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gold nanoparticles

Maheshkumar Prakash Patil, Gun-Do Kim
This review covers general information about the eco-friendly process for the synthesis of silver nanoparticles (AgNP) and gold nanoparticles (AuNP) and focuses on mechanism of the antibacterial activity of AgNPs and the anticancer activity of AuNPs. Biomolecules in the plant extract are involved in reduction of metal ions to nanoparticle in a one-step and eco-friendly synthesis process. Natural plant extracts contain wide range of metabolites including carbohydrates, alkaloids, terpenoids, phenolic compounds, and enzymes...
December 3, 2016: Applied Microbiology and Biotechnology
Raimundo Fernandes de Araújo, Aurigena Antunes de Araújo, Jonas Bispo Pessoa, Franscisco Paulo Freire Neto, Gisele Ribeiro da Silva, Ana Luiza C S Leitão Oliveira, Thaís Gomes de Carvalho, Heloiza F O Silva, Mateus Eugênio, Celso Sant'Anna, Luiz H S Gasparotto
BACKGROUND: Gold nanoparticles (GNPs) are regarded as potential platforms for drug delivery. However, their interaction with live organisms must be understood prior to their utilization as drug carriers. The present study reports the anti-inflammatory, analgesic and anti-tumor effects of GNPs. The biodistribution of GNPs and their effect on various tissues have also been studied. METHODS: GNPs were synthesized through an environmentally friendly route and characterized with TEM and UV-vis...
September 21, 2016: Pharmacological Reports: PR
Qiu-Mei Feng, Zhen Zhou, Mei-Xing Li, Wei Zhao, Jing-Juan Xu, Hong-Yuan Chen
Proximal metallic nanoparticles (NPs) could quench the electrochemiluminescence (ECL) emission of semiconductor quantum dots (QDs) due to Förster energy transfer (FRET), but at a certain distance, the coupling of light-emission with surface plasmon resonance (SPR) result in enhanced ECL. Thus, the modification strategies and distances control between QDs and metallic NPs are critical for the ECL intensity of QDs. In this strategy, a SPR enhanced ECL sensor based on DNA tetrahedral scaffolds modified platform was reported for the detection of telomerase activity...
November 27, 2016: Biosensors & Bioelectronics
Razvan Opris, Corina Tatomir, Diana Olteanu, Remus Moldovan, Bianca Moldovan, Luminita David, Andras Nagy, Nicoleta Decea, Mihai Ludovic Kiss, Gabriela Adriana Filip
Nanomaterials such as gold nanoparticles (NPs) conjugated with natural products have shown good results in lowering the glycated hemoglobin and have an anti-inflamatory effect. The aim of our study is to evaluate the antidiabetic effect of NPs functionalized with Sambucus nigra L. (SN) extract on experimental model of diabetes in rats. Diabetes was induced to 18 Wistar male rats (n=6) by a single intramuscular injection of streptozotocin (30mg/kg body weight - b.w.). SN extract (15mg/kg b.w.), NPs (0.3mg/kg b...
November 27, 2016: Colloids and Surfaces. B, Biointerfaces
Mingxuan Gao, Lin Yang, Yi Zheng, Xiaoxi Yang, Hongyan Zou, Jing Han, Zexi Liu, Yuanfang Li, Cheng Zhi Huang
Surface functionalization is an essential prerequisite for wide and specific applications of nanoparticles such as photoluminescent (PL) carbon quantum dots (CQDs), but still remains as a major challenge. In this report, alkynylated CQDs, which were prepared at first from carboxyl-rich CQDs through amidation with propargylamine in the presence of 1,1'-carbonyldiimidazole, were efficiently modified with azido molecular beacon DNA through copper(I)-catalyzed alkyne-azide cycloaddition reaction (CuAAC). As the proof of concept, the DNA-modified CQDs was then bonded with 5-nm gold nanoparticles (AuNPs) through gold-sulfur bond...
December 3, 2016: Chemistry: a European Journal
Dinh Bao Nguyen, Thanh Danh Nguyen, Sangsoo Kim, Sang-Woo Joo
Spectral differences between cytosine (Cyt) and 5-methylcytosine (5MC) were investigated by means of Raman spectroscopy with a combination of density functional theory (DFT) calculations. Surface-enhanced Raman scattering (SERS) revealed discriminating peaks of 5MC from those of Cyt upon adsorption on gold nanoparticles (AuNPs). Among the notable features, the multiple bands between 850 and 700cm(-1) for the ring-breathing modes of 5MC and Cyt could be correlated well with the simulated spectra based on the DFT calculations of the adsorbates on the gold cluster atoms...
