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silver nanoparticle

Amanda S Harper-Leatherman, Jean Marie Wallace, Debra R Rolison
Sol-gel-derived aerogels are three-dimensional, nanoscale materials that combine large surface area with high porosity. These traits make them useful for any rate-critical chemical process, particularly sensing or electrochemical applications, once physical or chemical moieties are incorporated into the gels to add their functionality to the ultraporous scaffold. Incorporating biomolecules into aerogels, other than such rugged species as lipases or cellulose, has been challenging due to the inability of most biomolecules to remain structurally intact within the gels during the necessary supercritical fluid (SCF) processing...
2017: Methods in Molecular Biology
Yuan Yang, Li Luo, Hai-Pu Li, Qiang Wang, Zhao-Guang Yang, Chen-Lu Long
In this study, cloud point extraction (CPE) combined inductively coupled plasma mass spectrometry (ICP-MS) was used to determinate silver nanoparticles (AgNPs) in environmental water. AgNPs dispersed in water could be extracted into surfactant phase based on optimized CPE parameters which including pH, incubation temperature and equilibration time, the content of nonionic surfactants (Triton X-114, TX-114) and Na2S3O3. Good separation results of AgNPs and ionic silver Ag(I) in aqueous environment was obtained with the addition of Na2S3O3 when the concentration of Ag(I) was lower than ten times of AgNPs...
December 1, 2016: Talanta
Fanyu Meng, Peng Miao, Bidou Wang, Yuguo Tang, Jian Yin
Glutathione (GSH), a common tripeptide, plays an essential role in a variety of cellular functions. GSH level is reported to be closely related to human health. In this study, we fabricate an ultrasensitive electrochemical biosensor for GSH quantification. DNA probes are firstly modified on the electrode surface and thymine-Hg(2+)-thymine is formed. Since GSH is able to chelate Hg(2+) from the DNA mismatched sites effectively, which leads to DNA structural switching from hairpin to linear strand, rolling circle amplification (RCA) could be initiated with the released linear primer probe...
November 2, 2016: Analytica Chimica Acta
Koichiro Saito, Ichiro Tanabe, Tetsu Tatsuma
Plasmon-induced charge separation (PICS) at the interface between a plasmonic nanoparticle and semiconductor is now widely used for photovoltaics and photocatalysis. Here we take advantage of PICS for site-selective nanoetching of silver nanocubes on TiO2 beyond the diffraction limit. A silver nanocube exhibits two resonance modes localized at the top and bottom of the nanocube (distal and proximal modes, respectively) when it is placed on TiO2. We achieved selective etching at the top and the bottom of the nanocubes by PICS based on the distal and proximal modes, respectively...
October 21, 2016: Journal of Physical Chemistry Letters
Quelen Letícia Shimabuku, Flávia Sayuri Arakawa, Marcela Fernandes Silva, Priscila Ferri Coldebella, Tânia Ueda-Nakamura, Márcia Regina Fagundes-Klen, Rosangela Bergamasco
Continuous flow experiments (450 mL min(-1)) were performed in household filter in order to investigate the removal and/or inactivation of T4 bacteriophage, using granular activated carbon (GAC) modified with silver and/or copper oxide nanoparticles at different concentrations. GAC and modified GAC were characterized by X-ray diffractometry, specific surface area, pore size and volume, pore average diameter, scanning electron microscopy, transmission electron microscopy, zeta potential and atomic absorption spectroscopy...
October 21, 2016: Environmental Technology
Nicole Cathcart, Neil Coombs, Ilya Gourevich, Vladimir Kitaev
In this work, we use silver decahedral nanoparticle (AgDeNP) seeds to synthesize pentagonal silver stars (AgStDeNPs) and study the sensing properties of these nanoparticles. The regrowth process of AgStDeNPs is kinetically-controlled, so the purity of the seed NPs is critical to avoid secondary deposition in the highly non-equilibrium reduction. To control the regrowth process, surface blocking with sodium polyacrylate (PANa) was implemented. PANa moderates rough silver nanostructures typically obtained by reduction with ascorbic acid...
