Preparation of Silver Nanoparticles through Alcohol Reduction with Organoalkoxysilanes

Silver nanoparticles of narrow size distribution were prepared through the chemical reduction in an alcohol solution with several organoalkoxysilanes. In this system, organoalkoxysilanes served as a stabilizer, protecting silver nanoparticles from aggregation. The changes in size and morphology of colloidal silver nanoparticles were investigated with the addition of organoalkoxysilanes such as 3-aminopropyltriethoxysilane (APS), methyltriethoxysilane (MTS), phenyltrimethoxysilane (PTS), vinyltriethoxysilane (VTS), and 3-glycidoxypropyltrimethoxysilane (GPS) as stabilizers. The organic functional groups of organoalkoxysilanes interact with silver ions and clusters, which stabilize silver nanoparticles in the system. The silver nanoparticles obtained were characterized with transmission electron microscopy (TEM), UV-vis spectroscopy, etc.     

以树形分子为模板制备银纳米颗粒

以硝酸银为原料,硼氢化钠为还原剂,PAMAM树形分子为模板兼稳定剂,制备出粒径分布范围在4～7mm的银纳米颗粒．实验发现,其他条件相同时,银纳米颗粒的粒径随着Ag^ ／树形分子摩尔比的增加而增加,并且树形分子代数越高,所起的模板作用越显著．还研究了溶液pH值的影响,发现当溶液pH值在7左右时,可以制得粒径较小、分散性较好的银纳米颗粒．用紫外-可见光谱,透射电镜(TEM)以及原子力显微镜(AFM)等测试手段对所制得的银纳米颗粒进行了表征．     

银纳米颗粒的制备及表征

用鞣酸还原法制得了PVP保护的Ag纳米颗粒,并通过TEM、XRD、TG、DTA及FT IR对其结构进行了表征.结果表明在所选择的实验条件下制备了粒径小、单分散且化学稳定的Ag PVP纳米颗粒,其粒径约10nm,有良好的水分散性.PVP的加入和银氨络离子的形成对制备出小尺寸纳米银起了重要作用.     

Mussel Inspired In Situ Preparation of Antibacterial Silver Nanoparticles by DOPA-Containing Silk Fibroin

Silver nanoparticles (AgNPs) attract a great deal of attention for potent antibacterial capacity, but their use is challenged by limited stability. Inspired by the adhesive and redox properties of the mussel foot proteins containing L -3,4-dihydroxyphenylalanine (DOPA), a facile strategy for in situ synthesis of AgNPs using DOPA-containing fibroin is developed. Tyrosine residues in fibroin are transformed into DOPA via biomimetic synthesis method with content of 0.55 mol%. In situ synthesis generates stable and small AgNPs through DOPA bound in fibroin as a reducing and stabilizing agent. Narrow size distribution with average diameter of 20 nm and excellent monodispersity are obtained. Cross-linking with lysine increases the content of β-sheet to form hydrogel and achieves gradual release of silver. The material exhibits excellent antibacterial properties against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. It can be potentially applied in biological and medical fields to treat bacterial infections.     

银纳米粒子的一步合成与表征

在水和乙醇溶液中,以对巯基苯胺作为还原剂,利用一步法合成了银纳米微粒,并利用拉曼光谱仪考察了对巯基苯胺在银纳米微粒表面的自组装行为.结果表明,合成的银纳米微粒的形貌与介质的pH值密切相关;对巯基苯胺可在银纳米微粒表面自组装.     

利用还原性多糖合成银纳米粒子

利用还原性多糖为稳定剂、AgNO₃为前驱物, 通过一条绿色途径合成银纳米粒子, 并探讨了纳米粒子的形成机理. 对多糖高浓度时制得的复合物在空气与氮气气氛下进行了热处理, 分别得到了银的大孔海绵体与银纳米粒子/碳的复合材料. 对产物进行了X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外-可见分光光度(UV-vis)以及BET吸附表征.     

配位自还原法制备纳米银及其电催化活性

Pt是质子交换膜燃料电池(PEMFC)阴极氧还原最好的催化剂,但价格昂贵,且易被渗透到阴极的燃料分子及中间体毒化,导致电池性能降低。 本文以乙二胺四甲叉膦酸(EDTMP)为配位剂和还原剂,采用配位自还原法快速合成银纳米粒子(Ag NPs),并研究了其对氧还原的电催化性能。 透射电子显微镜(TEM)、X射线衍射(XRD)等测试结果表明,Ag NPs分散性好且粒径均一,还原反应6 h所得Ag NPs的平均粒径约6 nm;循环伏安法(CV)等电化学测试发现,在碱性条件下此种合成方法制得的银作为电催化氧还原反应(ORR)的催化剂具有良好的催化活性,通过EDTMP配位自还原得到的Ag NPs对氧还原的半波电位(E1/2)比传统的NaBH4直接还原所制得Ag NPs的E1/2正移60 mV。     

