown. The topics include: 1) What Is Project Prometheus?; 2) What Capabilities Can Project Prometheus Offer? What Mission Types Are Being Considered?; 3) Jupiter Icy Moons Orbiter (JIMO); 4) How Are Mission Opportunities Changing?; 5) Missions Of Interest a Year Ago; 6) Missions Now Being Considered For Further Study; 7) Galileo-Style (Conventional) Probe Delivery; 8) Galileo-Style Probe Support; 9) Conventional Delivery and Support of Multiple Probes; 10) How Entry Probe Delivery From an NEP Vehicle Is Different; and 11) Concluding Remarks.

  3. [HPV contamination of endocavity vaginal ultrasound probes].

    Science.gov (United States)

    Heard, I; Favre, M

    2015-02-01

    While the use of endovaginal ultrasound probes is increasing, the risk of contamination of women with endocavity vaginal probes was not assessed. In particular, the clinical significance of detection of human papillomavirus (HPV) infection, the most common sexually transmitted viral infection, on endovaginal ultrasound probes is uncertain. The recommendations of good practice for decontamination of these probes developed by the High Council for Public Health and the Academy of Medicine have not been evaluated. The objective of this article was to review recent publications concluding to the detection of HPV and human cellular DNA after gynecological examination and disinfection of vaginal ultrasound probes. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  4. Probe Selection in Multiprobe OTA Setups

    DEFF Research Database (Denmark)

    Fan, Wei; Sun, Fan; Nielsen, Jesper Ødum

    2014-01-01

    is costly, so finding ways to limit the number of probes while still reproducing the target channels accurately could make the test system both cheaper and simpler to implement. Several probe selection algorithms are presented in this paper to address this issue. The proposed techniques provide a probe...... selection framework for the channel emulation techniques published in the literature. Simulation results show that good channel emulation accuracy can be achieved with the selected subset of probes for the considered target channel models. The probe selection algorithm is further supported by measurement...... results in a practical multiprobe setup...

  5. Zero voltage mass spectrometry probes and systems

    Science.gov (United States)

    Cooks, Robert Graham; Wleklinski, Michael Stanley; Bag, Soumabha; Li, Yafeng

    2017-10-10

    The invention generally relates to zero volt mass spectrometry probes and systems. In certain embodiments, the invention provides a system including a mass spectrometry probe including a porous material, and a mass spectrometer (bench-top or miniature mass spectrometer). The system operates without an application of voltage to the probe. In certain embodiments, the probe is oriented such that a distal end faces an inlet of the mass spectrometer. In other embodiments, the distal end of the probe is 5 mm or less from an inlet of the mass spectrometer.

  6. Multifunctional polypyrrole@fe3o4 nanoparticles for dual-modal imaging and in vivo photothermal cancer therapy

    KAUST Repository

    Tian, Qiwei

    2013-11-27

    Magnetic Fe3O4 crystals are produced in situ on preformed polypyrrole (PPY) nanoparticles by rationally converting the residual Fe species in the synthetic system. The obtained PPY@Fe3O4 composite nanoparticles exhibit good photostability and biocompatibility, and they can be used as multifunctional probes for MRI, thermal imaging, and photothermal ablation of cancer cells. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Electron Mobility and Trapping in Ferrihydrite Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Soltis, Jennifer A.; Schwartzberg, Adam M.; Zarzycki, Piotr; Penn, R. Lee; Rosso, Kevin M.; Gilbert, Benjamin

    2017-05-30

    Iron is the most abundant transition metal in the Earth's crust, and naturally occurring iron oxide minerals play a commanding role in environmental redox reactions. Although iron oxide redox reactions are well studied, their precise mechanisms are not fully understood. Recent work has shown that these involve electron transfer pathways within the solid, suggesting that overall reaction rates could be dependent on electron mobility. Initial ultrafast spectroscopy studies of iron oxide nanoparticles sensitized by fluorescein derivatives supported a model for electron mobility based on polaronic hopping of electron charge carriers between iron sites, but the constitutive relationships between hopping mobilities and interfacial charge transfer processes has remained obscured. We developed a coarse-grained lattice Monte Carlo model to simulate the collective mobilities and lifetimes of these photoinjected electrons with respect to recombination with adsorbed dye molecules for the essential nanophase ferrihydrite, and tested predictions made by the simulations using pump-probe spectroscopy. We acquired optical transient absorption spectra as a function of particle size and under a variety of solution conditions, and used cryogenic transmission electron microscopy to determine the aggregation state of the nanoparticles. We observed biphasic electron recombination kinetics over timescales that spanned picoseconds to microseconds, the slower regime of which was fit with a stretched exponential decay function. The recombination rates were weakly affected by nanoparticle size and aggregation state, suspension pH, and the injection of multiple electrons per nanoparticle. We conclude that electron mobility indeed limits the rate of interfacial electron transfer in these systems with the slowest processes relating to escape from deep traps, the presence of which outweighs the influence of environmental factors such as pH-dependent surface charge.

