Yi Jun, Cheng Jinping
State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China.
Shenzhen Key Laboratory for the Sustainable Use of Marine Biodiversity, Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China.
Ecotoxicology. 2017 Jul;26(5):639-647. doi: 10.1007/s10646-017-1796-1. Epub 2017 Apr 4.
The growing use of silver nanoparticles (AgNPs) has created concerns about its potential impacts on natural microbial communities. In this study, the physicochemical properties of AgNPs and its toxicity on natural bacteria Bacillus subtilis (B. subtilis) were investigated in aqueous conditions. The characterization data showed that AgNPs highly aggregated in aqueous conditions, and the hydrodynamic diameter of AgNPs in aqueous conditions was larger than its primary size. The studied AgNPs was less toxic to B. subtilis in estuarine water as compared to that in Milli-Q water and artificial seawater, which might be due to the observed enhanced aggregation of AgNPs in estuarine water. The toxicity of AgNPs to B. subtilis was greatly reduced when their surface contact was blocked by a dialysis membrane. Scanning electron microscope images showed that exposure contact to AgNPs resulted in damage of the microbial cell wall and enhanced formation of fibrillar structures. These results suggest that particle-cell contact is largely responsible for the observed toxicity of AgNPs in B. subtilis. This study can help to understand the potential impacts of AgNPs to natural microbes, especially in the complex aquatic environments.
银纳米颗粒（AgNPs）使用的日益增加引发了人们对其对天然微生物群落潜在影响的担忧。在本研究中，研究了AgNPs在水性条件下的物理化学性质及其对天然细菌枯草芽孢杆菌（B. subtilis）的毒性。表征数据表明，AgNPs在水性条件下高度聚集，且其在水性条件下的流体动力学直径大于其原始尺寸。与在超纯水和人工海水中相比，所研究的AgNPs在河口水中对枯草芽孢杆菌的毒性较小，这可能是由于观察到AgNPs在河口水中的聚集增强。当用透析膜阻断其表面接触时，AgNPs对枯草芽孢杆菌的毒性大大降低。扫描电子显微镜图像显示，与AgNPs的暴露接触导致微生物细胞壁受损，并增强了纤维状结构的形成。这些结果表明，颗粒与细胞的接触在很大程度上导致了观察到的AgNPs对枯草芽孢杆菌的毒性。本研究有助于了解AgNPs对天然微生物的潜在影响，尤其是在复杂的水生环境中。
