Tumor Microenvironment Responsive Chitosan-Coated W-doped MoOx Biodegradable Composite Nanomaterials for Photothermal/chemodynamic Synergistic Therapy

Chemodynamic therapy (CDT), an approach that eradicates tumor cells through the catalysis of hydrogen peroxide (H2O2) into highly toxic hydroxyl radicals (·OH), possesses distinct advantages in tumor specificity and minimal side effects. However, CDT's therapeutic efficacy is currently hampered by the low production efficiency of ·OH. To address this limitation, this study introduces a water-soluble chitosan-coated W-doped MoOx (WMoOx/CS) designed for the combined application of photothermal therapy (PTT) combined with CDT. The W-doped MoOx (WMoOx) was synthesized in one step by the hydrothermal method, and its surface was modified by water-soluble chitosan (carboxylated chitosan, CS) to enhance its biocompatibility. WMoOx boasts a high near-infrared photothermal conversion efficiency of 52.66 %, efficiently transducing near-infrared radiation into heat. Moreover, the Mo4+/Mo5+ and W5+ ions in WMoOx catalyze H2O2 to produce ·OH for CDT, and the Mo5+/Mo6+ and W6+ ions in WMoOx reduce intracellular glutathione levels and prevent the scavenging of ·OH by glutathione. Crucially, the combination of WMoOx/CS and near-infrared light irradiation demonstrates promising synergistic antitumor effects in both in vitro and in vivo models, highlighting its potential for the combined application of PTT and CDT.