Long retention of therapeutic agents in
tumors is imperative for improving the therapeutic index. In this work, the GSH responsive
porphyrin molecule (TPP 1) was synthesized, which is amphiphilic and linked by a
disulfide bond. TPP 1 molecules could self-assemble into nanoparticles (TPP 1 NPs) with a size of about 100 nm in aqueous
solution. The TPP 1 NPs exhibited high stability under different conditions and could form into large microparticles in the presence of
glutathione (GSH). The TPP 1 NPs could be internalized by
cancer cells, and they emitted enhanced red fluorescence compared to that of TPP 2 NPs (non-sensitive NPs) when cells were pretreated with GSH. In addition, in vitro MTT assays showed that TPP 1 NPs were biocompatible and could further be used as
photosensitizers in nanoparticle formation. The cellular photodynamic activity of TPP 1 NPs was obviously higher than that of TPP 2 NPs, due to the increasing retention of TPP in
cancer cells, which will generate more
reactive oxygen species in
cancer cells under light irradiation. These results highlight the potential of developing stimulus responsive nanoparticles for enhanced retention and improved therapeutic outcome.