Department of Chemistry, University of Minnesota, 207 Pleasant St SE, Minneapolis, Minnesota 55455, USA.
Anal Chem. 2013 Jun 18;85(12):5810-8. doi: 10.1021/ac400486u. Epub 2013 Jun 7.
Understanding of nanoparticle impacts on critical bacteria functions allows us to gain a mechanistic understanding of toxicity and guides us toward design rules for creating safe nanomaterials. Herein, biofilm formation, a general bacteria function, and riboflavin secretion, a species-specific function, were monitored in Shewanella oneidensis, a metal reducing bacterium, following exposure to a variety of TiO2 nanoparticle types (synthesized, Aeroxide P25, and T-Eco). Transmission electron microscopy (TEM) images show that dosed nanoparticles are in close proximity to the bacteria, but they are not internalized. Using quartz crystal microbalance (QCM), it was revealed that S. oneidensis biofilm formation is slowed in the presence of nanoparticles. Though S. oneidensis grows more slowly in the presence of TiO2 nanoparticles, riboflavin secretion, a function related to the S. oneidensis metal reducing capacity, was increased significantly in a nanoparticle dose-dependent manner. Both changes in biofilm formation and riboflavin secretion are supported by changes in gene expression in nanoparticle-exposed S. oneidensis. This broad study of bacterial nanotoxicity, including use of sensitive analytical tools for functional assessments of biofilm formation, riboflavin secretion, and gene expression, has implications for total ecosystem health as the use of engineered nanoparticles grows.
了解纳米颗粒对关键细菌功能的影响使我们能够深入了解毒性，并指导我们设计出安全的纳米材料。在此，我们监测了一种金属还原菌希瓦氏菌（Shewanella oneidensis）中的生物膜形成（一种普遍的细菌功能）和核黄素分泌（一种特定物种的功能），这些细菌暴露于各种 TiO2 纳米颗粒类型（合成、Aeroxide P25 和 T-Eco）中。透射电子显微镜（TEM）图像显示，处理过的纳米颗粒与细菌紧密接触，但未被内化。使用石英晶体微天平（QCM）发现，纳米颗粒的存在会减缓希瓦氏菌的生物膜形成。尽管在 TiO2 纳米颗粒存在的情况下希瓦氏菌生长较慢，但与金属还原能力有关的核黄素分泌却以纳米颗粒剂量依赖的方式显著增加。生物膜形成和核黄素分泌的变化都得到了纳米颗粒暴露的希瓦氏菌基因表达变化的支持。这项关于细菌纳米毒性的广泛研究，包括使用敏感的分析工具对生物膜形成、核黄素分泌和基因表达进行功能评估，对整个生态系统的健康具有重要意义，因为工程纳米颗粒的使用正在增加。