  8. An Evaluation of the Effectiveness of Color Coded Tactical Symbology Applied to Military Maps.

    Science.gov (United States)

    1981-09-01

    Kubala (Ref. 11 state, the symbology currently employed by the army in tactical displays is still less than optimum for present day use. This thesis...the display may be examined at a time. As Hemingway and Kubala (Ref. 11 state, the symbology currently employed by the army is still less than optimum...the four slides listed by symbols is shown in Table 2. Hemingway and Kubala Ref. I in a study comparing conventional symbols to an alternative set of

  9. The New Frontier: Envisioning an America beyond Racial Preferences and Color-Coded Public Policy

    Science.gov (United States)

    Hicks, Joe R.

    2008-01-01

    Significant voices have begun challenging the orthodox view of America as a land of limited opportunities for minorities, with the Obama phenomena constituting the most conspicuous case in point. Mr. Hicks explains why racial preferences have failed and discusses the challenges Americans face in transcending divisions caused by identity politics.…

  10. The Impact of Color-Coding Freshmen Integrated-Science Assignments on Student Achievement

    Science.gov (United States)

    Sturdivant Allen, Anita Kay

    Students in Grade 9 exhibit high rates of grade retention and absenteeism. Educators have used different strategies that will increase the achievement of those students. The purpose of this study was to determine whether a relationship existed between student achievement and the strategy to use colored paper for Grade 9 science assignments and tests. Itten's color theory provided the theoretical framework. Itten was one of the first researchers to explore the notion that the human eye can detect wavelengths as colors and that those colors can engage and create order in the human brain. A sample of students assigned to 4 classroom teachers at one high school who volunteered to take part in the study for 18 weeks were used in this quantitative study. Teachers administered student assessments on blue, green, yellow, and white paper. Each class was assigned 1 of the 4 colors for 4.5 weeks. The classes were then assigned a different color for the same length of time until each class had exposure to all 4 colors. Physical science exams given to students in the same grade or subject were used as the dependent variable. An ANOVA indicated that the groups using blue paper scored the highest on the physical science exams; students who used white paper earned the lowest scores. When comparing all 3 groups using colored paper (all three colored paper groups combined into one group) to the white paper groups, t-test results indicated that students using any colored paper scored higher than students using white paper. Further research on the impact of colored paper on student academic performance is necessary. Implications for positive social change indicate that new knowledge about instructional tools that impact student achievement deserves more attention.

  11. Color-Coded Graphic Organizers for Teaching Writing to Students with Learning Disabilities

    Science.gov (United States)

    Ewoldt, Kathy B.; Morgan, Joseph John

    2017-01-01

    A commonly used method for supporting the writing of students with learning disabilities (LD), graphic organizers have been shown to effectively support instruction for students with LD in a variety of content areas (Dexter & Hughes, 2011). Students with LD often struggle with the process of developing their ideas into organized sentences; the…

  12. RGB color coded images in scanning electron microscopy of biological surfaces

    Czech Academy of Sciences Publication Activity Database

    Kofroňová, Olga; Benada, Oldřich

    2017-01-01

    Roč. 61, č. 3 (2017), s. 349-352 ISSN 0001-723X R&D Projects: GA MŠk(CZ) LO1509; GA ČR(CZ) GA16-20229S Institutional support: RVO:61388971 Keywords : Biological surfaces * Color image s * Scanning electron microscopy Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 0.673, year: 2016

  13. Evidence on Discrimination in Employment: Codes of Color, Codes of Gender

    OpenAIRE

    William A. Darity; Patrick L. Mason

    1998-01-01

    There is substantial racial and gender disparity in the American economy. As we will demonstrate, discriminatory treatment within the labor market is a major cause of this inequality. Yet, there appear to have been particular periods in which racial minorities, and then women, experienced substantial reductions in economic disparity and discrimination. Some questions remain: Why did the movement toward racial equality stagnate after the mid-1970s? What factors are most responsible for the rem...

