Silver is an ancient antibiotic that has found many new uses due to its unique properties on the nanoscale. Due to its presence in many consumer products, the toxicity of nanosilver has become a hot topic. This review summarizes recent advances, particularly the molecular mechanism of nanosilver toxicity. The surface of nanosilver can easily be oxidized by O(2) and other molecules in the environmental and biological systems leading to the release of Ag(+), a known toxic ion. Therefore, nanosilver toxicity is closely related to the release of Ag(+). In fact, it is difficult to determine what portion of the toxicity is from the nano-form and what is from the ionic form. The surface oxidation rate is closely related to the nanosilver surface coating, coexisting molecules, especially thiol-containing compounds, lighting conditions, and the interaction of nanosilver with nucleic acids, lipid molecules, and proteins in a biological system. Nanosilver has been shown to penetrate the cell and become internalized. Thus, nanosilver often acts as a source of Ag(+) inside the cell. One of the main mechanisms of toxicity is that it causes oxidative stress through the generation of reactive oxygen species and causes damage to cellular components including DNA damage, activation of antioxidant enzymes, depletion of antioxidant molecules (e.g., glutathione), binding and disabling of proteins, and damage to the cell membrane. Several major questions remain to be answered: (1) the toxic contribution from the ionic form versus the nano-form; (2) key enzymes and signaling pathways responsible for the toxicity; and (3) effect of coexisting molecules on the toxicity and its relationship to surface coating.

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纳米银的分子毒性机理

银是一种古老的抗生素，由于其在纳米尺度上的独特特性，它发现了许多新用途。由于其存在于许多消费品中，纳米银的毒性已成为热门话题。本综述总结了最近的进展，特别是纳米银毒性的分子机制。纳米银的表面很容易被环境和生物系统中的 O(2) 和其他分子氧化，导致释放已知的有毒离子 Ag(+)。因此，纳米银的毒性与Ag(+)的释放密切相关。事实上，很难确定毒性的哪一部分来自纳米形式，哪一部分来自离子形式。表面氧化率与纳米银表面涂层、共存分子，尤其是含硫醇化合物、光照条件、以及纳米银与生物系统中的核酸、脂质分子和蛋白质的相互作用。纳米银已被证明可以穿透细胞并内化。因此，纳米银通常充当细胞内的 Ag(+) 来源。毒性的主要机制之一是它通过产生活性氧引起氧化应激，并对细胞成分造成损害，包括 DNA 损伤、抗氧化酶的激活、抗氧化分子（例如谷胱甘肽）的消耗、蛋白质的结合和失效, 并损伤细胞膜。几个主要问题仍有待回答：（1）离子形式与纳米形式的毒性贡献；(2) 产生毒性的关键酶和信号通路；