The use of manufactured nanomaterials is rapidly increasing, while our understanding of the consequences of releasing these materials into the environment is still limited and many questions remain, for example, how do nanoparticles affect living organisms in the wild? How do organisms adapt and protect themselves from exposure to foreign materials? How does the environment affect the performance of nanoparticles, including their surface properties? In an effort to address these crucial questions, our main aim has been to probe the effects of aquatic organisms on nanoparticle aggregation. We have, therefore, carried out a systematic study with the purpose to disentangle the effects of the freshwater zooplankter, Daphnia magna, on the surface properties, stability, and aggregation properties of gold (Au) nanoparticles under different aqueous conditions as well as identified the proteins bound to the nanoparticle surface. We show that Au nanoparticles aggregate in pure tap water, but to a lesser extent in water that either contains Daphnia or has been pre-conditioned with Daphnia. Moreover, we show that proteins generated by Daphnia bind to the Au nanoparticles and create a modified surface that renders them less prone to aggregation. We conclude that the surrounding milieu, as well as the surface properties of the original Au particles, are important factors in determining how the nanoparticles are affected by biological metabolism. In a broader context, our results show how nanoparticles released into a natural ecosystem become chemically and physically altered through the dynamic interactions between particles and organisms, either through biological metabolism or through the interactions with biomolecules excreted by organisms into the environment.

中文翻译：

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水蚤（Daphnia magna）对金纳米粒子的分解。

人造纳米材料的使用正在迅速增加，而我们对将这些材料释放到环境中的后果的理解仍然有限，并且仍然存在许多问题，例如，纳米颗粒如何影响野生生物？生物如何适应和保护自己免受异物影响？环境如何影响纳米颗粒的性能，包括其表面性能？为了解决这些关键问题，我们的主要目的是探究水生生物对纳米粒子聚集的影响。因此，我们进行了系统的研究，目的是弄清淡水浮游动物水蚤（Daphnia magna）的影响。，在不同的水性条件下金（Au）纳米粒子的表面性质，稳定性和聚集性质，并鉴定了与纳米粒子表面结合的蛋白质。我们表明，金纳米粒子在纯净自来水聚集，但在水中在较小程度上，要么包含水蚤或已与预调节水蚤。此外，我们证明了水蚤产生的蛋白质结合到Au纳米颗粒上并形成修饰的表面，使它们不易聚集。我们得出的结论是，周围环境以及原始Au颗粒的表面特性是决定纳米颗粒如何受到生物代谢影响的重要因素。在更广泛的背景下，我们的结果表明，释放到自然生态系统中的纳米颗粒如何通过颗粒与生物之间的动态相互作用，通过生物代谢或与生物排泄到环境中的生物分子的相互作用，发生化学和物理变化。