October 21, 2016: Nanoscale
Karolina Niska, Narcyz Knap, Anna Kędzia, Maciej Jaskiewicz, Wojciech Kamysz, Iwona Inkielewicz-Stepniak
Objectives: In dentistry, silver nanoparticles (AgNPs) have drawn particular attention because of their wide antimicrobial activity spectrum. However, controversial information on AgNPs toxicity limited their use in oral infections. Therefore, the aim of the present study was to evaluate the antibacterial activities against a panel of oral pathogenic bacteria and bacterial biofilms together with potential cytotoxic effects on human gingival fibroblasts of 10 nm AgNPs: non-functionalized - uncapped (AgNPs-UC) as well as surface-functionalized with capping agent: lipoic acid (AgNPs-LA), polyethylene glycol (AgNPs-PEG) or tannic acid (AgNPs-TA) using silver nitrate (AgNO3) as control...
2016: International Journal of Medical Sciences
K Gopinath, S Kumaraguru, K Bhakyaraj, S Mohan, K S Venkatesh, M Esakkirajan, P R Kaleeswarran, S A Naiyf, S Kadaikunnan, M Govindarajan, G Benelli, A Arumugam
The green fabrication of metal nanoparticles using botanical extracts is gaining increasing research attention in nanotechnology, since it does not require high energy inputs or the production of highly toxic chemical byproducts. Here, silver (Ag), gold (Au) and their bimetallic (Ag/Au) nanoparticles (NPs) were green synthesized using the Gloriosa superba aqueous leaf extract. Metal NPs were studied by spectroscopic (UV-visible spectroscopy, fluorescence spectroscopy, FT-IR spectroscopy, XRD and EDX) and microscopic (AFM and TEM) analysis...
October 17, 2016: Microbial Pathogenesis
Jun Hyuk Heo, Gyu Sung Yi, Byoung Sang Lee, Hui Hun Cho, Jin Woong Lee, Jung Heon Lee
Here, we report the development of an achromatic nanoparticle-based colorimetric sensor (achromatic nanosensor) with an on-off type color change that significantly enhances the color transition and increases the sensitivity of the sensor for naked-eye inspection. The achromatic nanosensor was prepared via a modified CMYK (CRYK) subtractive color model by combining DNA-functionalized gold nanoparticles (AuNPs-DNA), silver nanoparticles (AgNPs-DNA), and gold nanorods (AuNRs-DNA). The initially black-colored achromatic nanosensor not only allowed multiplexed detection by generating target-specific diverse color changes, but also improved the recognition of color changes by the naked eye...
October 20, 2016: Nanoscale
Peidang Liu, Haizhen Jin, Zhirui Guo, Jun Ma, Jing Zhao, Dongdong Li, Hao Wu, Ning Gu
Radiotherapy performs an important function in the treatment of cancer, but resistance of tumor cells to radiation still remains a serious concern. More research on more effective radiosensitizers is urgently needed to overcome such resistance and thereby improve the treatment outcome. The goal of this study was to evaluate and compare the radiosensitizing efficacies of gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) on glioma at clinically relevant megavoltage energies. Both AuNPs and AgNPs potentiated the in vitro and in vivo antiglioma effects of radiation...
2016: International Journal of Nanomedicine
Catia Contado, Roberto Argazzi, Vincenzo Amendola
Many advanced industrial and biomedical applications that use silver nanoparticles (AgNPs), require that particles are not only nano-sized, but also well dispersed, not aggregated and not agglomerated. This study presents two methods able to give rapidly sizes of monodispersed AgNPs suspensions in the dimensional range of 20-100nm. The first method, based on the application of Mie's theory, determines the particle sizes from the values of the surface plasmon resonance wavelength (SPRMAX), read from the optical absorption spectra, recorded between 190nm and 800nm...
October 13, 2016: Journal of Chromatography. A
Mallaiah Devanabanda, Shaik Abdul Latheef, Ramanadham Madduri
Understanding the effects of nanoparticles (NP) on immune cell functions is essential in designing safe and effective NP-based in vivo drug delivery systems. The immunomodulatory potential of gold nanoparticles (GNP) and silver nanoparticles (SNP) was investigated in vitro using murine splenic and human peripheral blood lymphocytes (PBL) in terms of effects on viability and mitogen-induced proliferation. Hydrodynamic size and number of NP were characterized using NP tracking analysis (NTA); modal diameters of GNP and SNP were 28 (±1...
