Cell density-dependent accumulation of low polarity gold nanocluster in cultured vascular endothelial cells.

Abstract

We have previously reported the cytotoxicity and various biological responses of organic-inorganic hybrid molecules. However, because all the molecules used were electrophilic, the effect of the hybrid molecule without electrophilicity remains unclear. The glutathione-protected gold nanocluster, Au25(SG)18, is an organic-inorganic hybrid molecule that shows a low intramolecular polarity and high stability. In this study, we examined the cytotoxicity and intracellular accumulation of Au25(SG)18 in cultured vascular endothelial cells and compared these characteristics with those of negatively charged gold nanoparticles (AuNPs). Both Au25(SG)18 and AuNPs accumulated in vascular endothelial cells in a dose-dependent manner without cytotoxicity and more accumulation was observed at low cell densities. However, Au25(SG)18 accumulated significantly less than AuNPs in the cells. These results suggest that the intramolecular polarity of organic-inorganic hybrid molecules could regulate intracellular accumulation.