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Gold nanoparticle

Baoyan Wu, Na Zhao, Shihua Hou, Cong Zhang
Here we report a facile eco-friendly one-step electrochemical approach for the fabrication of a polypyrrole (PPy), reduced graphene oxide (RGO), and gold nanoparticles (nanoAu) biocomposite on a glassy carbon electrode (GCE). The electrochemical behaviors of PPy-RGO-nanoAu and its application to electrochemical detection of hydrogen peroxide were investigated by cyclic voltammetry. Graphene oxide and pyrrole monomer were first mixed and casted on the surface of a cleaned GCE. After an electrochemical processing consisting of the electrooxidation of pyrrole monomer and simultaneous electroreduction of graphene oxide and auric ions (Au(3+)) in aqueous solution, a PPy-RGO-nanoAu biocomposite was synthesized on GCE...
November 21, 2016: Nanomaterials
Song-Hwa Bae, Jin Yu, Mi-Ran Go, Hyun-Jin Kim, Yun-Gu Hwang, Soo-Jin Choi
(1) Background: Application of nanotechnology or nanomaterials in agricultural food crops has attracted increasing attention with regard to improving crop production, quality, and nutrient utilization. Gold nanoparticles (Au-NPs) have been reported to enhance seed yield, germination rate, and anti-oxidant potential in food crops, raising concerns about their toxicity potential. In this study, we evaluated the oral toxicity of red ginseng exposed to colloidal Au-NPs during cultivation (G-red ginseng) in rats and their intestinal transport mechanism...
November 11, 2016: Nanomaterials
Gennady Eidelshtein, Moran Fattal, Gavriel Avishai, Benjamin Kempinski, Clelia Giannini, Alexander Kotlyar
Here we described the preparation and characterization by atomic force microscopy of dumbbell-shaped conjugates between 450 bp double-stranded DNA polymer, poly(dG)-poly(dC), and 5 nm gold nanoparticles (GNPs). We have demonstrated that the size of the nanoparticles in the conjugates can be increased in a controlled fashion. Application of the conjugates for measuring the electrical conductivity of DNA is discussed.
September 8, 2016: Nanomaterials
Ricardo Calderón-Gonzalez, Héctor Terán-Navarro, Elisabet Frande-Cabanes, Eva Ferrández-Fernández, Javier Freire, Soledad Penadés, Marco Marradi, Isabel García, Javier Gomez-Román, Sonsoles Yañez-Díaz, Carmen Álvarez-Domínguez
Listeriosis is a fatal infection for fetuses and newborns with two clinical main morbidities in the neonatal period, meningitis and diffused cutaneous lesions. In this study, we vaccinated pregnant females with two gold glyconanoparticles (GNP) loaded with two peptides, listeriolysin peptide 91-99 (LLO91-99) or glyceraldehyde-3-phosphate dehydrogenase 1-22 peptide (GAPDH1-22). Neonates born to vaccinated mothers were free of bacteria and healthy, while non-vaccinated mice presented clear brain affections and cutaneous diminishment of melanocytes...
August 19, 2016: Nanomaterials
Subramaniyan Bharathiraja, Panchanathan Manivasagan, Nhat Quang Bui, Yun-Ok Oh, In Gweon Lim, Suhyun Park, Junghwan Oh
Astaxanthin, a kind of photosynthetic pigment, was employed for gold nanoparticle formation. Nanoparticles were characterized using Ulteraviolet-Visible (UV-Vis) spectroscopy, transmission electron microscopy, and X-ray diffraction, and the possible presence of astaxanthin functional groups were analyzed by Fourier transform infrared spectroscopy (FTIR). The cytotoxic effect of synthesized nanoparticles was evaluated against MDA-MB-231 (human breast cancer cells) using a tetrazolium-based assay, and synthesized nanoparticles exhibited dose-dependent toxicity...
April 20, 2016: Nanomaterials
Van-Duong Dao, Ho-Suk Choi
Plasmon-assisted energy conversion is investigated in a comparative study of dye-sensitized solar cells (DSCs) equipped with photo-anodes, which are fabricated by forming gold (Au) and silver (Ag) nanoparticles (NPs) on an fluorine-doped tin oxide (FTO) glass surface by means of dry plasma reduction (DPR) and coating TiO₂ paste onto the modified FTO glass through a screen printing method. As a result, the FTO/Ag-NPs/TiO₂ photo-anode showed an enhancement of its photocurrent, whereas the FTO/Au-NPs/TiO₂ photo-anode showed less photocurrent than even a standard photo-anode fabricated by simply coating TiO₂ paste onto the modified FTO glass through screen printing...
April 14, 2016: Nanomaterials
Shahzadi Shamaila, Noshin Zafar, Saira Riaz, Rehana Sharif, Jawad Nazir, Shahzad Naseem
Enteric bacterial human pathogens, i.e., Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Klebsiella pneumoniae, are the major cause of diarrheal infections in children and adults. Their structure badly affects the human immune system. It is important to explore new antibacterial agents instead of antibiotics for treatment. This project is an attempt to explain how gold nanoparticles affect these bacteria. We investigated the important role of the mean particle size, and the inhibition of a bacterium is dose-dependent...
