Photosensitizer-conjugated polymeric nanoparticles for redox-responsive fluorescence imaging and photodynamic therapy.

Photosensitizers conjugated with hyaluronic acid via disulfide linkers were developed for biologically activatable near-infrared fluorescence imaging and photodynamic therapy. The nanoparticles prepared from the conjugate are nonfluorescent and nonphototoxic in their native state, but become highly fluorescent and phototoxic in response to reductive agents inside cancer cells.