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silver nanoparticle

Jérôme Cuny, Nathalie Tarrat, Fernand Spiegelman, Arthur Huguenot, Mathias Rapacioli
Density-functional based tight-binding (DFTB) is an efficient quantum mechanical method that can describe a variety of systems, going from organic and inorganic compounds to metallic and hybrid materials. The present topical review addresses the ability and performance of DFTB to investigate energetic, structural, spectroscopic and dynamical properties of gold and silver materials. After a brief overview of the theoretical basis of DFTB, its parametrization and its transferability, we report its past and recent applications to gold and silver systems, including small clusters, nanoparticles, bulks and surfaces, bare and interacting with various organic and inorganic compounds...
June 19, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Zhao Yu, Michael E Smith, Jinnan Zhang, Yan Zhou, Peng Zhang
A surface-enhanced Raman scattering (SERS) method has been developed to determine the concentration of trichloroethylene (TCE) in environmental water. Au-core/Ag-shell nanoparticles containing 4-mercaptophenylboronic acid (4-MPBA) between the core and shell are used as the SERS substrate. 4-MPBA serves as an internal reference with a Raman shift at 534 cm-1 . TCE reacts with 4-mercaptopyridine (4-MPy) in a so-called Fujiwara reaction. With the presence of TCE in water, the consumption of 4-MPy results in a change in the intensity of its Raman signal at 1220 cm-1 ...
June 18, 2018: Mikrochimica Acta
Kaifu Bian, Hattie Schunk, Dongmei Ye, Austin Hwang, Ting Shan Luk, Ruipeng Li, Zhongwu Wang, Hongyou Fan
Metallic nanoparticles, such as gold and silver nanoparticles, can self-assemble into highly ordered arrays known as supercrystals for potential applications in areas such as optics, electronics, and sensor platforms. Here we report the formation of self-assembled 3D faceted gold nanoparticle supercrystals with controlled nanoparticle packing and unique facet-dependent optical property by using a binary solvent diffusion method. The nanoparticle packing structures from specific facets of the supercrystals are characterized by small/wide-angle X-ray scattering for detailed reconstruction of nanoparticle translation and shape orientation from mesometric to atomic levels within the supercrystals...
June 18, 2018: Nature Communications
Sreekar B Marpu, Erin N Benton
Chitosan (CS) is a natural polymer derived from chitin that has found its usage both in research and commercial applications due to its unique solubility and chemical and biological attributes. The biocompatibility and biodegradability of CS have helped researchers identify its utility in the delivery of therapeutic agents, tissue engineering, wound healing, and more. Industrial applications include cosmetic and personal care products, wastewater treatment, and corrosion protection, to name a few. Many researchers have published numerous reviews outlining the physical and chemical properties of CS, as well as its use for many of the above-mentioned applications...
June 17, 2018: International Journal of Molecular Sciences
Tao Dong, Lei Lin, Yong He, Pengcheng Nie, Fangfang Qu, Shupei Xiao
Deltamethrin is widely used in pest prevention and control such as red spiders, aphids, and grubs in strawberry. It is important to accurately monitor whether the deltamethrin residue in strawberry exceeds the standard. In this paper, density functional theory (DFT) was used to theoretically analyze the molecular structure of deltamethrin, gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) were used to enhance the surface enhanced Raman spectroscopy (SERS) detection signal. As a result, the theoretical Raman peaks of deltamethrin calculated by DFT were basically similar to the measured results, and the enhancing effects based on AuNPs was better than that of AgNPs...
June 15, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Po-Hsun Lei, I-Jen Chen, Jia-Jan Chen, Po-Chun Yang, Yan-Hua Gong
We synthesized a silver nanoparticle/zinc oxide (Ag NP/ZnO) thin film by using spin-coating technology. The treatment solution for Ag NP/ZnO thin film deposition contained zinc acetate (Zn(CH₃COO)₂), sodium hydroxide (NaOH), and silver nitrate (AgNO₃) aqueous solutions. The crystalline characteristics, surface morphology, content of elements, and reflectivity of the Ag NPs/ZnO thin film at various concentrations of the AgNO₃ aqueous solution were investigated using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, and ultraviolet⁻visible⁻near infrared spectrophotometry...
June 15, 2018: Materials
Marta Gambucci, Luigi Tarpani, Giulia Zampini, Giuseppina Massaro, Morena Nocchetti, Paola Sassi, Loredana Latterini
Trans-membrane proteins play important roles in the inter-cellular signaling to regulate the interactions among adjacent cells and influence cell fate. The study of the interactions between membrane proteins and nanomaterials is paramount for the design of nanomaterial-based therapies. In the present work, the fluorescence properties of the trans-membrane receptor Notch2 have been investigated. In particular, steady state and time resolved fluorescence methods have been used to characterize the emission of tryptophan residues of Notch2 and then this emission is used to monitor the impact of silver colloids on protein behavior...