April 14, 2016: Nanomaterials
Bangbang Li, Peng Zhang, Jianwei Du, Xiao Zhao, Youxiang Wang
Multifunctional nanoprobe was drawing increased attention in tumor diagnosis and therapy. The simple and effective establishment of the theranostic nanoplatforms was still under urgent need. Meanwhile, the targeting ability and morphology of nanoprobe were essential for the effective endocytosis, which could further affect the diagnosis. In this work, two morphologies of nanoprobes were fabricated using gold nanorods (AuNRs) and gold nanospheres (AuNSs). Thiolated-hyaluronic acid labeled with nile blue (HS-HA-NB), a near-infrared (NIR) fluorescence dye, was coated on the surface of the gold nanoparticles to form stable nanoprobes (AuNR@HS-HA-NB, AuNS@HS-HA-NB)...
March 9, 2017: Colloids and Surfaces. B, Biointerfaces
Md Faruk Hossain, Jae Y Park
A highly sensitive amperometric glucose sensor was developed by immobilization of glucose oxidase (GOx) onto multi-layer reduced graphene oxide (MRGO) sheets decorated with platinum and gold flower-like nanoparticles (PtAuNPs) modified Au substrate electrode. The fabricated MRGO/PtAuNPs modified hybrid electrode demonstrated high electrocatalytic activities toward oxidation of H2O2, to which it had a wide linear response that ranged from 0.5 to 8 mM (R2 = 0.997), and high sensitivity of 506.25 μA/mMcm2. Furthermore, glucose oxidase-chitosan composite and cationic polydiallyldimethylammonium chloride (PDDA) were assembled by a casting method on the surface of MRGO/PtAuNPs modified electrode...
2017: PloS One
Moustafa R K Ali, Yue Wu, Deepraj Ghosh, Brian H Do, Kuangcai Chen, Michelle R Dawson, Ning Fang, Todd A Sulchek, Mostafa A El-Sayed
Most cancer patients die from metastasis. Recent studies have shown that gold nanoparticles (AuNPs) can slow down the migration/invasion speed of cancer cells and suppress metastasis. Since nuclear stiffness of the cell largely decreases cell migration, our hypothesis is that targeting AuNPs to the cell nucleus region could enhance nuclear stiffness, and therefore inhibit cell migration and invasion. Our results showed that upon nuclear targeting of AuNPs, the ovarian cancer cell motilities decrease significantly, compared with non-targeted AuNPs...
March 23, 2017: ACS Nano
Jun Lu, Yi-Xin Chang, Ning-Ning Zhang, Ying Wei, Ai-Ju Li, Jia Tai, Yao Xue, Zhao-Yi Wang, Yang Yang, Li Zhao, Zhong-Yuan Lu, Kun Liu
Gold nanorods are excellent anisotropic building blocks for plasmonic chiral nanostructures. The near-infrared plasmonic band of nanorods makes them highly desirable for biomedical applications such as chiral bioimaging and sensing, in which a strong circular dichroism (CD) signal is required. Chiral assemblies of gold nanorods induced by self-associating peptides are especially attractive for this purpose as they exhibit plasmonic-enhanced chiroptical activity. Here, we showed that the presence of cetyltrimethylammonium bromide (CTAB) micelles in a gold nanorod solution promoted the self-association of l-/d-glutathione (GSH) and significantly enhanced the chirality of the resulting plasmonic nanochains...
March 23, 2017: ACS Nano
Guohua Li, Liang Zhu, Yonghong He, Hui Tan, Shuqing Sun
A new analytical method has been developed to detect three kinds of DNA simultaneously based on magnetic beads and color-encoded plasmonic nanocrystals. Magnetic beads modified with capture DNA are employed to collect the specific target DNA, and color-encoded plasmonic nanocrystals are applied to signal the target through DNA hybridization. As a proof of concept, three types of representative metal nanocrystals of gold nanoparticle (AuNP), gold nanorod (AuNR), and gold/silver nanoparticle (Au/AgNP) were employed to signal three dissimilar virus-related protective antigen genes, Ebola virus (EV), Variola virus (VV), and Bacillus anthracis (BA), respectively...
March 22, 2017: Analytical and Bioanalytical Chemistry
Kai Sun, Yong Chang, Binbin Zhou, Xiaojin Wang, Lin Liu
This article presents a general method for the detection of protein kinase with a peptide-like kinase inhibitor as the bioreceptor, and it was done by converting gold nanoparticles (AuNPs)-based colorimetric assay into sensitive electrochemical analysis. In the colorimetric assay, the kinase-specific aptameric peptide triggered the aggregation of AuNPs in solution. However, the specific binding of peptide to the target protein (kinase) inhibited its ability to trigger the assembly of AuNPs. In the electrochemical analysis, peptides immobilized on a gold electrode and presented as solution triggered together the in situ formation of AuNPs-based network architecture on the electrode surface...
