Size-Dependent Regulation of Intracellular Trafficking of Polystyrene Nanoparticle-Based Drug-Delivery Systems

Nanopartides (NPs) have ahowia great promise as intracellular imaging probes or nanocarriers and are increasingly being used in biomedical applications. A detailed understanding of how NPs get "in and our of cells is important for developing new nanomkterials with improved selectivity and less cytotoxicify. Both cellular and chemical characteristics have been proven to regulate the cellular uptake of NPs. However, the exocytosis Ness and its regulation are less explored. Herein, we investigated the size-regulated endocytosis and exocytosis of carboxylated polystyrene (PS). NPs, PS NPs with a smaller site were endocytosed mainly through the clathrin-dependent pathlway, whereas PS NPs with a larger size preferred caveolae-mediated endocytosis, Furthermore, our results revealed exocytosis of larger PS NPs and tracked the dynamic process at the single-particle level. These results a indicate that particle size is a key factor for the regulation intracellular trafficking of NPs and provide new insight into the :development of more effective cellular nanocarriers.