Aggregation and dispersion of silver nanoparticles in exposure media for aquatic toxicity tests
Aggregation and dispersion of silver nanoparticles in exposure media for aquatic toxicity tests
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DOI：
10.1016/j.chroma.2011.03.034
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发表时间：
2011-07-08
影响因子：
4.1
通讯作者：
Lead, Jamie R.
中科院分区：
文献类型：
--
作者：
Roemer, Isabella;White, Thomas A.;Lead, Jamie R.
银纳米颗粒（AgNPs）目前在工业中被非常广泛地使用，主要是因为它们的抗菌特性，在许多领域中具有应用。一旦释放到环境中，AgNP在任何生态系统中的流动性、生物利用度和毒性都由胶体稳定性决定。已经有各种纳米粒子（NPs）在一系列环境条件下的稳定性或聚集的研究，但很少有充分表征的AgNPs在（生态）毒性研究中使用的介质中的信息。在这项研究中，单分散的7，10和20 nm的柠檬酸盐稳定的银纳米粒子的合成，其特征在于，然后通过流场流分级（FFF）分级和大小，并与动态光散射（DLS）在不同的稀释度的介质中测量由经合组织推荐的大型蚤（水蚤）毒性测试。在24小时内评估了NP的稳定性，在21天内评估的稳定性较低，与OECD D的急性和慢性毒性试验相似。magna.所有颗粒在具有高离子强度（medial）的介质中迅速聚集，导致溶液失去颜色。在大多数情况下，在24小时后可以通过DLS测量颗粒的尺寸，尽管由于样品的聚集和多分散性而无法获得FFF的分形图。将培养基稀释2、5或10倍后，聚集减少，尽管最小的NP在所有培养基条件下都不稳定。培养基稀释至10倍，在没有银纳米颗粒的情况下，没有引起任何损失的流动性或繁殖力的D。magna.这些结果证实，标准OECD培养基导致AgNP聚集，与暴露于完全分散的颗粒相比，这导致生物体暴露水平和暴露颗粒的性质发生变化。撇开剂量度量的问题不谈，在暴露期间浓度的显著和实质性降低表明，文献数据主要是不正确的解释和纳米粒子可能有更大的生物效应比迄今为止所建议的控制不良的暴露。我们建议将标准OECD培养基稀释约1倍。10与这些NP和该测试培养基一起使用，其减少AgNP聚集而不影响测试生物体的活力。(C)2011 Elsevier B.V.保留所有权利。
Silver nanoparticles (AgNPs) are currently being very widely used in industry, mainly because of their anti-bacterial properties, with applications in many areas. Once released into the environment, the mobility, bioavailability, and toxicity of AgNPs in any ecosystem are dominated by colloidal stability. There have been studies on the stability or the aggregation of various nanoparticles (NPs) under a range of environmental conditions, but there is little information on fully characterised AgNPs in media used in (eco)toxicity studies. In this study, monodisperse 7, 10 and 20 nm citrate-stabilised AgNPs were synthesised, characterised and then fractionated and sized by flow field-flow fractionation (FFF) and measured with dynamic light scattering (DLS) in different dilutions of the media recommended by OECD for Daphnia magna (water flea) toxicity testing. Stability of NPs was assessed over 24h, and less so over 21 days, similar time periods to the OECD acute and chronic toxicity tests for D. magna. All particles aggregated quickly in the media with high ionic strength (medial), resulting in a loss of colour from the solution. The size of particles could be measured by DLS in most cases after 24h, although a fractogram by FFF could not be obtained due to aggregation and polydispersity of the sample. After diluting the media by a factor of 2, 5 or 10, aggregation was reduced, although the smallest NPs were unstable under all media conditions. Media diluted up to 10-fold in the absence of AgNPs did not induce any loss of mobility or fecundity in D. magna. These results confirm that standard OECD media causes aggregation of AgNPs, which result in changes in organism exposure levels and the nature of the exposed particles compared to exposure to fully dispersed particles. Setting aside questions of dose metrics, significant and substantial reduction in concentration over exposure period suggests that literature data are in the main improperly interpreted and nanoparticles are likely to have far greater biological effects than suggested thus far by poorly controlled exposures. We recommend that the standard OECD media is diluted by a factor of ca. 10 for use with these NPs and this test media, which reduces AgNP aggregation without affecting the viability of the text organism. (C) 2011 Elsevier B.V. All rights reserved.