Critical parameters in the pegylation of gold nanoshells for biomedical applications: an in vitro macrophage study.

Pegylation of gold nanoshells provides an effective means to reduce their reticuloendothelial system (RES) clearance in body. In this study, we perform a parametric investigation on the factors that would affect the macrophage uptake of gold nanoshells with the aim to optimize their pegylation and minimize their macrophage uptake. We synthesized and pegylated the gold nanoshells using methoxy-poly(ethylene glycol)-thiol and employed an in vitro macrophage assay to examine the effect of surface density of poly(ethylene glycol) (PEG), chain length of the PEG, and size of the gold nanoshells on their macrophage uptake.