Microbial Uptake, Toxicity, and Fate of Biofabricated ZnS:Mn Nanocrystals.
Microbial Uptake, Toxicity, and Fate of Biofabricated ZnS:Mn Nanocrystals.
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DOI：
10.1371/journal.pone.0124916
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Baneyx F
中科院分区：
文献类型：
--
作者：
Swift BJ;Baneyx F
尽管它们在纳米环境健康和安全方面很重要，但工程纳米材料与微生物生命之间的相互作用仍然很难确定。在这里，我们使用了模式生物E。大肠杆菌的渗透要求，亚细胞定位，诱导应激反应，并在“绿色”加工条件下制造的发光锰掺杂的ZnS纳米晶体的长期命运与最小化的ZnS结合蛋白。我们发现这种蛋白质包覆的量子点（QD）不能穿透未修饰的E。大肠杆菌中，但很容易转移到通过化学处理变得有活性的细胞的细胞质中。该过程是剂量依赖性的，并使人联想到细菌转化。已经内化高达0.5 μg/mL纳米晶体的细胞不经历未折叠蛋白或SOS响应的显著活化，但当暴露于高QD剂量（2.5 μg/mL）时经历氧化应激。最后，尽管它们在4至42°C的温度范围内在静止细胞中是稳定的，但内化的QD在不涉及TolC依赖性流出的过程中被细胞分裂快速稀释。两者合计，我们的研究结果表明，仿生量子点的基础上，低毒性的无机核覆盖的蛋白质壳是不太可能造成显着损害的微生物生态系统。
Despite their importance in nano-environmental health and safety, interactions between engineered nanomaterials and microbial life remain poorly characterized. Here, we used the model organism E. coli to study the penetration requirements, subcellular localization, induction of stress responses, and long-term fate of luminescent Mn-doped ZnS nanocrystals fabricated under “green” processing conditions with a minimized ZnS-binding protein. We find that such protein-coated quantum dots (QDs) are unable to penetrate the envelope of unmodified E. coli but readily translocate to the cytoplasm of cells that have been made competent by chemical treatment. The process is dose-dependent and reminiscent of bacterial transformation. Cells that have internalized up to 0.5 μg/mL of nanocrystals do not experience a significant activation of the unfolded protein or SOS responses but undergo oxidative stress when exposed to high QD doses (2.5 μg/mL). Finally, although they are stable in quiescent cells over temperatures ranging from 4 to 42°C, internalized QDs are rapidly diluted by cell division in a process that does not involve TolC-dependent efflux. Taken together, our results suggest that biomimetic QDs based on low toxicity inorganic cores capped by a protein shell are unlikely to cause significant damage to the microbial ecosystem.