June 18, 2018: Journal of Physical Chemistry. B
Kuan-Jung Chen, Cheng-Kang Lee
Dispersin B (DspB) has shown a great potential for the hydrolysis of polymeric β-1,6-N-acetyl-d-glucosamine (PNAG) to disperse the biofilms formed by various bacteria but with no killing activity. Here we have investigated whether a silver-binding peptide (AgBP) fused to DspB can induce the in situ formation of silver nanoparticles (AgNP) and conjugated to the structure of DspB so that the bacteria cells released from the dispersed biofilm will be killed by the conjugated AgNP. However, the desired conjugate could be obtained because of the silver ions itself was found to precipitate DspB...
June 13, 2018: International Journal of Biological Macromolecules
Aisha Al-Asfar, Zoya Zaheer, Elham Shafik Aazam
Silver-iron bimetallic nanoparticles (BMNPs) were synthesized by using AgNO3 and Fe(NO3 )3 as an Ag/Fe source in presence of Palm dates fruit. Upon addition of extract to a solution of Ag+ and Fe3+ , a prefect transparent stable dark brown color appears with in a few minuets at room temperature. In order to conform the nature of resulting color, UV-visible spectroscopy, transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) techniques were used. The absence of surface plasmon resonance (SPR) peaks in the entire UV-visible region suggests the formation of silvercore -ironshell BMNPs...
June 6, 2018: Journal of Photochemistry and Photobiology. B, Biology
D Crisan, K Scharffetter-Kochanek, M Crisan, S Schatz, H Hainzl, L Olenic, A Filip, L A Schneider, A Sindrilaru
New biomaterials based on nanoparticles (NPs) carrying polyphenols-rich extracts (Cornus mas) recently showed promising anti-inflammatory activity in psoriasis. We aimed to understand how topically delivered silver and gold nanoparticles complexed with Cornus mas (Ag-NPs-CM, Au-NPs-CM) modulate inflammation in psoriasis at cellular and molecular level. The impact on psoriatic inflammation was assessed in vitro on pro-inflammatory macrophages, by clinical score, high-frequency ultrasonography and immunohistology of psoriasis plaques treated with Ag-NPs-CM, Au-NPs-CM or control...
June 15, 2018: Experimental Dermatology
Ana Espinosa, Alberto Curcio, Sonia Cabana, Guillaume Radtke, Matthieu Bugnet, Jelena Kolosnjaj-Tabi, Christine Péchoux, Carmen Alvarez-Lorenzo, Gianluigi A Botton, Amanda Silva, Ali Abou-Hassan, Claire Wilhelm
Despite their highly efficient plasmonic properties, gold nanoparticles are currently preferred to silver nanoparticles for biomedical applications such as photothermal therapy due to their high chemical stability in the biological environment. To confer protection while preserving their plasmonic properties, we allied the advantages of both materials and produced hybrid nanoparticles, made of an anisotropic silver nanoplate core coated with a frame of gold. The efficiency of such hybrid nanoparticles (Ag@AuNPs) in photothermia was compared to mono-metallic silver nanoplates (AgNPs) or gold nanostars (AuNPs)...
June 15, 2018: ACS Nano
Teodora Gancheva, Nick Virgilio
This work demonstrates that a model system of poly( N-isopropylacrylamide) (PNIPAam) macroporous hydrogels, with tailored microstructures and comprising gold (Au) or silver (Ag) nanoparticles, display enhanced and tunable catalytic activity. These nanocomposites are prepared using polymer templates obtained from melt-processed cocontinuous polymer blends. The reaction rate, controlled by both hydrogel porosity and the PNIPAam lower critical solution temperature, increases by more than an order of magnitude as compared to nonporous gels, and is comparable to micro- or nanocarrier-based systems, with easier catalyst recovery...
June 15, 2018: ACS Applied Materials & Interfaces
Janja Vidmar, Katrin Loeschner, Manuel Correia, Erik H Larsen, Pius Manser, Adrian Wichser, Kailen Boodhia, Zahraa S Al-Ahmady, Jaimé Ruiz, Didier Astruc, Tina Buerki-Thurnherr
With the extensive use of silver nanoparticles (AgNPs) in various consumer products their potential toxicity is of great concern especially for highly sensitive population groups such as pregnant women and even the developing fetus. To understand if AgNPs are taken up and cross the human placenta, we studied their translocation and accumulation in the human ex vivo placenta perfusion model by single particle ICP-MS (spICP-MS). The impact of different surface modifications on placental transfer was assessed by AgNPs with two different modifications: polyethylene glycol (AgPEG NPs) and sodium carboxylate (AgCOONa NPs)...
