a School of Chemical Engineering , UNSW Australia , Sydney , Australia.
b School of Biotechnology and Biomolecular Sciences , UNSW Australia , Sydney , Australia.
Nanotoxicology. 2018 Apr;12(3):263-273. doi: 10.1080/17435390.2018.1434910. Epub 2018 Feb 15.
Nanosilver (Ag NPs) is currently one of the most commercialized antimicrobial nanoparticles with as yet, still unresolved cytotoxicity origins. To date, research efforts have mostly described the antimicrobial contribution from the leaching of soluble silver, while the undissolved solid Ag particulates are often considered as being microbiologically inert, serving only as source of the cytotoxic Ag ions. Here, we show the rapid stimulation of lethal cellular oxidative stress in bacteria by the presence of the undissolved Ag particulates. The cytotoxicity characteristics are distinct from those arising from the leached soluble Ag, the latter being locked in organic complexes. The work also highlights the unique oxidative stress-independent bacterial toxicity of silver salt. Taken together, the findings advocate that future enquiries on the antimicrobial potency and also importantly, the environmental and clinical impact of Ag NPs use, should pay attention to the potential bacterial toxicological responses to the undissolved Ag particulates, rather than just to the leaching of soluble silver. The findings also put into question the common use of silver salt as model material for evaluating bacterial toxicity of Ag NPs.
纳米银（Ag NPs）是目前商业化应用最广泛的抗菌纳米颗粒之一，但其中细胞毒性的起源仍未得到解决。迄今为止，大多数研究都描述了可溶银浸出对其抗菌作用的贡献，而不溶性固体 Ag 颗粒通常被认为在微生物学上是惰性的，仅作为细胞毒性 Ag 离子的来源。在这里，我们展示了不溶性 Ag 颗粒的存在会迅速刺激细菌产生致命的细胞氧化应激。其细胞毒性特征与可浸出可溶性 Ag 引起的细胞毒性特征明显不同，后者被锁定在有机复合物中。这项工作还强调了银盐具有独特的氧化应激无关的细菌毒性。总之，这些发现表明，未来对 Ag NPs 的抗菌效力以及更重要的是其环境和临床影响的研究，应该关注到细菌对不溶性 Ag 颗粒的潜在毒理学反应，而不仅仅是可溶银的浸出。这些发现也对将银盐作为评价 Ag NPs 细菌毒性的模型材料的常用做法提出了质疑。
