Natural Polyphenol–Vanadium Oxide Nanozymes for Synergistic Chemodynamic/Photothermal Therapy

Graphical Anti-cancer nanozymes : Nanozymes comprising natural polyphenol–vanadium oxide nanosheets (TA@VO x NSs) are developed. In this nanosystem, the peroxidase-like activity of VO x provides the possibility to achieve tumor-specific chemodynamic therapy (CDT). As a valid supplement to CDT, NIR absorption enables that TA@VO x NSs can realize NIR light-mediated photothermal therapy (PTT). Such combination of chemodynamic and photothermal activities means that TA@VO x NSs can be applied for effective synergistic CDT/PTT of cancers. The selection of suitable nanozymes with easy synthesis, tumor specificity, multifunction, and high therapeutics is meaningful for tumor therapy. Herein, a facile one-step assembly approach was employed to successfully prepare a novel kind of natural polyphenol tannic acid (TA) hybrid with mixed valence vanadium oxide nanosheets (TA@VO x NSs). In this system, VO x is assembled with TA through metal–phenolic coordination interaction to both introduce superior peroxidase-like activity and high near infrared (NIR) absorption owing to partial reduction of vanadium from V 5+ to V 4+ . The presence of mixed valence vanadium oxide in TA@VO x NSs is proved to be the key for the catalytic reaction of hydrogen peroxide (H 2 O 2 ) to . OH, and the corresponding catalytic mechanism of H 2 O 2 by TA@VO x NSs is proposed. Benefitting from such peroxidase-like activity of TA@VO x NSs, the overproduced H 2 O 2 of the tumor microenvironment allows the realization of tumor-specific chemodynamic therapy (CDT). As a valid supplement to CDT, the NIR absorption enables TA@VO x NSs to have NIR light-mediated conversion ability for photothermal therapy (PTT) of cancers. Furthermore, in vitro and in vivo experiments confirmed that TA@VO x NSs can effectively inhibit the growth of tumors by synergistic CDT/PTT. These results offer a promising way to develop novel vanadium oxide-based nanozymes for enhanced synergistic tumor-specific treatment.