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gold nanoparticles

Yuki Osaka, Satoshi Sugano, Shuichi Hashimoto
Fabricating nano-sized through-holes on a coverslip approximately 100 μm thick is challenging but rewarding when applied to ultrafine filters that separate proteins and DNA of various sizes and isolate viruses from cells. Toward this end, we developed an in situ etching-assisted laser processing technique exploiting gold nanoparticles. Plasmonic heating of a single gold nanoparticle through focused illumination of a continuous-wave laser beam enables structural modifications to be localized to the contact area on the glass surface...
October 18, 2016: Nanoscale
Kuen-Lin Chen, Yao-Wei Yeh, Jian-Ming Chen, Yu-Jie Hong, Tsung-Lin Huang, Zu-Yin Deng, Chiu-Hsien Wu, Su-Hsien Liao, Li-Min Wang
Magnetoplasmonic nanoparticles, composed of a plasmonic layer and a magnetic core, have been widely shown as promising contrast agents for magnetic resonance imaging (MRI) applications. However, their application in low-field nuclear magnetic resonance (LFNMR) research remains scarce. Here we synthesised γ-Fe2O3/Au core/shell (γ-Fe2O3@Au) nanoparticles and subsequently used them in a homemade, high-Tc, superconducting quantum interference device (SQUID) LFNMR system. Remarkably, we found that both the proton spin-lattice relaxation time (T1) and proton spin-spin relaxation time (T2) were influenced by the presence of γ-Fe2O3@Au nanoparticles...
October 18, 2016: Scientific Reports
Dongqing Kong, Sai Bi, Zonghua Wang, Jianfei Xia, Feifei Zhang
In this work, an in situ growth protocol is introduced to fabricate three-dimensional graphene films (3D GFs) on gold substrates, which are successfully utilized as working electrode for electrochemical detection of nucleic acid (microRNA) and protein (lysozyme) based on a signal-on sensing mechanism. To realize the bridge between the gold substrate and graphene film, a monolayer of 4-aminothiophenol is self-assembled on the substrate, which is then served as connectors for the growth of 3D GFs on the gold substrate by the hydrothermal reduction (HR) technique...
October 18, 2016: Analytical Chemistry
Yiru Wang, Zhengpeng Qin, David R Boulware, Bobbi S Pritt, Lynne M Sloan, Iveth J González, David Bell, Roxanne R Rees-Channer, Peter Chiodini, Warren C W Chan, John C Bischof
There is an increasing need for highly sensitive and quantitative diagnostics at the point-of-care. The lateral flow immunoassay (LFA) is one of the most widely used point-of-care diagnostic tests; however, LFAs generally suffers from low sensitivity and lack of quantification. To overcome these limitations, thermal contrast amplification (TCA) is a new method that is based on the laser excitation of gold nanoparticles (GNP), the most commonly used visual signature, to evoke a thermal signature. To facilitate the clinical translation of the TCA technology, we present the development of a TCA reader, a platform technology that significantly improves the limit of detection and provides quantification of disease antigens in LFAs...
October 17, 2016: Analytical Chemistry
Sadegh Sadeghzadeh
A multi-scale method is employed in this paper to conduct a virtual study of the high-strain behavior of single- and multi-layer graphene sheets and to investigate the design of related graphene-based devices. By bridging the length and time scales by combining the Molecular Dynamics and Finite Element methods together, a comprehensive multiscale model is developed to study the fascinating capabilities of single- and multi-layer graphene sheets in withstanding the impact of ultrafast projectiles. In order to contribute to future developments and innovations in this field, several quantitative and qualitative comparisons are also performed...
October 5, 2016: Journal of Molecular Graphics & Modelling
Yu-Hong Cheng, Yue Zhang, Siu-Leung Chau, Samuel Kin-Man Lai, Ho-Wai Tang, Kwan-Ming Ng
Metal alloy nanoparticles (NPs) offer a new combination of unique physicochemical properties based on their pure counterparts, which can facilitate the development of novel analytical methods. Here, we demonstrated that Ag-Au alloy NPs could be utilized for optical and mass spectrometric imaging of latent fingerprints (LFPs) with improved image contrast, stability, and detection sensitivity. Upon deposition of Ag-Au alloy NPs (Ag:Au = 60:40% wt), ridge regions of the LFP became amber-coloured, while the groove regions appeared purple-blue...
October 17, 2016: ACS Applied Materials & Interfaces
Artur Carnicer, Oriol Arteaga, Josep M Suñé-Negre, Bahram Javidi
The counterfeiting of pharmaceutical products represents concerns for both industry and the safety of the general public. Falsification produces losses to companies and poses health risks for patients. In order to detect fake pharmaceutical tablets, we propose producing film-coated tablets with gold nanoparticle encoding. These coated tablets contain unique polarimetric signatures. We present experiments to show that ellipsometric optical techniques, in combination with machine learning algorithms, can be used to distinguish genuine and fake samples...
