Redox-responsive biodegradable nanogels for photodynamic therapy using Chlorin e6

Recent advances in drug carrier design in the field of photodynamic therapy (PDT) have stimulated the development of numerous sophisticated drug delivery carriers. We developed novel biodegradable and biocompatible nanogels as PDT carriers. The nanogels were synthesized by ATRP technique using inverse miniemulsion and their biodegradability was determined in the presence of glutathione. The model photosensitizer (PS) was encapsulated in the biodegradable nanogels by simple mixing and sonication. The cellular uptake of the PS-loaded nanogels and the cytotoxicity of the nanogels before and after laser irradiation were determined using HeLa cells. The results showed that the Ce6-nanogel complex was well internalized into the tumor cells, and the Ce6-loaded nanogels did not influence on cellular viability of the cells before light irradiation. Under light exposure, however, the Ce6-nanogel complex-treated HeLa cells revealed strong photoactivity. These nanogels may enhance therapeutic efficacy of PSs without any complex chemical modifications with PSs.