四硫富瓦烯衍生物修饰的银溶胶

四硫富瓦烯衍生物修饰的银溶胶;银溶胶;纳米粒子;四硫富瓦烯;氧化还原;表面修饰     

Preparation of Phenolic Resin/Silver Nanocomposites via in-situ Reduction

Polymer/metal nanocomposites have attracted considerable interest because of their potential application in catalysts, electronics, electromagnetics and nonlinear optics1-3. They have been prepared by blending polymer with nanometer metal particles4, reducing polymer-metal ion complexes with reducing agents5, and reducing metal ions in the polymer matrix by high-energy radial irradiation3. In this paper, we report a new approach to phenolic resin/silver nanocomposites, which have potential a…     

银纳米微球和银纳米棒自组装膜的制备及SERS研究

采用硼氢化钠还原硝酸银,用振荡器在不同转速下振荡得到单分散的银纳米微球和银纳米棒,再将银纳米微球及银纳米棒自组装于被3-氨丙基-三甲氧基硅烷(APTMS)修饰的玻璃基片上,制得了具有表面增强拉曼(SERS)活性的基底,分别以罗丹明6G(R6G)和罗丹明B(RB)为探针分子对这两种基底进行SERS活性检测,结果发现这两种基底均为较理想的SERS衬底。     

纳米银的电解质效应

向2种不同电性的纳米银溶胶中分别加入KCl、KBr、KI、KNO3、Mg(NO3)2、Al(NO3)3、K2CO3、K2SO4、KOH和HNO3电解质溶液,利用透射电子显微镜、紫外-可见分光光度计等研究电解质对纳米银的显微结构和光谱学性质的影响。结果表明,不同电解质离子在纳米银胶体表面吸附程度以及导致纳米银胶体聚集和生长程度不同,从而对纳米银胶体的分散状态和表面电势产生不同影响。这种影响的结果导致其对相同电性纳米银粒子和不同电性纳米银粒子的显微结构和光谱学性质影响不同。     

聚丙烯酰胺存在下微波高压合成银纳米粒子及其光谱特性

以聚丙烯酰胺为还原剂和稳定剂 ,采用微波高压液相合成法制备了黄色银纳米粒子。用吸收光谱和共振散射光谱研究了其制备条件的影响。在 4 2 1.6nm处产生最大吸收峰 ,在 4 70nm处产生一个最强共振散射峰。实验表明 :该法制备的银纳米粒子粒径均匀 ,平均粒径为 6 6nm ,其稳定性和分散性较好 ,合成方法简便、快捷。     

生物素修饰纳米银探针的制备及在蛋白芯片可视化检测中的应用

采用寡核苷酸为连接分子成功制备了生物素修饰的纳米银探针, 并建立了纳米银催化同种金属离子的特异性还原显色反应. 实验采用蛋白质芯片为分析工具, 以微量人IgG为蛋白分析模式研究了纳米银探针/氢醌/硝酸银体系的显色分析性能. 实验结果表明, 上述检测体系可对160 fg~100 pg含量范围内的微量蛋白显示可视化结果, 蛋白点的灰度值与其浓度具有良好的相关性, 最小蛋白检测量可达160 fg. 同时还开展了与商品化链亲和素纳米金/银增强试剂显色方法的对比实验, 结果表明, 本法制备的探针对蛋白的检出限降低了约40倍, 且具有存储稳定、反应快速等优点.     

过氧化氢溶液中单和双金属金-银纳米粒子氧化L-亮氨酸的动力学(英文)

The catalytic activity of surfactant stabilized mono-and bimetallic Au and Ag nanoparticles for the oxidation of an amino acid,L-leucine,was studied using hydrogen peroxide as the oxidant.The Au and Ag nanoparticle catalysts exhibited very good catalytic activity and the kinetics of the reaction were found to be pseudo-first order with respect to the amino acid.The effects of several factors,such as oxidant concentration,ionic strength,pH,and catalyst concentration on the reaction,were also investigated.In particular,optimal oxidant and catalyst concentrations were determined.Very high concentrations of the metal nano-catalysts or the oxidant led to a dramatic increase in reaction rate.Moreover,bimetallic Au-Ag catalysts provided higher selectivity than pure Au or Ag.     

Green Silver and Gold Nanoparticles: Biological Synthesis Approaches and Potentials for Biomedical Applications

The nanomaterial industry generates gigantic quantities of metal-based nanomaterials for various technological and biomedical applications; however, concomitantly, it places a massive burden on the environment by utilizing toxic chemicals for the production process and leaving hazardous waste materials behind. Moreover, the employed, often unpleasant chemicals can affect the biocompatibility of the generated particles and severely restrict their application possibilities. On these grounds, green synthetic approaches have emerged, offering eco-friendly, sustainable, nature-derived alternative production methods, thus attenuating the ecological footprint of the nanomaterial industry. In the last decade, a plethora of biological materials has been tested to probe their suitability for nanomaterial synthesis. Although most of these approaches were successful, a large body of evidence indicates that the green material or entity used for the production would substantially define the physical and chemical properties and as a consequence, the biological activities of the obtained nanomaterials. The present review provides a comprehensive collection of the most recent green methodologies, surveys the major nanoparticle characterization techniques and screens the effects triggered by the obtained nanomaterials in various living systems to give an impression on the biomedical potential of green synthesized silver and gold nanoparticles.     

