Nanotoxicity of Silver Nanoparticles on HEK293T Cells: A Combined StudyUsing Biomechanical and Biological Techniques

摘要

Human embryonic kidney 293T cells (HEK293T cells) before and after treatment with silver nanoparticles (AgNPs) were measured using advanced atomic force microscopy (AFM) force measurement technique, and the biomechanical property of cells was analyzed using a theoretical model. The biomechanical results showed that the factor of viscosity of untreated HEK293T cells reduced from 0.65 to 0.40 for cells exposure to 40 μg/mL of AgNPs. Comet assay indicated that significant DNA damage occurred in the treated cells, measured as tail DNA% and tail moment. Furthermore, gene expression analysis showed that for the cells treated with 40 μg/mL of AgNPs, the antiapoptosis genes Bcl2-t and Bclw were, respectively, downregulated to 0.65- and 0.66-fold of control, and that the proapoptosis gene Bid was upregulated to 1.55-fold of control, which indicates that apoptosis occurred in cells exposed to AgNPs. Interestingly, excellent negative correlations were found between the factor of viscosity and tail DNA%, and tail moment, which suggest that the biomechanical property can be correlated with genotoxicity of nanoparticles on the cells. Based on the above results, we conclude that (1) AgNPs can lead to biomechanicalchanges in HEK293T cells, concomitantly with biological changes includingcell viability, DNA damage, and cell apoptosis; (2) the factor ofviscosity can be exploited as a promising label-free biomechanicalmarker to assess the nanotoxicity of nanoparticles on the cells; and(3) the combination of AFM-based mechanical technique with conventionalbiological methods can provide more comprehensive understanding ofthe nanotoxicity of nanoparticles than merely by using the biologicaltechniques.