2017: International Journal of Nanomedicine
Fang Yang, René Riedel, Pablo Del Pino, Beatriz Pelaz, Alaa Hassan Said, Mahmoud Soliman, Shashank R Pinnapireddy, Neus Feliu, Wolfgang J Parak, Udo Bakowsky, Norbert Hampp
BACKGROUND: The adhesion of cells to an oscillating cantilever sensitively influences the oscillation amplitude at a given frequency. Even early stages of cytotoxicity cause a change in the viscosity of the cell membrane and morphology, both affecting their adhesion to the cantilever. We present a generally applicable method for real-time, label free monitoring and fast-screening technique to assess early stages of cytotoxicity recorded in terms of loss of cell adhesion. RESULTS: We present data taken from gold nanoparticles of different sizes and surface coatings as well as some reference substances like ethanol, cadmium chloride, and staurosporine...
March 22, 2017: Journal of Nanobiotechnology
Preeti Dauthal, Mausumi Mukhopadhyay
Biological methods of nanoparticles synthesis are ecologically sound and sustainable alternative to the conventional methods. On the basis of aforesaid premise, the present study deals with the optimization and fabrication of gold nanoparticles (Au-NPs) using easily available bio-resource, Delonix regia leaf extract. The use of practically nontoxic natural extracts and water allows the synthesis pathways presented to be considered as ''green'' and so permitting the synthesized Au-NPs to be used in sensitive areas, such as bioremediation...
December 2016: 3 Biotech
Guang Yang, Jagjit Nanda, Boya Wang, Gang Chen, Daniel T Hallinan
Performance of portable technologies from mobile phones to electric vehicles is currently limited by the energy density and lifetime of lithium batteries. Expanding the limits of battery technology requires in situ detection of trace components at electrode-electrolyte interphases. Surface-enhance Raman spectroscopy could satisfy this need if a robust and reproducible substrate were available. Gold nanoparticles (Au NPs) larger than 20 nm diameter are expected to greatly enhance Raman intensity if they can be assembled into ordered monolayers...
March 22, 2017: ACS Applied Materials & Interfaces
W Colomb, J Czerski, J D Sau, S K Sarkar
Fiducial markers are used to correct the microscope drift and should be photostable, be usable at multiple wavelengths and be compatible for multimodal imaging. Fiducial markers such as beads, gold nanoparticles, microfabricated patterns and organic fluorophores lack one or more of these criteria. Moreover, the localization accuracy and drift correction can be degraded by other fluorophores, instrument noise and artefacts due to image processing and tracking algorithms. Estimating mechanical drift by assuming Gaussian distributed noise is not suitable under these circumstances...
March 22, 2017: Journal of Microscopy
Matthias Thiele, Andrea Knauer, Daniéll Malsch, Andrea Csáki, Thomas Henkel, J Michael Köhler, Wolfgang Fritzsche
Metal nanoparticles and their special optical properties, the so-called localized surface plasmon resonance (LSPR), facilitate many applications in various fields. Due to the strong dependency of the LSPR on particle geometry, their synthesis is a challenging and time-consuming procedure especially for non-spherical shapes. In contrast, micromixers offer new experimental approaches and therefore enable the simplification of several processes. By using a zigzag micromixer (Dean-Flow-Mixer, DFM) that induces Dean-flow secondary flow patterns, we theoretically and experimentally show the mixing efficiency...
March 22, 2017: Lab on a Chip
Zhen Geng, Yuanyuan Han, Wei Jiang
Asymmetric vesicles with different inner and outer corona compositions are applicable in microreactors, drug delivery, and biomimics because of their unique functions in membrane permeability and protein localization. In this study, we develop a novel approach to construct asymmetric vesicles and demonstrate the first structural transformation of polymeric vesicles from symmetric to asymmetric membranes. Experimental results and Monte Carlo simulation results clearly reveal that increased intercorona repulsion and enhanced hydrophobic chain mobility are essential to realize this transformation...
March 22, 2017: Soft Matter
Iqra Munir, Sadia Ajmal, Muhammad Raza Shah, Aftab Ahmad, Abdul Hameed, Syed Abid Ali
Present study was conducted to establish the interaction of bovine fetuin-A to validate its binding modalities with doxorubicin (Dox). Fetuin-A was purified to highest purity and monodispersity. Green synthesis of fetuin-A conjugated gold nanoparticles (F-GNPs) have been performed giving typical UV-maxima with subtle variation in fourier transform infrared spectroscopy (FTIR). Atomic force microscopy (AFM) revealed spherical shaped, polydisperse F-GNPs of varying sizes, complementing the radius of hydration (19...
March 18, 2017: International Journal of Biological Macromolecules
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