Aging reduces the toxicity of pristine but not sulphidised silver nanoparticles to soil bacteria
Aging reduces the toxicity of pristine but not sulphidised silver nanoparticles to soil bacteria
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DOI：
10.1039/c8en00054a
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发表时间：
2018-11
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影响因子：
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通讯作者：
C. Schultz;Joanna Gray;R. Verweij;M. Busquets-Fité;V. Puntes;C. Svendsen;E. Lahive;M. Matzke
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文献类型：
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作者：
C. Schultz;Joanna Gray;R. Verweij;M. Busquets-Fité;V. Puntes;C. Svendsen;E. Lahive;M. Matzke
在环境中，工程化纳米颗粒（ENPs）会经历化学和物理转化过程。因此，要了解它们的影响，重要的是要考虑如何生物利用度和毒性的影响，这些“老化”的转换与环境条件和ENP的属性。在这里，两个土壤细菌暴露于银ENPs在ISO介质（±富里酸）和土壤孔隙水提取物与pH 6和pH 8。测试的ENP为49 nm未官能化、柠檬酸盐稳定化（Ag-citr）、58 nm PVP涂覆（Ag-PVP）和36 nm硫化（Ag 2S-PVP）; AgNO 3用作阳性对照。使用原始（未老化）和24小时老化的ENP以及24小时可溶性级分进行暴露。总体毒性大小为AgNO 3> Ag-PVP ≥ Ag-citr> Ag 2S。AgNO_3、Ag-PVP和Ag-citr在ISO介质中老化后与未老化时相比变化不大，生长抑制主要是由可溶性银引起的。添加富里酸降低老化后的银毒性，并减少溶解的贡献，在土壤孔隙沃茨的情况下，毒性不能归因于离子银。Ag_2S对A.两种ISO变体中的球状体在老化后增加，但遵循与孔隙沃茨的金属ENP相同的模式。对于所有ENPs pH值的影响是物种依赖性的。总之，这些数据表明，老化降低了有机物质介质中的毒性，尽管可溶性银是标准ISO介质中原始ENP毒性的主要驱动因素，但溶解并不能完全解释有机物质存在下的毒性。
In the environment engineered nanoparticles (ENPs) are subject to chemical and physical transformation processes. Thus, to understand their impact, it is important to consider how bioavailability and toxicity are influenced by these “aging” transformations with relation to environmental conditions and ENP properties. Here, two soil bacteria were exposed to Ag ENPs in ISO media (± fulvic acid) and soil pore water extracts with pH 6 and pH 8. The ENPs tested were 49 nm unfunctionalised, citrate stabilised (Ag-citr), 58 nm PVP-coated (Ag-PVP) and 36 nm sulphidised (Ag2S-PVP); AgNO3 was used as a positive control. Exposures were carried out using pristine (unaged) and 24 h aged ENPs, and the 24 h soluble fraction. Overall, toxicity was ranked AgNO3 > Ag-PVP ≥ Ag-citr ≫ Ag2S. Aging of AgNO3, Ag-PVP and Ag-citr in the ISO medium caused little change from unaged exposures and growth inhibition was mainly caused by soluble silver. Added fulvic acid decreased silver toxicity after aging and reduced the contribution of dissolution; as was the case in the soil pore waters where toxicity could not be attributed to ionic silver. Ag2S toxicity to A. globiformis in both ISO variants increased after aging, yet followed the same patterns as the metallic ENPs in the pore waters. For all ENPs pH effects were species dependent. Together this data showed that aging reduced toxicity in media with organic matter and despite soluble silver being the main driver of pristine ENP toxicity in the standard ISO medium, dissolution did not fully explain toxicity in the presence of organic matter.