Nanobio-Medicine Laboratory, School of Bio-Sciences and Technology, VIT University, Vellore, India.
J Basic Microbiol. 2011 Apr;51(2):183-90. doi: 10.1002/jobm.201000067. Epub 2010 Nov 12.
Use of silver nanoparticles (SNPs) is increasing in a large number of consumer products. Thus, the possible build-up of the nanoparticles in the environment is becoming a major concern. Aeromonas punctata isolated from sewage showed tolerance to 200 μg/ml SNPs. The growth kinetics data for A. punctata treated with nanoparticles were similar to those in the absence of nanoparticles. There was a reduction in the amount of exopolysaccharides (EPS) in bacterial culture supernatant after nanoparticle-supernatant interaction. EPS capping of the nanoparticles was confirmed by UV-visible, XRD and comparative FTIR analysis. The EPS-capped SNPs showed less toxicity to Escherichia coli, Staphylococcus aureus and Micrococcus luteus compared to the uncapped ones. The study suggests capping of nanoparticles by bacterially produced EPS as a probable physiological defense mechanism.
银纳米粒子（SNPs）在大量消费品中的应用越来越广泛。因此，纳米粒子在环境中的累积可能成为一个主要关注点。从污水中分离出的气单胞菌对 200μg/ml SNPs 表现出耐受性。用纳米粒子处理的气单胞菌的生长动力学数据与没有纳米粒子时相似。纳米粒子-上清液相互作用后，细菌培养液上清液中的胞外多糖（EPS）含量减少。通过紫外可见分光光度法、XRD 和比较傅里叶变换红外分析证实了纳米粒子的 EPS 帽。与未加帽的 SNPs 相比，EPS 包裹的 SNPs 对大肠杆菌、金黄色葡萄球菌和藤黄微球菌的毒性较小。该研究表明，细菌产生的 EPS 对纳米粒子的包被可能是一种可能的生理防御机制。