November 9, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Lisa Terranova, Diana Maria Dragusin, Romain Mallet, Eugeniu Vasile, Izabela-Cristina Stancu, Catherine Behets, Daniel Chappard
Non-biodegradable porous polystyrene (PS) scaffolds, composed of microfibers, have been prepared by electrospinning for the reconstruction of large bone defects. PS microfibers were prepared by incorporating β-TCP grains inside the polymer or grafting gold nanoparticles surface functionalized with mercaptosuccinic acid. Cytocompatibility of the three types of scaffolds (PS, β-TCP-PS and Au-PS) was studied by seeding human mesenchymal stem cells. Biocompatibility was evaluated by implanting β-TCP-PS and Au-PS scaffolds into a critical size (4mm) calvarial defect in mice...
November 8, 2016: Micron: the International Research and Review Journal for Microscopy
Asaf Ilovitsh, Pazit Polak, Zeev Zalevsky, Orit Shefi
We report a novel method for specific deactivation of conjugated enzymes using laser-heated gold nanoparticles. Current methods involve treatment of the entire solution, thereby inactivating all bioactive components. Our method enables inactivation of only a single or subset of targeted enzymes. The selected enzyme is pre-conjugated to gold nanoparticles, which are specifically heated by a laser tuned to their surface plasmon resonance. We demonstrate inactivation of a selected enzyme, glucose oxidase, within a mixture of biomolecules...
December 2, 2016: Cytometry. Part A: the Journal of the International Society for Analytical Cytology
Fei Gao, Linyi Bai, Siyu Liu, Ruochong Zhang, Jingtao Zhang, Xiaohua Feng, Yuanjin Zheng, Yanli Zhao
Photoacoustic tomography has emerged as a promising non-invasive imaging technique that integrates the merits of high optical contrast with high ultrasound resolution in deep scattering medium. Unfortunately, the blood background in vivo seriously impedes the quality of imaging due to its comparable optical absorption with contrast agents, especially in conventional linear photoacoustic imaging modality. In this study, we demonstrated that two hybrids consisting of gold nanorods (Au NRs) and zinc tetra(4-pyridyl)porphyrin (ZnTPP) exhibited a synergetic effect in improving optical absorption, conversion efficiency from light to heat, and thermoelastic expansion, leading to a notable enhancement in both linear (four times greater) and nonlinear (more than six times) photoacoustic signals as compared with conventional Au NRs...
December 2, 2016: Nanoscale
B Koger, C Kirkby
As a recent area of development in radiation therapy, gold nanoparticle (GNP) enhanced radiation therapy has shown potential to increase tumour dose while maintaining acceptable levels of healthy tissue toxicity. In this study, the effect of varying photon beam energy in GNP enhanced arc radiation therapy (GEART) is quantified through the introduction of a dose scoring metric, and GEART is compared to a conventional radiotherapy treatment. The PENELOPE Monte Carlo code was used to model several simple phantoms consisting of a spherical tumour containing GNPs (concentration: 15 mg Au g(-1) tumour, 0...
December 2, 2016: Physics in Medicine and Biology
Chie Kojima, Yusuke Nakajima, Naoya Oeda, Takeshi Kawano, Yusuke Taki
Cell sorting is important for cell biology and regenerative medicine. A visible light-responsive cell scaffold is produced using gold nanoparticles and collagen gel. Various kinds of cells are cultured on the visible light-responsive cell scaffold, and the target cells are selectively detached by photoirradiation without any cytotoxicity. This is a new image-guided cell sorting system.
December 2, 2016: Macromolecular Bioscience
Xiao-Yu Wang, Cheng-Gang Niu, Li-Juan Guo, Liu-Yin Hu, Sheng-Quan Wu, Guang-Ming Zeng, Fei Li
This paper describes a label-free 17E DNAzyme-based time-gated fluorescence sensor for Pb(2+) detection by unmodified gold nanoparticles (GNPs) and a terbium ternary complex. The fluorophore that used in this paper is a terbium ternary complex. Its signal can be measured in a time-gated manner which could eliminate most of the unspecific fluorescent background. It is well known that unfolded single-stranded DNA (ssDNA) could be adsorbed on GNPs while double-stranded DNA could not. The cleavage of the substrate by the 17E DNAzyme in the presence of Pb(2+) causes the release of ssDNA from the 17E-17S duplex to be absorbed onto GNPs, preventing the aggregation of GNPs and then leading to a fluorescence decrease of terbium ternary complex...
December 1, 2016: Journal of Fluorescence
Shokoufeh Delkhahi, Mahdi Rahaie, Fereshteh Rahimi
MicroRNAs are small RNAs which regulate gene expression by translational repression or degradation of messenger RNAs. Regards to important role of these biomolecules in human disease progress, to produce sensitive, simple and cost-effective assays for microRNAs are in urgent demand. miR-137 in Alzheimer's patients has demonstrated its potential as non-invasive biomarkers in blood for Alzheimer's disease diagnosis and prognosis. This paper describes a novel, sensitive and specific microRNA assay based on Colorimetric detection of gold nanoparticles and hybridization chain reaction amplification (HCR)...