  14. Overcoming Misconceptions in Neurophysiology Learning: An Approach Using Color-Coded Animations

    Science.gov (United States)

    Guy, Richard

    2012-01-01

    Anyone who has taught neurophysiology would be aware of recurring concepts that students find difficult to understand. However, a greater problem is the development of misconceptions that may be difficult to change. For example, one common misconception is that action potentials pass directly across chemical synapses. Difficulties may be…

  15. Synthesis of streptavidin-conjugated magnetic nanoparticles for DNA detection

    Energy Technology Data Exchange (ETDEWEB)

    Gong Peijun, E-mail: skygpj@zjnu.cn; Peng Zheyang; Wang Yao; Qiao Ru; Mao Weixing; Qian Haisheng; Zhang Mengya; Li Congcong; Shi Shenyuan [College of Chemistry and Life Sciences, Zhejiang Normal University (China)

    2013-04-15

    In this paper, we report a fabrication of streptavidin-coated magnetic nanoparticles used for DNA detection. Initially, amino-functionalized Fe{sub 3}O{sub 4} nanoparticles with high saturation magnetization are prepared by a photopolymerization method using allylamine as monomer. It is followed by covalent immobilization of streptavidin onto the particle surface via a two-step reaction using glutaraldehyde as coupling agent. Streptavidin-coated magnetic nanoparticles are characterized and further tested for their ability to capture DNA target after binding biotinylated oligonucleotide probes. The results show that the products ({approx}27.2 nm) have a maximum biotin-binding capacity of 0.71 nmol mg{sup -1} when the immobilization reaction is conducted with a mass ratio of streptavidin to magnetic carriers above 0.2 in phosphate buffered saline (pH 7.4) for 24 h. In addition, highly negative {zeta}-potential and good magnetic susceptibility of the nanocomposites make them applicable for DNA collection and detection, which is verified by the results from the preliminary application of streptavidin-coated magnetic nanoparticles in DNA detection. Therefore, the magnetic nanoparticles provide a promising approach for rapid collection and detection of gene.

  16. Synthesis of streptavidin-conjugated magnetic nanoparticles for DNA detection

    Science.gov (United States)

    Gong, Peijun; Peng, Zheyang; Wang, Yao; Qiao, Ru; Mao, Weixing; Qian, Haisheng; Zhang, Mengya; Li, Congcong; Shi, Shenyuan

    2013-04-01

    In this paper, we report a fabrication of streptavidin-coated magnetic nanoparticles used for DNA detection. Initially, amino-functionalized Fe3O4 nanoparticles with high saturation magnetization are prepared by a photopolymerization method using allylamine as monomer. It is followed by covalent immobilization of streptavidin onto the particle surface via a two-step reaction using glutaraldehyde as coupling agent. Streptavidin-coated magnetic nanoparticles are characterized and further tested for their ability to capture DNA target after binding biotinylated oligonucleotide probes. The results show that the products ( 27.2 nm) have a maximum biotin-binding capacity of 0.71 nmol mg-1 when the immobilization reaction is conducted with a mass ratio of streptavidin to magnetic carriers above 0.2 in phosphate buffered saline (pH 7.4) for 24 h. In addition, highly negative ζ-potential and good magnetic susceptibility of the nanocomposites make them applicable for DNA collection and detection, which is verified by the results from the preliminary application of streptavidin-coated magnetic nanoparticles in DNA detection. Therefore, the magnetic nanoparticles provide a promising approach for rapid collection and detection of gene.

  17. Electronically cloaked nanoparticles

    Science.gov (United States)

    Shen, Wenqing

    The concept of electronic cloaking is to design objects invisible to conduction electrons. The approach of electronic cloaking has been recently suggested to design invisible nanoparticle dopants with electronic scattering cross section smaller than 1% of the physical cross section (pi a2), and therefore to enhance the carrier mobility of bulk materials. The proposed nanoparticles have core-shell structures. The dopants are incorporated inside the core, while the shell layer serves both as a spacer to separate the charge carriers from their parent atoms and as a cloaking shell to minimize the scattering cross section of the electrons from the ionized nanoparticles. Thermoelectric materials are usually highly doped to have enough carrier density. Using invisible dopants could achieve larger thermoelectric power factors by enhancing the electronic mobility. Core-shell nanoparticles show an advantage over one-layer nanoparticles, which are proposed in three-dimensional modulation doping. However designing such nanoparticles is not easy as there are too many parameters to be considered. This thesis first shows an approach to design hollow nanoparticles by applying constrains on variables. In the second part, a simple mapping approach is introduced where one can identify possible core-shell particles by comparing the dimensionless parameters of chosen materials with provided maps. In both parts of this work, several designs with realistic materials were made and proven to achieve electronic cloaking. Improvement in the thermoelectric power factor compared to the traditional impurity doping method was demonstrated in several cases.

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  19. Soft X-ray spectroscopy of nanoparticles by velocity map imaging

    Science.gov (United States)

    Kostko, O.; Xu, B.; Jacobs, M. I.; Ahmed, M.

