Smart gold nanoparticles enhance killing effect on cancer cells

Abstract

The present study explored the cellular uptake dynamics, the subcellular location and the internalization mechanisms of gold nanoparticles (GNPs) and glucose-capped GNPs (Glu-GNPs). The cancer radiotherapy-enhancing effects of GNPs were also evaluated. We synthesized the GNPs and Glu-GNPs by the seeding technique. The effects on cellular uptake and the radiosensitizing effect induced by GNPs and Glu-GNPs at lower doses were investigated using two human cancer cell lines (HeLa and MCF-7). The intracellular location of the nanoparticles was analyzed by transmission electron microscopy (TEM). Analysis of cellular apoptosis following GNP-based radiotherapy was performed by flow cytometry and TUNEL assay. Cancer cells took up more Glu-GNPs than naked GNPs and the uptake curve showed size- and cell-dependent uptake. GNPs were mainly located in the cytoplasm and endocytosis is the mechanism behind the internalization of GNPs and Glu-GNPs. Lower doses of GNPs and Glu-GNPs still enhanced the killing effect using X-ray irradiation, although the apoptotic rate was not altered. The results presented in this study provide evidence that Glu-GNPs may have a bright future in tumor-targeted diagnosis and treatment.