Predicting the fate of engineered nanoparticles (ENPs) once they are released in the environment is essential to evaluate their impacts to ecosystems. Microbial biofilms, as highly reactive compartments in soils and sediments, have the potential to impose strong controls on ENPs life cycle in natural settings. However, information regarding impacts of biofilms toward ENPs environmental fate are not easily accessible, and such evidences are collected and discussed in this review, in order to identify common trends and to better constrain the role played by these microbial structures. Biofilms are reported to exhibit important ENPs accumulation capacities, and short to long-term ENPs immobilization can thus be expected. Mechanisms that govern such accumulation and ENPs migration within biofilms depend strongly on electrostatic and hydrophobic interactions, as well as biofilm structural properties, such as density and permeability. They are a combination of key parameters that include ENPs size and surface properties, mineral substrate reactivity, ability to develop organic corona around ENPs, or formation of aggregates within the biofilm thickness. In addition, these microbial structures exhibit highly reactive microenvironments, and are consequently able to impose major ENPs transformations such as dissolution, through ligand- or redox-mediated pathways, as well as passivation or stabilization processes. Interestingly, exposure to toxic ENPs can even trigger a response from micro-organisms biofilms which has the potential to strongly modify ENPs speciation. Promising approaches to investigate the role of microbial biofilms for ENPs cycling in realistic systems are introduced through the use of mesocosms, medium-size replicated ecosystems that allow to integrate the complexity of natural settings. Finally, biofilm-mediated nanoparticles synthesis in man-impacted systems is presented. This raises important questions regarding biofilms role as secondary sources of nanoparticles.

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微生物生物膜如何控制工程纳米粒子的环境命运？

预测工程纳米粒子 (ENP) 在环境中释放后的命运对于评估它们对生态系统的影响至关重要。微生物生物膜作为土壤和沉积物中的高反应性隔室，有可能对自然环境中的 ENP 生命周期施加强有力的控制。然而，关于生物膜对 ENP 环境命运影响的信息并不容易获得，本综述收集和讨论了这些证据，以识别共同趋势并更好地限制这些微生物结构所起的作用。据报道，生物膜表现出重要的 ENPs 积累能力，因此可以预期短期到长期的 ENPs 固定。控制生物膜内这种积累和 ENP 迁移的机制在很大程度上取决于静电和疏水相互作用，以及生物膜结构特性，如密度和渗透性。它们是关键参数的组合，包括 ENP 的大小和表面特性、矿物底物反应性、在 ENP 周围形成有机电晕的能力，或在生物膜厚度内形成聚集体。此外，这些微生物结构表现出高度反应性的微环境，因此能够通过配体或氧化还原介导的途径以及钝化或稳定过程施加主要的 ENP 转化，例如溶解。有趣的是，暴露于有毒 ENPs 甚至可以触发微生物生物膜的反应，这有可能强烈改变 ENPs 的形态。研究微生物生物膜在现实系统中对 ENP 循环的作用的有希望的方法是通过使用中型宇宙、中等规模的复制生态系统引入的，这些生态系统允许整合自然环境的复杂性。最后，介绍了人为影响系统中生物膜介导的纳米粒子合成。这提出了关于生物膜作为纳米粒子二次来源的重要问题。