October 18, 2016: Journal of Immunotoxicology
Taeho Kim, Gary B Braun, Zhi-Gang She, Sazid Hussain, Erkki Ruoslahti, Michael J Sailor
A theranostic nanoparticle with biochemically triggered antibacterial activity is demonstrated. Metallic silver is deposited onto porous silicon nanoparticles (pSiNPs) by galvanic displacement. When aqueous diaminesilver ([Ag(NH3)2](+)) is used as a silver source, the pSiNPs template the crystalline silver as small (mean diameter 13 nm) and well-dispersed nanoparticles embedded within and on the larger (100 nm) pSiNPs. The silver nanoparticles quench intrinsic photoluminescence (PL) from the porous silicon matrix...
October 18, 2016: ACS Applied Materials & Interfaces
S Schiavo, N Duroudier, E Bilbao, M Mikolaczyk, J Schäfer, M P Cajaraville, S Manzo
In the last years, applications for silver nanoparticles (Ag NPs) continue to increase together with the concerns about their potential input and hazards in aquatic ecosystems, where microalgae are key organisms. The aim of the present study was to assess the relative sensitivity of three marine microalgae species with differences in cell wall composition/structure exposed to Poly N-vinyl-2-pirrolidone/Polyethyleneimine (PVP/PEI) coated 5nm Ag NPs and uncoated 47nm Ag NP. As limited attention has been paid to the role of coating agents in NP toxicity, the effect of PVP/PEI alone was also evaluated...
October 15, 2016: Science of the Total Environment
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
Sarbani Ashe, Debasis Nayak, Manisha Kumari, Bismita Nayak
Advanced glycation end-products (AGEs) resulting from non-enzymatic glycation are one of the major factors involved in diabetes and its secondary complications and diseases. This necessitates our urge to discover new compounds that may be used as potential AGEs inhibitors without affecting the normal structure and function of biomolecules. In the present study, we investigated the inhibitory effects of AgNP (silver nanoparticles) on AGEs formation as well as their inhibitory effects on glycation mediated cell toxicity via ROS production and DNA damage...
October 17, 2016: ACS Applied Materials & Interfaces
Suhas Ramesh, Marcelo Grijalva, Alexis Debut, Beatriz G de la Torre, Fernando Albericio, Luis H Cumbal
Nanotechnology is gaining impetus in the present century and particularly the use of nanoparticles (NPs), whose properties are significantly different from the larger matter. These have found wider and potential applications in the fields of medicine, energy, cosmetics, environment and biomedicine. Among the NPs, silver nanoparticles (AgNPs) are of particular interest for scientists and technologists due to their unique physico-chemical and biological properties. Besides, AgNPs by themselves also possess broad-spectrum microbial activity, which has further expanded their application in both academia and industries...
October 17, 2016: Biomaterials Science
Patrycja Golinska, Dnyaneshwar Rathod, Magdalena Wypij, Indarchand Gupta, Marek Składanowski, Priti Paralikar, Hanna Dahm, Mahendra Rai
Mycoendophytes are the fungi that occur inside the plant tissues without exerting any negative impact on the host plant. They are most frequently isolated endophytes from the leaf, stem, and root tissues of various plants. Among all fungi, the mycoendophytes as biosynthesizer of noble metal nanoparticles (NPs) are less known. However, some reports showing efficient synthesis of metal nanoparticles, mainly silver nanoparticles and its remarkable antimicrobial activity against bacterial and fungal pathogens of humans and plants...
October 17, 2016: Critical Reviews in Biotechnology
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
Anatoliy Kubyshkin, Denis Chegodar, Andrew Katsev, Armen Petrosyan, Yuri Krivorutchenko, Olga Postnikova
BACKGROUND/PURPOSE: To investigate the effect of nanosilver particles in solution stabilized in a matrix of sodium alginate on the growth and development of pathogenic bacteria such as Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Proteus vulgaris, Enterobacter cloacae, the antibiotic-resistant strain of Pseudomonas aeruginosa, the yeast-like fungus Candida albicans, and the luminescent bacteria Photobacterium leiognathi Sh1. METHODS: Isolates of pathogenic bacteria obtained from bronchoalveolar and peritoneal lavage samples from Wistar rats with experimental pneumonia and peritonitis were tested for their susceptibility to silver nanoparticles in solution with an alginate stabilizer...
2016: Biochemistry & Molecular Biology Journal
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