June 15, 2018: Nanoscale
Xiaoyong Wang, Lan Zhang, Junqing Wang, Xuan Liu, Peng Lv, Jie Zeng, Gang Liu
Triangular Ag nanoplates with a thickness of 5 nm and tunable edge lengths were fabricated using a seed-mediated protocol, featuring enhanced near-infrared absorption as the edge length of nanoplates increased. The photoacoustic (PA) efficiency of these Ag nanoplates were assessed. Nanoplates with an edge length of 100 nm (r1) performed best among others in the in vitro assessment. In the following in vivo test, r1 nanoplates were also found to boost the PA signal of tumor vessels, while a detailed PA imaging of tumor vasculature was obtained...
August 1, 2018: Journal of Biomedical Nanotechnology
Shigeru Yamada, Daiju Yamazaki, Yasunari Kanda
Silver nanoparticles (AgNPs) have been widely used as consumer products due to their antibacterial activities. Despite their extensive use, AgNPs have been reported to cause various types of cytotoxicity, including neurotoxicity. However, the potential action of AgNPs on early fetal development has not been elucidated. This study determined the effects of AgNPs on neural induction in human induced pluripotent stem cells (iPSCs), used as a model for human fetal stage development. It was observed that exposure to AgNPs reduced the expression of several neural differentiation marker genes, including OTX2, an early biomarker for neurogenesis in iPSCs...
June 14, 2018: Nanotoxicology
Gal Schkolnik, Matthias Schmidt, Marco G Mazza, Falk Harnisch, Niculina Musat
[This corrects the article DOI: 10.1371/journal.pone.0145871.].
2018: PloS One
Alexandra Y Grün, Constantin B App, Andreas Breidenbach, Jutta Meier, George Metreveli, Gabriele E Schaumann, Werner Manz
The application of engineered silver nanoparticles (AgNPs) in a considerable amount of registered commercial products inevitably will result in the continuous release of AgNPs into the natural aquatic environment. Therefore, native biofilms, as the prominent life form of microorganisms in almost all known ecosystems, will be subjected to AgNP exposure. Despite the exponentially growing research activities worldwide, it is still difficult to assess nanoparticle-mediated toxicity in natural environments. In order to obtain an ecotoxicologically relevant exposure scenario, we performed experiments with artificial stream mesocosm systems approaching low dose AgNP concentrations close to predicted environmental concentrations...
2018: PloS One
Lin Yang, Shu Jun Zhen, Yuan Fang Li, Cheng Zhi Huang
Graphene oxide (GO) exhibits distinctive Raman scattering features for its high frequency D (disordered) and tangential modes (G-band), which are characteristically sharp at 1580 cm-1 and 1350 cm-1, respectively, but are too weak for sensitive quantitation purposes. By depositing silver nanoparticles on the surface of GO in this contribution, both D and G bands of GO become enhanced. The enzyme label of this method controls the dissolution of silver nanoparticles on the surface of GO through hydrogen peroxide which is produced by the oxidation of the enzyme substrate...
June 14, 2018: Nanoscale
Josiane de Almeida, Bruna Casagrande Cechella, Anarela Vassen Bernardi, Andrea de Lima Pimenta, Wilson Tadeu Felippe
Context: To overcome the challenge imposed by the presence of biofilm and reach significant bacterial reduction of the root canals, many irrigants have been indicated during endodontic treatment, among them nanoparticles solutions. Aims: This study aims to evaluate the effectiveness of experimental solutions containing silver and zinc oxide nanoparticles (ZnO Np) and conventional endodontic irrigants against Enterococcus faecalis biofilm, in root canals. Methods: Seventy-six extracted human teeth were biomechanically prepared and sterilized...
May 2018: Indian Journal of Dental Research: Official Publication of Indian Society for Dental Research
Jayasheelan Vaithilingam, Ehab Saleh, Ricky D Wildman, Richard J M Hague, Christopher J Tuck
Three dimensional inkjet printing of multiple materials for electronics applications are challenging due to the limited material availability, inconsistencies in layer thickness between dissimilar materials and the need to expose the printed tracks of metal nanoparticles to temperature above 100 °C for sintering. It is envisaged that instead of printing a dielectric and a conductive material on the same plane, by printing conductive tracks on an angled dielectric surface, the required number of silver layers and consequently, the exposure of the polymer to high temperature and the build time of the component can be significantly reduced...
June 13, 2018: Scientific Reports
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