Influences of surface coating of PLGA nanoparticles on immune activation of macrophages

BSA was exposed onto the surface of the BSA/PLGA NPs. No degradation of the PLGA NPs was detected after being incubated in artificial lysosomal fluid or with macrophages in a culture medium for 7 days. The innate immune activation behavior of the BSA/PLGA and PEI/PLGA NPs was evaluated by co-incubation with RAW264.7 cells in vitro. PLGA NPs fabricated with different molecular weights of PLGA showed no difference in stimulating RAW264.7 cells. The PEI/PLGA NPs did not show significant immune activation in terms of secretion of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) too. By contrast, the BSA/PLGA NPs induced a significantly higher expression of TNF-α, likely due to the heterogeneous albumin and existence of endotoxin, and the synergistic role of larger uptake of the BSA/PLGA NPs by macrophages.