Silver Nanoparticles in Polyacrylamide and Hyperbranched Polyamine Matrix

Silver nanoparticles have been prepared in a polyacrylamide (PA) matrix, as well as in the presence of a hyperbranched polyamine/polyacrylamide combined system (HB‐PA) by using a reductive technique. The stability of colloidal solution of silver nanoparticles is higher (5 months) in combined matrix compared to PA alone (4 months). The prepared silver nanoparticles were characterized by different spectroscopic and analytical techniques such as FTIR, UV‐visible, X‐ray diffraction, TEM etc. TEM and XRD studies confirmed the formation of well‐dispersed nanoparticles with an average size of 9.91 nm and 8.5 nm for PA and HB‐PA matrices, respectively. The antibacterial activity of silver nanoparticles in both the matrices was tested against Bacillus Subtilis bacteria by using the diffusion disc technique. The result shows that the antibacterial activity of the active agent, Ag(0) is a little higher in the case of HB‐PA system. The dielectric constant of the matrices decreases with an increase in frequency, but the values increase with an increase of concentration of silver nanoparticles in PA matrix.     

纳米银的绿色合成: 丝胶蛋白作为还原剂和分散剂

利用基于天然生物高分子的绿色环保法制备纳米贵金属材料是当今纳米技术发展的一个重要方向之一. 利用丝胶蛋白(SS)为还原剂和分散剂合成了纳米银颗粒, 利用紫外-可见(UV-Vis)光谱、X射线衍射(XRD)、透射电镜(TEM)等研究了反应温度、pH值、SS/Ag^＋物质的量比对反应速率和合成的纳米银粒子形貌的影响. 实验结果表明, 利用本方法可以合成尺寸均匀且分散性良好的球形纳米银粒子, 且随着反应温度和溶液pH值的逐渐升高, 反应速率随之加快, 合成的纳米银粒子的粒径逐渐变小, 而SS/Ag^＋物质的量比的变化主要对纳米银粒子的尺寸有影响.     

超声辐射法制备银纳米微粒

在有机介质十氢化萘中,以金属钠、硝酸银和油酸钠为起始原料,通过超声辐射使金属钠和硝酸银发生置换反应,成功制备了油酸表面修饰的Ag纳米微粒.采用透射电子显微镜、X射线粉末衍射仪和热分析仪对其形貌、结构和性能进行了表征.透射电镜和X射线粉末衍射研究表明:所制备的油酸表面修饰Ag纳米微粒粒径较小,平均尺寸为10 nm,分布均匀,无团聚现象,且具有面心立方晶型结构.热分析结果表明:所制备的样品含有约9.7%的有机物,并具有良好的热稳定性能.     

Preparation of Hybrid Microgels Functionalized by Silver Nanoparticles

Summary: Hybrid microgels functionalized with silver nanoparticles (AgNP) have been prepared and their physico‐chemical properties examined. Composite particles have been obtained by formation of AgNP in presence of poly[vinylcaprolactam‐co‐(acetoacetoxyethyl methacrylate)] (VCL/AAEM) microgel particles. It has been demonstrated that hybrid particles with different AgNP amounts can be prepared. Hybrid particles are sensitive to temperature and swelling, and collapse processes are reversible. Incorporation of AgNP leads to shrinkage of microgel template due to the partial immobilization of polymer chains on the microgel surface. As a consequence, gradual loss of temperature sensitivity is observed. Hybrid microgels form highly transparent well‐organized films on solid substrates, providing homogeneous distribution of AgNP in bulk material. Presence of AgNP increases considerably the thermal stability of composite films.

Schematic representation (left) and TEM image (right) of hybrid microgels containing silver nanoparticles (AgNP).     

基于超支化温敏聚合物制备温敏金纳米粒子

通过对不同分子量的超支化聚乙烯亚胺(hyperbranched polyethyleni mine,HPEI)的端基进行部分或完全异丁酰胺(isobutyric amide,IBAm)化,可以制备一系列具有不同低临界溶解温度(Lower Critical SolutionTemperature,LCST)的超支化温敏聚合物HPEI-IBAm。通过离子键或氢键之间的相互作用,所得超支化温敏聚合物可以吸附于柠檬酸钠还原并稳定的14nm的金纳米粒子(AuNP)的表面,从而得到具有温敏性质的金纳米粒子。所得温敏金的LCST都低于其相应的温敏聚合物,其差值在0.8至6℃之间。在pH值为9.18的缓冲溶液中,通过改变所用聚合物的分子量以及异丁酰胺基团的取代度,所得温敏金的LCST可控制在21.7~48.2℃之间。此外,所得温敏金的LCST也是pH值敏感的,通过溶液pH值的改变,所得温敏金的LCST值可以在更宽的范围内调节。增加溶液的碱性,LCST可能变化不大或降低,减小溶液的碱性会使LCST升高,直到消失。在偏酸的条件下,所得金复合物通常发生聚集,变得不稳定。此外,溶液中的盐度对所得温敏金的LCST也有影响,氯化钠和硫酸钠会降低其LCST,尤其是硫酸钠的效果更显著。