Polymerization-Induced Self-Assembly Generating Vesicles with Adjustable pH-Responsive Release Performance

Stimuli-responsive polymeric vesicles have attracted great attention in drug delivery due to their intrinsic hollow structures and “on demand” release of drugs upon environmental stimuli. The drug-release kinetics from polymeric vesicles, which is usually dependent on the stimuli-responsive behaviors of the polymeric vesicle, has great impacts on the therapeutic efficacy. Over the past decade, polymerization-induced self-assembly (PISA) has been demonstrated to be a powerful strategy to prepare the polymeric vesicles. However, fabrication of stimuli-responsive vesicles with adjustable drug release kinetics via PISA has been rarely reported, which may be due to the poor selectivity of functional membrane-forming polymers in the PISA system. Herein, a series of vesicles with different pH-responsive behaviors were fabricated via RAFT dispersion copolymerization of (diisopropylamino)ethyl methacrylate (DIPEMA) and benzyl methacrylate (BzMA). Both the content of DIPEMA units in hydrophobic P(DIPEMA-co-BzMA) blocks and the DP of P(DIPEMA-co-BzMA) have great influence on the pH-responsive behaviors of the vesicles, which can be used to adjust the responsive release rate of RhB from the vesicles upon the same pH switch.