Rational design of a meso phosphate-substituted pyronin as a type I photosensitizer for photodynamic therapy

Type I photodynamic therapy (PDT) with less oxygen consumption shows great potential to overcome the malignant hypoxia in solid tumors. Herein, a novel meso phosphate-substituted pyronin PY-P and its nanoparticles (PY-P NPs) were prepared as an efficient type I organic photosensitizer. The in vivo data prove that PY-P NPs have outstanding low dark toxicity but high photocytotoxicity under hypoxia (<1% O2).