Serum proteins opsonization and phagocytic uptake of PEG-modified PLGA nanoparticles: Effect of particle size

摘要

The purpose of this study is to evaluate the effect of particle size on serum protein opsonization and in vitro macrophage uptake of polyethyleneglycol modified poly (D, L-lactide-co-glycolide) nanoparticles (PEG-PLGA-NPs). PEG-PLGA-NPs were prepared by modified-spontaneous emulsification solvent diffusion (modified-SESD) method. Serum protein adsorptions to PEG-PLGA-NPs were evaluated by bicinchoninic acid (BCA) protein assay and enzyme-linked immunosorbent assay (ELISA). Complement activation was also investigated by ELISA for complement fragments iC3b. Uptake of PEG-PLGA-NPs by macrophages was measured by fluorescence spectrometer. The results showed that serum protein adsorption and complement activation were augmented for nanoparticles with a larger size below 400 nm. Phagocytosis of PEG-PLGA-NPs by murine peritoneal macrophages involved serum-independent and serum-dependent phagocytosis. Serum-independent phagocytosis decreased, while serum-dependent phagocytosis increased with the increase of particle size in the nanometer and submicrometer range. Consequently, nanoparticles with size of about 400 nm were phagocytosed more readily than either smaller or larger particles.