A pH-responsive shell-sheddable polymeric nanoparticles as the photodynamic drug carrier: synthesis, characterization, and in vitro studies

Shell-sheddable nanoparticles, composed of amphiphilic blockpolymers, have emerged as an attractive vehicle for the site-specific delivery therapeutic agents. In this study, pH-responsive sheddable copolymers bearing orthoester linker were synthesized via ring-opening polymerization between γ-benzyl-L-glutamate N-carboxyanhydride and orthoester-bearing poly (ethylene glycol) macroinitiator (PEG-pH-NH2). The obtained glycol)-b-poly(γ-benzyl-L-glutamate) (PEG-PBLG) could form stable nanoparticles in aqueous solutions due to nature block copolymers. PEG-PBLG-based nanoparticle exhibited good stability physiological conditions (pH 7.4), whereas was disassembled under acidic 5.0). encapsulate a photosensitizer, protophorphyrin IX (PpIX), deliver it into environments. According optical imaging test, found that quenched fluorescence signal PpIX highly recovered conditions. Acid-responsive rapidly release when they are incubated 5.0), remarkably reduced buffer 7.4). vitro cytotoxicity test showed cells treated with became phototoxic upon irradiation. Microscopic observation demonstrated PpIX-loaded degraded at endosome SCC7 cancer cells, which enabled cells. These results suggest promising carrier photodynamic