Interaction of gold nanorods with cell culture media: Colloidal stability, cytotoxicity and cellular death modality

Abstract

Behavior of nanoparticles in biological media is crucial in predicting their cellular responses. In this study, gold nanorods (GNR) were chosen as a model to evaluate the influence of nanoparticle's surface modification and the composition of cell culture media on the colloidal stability and dispersibility of the nanoparticles in media. Optical spectra, zeta potential and hydrodynamic size were measured to evaluate the colloidal stability. The results indicate that incorporation of fetal bovine serum (FBS) into the cell culture media drastically enhanced their colloidal stability by protein adsorption, while nanoparticles dispersed in serum-free media demonstrated obvious aggregation. Nanoparticles dispersed in serum-free media showed high rate and extent of cellular internalization and dose-independent cytotoxicity compared to those dispersed in serum-containing media. Flow cytometry revealed that both late apoptosis and necrosis are responsible for the cellular death of breast cancer cells exposed to well-dispersed GNR in serum-containing media, while cells exposed to nano-aggregates experienced necrosis as the major modality of their cellular death.