Pericellular matrix plays an active role in retention and cellular uptake of large-sized nanoparticles.

As the outmost coating of cells, the pericellular matrix (PCM) involved in various cellular functions has been exploited previously to be able to accumulate 120 nm Au nanoparticles (NPs), adjust their diffusion coefficient similar to that of membrane receptors, and enhance their uptake efficiency. In this study, the interactions between PCM and NPs with different sizes and materials were systematically investigated. We found that PCM can selectively enhance the retention and cellular uptake of NPs with diameters from 50 to 180 nm, but has no enhancement effect for 20 nm NPs. Identical behaviors of PCM was observed for both Au NPs and polystyrene NPs, indicating that this unique phenomenon is more related to the dimensions of the NPs. The study of single-particle tracking of 50-180 nm NPs on the surface of thick PCM cells revealed that PCM actively adjusts the diffusion coefficient of NPs to ∼0.1 µm(2)/s regardless of their sizes. By blocking the receptor-mediated endocytosis (RME) pathway with four different inhibitors, this active role of PCM can be effectively suppressed, further confirming that the trapping and retention of NPs by PCM is an inherent biological function. These findings provided new insights for better understanding of the RME pathway and may have promising NP-based applications for controlled drug delivery and therapy in biomedicine.