Switching between type I/II photosensitization processes for of an unconventional dye as modulated by the tumor microenvironment for inducing immunogenic death

In this work, an unconventional Se-substituted hemicyanine dye (HCySe-O-NO₂) decorated with a p-nitrophenyl moiety as a recognition site was investigated. Its type I/II photosensitization processes could be regulated by the tumor microenvironment, alleviating the oxygen dependence of conventional photodynamic therapy (PDT) for the treatment of solid tumors. Upon being exposed to 760-nm-wavelength laser irradiation, cancer cells treated with HCySe-O-NO₂ exhibited the phenomenon of pyroptosis, resulting in an amplification of cellular immunogenic death (ICD), and hence demonstrating the potential value of this dye for photoimmunotherapy.