Tumor microenvironment responsive chitosan-coated W-doped MoO_x biodegradable composite nanomaterials for...

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 MoO_x (WMoO_x/CS) designed for the combined application of photothermal therapy (PTT) combined with CDT. The W-doped MoO_x (WMoO_x) 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 WMoO_x catalyze H₂O₂ to produce ·OH for CDT, and the Mo⁵⁺/Mo⁶⁺ and W⁶⁺ ions in WMoO_x reduce intracellular glutathione levels and prevent the scavenging of ·OH by glutathione. Crucially, the combination of WMoO_x/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.