Singlet Oxygen Generation in Dark‐Hypoxia by Catalytic Microenvironment‐Tailored Nanoreactors for NIR‐II Fluorescence‐Monitored Chemodynamic Therapy

Abstract

AbstractSinglet oxygen (1O2) has a potent anticancer effect, but photosensitized generation of1O2is inhibited by tumor hypoxia and limited light penetration depth. Despite the potential of chemodynamic therapy (CDT) to circumvent these issues by exploration of1O2‐producing catalysts, engineering efficient CDT agents is still a formidable challenge since most catalysts require specific pH to function and become inactivated upon chelation by glutathione (GSH). Herein, we present a catalytic microenvironment‐tailored nanoreactor (CMTN), constructed by encapsulating MoO42−catalyst and alkaline sodium carbonate within liposomes, which offers a favorable pH condition for MoO42−‐catalyzed generation of1O2from H2O2and protects MoO42−from GSH chelation owing to the impermeability of liposomal lipid membrane to ions and GSH. H2O2and1O2can freely cross the liposomal membrane, allowing CMTN with a built‐in NIR‐II ratiometric fluorescent1O2sensor to achieve monitored tumor CDT.