    2017-07-01

    Velocity map imaging (VMI), a technique traditionally used to study chemical dynamics in the gas phase, is applied here to study X-ray photoemission from aerosol nanoparticles. Soft X-rays from the Advanced Light Source synchrotron, probe a beam of nanoparticles, and the resulting photoelectrons are velocity mapped to obtain their kinetic energy distributions. A new design of the VMI spectrometer is described. The spectrometer is benchmarked by measuring vacuum ultraviolet photoemission from gas phase xenon and squalene nanoparticles followed by measurements using soft X-rays. It is demonstrated that the photoelectron distribution from X-ray irradiated squalene nanoparticles is dominated by secondary electrons. By scanning the photon energies and measuring the intensities of these secondary electrons, a near edge X-ray absorption fine structure (NEXAFS) spectrum is obtained. The NEXAFS technique is used to obtain spectra of aqueous nanoparticles at the oxygen K edge. By varying the position of the aqueous nanoparticle beam relative to the incident X-ray beam, evidence is presented such that the VMI technique allows for NEXAFS spectroscopy of water in different physical states. Finally, we discuss the possibility of applying VMI methods to probe liquids and solids via X-ray spectroscopy.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-09-30

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

  1. Impact of Particle Aggregation on Nanoparticle Reactivity

    Science.gov (United States)

    Jassby, David

    2011-12-01

    nanoparticle that photoluminesces after exposure to UV; TiO2 and ZnO nanoparticles---photocatalytic nanoparticles that generate reactive oxygen species upon UV irradition; and, fullerene nanoparticles used in the filtration experiments, selected for their potential use, small size, and surface chemistry. Our primary methods used to characterize particle and aggregate characteristics include dynamic light scattering used to describe particle size, static light scattering used to characterize aggregate structure (fractal dimension), transmission electron microscopy used to verify primary particle sizes, and electrophoretic mobility measurements to evaluate suspension stability. The reactive property of ZnS that was measured as a function of aggregation was photoluminescence, which was measured using a spectrofluorometer. The reactive property of TiO2 and ZnO that was studied was their ability to generate hydroxyl radicals; these were measured by employing a fluorescent probe that becomes luminescent upon interaction with the hydroxyl radical. To detect the presence of fullerene nanoparticles and calculate removal efficiencies, we used total organic carbon measurements. Additionally, we used UV-vis spectroscopy to approximate the impact of particle shadowing in TiO2 and ZnO aggregates, and Fourier transformed infrared spectroscopy to determine how different electrolytes interact with fullerene surface groups. Our findings indicate that the impact of aggregation on nanoparticle reactivity is material specific. ZnS nanoparticles exhibit a 2-fold increase in band-edge photoluminescence alongside a significant decrease in defect-site photoluminescence. This is attributed to aggregate size-dependent surface tension. Additionally, we used photoluminescence measurements to develop a new method for calculating the critical coagulation concentration of a nanoparticle suspension. The ability of both TiO2 and ZnO to generate hydroxyl radicals was significantly hampered by aggregation. The

  2. Assembling RNA Nanoparticles.

    Science.gov (United States)

    Xiao, Shou-Jun

    2017-01-01

    RNA nanoparticles are designed and self-assembled according to noncanonical interactions of naturally conserved RNA motifs and/or canonical Watson-Crick base-pairing interactions, which have potential applications in gene therapy and nanomedicine. These artificially engineered nanoparticles are mainly synthesized from in vitro transcribed RNAs, purified by denaturing and native polyacrylamide gel electrophoresis (PAGE), and characterized with native PAGE, AFM, and TEM technologies. The protocols of in vitro transcription, denaturing and native PAGE, and RNA nanoparticle self-assembly are described in detail.

  3. The Cytotoxicity, Characteristics, and Optimization of Insulin-loaded Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yasemin Budama-Kilinc

    2017-04-01

    Full Text Available Controlled release systems for insulin are frequent subjects of research, because it is rapidly degraded by proteolytic enzymes in the gastrointestinal tract and minimally absorbed after oral administration. Controlled release systems also provide significant contribution to its stability.  Different techniques are used for the preparation of drug-loaded nanoparticles, and many novel techniques are being developed. The size and morphology of insulin-loaded nanoparticles may vary according to performed techniques, even if the same polymer is used. The aim of this study was to demonstrate the cytotoxicity of insulin loaded nanoparticles and the effect of various synthesis parameters on the particle size, polydispersity index (PdI, loading efficiency, and particle morphology. In the experiments, poly(lactic-co-glycolic acid (PLGA and insulin-loaded PLGA nanoparticles were prepared using the double emulsion (w/o/w method. The characterization of the nanoparticles were performed with a UV spectrometer, the Zeta-sizer system, FTIR spectroscopy, and a scanning probe microscope. Cell toxicity of different concentrations was assayed with MTT methods on L929 fibroblast cells. The optimum size of the insulin-loaded PLGA nanoparticle was obtained with a 96.5% encapsulation efficiency, a 224.5 nm average particle size, and a 0.063 polydispersity index. This study obtained and characterized spherical morphology, determined that the nanoparticles have very low toxicity, and showed the effect of different parameters on particle size and polydispersity. DOI: http://dx.doi.org/10.17807/orbital.v9i1.934 

