Entry of nanoparticles into cells: the importance of nanoparticle properties

Knowledge of the interactions between nanoparticles (NPs) and cell membranes is of great importance for the design of safe and efficient nanomedicines. Extensive studies aimed at understanding the correlation of NP properties with endocytosis have been carried out in the past few years. Here, we review the recent progress of these studies and provide an overview of the current state of knowledge on the influence of NP size, shape, stiffness and surface chemistry on cellular uptake. Special attention was dedicated to the uptake of non-spherical nanoparticles. Some general principles obtained from these fundamental studies will serve as guidelines for the design of optimised NP for enhanced cellular uptake. Finally, the opportunities for polymer chemists are discussed.