Isotopically modified silver nanoparticles to assess nanosilver bioavailability and toxicity at environmentally relevant exposures
Isotopically modified silver nanoparticles to assess nanosilver bioavailability and toxicity at environmentally relevant exposures
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DOI：
10.1071/en13141
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发表时间：
2014-05
影响因子：
4.3
通讯作者：
M. Croteau;A. Dybowska;S. Luoma;S. Misra;E. Valsami-Jones
中科院分区：
文献类型：
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作者：
M. Croteau;A. Dybowska;S. Luoma;S. Misra;E. Valsami-Jones
预测纳米技术对环境的影响是复杂的，部分原因是在环境现实的暴露下研究生物体中纳米颗粒的吸收是困难的。通常，需要高接触浓度来检测积累和影响。我们使用标记的银纳米粒子，以确定是否银生物累积响应是线性的浓度可能发生在环境中，以及是否浓度依赖性的变化，在团聚和溶解影响生物利用度。摘要了解纳米技术对环境的影响的一个主要挑战在于研究环境现实暴露浓度下生物体对纳米颗粒的吸收。通常，需要较高的接触浓度才能引发可测量的效应，并检测出超出本底的累积。但示踪技术的应用可以克服这些局限性。在这里，我们首次合成了柠檬酸盐包覆的银纳米粒子，使用的银是99.7%的109银。除了进行反应性和溶解研究，我们评估了这些同位素修饰的银纳米粒子（109银纳米粒子）的生物利用度和毒性的淡水蜗牛在典型的自然条件下。我们发现，109 Ag纳米颗粒的109 Ag的积累是可检测到的组织中的滞水24小时后，暴露于水浓度低至6 ngL-1，以及3小时后的饮食暴露浓度低至0.07μ gL-1。在类似的暴露条件下，未标记的Ag纳米颗粒的银吸收不会被检测到。从与食物混合或分散在水中的109 Ag纳米颗粒中摄取109 Ag的速率在很宽的浓度范围内基本上是线性的。颗粒溶解是最重要的在低水性浓度。我们估计，70%的109 Ag在L.在暴露量<0.1µgL-1时，stagnalis源自新溶解的Ag。在该浓度以上，我们预测80%的生物累积的109 Ag浓度源自109 Ag NP。不清楚结块是否对吸收率有重大影响。
Environmental context Predicting the environmental implications of nanotechnology is complex in part because of the difficulty in studying nanoparticle uptake in organisms at environmentally realistic exposures. Typically, high exposure concentrations are needed to detect accumulation and effects. We use labelled Ag nanoparticles to determine whether Ag bioaccumulation responses are linear over concentrations likely to occur in the environment, and whether concentration-dependent changes in agglomeration and dissolution affect bioavailability. Abstract A major challenge in understanding the environmental implications of nanotechnology lies in studying nanoparticle uptake in organisms at environmentally realistic exposure concentrations. Typically, high exposure concentrations are needed to trigger measurable effects and to detect accumulation above background. But application of tracer techniques can overcome these limitations. Here we synthesised, for the first time, citrate-coated Ag nanoparticles using Ag that was 99.7% 109Ag. In addition to conducting reactivity and dissolution studies, we assessed the bioavailability and toxicity of these isotopically modified Ag nanoparticles (109Ag NPs) to a freshwater snail under conditions typical of nature. We showed that accumulation of 109Ag from 109Ag NPs is detectable in the tissues of Lymnaea stagnalis after 24-h exposure to aqueous concentrations as low as 6ngL–1 as well as after 3h of dietary exposure to concentrations as low as 0.07μgg–1. Silver uptake from unlabelled Ag NPs would not have been detected under similar exposure conditions. Uptake rates of 109Ag from 109Ag NPs mixed with food or dispersed in water were largely linear over a wide range of concentrations. Particle dissolution was most important at low waterborne concentrations. We estimated that 70% of the bioaccumulated 109Ag concentration in L. stagnalis at exposures <0.1µgL–1 originated from the newly solubilised Ag. Above this concentration, we predicted that 80% of the bioaccumulated 109Ag concentration originated from the 109Ag NPs. It was not clear if agglomeration had a major influence on uptake rates.