  4. CO surface electrochemistry on Pt-nanoparticles: A selective review

    Energy Technology Data Exchange (ETDEWEB)

    Mayrhofer, K.J.J. [Materials Science Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Arenz, M. [Materials Science Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Blizanac, B.B. [Materials Science Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Stamenkovic, V. [Materials Science Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Ross, P.N. [Materials Science Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Markovic, N.M. [Materials Science Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States)]. E-mail: nmmarkovic@lbl.gov

    2005-09-05

    Oxidation of CO on platinum nanoparticles ranging in size from 1 to 30 nm has been studied in acid electrolytes. We found that Pt nanoparticles, characterized by transmission electron microscopy, are not perfect cubo-octahedrons and that large particles have 'rougher' surfaces than small particles. The importance of 'defect' sites for the catalytic properties of nanoparticles was probed by using infrared reflection absorption spectroscopy (IRAS) and rotating disk electrode. From IRAS experiments, by monitoring how the vibrational frequency of a-top CO ({nu} {sub CO}) as well as the concomitant development of dissolved CO{sub 2} are affected by the number of defects on Pt nanoparticles, we suggested that defects play a significant role in CO 'clustering' on nanoparticles, causing CO to decrease/increase in local coverage, which results in anomalous redshift/blueshift {nu} {sub CO} frequency deviations from the normal Stark-tuning behavior. The observed {nu} {sub CO} deviations are accompanied by CO{sub 2} production, which increases by increasing the number of defects on the nanoparticles, i.e., 1 {<=} 2 < 5 << 30 nm. We suggest that the catalytic activity for CO adlayer oxidation (CO stripping) is predominantly influenced by the ability of the surface to dissociate water and to form OH{sub ad} on defect sites. We demonstrate that the catalytic activity of Pt nanoparticles for CO oxidation under the condition of continuous CO supply to the surface depends on the pre-history of the electrode. If the surface is precovered by CO, the particle size has a negligible effect on CO oxidation. However, on an oxide-precovered surface CO bulk oxidation increases with decreasing particle size, i.e., with increasing oxophilicity of the particles. We found, if specific sites on the surface are active for OH adsorption, then the electrocatalytic activity for CO oxidation changes as the concentration of these sites changes with particle size.

  5. ANALYSIS OF THE ELECTROPHYSICAL AND PHOTOELECTRIC PROPERTIES OF NANOCOMPOSITE POLYMERS BY THE MODIFIED KELVIN PROBE

    Directory of Open Access Journals (Sweden)

    K. U. Pantsialeyeu

    2017-01-01

    Full Text Available At present for analysis of the homogeneity of materials properties are becoming widely used various modifications of a scanning Kelvin probe. These methods allow mapping the spatial distribution of the electrostatic potential. Analysis of the electropotential profile is not sufficient to describe any specific physical parameters of the polymer nanocomposites. Therefore, we use an external energy impact, such as light. Purpose of paper is the modification of the Kelvin scanning probe and the conduct of experimental studies of the spatial distribution and response of the electrostatic potential of the actual polymer nanocomposites to the optical probing.Carried out the investigations on experimental Low density polyethylene composites. Carbon nanomaterials and nanoparticles of silicon dioxide or aluminum as fillers are used. As a result, maps of the spatial distribution of the electrostatic potential relative values and the surface photovoltage. Statistical analysis of the electrophysical and photoelectric properties homogeneity, depending on the component composition of the composites carried out. In addition, with reference to matrix polymers, the Kelvin scanning probe, in combination with the optical probing, made it possible to detect a piezoelectric effect. The latter, can used as a basis for the development of new methods for studying the mechanical properties of matrix polymers.

  6. Near-infrared fluorescent probes in cancer imaging and therapy: an emerging field

    Science.gov (United States)

    Yi, Xiaomin; Wang, Fuli; Qin, Weijun; Yang, Xiaojian; Yuan, Jianlin

    2014-01-01

    Near-infrared fluorescence (NIRF) imaging is an attractive modality for early cancer detection with high sensitivity and multi-detection capability. Due to convenient modification by conjugating with moieties of interests, NIRF probes are ideal candidates for cancer targeted imaging. Additionally, the combinatory application of NIRF imaging and other imaging modalities that can delineate anatomical structures extends fluorometric determination of biomedical information. Moreover, nanoparticles loaded with NIRF dyes and anticancer agents contribute to the synergistic management of cancer, which integrates the advantage of imaging and therapeutic functions to achieve the ultimate goal of simultaneous diagnosis and treatment. Appropriate probe design with targeting moieties can retain the original properties of NIRF and pharmacokinetics. In recent years, great efforts have been made to develop new NIRF probes with better photostability and strong fluorescence emission, leading to the discovery of numerous novel NIRF probes with fine photophysical properties. Some of these probes exhibit tumoricidal activities upon light radiation, which holds great promise in photothermal therapy, photodynamic therapy, and photoimmunotherapy. This review aims to provide a timely and concise update on emerging NIRF dyes and multifunctional agents. Their potential uses as agents for cancer specific imaging, lymph node mapping, and therapeutics are included. Recent advances of NIRF dyes in clinical use are also summarized. PMID:24648733

