pH-responsive biodegradable nanozymes for mild NIR-II hyperthermia-enhanced tumor-specific chemotherapy and chemodynamic therapy

Although nanozymes are extensively utilized in chemodynamic therapy (CDT), their limited catalytic activity in conjunction with the complicated tumor microenvironment severely hinder the efficacy of CDT. Furthermore, the pursuit of a highly efficient nanozyme with pH-responsive biodegradability remains a formidable obstacle. Herein, this work reports the fabrication of DOX loaded CoSnO 3 (DOX/CoSnO 3 ) nanoplatforms for the mild NIRII photothermal therapy (PTT)-enhanced CDT and chemotherapy. The cascade amplification of reactive oxygen species generation efficiency is realized by the Co 2 + -mediated peroxidase (POD)-like and Sn 4 + -facilitated glutathione peroxidase (GSH-px)-like catalytic activities. The obtained CoSnO 3 also exhibited efficient NIR-II photothermal performances, which is beneficial to the further improvement of their catalytic activities. The prepared CoSnO 3 nanocubes could act as an excellent stimulate-responsive drug delivery system to achieve the tumor-specific release of DOX owing to the pH-responsive degradation features. In addition, the mild hyperthermia could further enhance the release kinetics of DOX to amplify the therapeutic effects. Complete tumor eradication is achieved through the mild hyperthermia-augmented CDT and chemotherapy. This study highlights the utilization of pH-responsive biodegradable nanozymes with high-efficiency photothermal properties as a drug delivery system, enabling tumor-specific drug release for efficient tumor therapy.