Biochemical Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland, USA.
Nanotoxicology. 2011 Dec;5(4):517-30. doi: 10.3109/17435390.2010.536615. Epub 2010 Dec 13.
To study the toxicity of nanoparticles under relevant conditions, it is critical to disperse nanoparticles reproducibly in different agglomeration states in aqueous solutions compatible with cell-based assays. Here, we disperse gold, silver, cerium oxide, and positively-charged polystyrene nanoparticles in cell culture media, using the timing between mixing steps to control agglomerate size in otherwise identical media. These protein-stabilized dispersions are generally stable for at least two days, with mean agglomerate sizes of ∼23 nm silver nanoparticles ranging from 43-1400 nm and average relative standard deviations of less than 10%. Mixing rate, timing between mixing steps and nanoparticle concentration are shown to be critical for achieving reproducible dispersions. We characterize the size distributions of agglomerated nanoparticles by further developing dynamic light scattering theory and diffusion limited colloidal aggregation theory. These theories frequently affect the estimated size by a factor of two or more. Finally, we demonstrate the importance of controlling agglomeration by showing that large agglomerates of silver nanoparticles cause significantly less hemolytic toxicity than small agglomerates.
为了研究相关条件下纳米颗粒的毒性，在细胞水平的实验中，将纳米颗粒以不同的团聚状态重现性地分散在与细胞实验兼容的水溶液中是至关重要的。在这里，我们使用混合步骤之间的时间间隔来控制团聚体尺寸，从而在相同的介质中分散金、银、氧化铈和带正电荷的聚苯乙烯纳米颗粒。这些由蛋白质稳定的分散体通常至少稳定两天，平均团聚体尺寸约为 23nm 的银纳米颗粒的范围从 43nm 到 1400nm，平均相对标准偏差小于 10%。混合速度、混合步骤之间的时间间隔和纳米颗粒浓度对于实现重现性分散是至关重要的。我们通过进一步开发动态光散射理论和扩散受限胶体聚集理论来描述团聚体纳米颗粒的尺寸分布。这些理论通常会使估计的尺寸偏差增加一个数量级或更多。最后，我们通过证明控制团聚体的重要性来证明，大的银纳米颗粒团聚体比小的团聚体引起的溶血毒性小得多。