  7. Molecular Probes: An Innovative Technology for Monitoring Membrane Processes

    Science.gov (United States)

    Santoro, Sergio

    The ultimate objective of this study is to use molecular probes as an innovative and alternative technology contributing to the advance of membrane science by monitoring membrane processes in-situ, on-line and at sub-micron scale. An optical sensor for oxygen sensing was developed by the immobilization of tris (1,10-phenanthroline) ruthenium (II) (Ru(phen)3) in a dense polymeric membrane made of polystyrene (PS) or Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The emission of the probe was quenched by both the temperature and by the oxygen. Moreover, the oxygen sensitivity was affected by the oxygen permeability of the membrane. The evaluation of the oxygen concentration is prone to errors since the emission of a single probe depends on several parameters (i.e. optical path, source intensity). The correction of these artefacts was obtained by the immobilization of a second luminescent molecule non-sensitive to the oxygen, Coumarin. The potential of the luminescent ratiometric sensor for the non-invasive monitoring of oxygen in food packaging using polymeric films with different oxygen permeability was evaluated. Emphasis was given to the efficiency of the optical sensor for the on-line, in-situ and non invasive monitoring of the oxygen by comparing the experimental data with a model which takes into account the oxygen permeability of the packaging materials evaluated independently. A nano-thermometer based on silica nano-particles doped with Ru(phen)3 was developed. A systematic study shows how it is possible to control the properties of the nano-particles as well as their temperature sensitivity. The nano-thermometer was immobilized on a membrane surface by dip-coating providing information about the temperature on the membrane surface. Hydrophobic porous membrane made of Poly(vinylidene fluoride) was prepared via electrospinning and employed in a direct contact membrane distillation process. Using a designed membrane module and a membrane doped with Ru

  8. 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)

  9. Soft QGP probes with ALICE

    CERN Document Server

    Graczykowski, Łukasz Kamil

    2016-01-01

    In heavy-ion collisions at the LHC a hot and dense medium of deconfided partons, the Quark-Gluon Plasma (QGP), is created. Its global properties can be characterized by the measurements of particles in the low transverse momentum (or "soft") regime, which represent the majority of created particles. In this report we outline a selection of measurements of the soft probes by the ALICE experiment in pp, p--Pb, and Pb--Pb collisions. The paper focuses on recent flow measurements via angular correlations and femtoscopic studies. The first ever preliminary analysis of $\\mathrm{K}^0_{\\rm S}\\mathrm{K}^{\\pm}$ femtoscopy is also presented.

  10. Synthesis and toxicity characterization of carbon coated iron oxide nanoparticles with highly defined size distributions.

    Science.gov (United States)

    Mendes, Rafael Gregorio; Koch, Britta; Bachmatiuk, Alicja; El-Gendy, Ahmed Aboud; Krupskaya, Yulia; Springer, Armin; Klingeler, Rüdiger; Schmidt, Oliver; Büchner, Bernd; Sanchez, Samuel; Rümmeli, Mark Hermann

    2014-01-01

    Iron oxide nanoparticles hold great promise for future biomedical applications. To this end numerous studies on iron oxide nanoparticles have been conducted. One aspect these studies reveal is that nanoparticle size and shape can trigger different cellular responses through endocytic pathways, cell viability and early apoptosis. However, systematic studies investigating the size dependence of iron oxide nanoparticles with highly defined diameters across multiple cells lines are not available yet. Iron oxide nanoparticles with well-defined size distributions were prepared. All samples were thoroughly characterized and the cytotoxicity for four standard cell lines (HeLa Kyoto, human osteosarcoma (U2OS), mouse fibroblasts (NIH 3T3) and mouse macrophages (J7442)) where investigated. Our findings show that small differences in size distribution (ca. 10nm) of iron oxide nanoparticles do not influence cytotoxicity, while uptake is size dependent. Cytotoxicity is dose-dependent. Broad distributions of nanoparticles are more easily internalized as compared to the narrow distributions for two of the cell lines tested (HeLa Kyoto and mouse macrophages (J7442)). The data indicate that it is not feasible to probe changes in cytotoxicity within a small size range (10nm). However, TEM investigations of the nanoparticles indicate that cellular uptake is size dependent. The present work compares narrow and broad distributions for various samples of carbon-coated iron oxide nanoparticles. The data highlights that cells differentiate between nanoparticle sizes as indicated by differences in cellular uptake. This information provides valuable knowledge to better understand the interaction of nanoparticles and cells. © 2013.

