The dye-doped SiO2 particles with diameters of 80

160 and 500 nm were prepared by using the St-ber sol-gel method.Cellular uptake of the luminescent SiO2 particles by HepG2 cells and the endocytic pathway were studied by fluorescent microscopy and flow cytometry.Influence of the SiO2 particles on HepG2 cells was tested in terms of cytotoxicity

cell adhesion and migration by MTT assay

cell adhesion assay

the wound healing and transwell assay.According to the results of flow cytometry

the uptake efficiency of the SiO2 particles was significantly decreased when the culture was performed at 4℃ as well as in the presence of sodium azide or amandatine-HCl

while only very limited reduction was observed with the addition of genestein

revealing that the clathrinmediated endocytosis was the main uptake pathway.The MTT assay found that the 80 nm SiO2 particles caused cytotoxicity in a dose-dependent manner

while the 160 nm and 500 nm particles didn’t show significant cytotoxicity in a concentration range of 0 ～ 200 μg/mL.However

the results of the wound healing assay

cell adhesion and transwell assay demonstrate that the cell adhesion and migration were greatly inhibited by uptake of the SiO2 particles regardless of their size

most possibly because the endocytic process leads to disruption of the cytoskeleton.These studies suggest that the effect of endocytosis on functions of cells should also be assessed to evaluate the biocompatibility of nanoparticles.