Nominal and effective dosimetry of silica nanoparticles in cytotoxicity assays
Nominal and effective dosimetry of silica nanoparticles in cytotoxicity assays
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DOI：
10.1093/toxsci/kfn072
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发表时间：
2008-07-01
影响因子：
3.8
通讯作者：
Martens, Johan A.
中科院分区：
文献类型：
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作者：
Lison, Dominique;Thomassen, Leen C. J.;Martens, Johan A.
由于其尺寸小和比表面积（SA）大，不溶性纳米粒子几乎不受重力影响，通常配制成稳定的悬浮液或溶胶。然而，这在体外检测系统中引发了一个潜在的难题，即贴附在培养容器底部的细胞可能不会接触到悬浮液中的大多数纳米粒子。J. G. 蒂加登等人在2007年的《毒理学杂志》95卷，300 - 312页从理论上探讨了这个问题，强调需要确定有效剂量（影响细胞的粒子质量、数量或表面积剂量），根据他们基于沉降和重力的模型，有效剂量可能仅占标称剂量的极小部分。相反，我们假设由于溶胶中通常会产生对流力，大多数粒子可能会到达靶细胞并发挥其潜在毒性。为了解决这个问题，我们在三个不同的实验室中，将三种不同的细胞系（A549上皮细胞、EAHY926内皮细胞和J774单核巨噬细胞）暴露于单分散的斯托伯二氧化硅纳米粒子（SNP）悬浮液中。使用了四种不同的检测终点（乳酸脱氢酶[LDH]释放、LDH细胞含量、四唑盐[MTT]和结晶紫染色）来评估细胞对纳米粒子的反应。我们发现，在所有细胞系和所有检测终点中，细胞反应由粒子的总质量/数量/表面积以及它们的浓度决定。实际上，对于给定体积的分散液，这两个参数当然是密切相关的。我们得出结论，标称剂量仍然是对分散在水介质中的不溶性SNP进行体外毒性测试的最合适指标。这一观察结果对纳米粒子体外毒理学研究的实验设计和结果解释具有重要意义。
Because of their small size and large specific surface area (SA), insoluble nanoparticles are almost not affected by the gravitational force and are generally formulated in stable suspensions or sols. This raises, however, a potential difficulty in in vitro assay systems in which cells adhering to the bottom of a culture vessel may not be exposed to the majority of nanoparticles in suspension. J. G. Teeguarden et al., 2007, Toxicol. Sci. 95, 300-312 have recently addressed this issue theoretically, emphasizing the need to characterize the effective dose (mass or number or SA dose of particles that affect the cells) which, according to their model based on sedimentation and gravitation forces, might only represent a very small fraction of the nominal dose. We hypothesized, in contrast, that because of convection forces that usually develop in sols, the majority of the particles may reach the target cells and exert their potential toxicity. To address this issue, we exposed three different cell lines (A549 epithelial cells, EAHY926 endothelial cells, and J774 monocyte-macrophages) to a monodisperse suspension of Stober silica nanoparticles (SNP) in three different laboratories. Four different end points (lacticodehydrogenase [LDH] release, LDH cell content, tetrazolium salt (MTT), and crystal violet staining) were used to assess the cell response to nanoparticles. We found, in all cell lines and for all end points, that the cellular response was determined by the total mass/number/SA of particles as well as their concentration. Practically, for a given volume of dispersion, both parameters are of course intimately interdependent. We conclude that the nominal dose remains the most appropriate metric for in vitro toxicity testing of insoluble SNP dispersed in aqueous medium. This observation has important bearings on the experimental design and the interpretation of in vitro toxicological studies with nanoparticles.