October 1, 2016: Optics Letters
Hinojal Zazo, Clara I Colino, Klaudia T Warzecha, Mareike Hoss, Uwe Gbureck, Christian Trautwein, Frank Tacke, José M Lanao, Matthias Bartneck
The human immunodeficiency virus (HIV) continues to be a global pandemic and there is an urgent need for innovative treatment. Immune cells represent a major target of virus infection, but are also therapeutic targets. Currently, no antiretroviral therapy targets macrophages, which function as portal of entry and as major long-term deposit of HIV. It has been shown before that human macrophages efficiently internalize gold nanoparticles, a fact which might be used to target them with drug-nanoparticle conjugates...
October 17, 2016: Macromolecular Bioscience
Gaoxing Su, Xiaofei Zhou, Hongyu Zhou, Ye Li, Xianren Zhang, Yin Liu, Dapeng Cao, Bing Yan
Understandings of how biomolecules modify nanoparticles in a biological context and how these exchanges impact nano-bio interactions are fundamental to nanomedicine and nanotoxicology research. In this work, cancer-targeting gold nanoparticles (TGNPs) with different sizes (5, 15, and 40 nm) were designed and synthesized. These nanoparticles spontaneously adsorbed proteins in complete cell culture medium (DMEM with 10% human serum). Although the targeting ligands on the surface of nanoparticles were likely to be shielded by adsorbed proteins, the targeting capability of nanoparticles was maintained due to the highly dynamic nature of protein adsorption...
October 17, 2016: ACS Applied Materials & Interfaces
Zhi Wang, Ravithree Senanayake, Christine M Aikens, Wen-Miao Chen, Chen-Ho Tung, Di Sun
Here we report the single-crystal structure, experimental and theoretical characterization of a 41-metal atom Au-Ag alloy nanocluster [Au3Ag38(SCH2Ph)24X5](2-) (1, X = Cl or Br). The nanocluster 1 is co-protected by thiolate and halogen atoms and features an all-metallic face-fused biicosahedral Au2@AuAg20 rod-like kernel enwrapped by the outermost Ag18(SCH2Ph)24X3 shell. Two sites on the surface of the biicosahedral kernel are partially occupied by Au and Ag atoms. The outer Ag18(SCH2Ph)24X3 shell is composed of two Ag6S6 cycles at the two poles and one Ag6S2X3 arc at the equator with both 2- and 3-coordinated Ag atoms, which has not been observed in gold or silver nanoclusters ever before...
October 17, 2016: Nanoscale
Chi K Tang, Abhay Vaze, Min Shen, James F Rusling
Microchip-based microfluidic electrochemical arrays hold great promise for fast, high-throughput multiplexed detection of cancer biomarker proteins at low cost per assay using relatively simple instrumentation. Here we describe an inexpensive high-throughput electrochemical array featuring 32 individually addressable microelectrodes that is further multiplexed with an 8-port manifold to provide 256 sensors. The gold electrode arrays were fabricated by wet-etching commercial gold compact discs (CD-R) followed by patterned insulation...
August 26, 2016: ACS Sensors
Sangho Won, Daniel J Phillips, Marc Walker, Matthew I Gibson
Responsive polymers and polymer-coated nanoparticles have many potential bio-applications with the crucial parameter being the exact temperature where the transition occurs. Chemical modification of hydrophobic/hydrophilic or ligand binding sites has been widely explored as a tool for controlling this transition, but requires the synthesis of many different components to achieve precise control. This study reports an extensive investigation into the use of blending (i.e. mixing) as a powerful tool to modulate the transition temperature of poly(N-isopropylacrylamide) (PNIPAM) coated gold nanoparticles...
September 14, 2016: Journal of Materials Chemistry. B, Materials for Biology and Medicine
Romana Parveen, Tooba Naz Shamsi, Sadaf Fatima
This review helps to understand protein misfolding events, which results in protein aggregation, and hence to related neurodegenerative diseases. Many chaperones and folding factors are found inside the cell system for the proper folding of protein. If protein gets misfolded, it may accumulate in cells and can lead to several fatal diseases. In some cases, misfolded proteins aggregated in form of loop-sheet polymer and amyloid fibril when they escape the degradation process and leads to neurodegenerative disorders...
October 13, 2016: International Journal of Biological Macromolecules
Mónica Catalá-Icardo, Carmen Gómez-Benito, Ernesto Francisco Simó-Alfonso, José Manuel Herrero-Martínez
This paper describes a novel and sensitive method for extraction, preconcentration, and determination of two important widely used fungicides, azoxystrobin, and chlorothalonil. The developed methodology is based on solid-phase extraction (SPE) using a polymeric material functionalized with gold nanoparticles (AuNPs) as sorbent followed by high-performance liquid chromatography (HPLC) with diode array detector (DAD). Several experimental variables that affect the extraction efficiency such as the eluent volume, sample flow rate, and salt addition were optimized...
