Department of Mechanical and Aerospace Engineering, University of California, Davis, CA 95616, USA.
Nanotoxicology. 2012 Dec;6:837-46. doi: 10.3109/17435390.2011.625131. Epub 2011 Dec 12.
Aggregation of metal oxide nanoparticles in aqueous media complicates interpretation of in vitro studies of nanoparticle-cell interactions. We used dynamic light scattering to investigate the aggregation dynamics of iron oxide and zinc oxide nanoparticles. Our results show that iron oxide particles aggregate more readily than zinc oxide particles. Pretreatment with serum stabilises iron oxide and zinc oxide nanoparticles against aggregation. Serum-treated iron oxide is stable only in pure water, while zinc oxide is stable in water or cell culture media. These findings, combined with zeta potential measurements and quantification of proteins adsorbed on particle surface, suggest that serum stabilisation of iron oxide particles occurs primarily through protein adsorption and resulting net surface charge. Zinc oxide stabilisation, however, also involves steric hindrance of particle aggregation. Fluid shear at levels used in flow experiments breaks up iron oxide particle aggregates. These results enhance our understanding of nanoparticle aggregation and its consequences for research on the biological effects of nanomaterials.
金属氧化物纳米颗粒在水介质中的聚集，使得纳米颗粒与细胞相互作用的体外研究的解释变得复杂。我们使用动态光散射研究了氧化铁和氧化锌纳米颗粒的聚集动力学。结果表明，氧化铁颗粒比氧化锌颗粒更容易聚集。用血清预处理可以稳定氧化铁和氧化锌纳米颗粒，防止聚集。经血清处理的氧化铁仅在纯水中稳定，而氧化锌在水或细胞培养基中稳定。这些发现，结合动电电位测量和颗粒表面吸附蛋白的定量分析，表明氧化铁颗粒的血清稳定主要是通过蛋白质吸附和净表面电荷实现的。然而，氧化锌的稳定还涉及颗粒聚集的空间位阻。在流动实验中使用的流体剪切力会破坏氧化铁颗粒的聚集物。这些结果增强了我们对纳米颗粒聚集及其对纳米材料生物效应研究的影响的理解。
