Collaborative Research: The Antimicrobial Properties of Silver Nanoparticles: mechanisnms and water chemistry effects

CraverNanosilver是目前市场上超过20%的纳米产品的活性成分，是商业应用中最常用的纳米材料。 这些产品中约88%具有某种形式的抗菌或抗微生物活性。 银纳米颗粒表现出不同于离子和本体材料的物理性质。 由于其强大的抗菌性能，几项研究表明，银纳米粒子在生物医学和环境应用中的潜在用途，如治疗伤口和烧伤以及水消毒。 虽然银纳米颗粒的抗菌特性已被广泛证实，但其在细菌、病毒和原生动物灭活中的消毒机制和动力学尚未阐明。 事实上，还没有研究测试银纳米颗粒灭活原生动物病原体如隐孢子虫和贾第鞭毛虫的能力。 之前的研究尚未解决环境条件对银纳米颗粒抗菌性能的影响。研究人员假设银纳米颗粒有三种可能的抗菌过程：（1）银颗粒与细胞膜的直接相互作用和随后对膜的损伤以及与细胞内组分的络合，（2）Ag+离子的释放和随后的消毒，（3）活性氧（ROS）的形成。 这些机制均未得到最终证实，也未阐明每种机制在灭活不同类型病原微生物中的相对重要性。 本工作将合成具有不同平均粒径和比表面积的银纳米粒子，并量化其对病原体消毒机制和速率的影响。 拟用于研究的病原体包括病毒（MS 2）、细菌（E. coli）和原生动物（隐孢子虫（Cryptosporidium parvum））。 实验设计将使我们能够单独识别每种潜在的机制，并确定其对每种病原体总体消毒率的相对贡献。预计这项工作将在几个方面产生更广泛的影响，包括高中生暑期课程，在现有课程中增加环境纳米技术课程模块，并与罗得岛大学工程学生无国界（ESWB）分会合作开发一个服务项目，涉及制造和销售专门设计用于陶瓷水过滤器的纳米银颗粒，和平 他们设想后者的努力是一个可持续的服务项目，为学生章，将教他们有关发展中国家的水问题，向他们介绍银纳米技术，并提供资金，以支持他们的学生章服务的努力。

0854113CraverNanosilver, the active component of more than 20% of the nanoproducts currently available on the market, is the most commonly used nanomaterial for commercial applications. Approximately 88% of these products have some form of antibacterial or antimicrobial activity. Silver nanoparticles exhibit physical properties that are different from both the ion and the bulk material. Because of their strong antibacterial properties, several studies have shown the potential use of silver nanoparticles in biomedical and environmental applications, such as the treatment of wounds and burns and water disinfection. While the antibacterial properties of silver nanoparticles have been extensively demonstrated, their disinfectant mechanism(s) and kinetics in the inactivation of bacteria, viruses, and protozoa have not yet been elucidated. Indeed, there have been no studies testing the ability of silver nanoparticles to deactivate protozoan pathogens like Cryptosporidium parvum and Giardia lamblia. Previous studies have not addressed the effect of environmental conditions on the antimicrobial properties of silver nanoparticles.The researchers hypothesize that there are three possible antimicrobial processes for silver nanoparticles: (1) direct interaction of the silver particle with the cell membrane and subsequent damage to the membrane and complexation with intracellular components, (2) release of Ag+ ions and subsequent disinfection, and (3) formation of reactive oxygen species (ROS). None of these mechanisms have been conclusively confirmed, nor has the relative importance of each mechanism in the inactivation of different types of pathogenic microorganisms been elucidated. This work will synthesize silver nanoparticles with different mean particle sizes and specific surface areas and quantify their effects on pathogen disinfection mechanism and rate. Pathogens proposed for study include a virus (MS2), a bacteria (E. coli), and a protozoa (Cryptosporidium parvum). Experimental design will allow us to identify each potential mechanism individually and determine its relative contribution to the overall disinfection rate for each pathogen.It is anticipated that this work will have broader impacts in several ways, including a summer program for high-school students, adding an environmental nanotechnology course module to an existing course, and working with the University of Rhode Island chapter of Engineering Students without Borders (ESWB) to develop a service project involving the manufacture and distribution of nanosilver particles specifically designed for use in ceramic water filters manufactured by Potters for Peace. They envision this latter effort to be a sustainable service project for the student chapter that will teach them about developing-world water problems, introduce them to silver nanotechnology, and provide funds to support their student chapter service efforts.