December 1, 2016: Journal of Fluorescence
Yao Chen, Mengjiao Xu, Yi Guo, Keyao Tu, Weimin Wu, Jianjun Wang, Xiaowen Tong, Wenjuan Wu, Lifeng Qi, Donglu Shi
Efficient delivery of small interfering RNAs (siRNAs) to the targeted cells has remained a significant challenge in clinical applications. In the present study, we developed a novel aptamer-siRNA chimera delivery system mediated by cationic Au-Fe3O4 nanoparticles (NPs). The chimera constructed by VEGF RNA aptamer and Notch3 siRNA was bonded with heterogeneous Au-Fe3O4 nanoparticles by electrostatic interaction. The obtained complex exhibited much higher silencing efficiency against Notch3 gene compared with chimera alone and lipofectamine-siRNA complex, and improved the antitumor effects of the loaded chimera...
December 1, 2016: Nanotechnology
Shreedhar Gautam, Bhagwan S Batule, Hyo Yong Kim, Ki Soo Park, Hyun Gyu Park
Rapid and accurate on-site wireless measurement of hazardous molecules or biomarkers is one of the biggest challenges in nanobiotechnology. We herein describe a novel smartphone-based Portable and Wireless Optical System (PAWS) for rapid, quantitative, and on-site analysis of target analytes. As a proof-of-concept, we employed gold nanoparticles (GNP) and an enzyme, horse radish peroxidase (HRP), to generate colorimetric signals in response to two model target molecules, melamine and hydrogen peroxide, respectively...
December 1, 2016: Biotechnology Journal
Fengli Gao, Liqiang Liu, Gang Cui, Liguang Xu, Xiaoling Wu, Hua Kuang, Chuanlai Xu
Reliable and ultrasensitive quantification of dopamine (DA) is essential in the precise diagnotherapy of neurological diseases. In this study, dual mode counterpropagating-responsive gold@silver nanoparticle-gold nanorod (Au@AgNP-AuNR) nano-assemblies were fabricated for the precise quantification of DA. The plasmonic Au@AgNP-AuNR assemblies possessed high surface-enhanced Raman scattering (SERS) activity and strong fluorescence quenching, due to the prominent electromagnetic enhancement between the hotspots of the assemblies...
December 1, 2016: Nanoscale
Di Liu, Le Yu, Xiao Xiong, Lei Yang, Yan Li, Ming Li, Hai-Ou Li, Gang Cao, Ming Xiao, Bin Xiang, Chang-Jun Min, Guang-Can Guo, Xi-Feng Ren, Guo-Ping Guo
Monolayer transition-metal dichalcogenides (TMDs) have grown as fantastic building blocks for optoelectronic applications, owing to their direct band gap, transparency, and mechanical flexibility. Since the luminescence of monolayer TMDs suffers from low light absorption and emission, surface plasmons, which confine light at subwavelength and enhance the local electric field, are utilized to boost both excitation and emission fields of TMDs, enabling strong light-matter interaction at the nano-scale. Meanwhile, radially-polarized beams (RPBs) as new and attractive excitation source have found many applications in surface plasmon polaritons, optical tweezer and so on...
November 28, 2016: Optics Express
Jun Young Kim, Jeongyong Kim, Jinsoo Joo
Two-dimensional (2-D) transition metal dichalcogenides, such as MoS<sub>2</sub>, WSe<sub>2</sub>, and WS<sub>2</sub>, are promising materials for application in field effect transistors, optoelectronics, and sensing devices. In this study, 2-D WSe<sub>2</sub> samples with various numbers of layers were hybridized with functionalized gold nanoparticles (Au-NPs) to achieve surface-enhanced Raman scattering (SERS). The nanoscale Raman and photoluminescence spectra of the WSe<sub>2</sub> layers and WSe<sub>2</sub>/Au-NP hybrids were measured using a high-resolution laser confocal microscope...
November 28, 2016: Optics Express
I A Kolmychek, A N Shaimanov, A V Baryshev, T V Murzina
We present an experimental study of optical second harmonic generation (SHG) from arrays of nanostructures exhibiting collective plasmon resonances in the visible spectral range. Gold nanoparticles with the lateral diameter of 100 nm are packed in a square lattice with the period of 400 nm and are covered by a 90 nm thick iron garnet layer. We show an enhancement of SHG in the spectral vicinity of the lattice surface plasmon resonance. It is demonstrated that application of the external DC magnetic field results in a spectral shift of the SHG maximum up to 5 nm, accompanied by a pronounced phase modulation of the second harmonic wave...
December 1, 2016: Optics Letters
Alok Pani, Tran Duy Thanh, Nam Hoon Kim, Joong Hee Lee, Soon-Il Yun
Sustainable methods are needed for rapid and efficient detection of environmental and food pollutants. The Sudan group of dyes has been used extensively as adulterants in food and also are found to be polluting the soil and water bodies. There have been several methods for detection of Sudan dyes, but most of them are not practical enough for common use. In this study, the electrochemical detection efficiency and stability of gold nanoparticle (AuNPs), silver NPs and Au-Ag bionanocomposites, synthesised by peanut skin extract, modified glassy carbon electrode has been investigated...
December 2016: IET Nanobiotechnology
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