  11. Developpement of a photoaffinity probe for the sensitive detection of matrix metallo-protease active forms from complex biological systems

    International Nuclear Information System (INIS)

    Nury, Catherine

    2012-01-01

    A new activity-based probe able to covalently modify the active site of proteases belonging to the matrix metallo-protease family (MMPs) has been developed in this thesis project. The probe was shown to behave as potent inhibitor of several MMPs, with nanomolar Ki values. This probe was also able to modify specifically only the free active site of MMPs, with particular high yields of cross-linking varying from 50 % to 11 %, depending of the MMPs tested. Using radioactivity as means of detection, this probe was able to detect active form of MMPs with a threshold of 1 femto-mole. Applied to the study of bronchoalveolar fluids (BAL) from mice exposed to nanoparticles by a lung aspiration protocol, this probe revealed the presence of the catalytic domain of MMP-12 under its active form, but not in control animals. When used to detect active form of MMPs from extracts obtained from human arteries of patient suffering from atherosclerosis, the probe was not able to detect such MMP active forms. Despite this negative result, the detection of active form of MMP in pathological fluid like BAL has never been reported before this work. Having validated this novel MMP activity-based probe, it will be possible to use it now for detecting MMPs from other pathological fluids or tissues extracts in which MMPs can be good markers of the pathology. (author) [fr

  12. An off-on fluorescence probe targeting mitochondria based on oxidation-reduction response for tumor cell and tissue imaging

    Science.gov (United States)

    Yao, Hanchun; Cao, Li; Zhao, Weiwei; Zhang, Suge; Zeng, Man; Du, Bin

    2017-10-01

    In this study, a tumor-targeting poly( d, l-lactic-co-glycolic acid) (PLGA) loaded "off-on" fluorescent probe nanoparticle (PFN) delivery system was developed to evaluate the region of tumor by off-on fluorescence. The biodegradability of the nanosize PFN delivery system readily released the probe under tumor acidic conditions. The probe with good biocompatibility was used to monitor the intracellular glutathione (GSH) of cancer cells and selectively localize to mitochondria for tumor imaging. The incorporated tumor-targeting probe was based on the molecular photoinduced electron transfer (PET) mechanism preventing fluorescence ("off" state) and could be easily released under tumor acidic conditions. However, the released tumor-targeting fluorescence probe molecule was selective towards GSH with high selectivity and an ultra-sensitivity for the mitochondria of cancer cells and tissues significantly increasing the probe molecule fluorescence signal ("on" state). The tumor-targeting fluorescence probe showed sensitivity to GSH avoiding interference from cysteine and homocysteine. The PFNs could enable fluorescence-guided cancer imaging during cancer therapy. This work may expand the biological applications of PFNs as a diagnostic reagent, which will be beneficial for fundamental research in tumor imaging. [Figure not available: see fulltext.

  13. Repairing Nanoparticle Surface Defects

    NARCIS (Netherlands)

    Marino, Emanuele; Kodger, Thomas E.; Crisp, R.W.; Timmerman, Dolf; MacArthur, Katherine E.; Heggen, Marc; Schall, Peter

    2017-01-01

    Solar devices based on semiconductor nanoparticles require the use of conductive ligands; however, replacing the native, insulating ligands with conductive metal chalcogenide complexes introduces structural defects within the crystalline nanostructure that act as traps for charge carriers. We

  14. Functionalized diamond nanoparticles

    KAUST Repository

    Beaujuge, Pierre M.

    2014-10-21

    A diamond nanoparticle can be functionalized with a substituted dienophile under ambient conditions, and in the absence of catalysts or additional reagents. The functionalization is thought to proceed through an addition reaction.

  15. Metallic Magnetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    A. Hernando

    2005-01-01

    Full Text Available In this paper, we reviewed some relevant aspects of the magnetic properties of metallic nanoparticles with small size (below 4 nm, covering the size effects in nanoparticles of magnetic materials, as well as the appearance of magnetism at the nanoscale in materials that are nonferromagnetic in bulk. These results are distributed along the text that has been organized around three important items: fundamental magnetic properties, different fabrication procedures, and characterization techniques. A general introduction and some experimental results recently obtained in Pd and Au nanoparticles have also been included. Finally, the more promising applications of magnetic nanoparticles in biomedicine are indicated. Special care was taken to complete the literature available on the subject.

