In vitro controlled release of antigen in dendritic cells using pH-sensitive liposome-polymeric hybrid nanoparticles.

A hybrid nanoparticle (NP) consisting of a pH sensitive lipid shell and a poly(lactic-co-glycolic) acid (PLGA) core was constructed. This hybrid NP has a mean size of 120.1 ± 8.8 nm and positively charged surface (zeta potential of 14.2 ± 1.4 mV). The lipid shell of the hybrid NP was quickly disintegrated in buffer with a pH of 5.5, which resembles the acidic environment of endosomes in dendritic cell (DC). Less than 20% of the antigen enclosed in pH-sensitive hybrid NP was released into human serum at physiological pH within 24 h, but more than 40% of the enclosed antigen was released within 8 h after pH was adjusted to 5.5. Fast uptake of the pH sensitive hybrid NP by DC was also observed. It was found that pH sensitive hybrid NP displayed faster degradation and antigen release compared to regular hybrid NPs after uptake by DC.