Department of Environmental and Molecular Toxicology, the Sinnhuber Aquatic Research Laboratory and the Environmental Health Sciences Center at Oregon State University, and Safer Nanomaterials and Nanomanufacturing Initiative, Oregon Nanoscience and Microtechnologies Institute, Corvallis, OR.
Nanotechnology. 2013 Mar 22;24(11):115101. doi: 10.1088/0957-4484/24/11/115101. Epub 2013 Feb 28.
The mechanism of action of silver nanoparticles (AgNPs) is unclear due to the particles' strong tendency to agglomerate. Preventing agglomeration could offer precise control of the physicochemical properties that drive biological response to AgNPs. In an attempt to control agglomeration, we exposed zebrafish embryos to AgNPs of 20 or 110 nm core size, and polypyrrolidone (PVP) or citrate surface coatings in media of varying ionic strength. AgNPs remained unagglomerated in 62.5 μM CaCl2 (CaCl2) and ultrapure water (UP), but not in standard zebrafish embryo medium (EM). Zebrafish embryos developed normally in the low ionic strength environments of CaCl2 and UP. Exposure of embryos to AgNPs suspended in UP and CaCl2 resulted in higher toxicity than suspensions in EM. 20 nm AgNPs were more toxic than 110 nm AgNPs, and the PVP coating was more toxic than the citrate coating at the same particle core size. The silver tissue burden correlated well with observed toxicity but only for those exposures where the AgNPs remained unagglomerated. Our results demonstrate that size- and surface coating-dependent toxicity is a result of AgNPs remaining unagglomerated, and thus a critical-design consideration for experiments to offer meaningful evaluations of AgNP toxicity.
由于银纳米粒子（AgNPs）强烈的团聚倾向，其作用机制尚不清楚。防止团聚可以精确控制驱动 AgNPs 产生生物响应的物理化学性质。为了控制团聚，我们将斑马鱼胚胎暴露于具有 20 或 110nm 核心大小的 AgNPs 以及多聚吡咯烷酮（PVP）或柠檬酸表面涂层的不同离子强度的介质中。AgNPs 在 62.5μM CaCl2（CaCl2）和超纯水中（UP）保持不团聚，但在标准斑马鱼胚胎培养基（EM）中不团聚。斑马鱼胚胎在 CaCl2 和 UP 的低离子强度环境中正常发育。在 UP 和 CaCl2 悬浮液中暴露于 AgNPs 的胚胎比在 EM 悬浮液中暴露的胚胎毒性更高。20nm 的 AgNPs 比 110nm 的 AgNPs 毒性更大，而相同颗粒核心尺寸的 PVP 涂层比柠檬酸涂层毒性更大。银组织负担与观察到的毒性相关性良好，但仅在 AgNPs 保持不团聚的情况下才如此。我们的结果表明，大小和表面涂层依赖性毒性是由于 AgNPs 保持不团聚所致，因此对于提供有意义的 AgNP 毒性评估的实验而言，这是一个关键的设计考虑因素。
