Division of Toxicology, Wageningen University & Research, P.O. Box 8000, 6700, EA, Wageningen, the Netherlands.
Department of Environmental Geosciences, University of Vienna, 14 Althanstraße, Vienna, 1090, Austria.
Chemosphere. 2022 Sep;302:134909. doi: 10.1016/j.chemosphere.2022.134909. Epub 2022 May 10.
A key aspect in the safety testing of metal nanoparticles (NPs) is the measurement of their dissolution and of the true particle uptake in organisms. Here, based on the tendency of Ag-NP to dissolve and Au-NP to be inert in the environment, we exposed the earthworm Eisenia fetida to Au core-Ag shell NPs (Au@Ag-NPs, Ag-NPs with a Au core) and to both single and combined exposures of non-coated Au-NPs, Ag-NPs, Ag and Au ions in natural soil. Our hypothesis was that the Ag shell would partially or completely dissolve from the Au@Ag-NPs and that the Au core would thereby behave as a tracer of particulate uptake. Au and Ag concentrations were quantified in all the soils, in soil extract and in organisms by inductively coupled plasma mass spectrometry (ICP-MS). The earthworm exposed to Au@Ag-NPs, and to all the combinations of Ag and Au, were analyzed by single particle inductively coupled plasma time-of-flight mass spectrometry (spICP-TOFMS) to allow the quantification of the metals that were truly part of a bimetallic particle. Results showed that only 5% of the total metal amounts in the earthworm were in the bimetallic particulate form and that the Ag shell increased in thickness, suggesting that biotransformation processes took place at the surface of the NPs. Additionally, the co-exposure to both metal ions led to a different uptake pattern compared to the single metal exposures. The study unequivocally confirmed that dissolution is the primary mechanism driving the uptake of (dissolving) metal NPs in earthworms. Therefore, the assessment of the uptake of metal nanoparticles is conservatively covered by the assessment of the uptake of their ionic counterpart.
在金属纳米粒子（NPs）的安全性测试中，一个关键方面是测量它们的溶解和在生物体中的真实颗粒摄取量。在这里，基于 Ag-NP 易溶解和 Au-NP 在环境中惰性的趋势，我们将赤子爱胜蚓暴露于 Au 核-Ag 壳 NPs（Au@Ag-NPs，具有 Au 核的 Ag-NPs）以及非涂覆的 Au-NPs、Ag-NPs、Ag 和 Au 离子在天然土壤中的单一和组合暴露中。我们的假设是，Ag 壳会部分或完全从 Au@Ag-NPs 中溶解，并且 Au 核将作为颗粒摄取的示踪剂。通过电感耦合等离子体质谱法（ICP-MS）在所有土壤、土壤提取物和生物体中定量测定 Au 和 Ag 浓度。用单颗粒电感耦合等离子体质谱飞行时间法（spICP-TOFMS）分析暴露于 Au@Ag-NPs 以及所有 Ag 和 Au 组合的赤子爱胜蚓，以定量测定真正属于双金属颗粒的金属。结果表明，只有 5%的金属总量以双金属颗粒形式存在于蚯蚓中，并且 Ag 壳增厚，表明纳米颗粒表面发生了生物转化过程。此外，与单一金属暴露相比，两种金属离子的共同暴露导致了不同的摄取模式。该研究明确证实，溶解是驱动（溶解）金属 NPs 在蚯蚓中摄取的主要机制。因此，金属纳米粒子摄取的评估保守地涵盖了其离子对应物摄取的评估。