October 15, 2016: Analytical and Bioanalytical Chemistry
Wei-Yuan Wang, Xiu-Fen Zhao, Xiao-Han Ju, Yu Wang, Lin Wang, Shu-Ping Li, Xiao-Dong Li
A novel morphology change of Au-methotrexate (Au-MTX) conjugates that could transform from nanochains to discrete nanoparticles was achieved by a simple, one-pot, and hydrothermal growth method. Herein, MTX was used efficiently as a complex-forming agent, reducing agent, capping agent, and importantly a targeting anticancer drug. The formation mechanism suggested a similarity with the molecular imprinting technology. The Au-MTX complex induced the MTX molecules to selectively adsorb on different crystal facets of gold nanoparticles (AuNPs) and then formed gold nanospheres...
October 12, 2016: International Journal of Pharmaceutics
Giovanni Fusco, Francesca Gallo, Cristina Tortolini, Paolo Bollella, Federica Ietto, Antonella De Mico, Andrea D'Annibale, Riccarda Antiochia, Gabriele Favero, Franco Mazzei
In this work, we developed an impedimetric label-free immunosensor for the detection of 2,4-Dichlorophenoxy Acetic Acid (2,4-D) herbicide either in standard solution and spiked real samples. For this purpose, we prepared by electropolymerization a conductive polymer poly-(aniline-co-3-aminobenzoic acid) (PANABA) then we immobilized anti-2,4-D antibody onto a nanocomposite AuNPs-PANABA-MWCNTs employing the carboxylic moieties as anchor sites. The nanocomposite was synthesized by electrochemical polymerization of aniline and 3-aminobenzoic acid, in the presence of a dispersion of gold nanoparticles, onto a multi-walled carbon nanotubes-based screen printed electrode...
October 5, 2016: Biosensors & Bioelectronics
Alexander W Scott, Viswanadham Garimella, Colin M Calabrese, Chad A Mirkin
Novel biotin-polyethylene glycol (biotin-PEG) gold nanoparticle probes have been synthesized and used as universal constructs for the detection of protein (prostate-specific antigen, PSA) and nucleic acid targets (microRNAs) from a single sample. Microarray assays based upon these probes enabled sensitive detection of biomarker targets (50 fM for nucleic acid targets and 1 pg/μL for the PSA target). Ways of detecting biomarkers, including nucleic acids and proteins, are necessary for the clinical diagnosis of many diseases, but currently available diagnostic platforms rely primarily on the independent detection of proteins or nucleic acids...
October 14, 2016: Bioconjugate Chemistry
Roberto Matassa, Giuseppe Familiari, Ezio Battaglione, Concita Sibilia, Grigore Leahu, Alessandro Belardini, Iole Venditti, Laura Fontana, Ilaria Fratoddi
Today, nanochemistry research of hybrid materials growth in liquid media represents a new challenge for tailoring specific nano-sized materials directly related to the hybrid electron-optical properties. Distinctive assumptions about the origin, the growth, and the functionalization of hybrid nanoparticles have recently been proposed by scientific research to attend the different aspects of observable behaviors. Therefore, appropriate morpho-structural observation of the hybrid nanoparticles is the most important factor for controlling the chemical and physical properties...
October 14, 2016: Nanoscale
M H Jazayeri, H Amani, A A Pourfatollah, A Avan, G A Ferns, H Pazoki-Toroudi
Prostate-specific antigen (PSA) is used to screen for prostate disease, although it has several limitations in its application as an organ-specific or cancer-specific marker. Furthermore, a highly specific/sensitive and/or label-free identification of PSA still remains a challenge in the diagnosis of prostate anomalies. We aimed to develop a gold nanoparticle (GNP)-conjugated anti-PSA antibody-based localized surface plasmon resonance (LSPR) as a novel approach to detect prostatic disease. A total of 25 nm colloidal gold particles were prepared followed by conjugation with anti-PSA pAb (GNPs-PSA pAb)...
October 14, 2016: Cancer Gene Therapy
Ferdaous Maâtouk, Mouna Maâtouk, Karima Bekir, Houcine Barhoumi, Abderrazak Maaref, Hedi Ben Mansour
In this work we report the development of an electrochemical DNA biosensor with high sensitivity for mercury ion detection. A new matrix based on gold nanoparticles (AuNPs)-glutathione (GSH)/cysteine was investigated. The interaction between DNA oligonucleotides and Hg(2+) ions followed by the formation of Thymine-Hg(2+)-Thymine (T-Hg(2+)-T) structures was quantified using different electrochemical methods. It has been shown that the electrochemical impedance spectroscopy (EIS) measurements and the differential pulse voltammetry (DPV) confirmed the specific interaction between the oligonucleotide receptor layer and the Hg(2+) ions...
October 2016: Journal of Water and Health
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