Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.
Chemistry Department, Augsburg University, 2211 Riverside Avenue, Minneapolis, Minnesota 55454, United States.
Chem Res Toxicol. 2020 Mar 16;33(3):806-816. doi: 10.1021/acs.chemrestox.9b00465. Epub 2020 Feb 18.
Cobalt phosphate engineered nanomaterials (ENMs) are an important class of materials that are used as lithium ion battery cathodes, catalysts, and potentially as super capacitors. As production of these nanomaterials increases, so does the likelihood of their environmental release; however, to date, there are relatively few investigations of the impact of nanoscale metal phosphates on biological systems. Furthermore, nanomaterials used in commercial applications are often multiphase materials, and analysis of the toxic potential of mixtures of nanomaterials has been rare. In this work, we studied the interactions of two model environmental bacteria, MR-1 and , with a multiphase lithiated cobalt phosphate (mLCP) nanomaterial. Using a growth-based viability assay, we found that mLCP was toxic to both bacteria used in this study. To understand the observed toxicity, we screened for production of reactive oxygen species (ROS) and release of Co from mLCP using three abiotic fluorophores. We also used Newport Green DCF dye to show that cobalt was taken up by the bacteria after mLCP exposure. Using transmission electron microscopy, we noted that the mLCP was not associated with the bacterial cell surface. In order for us to further probe the mechanism of interaction of mLCP, the bacteria were exposed to an equivalent dose of cobalt ions that dissolved from mLCP, which recapitulated the changes in viability when the bacteria were exposed to mLCP, and it also recapitulated the observed bacterial uptake of cobalt. Taken together, this implicates the release of cobalt ions and their subsequent uptake by the bacteria as the major toxicity mechanism of mLCP. The properties of the ENM govern the release rate of cobalt, but the toxicity does not arise from nanospecific effects-and importantly, the chemical composition of the ENM may dictate the oxidation state of the metal centers and thus limit ROS production.
钴磷酸酯工程纳米材料（ENMs）是一类重要的材料，可用作锂离子电池的阴极、催化剂，并且具有潜在的超级电容器用途。随着这些纳米材料的产量增加，它们在环境中释放的可能性也会增加；然而，迄今为止，对纳米尺度金属磷酸盐对生物系统的影响的研究相对较少。此外，商业应用中使用的纳米材料通常是多相材料，而对纳米材料混合物的毒性潜力的分析很少。在这项工作中，我们研究了两种模型环境细菌 MR-1 和 与多相锂化钴磷酸盐 (mLCP) 纳米材料的相互作用。使用基于生长的生存能力测定法，我们发现 mLCP 对本研究中使用的两种细菌均有毒性。为了了解观察到的毒性，我们使用三种非生物荧光染料筛选了 mLCP 产生活性氧 (ROS) 和钴释放的情况。我们还使用 Newport Green DCF 染料表明，钴在 mLCP 暴露后被细菌摄取。使用透射电子显微镜，我们注意到 mLCP 与细菌细胞表面没有关联。为了进一步探究 mLCP 相互作用的机制，我们将细菌暴露于从 mLCP 中溶解的钴离子的等效剂量下，这再现了当细菌暴露于 mLCP 时生存能力的变化，并且还再现了观察到的细菌对钴的摄取。总之，这表明钴离子的释放及其随后被细菌摄取是 mLCP 的主要毒性机制。ENM 的性质控制钴的释放速率，但毒性不是由纳米特异性效应引起的，而且重要的是，ENM 的化学组成可能决定金属中心的氧化态，并因此限制 ROS 的产生。
