In Vivo Cellular Uptake of PEGylated Nanoparticles

Polyethylene glycol (PEG) has been broadly utilized as a strategy in nanoparticle surface functionalization to prolong circulation and reduce nonspecific distribution in drug delivery systems.  Modification of nanoparticles with PEG prevents protein adsorption and opsonization to delay non-specific phagocytosis. Previously we have shown PEG-mediated non-specific cellular uptake is cell-type dependent in a range of cell lines. In this study, we examined the in vivo uptake of polystyrene nanoparticles with varying PEG density on their surface. Unmodified nanoparticles showed high uptake by different cell types while highly PEGylated particles reduced internalization. Nanoparticles with low and intermediate PEG density showed cell-type dependent internalization. Internalization by phagocytes was highly affected by PEG density while epithelial cells internalized particles independent of PEG density.