Abstract:

Objective To study the effects of SiO₂ nanoparticles (SiO₂ NPs) on the cell adhesion and migration of HL-7702 cells, and to provide experimental basis for safety evaluation of SiO₂ NPs. Methods The in vitro cultured human normal liver cell line HL-7702 were randomly divided into control and SiO₂ NPs exposure groups at the concentrations of 12.5,25.0,50.0,and 100.0 mg·L^-1,respectively.Transmission electron microscope (TEM) and dynamic light scattering (DLS) method were used to observe the characteristics of SiO₂ NPs.After 24 h exposure,cell adhesion assay was applied to examine the changes of cell adherence;wound healing assay was used to discover the changes of cell migration;the cellular uptake and biodistribution of SiO₂ NPs were observed using TEM. Results Based on the result of TEM,SiO₂ NPs were spherically shaped,uniformly sized and sporadically dispersed with the diameter of (67.42±5.69) nm. The results of DLS method showed that the average hydrated particle size of SiO₂ NPs dispersing in RPMI-1640 serum-free medium was (134.13±2.78) nm,while the hydrated particle sizes of SiO₂ NPs dispersing in RPMI-1640 with 1%,5%,or 10% serum were apparently enlarged.The results of cell adhesion and wound healing assays showed that the adhesion rates and the healing rates of cells could be down-regulated by SiO₂ NPs even under a dose that did not affect the cell viability and membrane integrity(P<0.05),furthermore,the down regulation effect was significantiy increased along with the enlargement of the SiO₂ NPs' concentration. The TEM results showed that after exposed to nontoxic dose of SiO₂ NPs,the cells accumulated a large number of nanoparticles,the particles mostly dispersed in endocytic recycling compartment,and some were in the cytoplasm;some parts of the cell membrans were caved,and the procedure of endocytose could be captured. Conclusion SiO₂ NPs could inhibit the cell adhesion and migration in a dose-dependent manner.

Key words: SiO₂ nanoparticles, HL-7702 cells, cell adhesion, cell migration, cellular uptake