纳米银胶体颗粒制备新方法及其荧光增强效应研究

在纳米银胶体颗粒的制备中引入固相分散基体——天然纤维素,利用其表面丰富的羟基、醚基等含氧基团,均匀吸附银离子后,浸入低浓度硼氢化钠,经历脱附、还原过程生成银纳米颗粒的胶体溶液.与经典制备方法相比,反应过程温和且无需添加任何稳定剂,所制得的银纳米颗粒细小、均一、稳定性高.荧光增强实验表明,由于消除了大分子稳定剂的阻碍,胶体溶液在较低浓度下即可获得很好的荧光增强作用.     

PVP催化还原及稳定化纳米银的微波合成

在聚乙烯基吡咯烷酮(PVP)的存在下,微波辐射硝酸银水溶液,合成了纳米银/PVP复合物。UV-Vis和XRD结果证明了生成的纳米银具有面心立方结构,PVP中N原子对银离子具有催化还原作用。TEM结果表明纳米银粒径在10～25nm,且较均匀分散在聚合物基体中;XPS结果表明PVP与纳米银之间存在相互作用。     

超声引发无皂乳液聚合制备纳米银/PAAEM复合材料及其表征

在不使用气体保护及乳化剂的条件下,超声辐射引发无皂乳液聚合双原位合成纳米银/聚乙酰乙酸基甲基丙烯酸乙酯(PAAEM)复合材料。并通过XRD、FTIR、TEM、HRTEM、XPS和TG等分析方法对其进行表征。结果表明:纳米银粒子具有面心立方结构和球形或近球形形貌,且较均匀地分散在聚合物基体中;纳米银粒子与基体之间的相互作用是纳米银与基体中乙酰乙酸基的羰基氧原子配位所产生的;而且纳米银粒子对基体PAAEM的热学性能有很大影响。     

New Perspectives of Using Chitosan,Silver, and Chitosan–Silver Nanoparticles against Multidrug-Resistant Bacteria

Nanomaterials with antimicrobial activity are promising alternatives to overcome microbial resistance in medical devices. Catheters, probes, and wound dressings are among the medical devices mostly affected by microbial contamination and the formation of polymicrobial biofilms. Nanoparticles (NPs) derived from natural sources, such as chitosan nanoparticles (CsNPs), and metal-based nanoparticles, including silver nanoparticles (AgNPs), are receiving increased interest in nanomedicine. CsNPs have been widely explored as a coating material and antimicrobial agent. AgNPs have a strong antimicrobial effect against bacteria and fungi. The nanocomposite chitosan–silver nanoparticles (Cs-AgNPs) can be more effective against several microorganisms, including multidrug-resistant bacteria, due to the synergistic effect between chitosan and silver. This review addresses the most used synthesis methods, including green routes, to produce CsNPs, AgNPs, and Cs–AgNPs. It also discusses physicochemical characteristics and antimicrobial properties of these NPs in medical, pharmaceutical, and biotechnological areas.     

高温功率半导体器件连接的低温烧结技术

综述了功率电子器件和模块的连接和封装工艺,介绍了粉末致密烧结技术和用于电子封装的现状,对纳米银金属焊膏烧结技术进行了讨论。研究表明,纳米银可有效降低烧结温度,提高设备的高温稳定性、导热性、导电性、机械强度、抗疲劳性等。由于银的熔点较高,这种新技术可应用于高温功率器件的封装。     

大功率LED封装界面材料的热分析

基于简单的大功率LED器件的封装结构,利用ANSYS有限元分析软件进行了热分析,比较了四种不同界面材料LED封装结构的温度场分布。同时对纳米银焊膏低温烧结和Sn63Pb37连接时的热应力分布进行了对比,得出纳米银焊膏低温烧结粘接有着更好的热机械性能。     

银纳米粒子有序结构中电荷转移的表面增强拉曼光谱

对疏基苯胺;自组装阵列;银纳米粒子有序结构中电荷转移的表面增强拉曼光谱     

高分散纳米银/蒙脱土复合材料的制备及表征

In this paper, the nanosized silver particles with a narrow size distribution and high dispersivity located in both interior and exterior layers of montmorillonite as a confinement reactor by a chemical reduction method were prepared. It was found that the obvious changes of the particle size and dispersivity of the nanosilver located in both interior and exterior layers of montmorillonite did not occur after being treated by supercritical ethanol dried at the temperature of 270 ℃ and proven that the nanosilver/montmorillonite composites had a good thermal stability, which will have some potential applications as a high activity catalyst, antibacterial agents etc.     

非标记纳米银探针催化共振散射光谱检测痕量ATP

在pH 7.8 Tris-HCl缓冲液中, 三磷酸腺苷(adenosine triphosphate, ATP)的核酸适体(Apt 1)与其互补链(Apt 2)结合生成双链DNA (double-strand DNA, dsDNA). 此dsDNA不能稳定纳米银(AgNP), NaCl可致AgNP聚集, 在500 nm波长处产生一个较强的共振散射峰. 加入ATP后, ATP与dsDNA中的Apt 1结合形成较稳定的发夹结构结合物并释放出可稳定AgNP的Apt 2. 随着ATP浓度(16.5～1650 nmol/L)增加, 生成的Apt 2增加, 被Apt 2稳定的AgNP即AgNP-Apt 2结合物增加, 聚集的AgNP减少, 500 nm处的共振散射值线性减小. 该适配体反应中的AgNP-Apt 2对葡萄糖-铜(II)微粒反应具有较强的催化作用, 其产物氧化亚铜微粒在610 nm处有一较强共振散射峰. 随着ATP浓度增大, 反应液中AgNP-Apt 2增多, 催化作用增强, 610 nm处的共振散射峰增强. ATP浓度在4.95～165 nmol/L范围内与共振散射增大值ΔI_{610 nm}呈线性关系, 检出限为1.8 nmol/L ATP. 据此建立了灵敏度高、选择性好、简便快速检测ATP的共振散射光谱新方法.