  16. Soil moisture calibration of TDR multilevel probes

    Directory of Open Access Journals (Sweden)

    Serrarens Daniel

    2000-01-01

    Full Text Available Time domain reflectometry (TDR probes are increasingly used for field estimation of soil water content. The objective of this study was to evaluate the accuracy of the multilevel TDR probe under field conditions. For this purpose, eight such TDR probes were installed in small plots that were seeded with beans and sorghum. Data collection from the probes was such that soil moisture readings were automated and logged using a standalone field unit. Neutron probe measurements were used to calibrate the TDR probes. Soil-probe contact and soil compaction were critical to the accuracy of the TDR, especially when a number of TDR probes are combined for a single calibration curve. If each probe is calibrated individually, approximate measurement errors were between 0.005 and 0.015 m³ m-3. However, measurement errors doubled to approximately 0.025 to 0.03 m³ m-3, when TDR probes were combined to yield a single calibration curve.

  17. Biomimetic magnetic nanoparticles

    OpenAIRE

    Klem, Michael T.; Young, Mark; Douglas, Trevor

    2005-01-01

    Magnetic nanoparticles are of considerable interest because of their potential use in high-density memory devices, spintronics, and applications in diagnostic medicine. The conditions for synthesis of these materials are often complicated by their high reaction temperatures, costly reagents, and post-processing requirements. Practical applications of magnetic nanoparticles will require the development of alternate synthetic strategies that can overcome these impediments. Biomimetic approaches...

  18. Eddy current flaw detecting probe

    International Nuclear Information System (INIS)

    Hashimoto, Mitsuo; Harada, Yutaka; Shimone, Junri; Maeda, Kotaro

    1998-01-01

    The present invention provides an eddy current-flaw detection probe facilitating quantitative evaluation, which is used for maintenance and inspection of metal fine tubes of a heat exchanger of a nuclear power plant. Namely, the probe comprises a substantially cylindrical or columnar flow detection main body to be inserted to a metal tube. Wires are wound on the circumferential surface of the flaw detection main body substantially uniformly and in parallel to form a solenoid portion having a predetermined width. Magnetic sensors are disposed on the lateral center of the solenoid portion. With such a constitution, the solenoid portion forms eddy current in the circumferential direction. The eddy current is substantially in parallel having the same intensity at the lateral central portion of the solenoid. Accordingly, the quantitative evaluation for the shape and the size of cracks in the axial direction of the tube can be conducted by the magnetic sensors disposed to the portion. In addition, since the eddy current is substantially uniform, parameters upon reverse analysis can be reduced upon determination of the shape of flaws. (I.S.)

  19. The Gravity Probe B Experiment

    Science.gov (United States)

    Kolodziejczak, Jeffrey

    2008-01-01

    This presentation briefly describes the Gravity Probe B (GP-B) Experiment which is designed to measure parts of Einstein's general theory of relativity by monitoring gyroscope orientation relative to a distant guide star. To measure the miniscule angles predicted by Einstein's theory, it was necessary to build near-perfect gyroscopes that were approximately 50 million times more precise than the best navigational gyroscopes. A telescope mounted along the central axis of the dewar and spacecraft provided the experiment's pointing reference to a guide star. The telescope's image divide precisely split the star's beam into x-axis and y-axis components whose brightness could be compared. GP-B's 650-gallon dewar, kept the science instrument inside the probe at a cryogenic temperature for 17.3 months and also provided the thruster propellant for precision attitude and translation control. Built around the dewar, the GP-B spacecraft was a total-integrated system, comprising both the space vehicle and payload, dedicated as a single entity to experimentally testing predictions of Einstein's theory.

  20. Portal monitor incorporating smart probes

    International Nuclear Information System (INIS)

    Bartos, D.; Constantin, F.; Guta, T.

    2003-01-01

    Portal monitors are intended for detection of radioactive and special nuclear materials in vehicles, pedestrians, luggage, as well as for prevention of illegal traffic of radioactive sources. Monitors provide audio and visual alarms when radioactive and/or special nuclear materials are detected. They can be recommended to officers of customs, border guard and emergency services, civil defense, fire brigades, police and military departments or nuclear research or energetic facilities. The portal monitor developed by us consists in a portal frame, which sustains five intelligent probes having long plastic scintillator (0.5 liters each). The probes communicate, by serial transmission, with a Central Unit constructed on the basis of the 80552 microcontroller. This one manages the handshake, calculates the background, establishes the measuring time, starts and stops each measurement and makes all the other decisions. Sound signals and an infrared sensor monitor the passing through the portal and the measuring procedure. For each measurement the result is displayed on a LCD device contaminated/uncontaminated; for the contaminated case a loud and long sound signal is also issued. An RS 232 serial interface is provided in order to further developments or custom made devices. As a result, the portal monitor detects 1 μ Ci 137 Cs, spread all over a human body, in a 20 μR/h gamma background for a measuring time of 1.5 or 10 seconds giving a 99% confidence factor. (authors)