Construction of BaTiO₃-TiO₂ hollow sphere heterojunctions for enhanced microwave dynamic therapy in cancer treatment

Cancer is one of the primary health concerns among humans due to its high incidence rate and lack of effective treatment. Currently, medical techniques to achieve the precise elimination of local cancer lesions with negligible damage to normal tissues are still intensely desired. Herein, we synthesized BaTiO₃-TiO₂ hollow spheres (BTHSs) for use in microwave dynamic therapy (MWDT) for cancer. Under UV irradiation, BTHSs can mediate the production of multiple reactive oxygen species (ROS), mainly ¹O₂, which results in a rapid photocatalytic degradation rate (97%), 1.6-fold that of commercial P25. Importantly, the ROS production process can be triggered by microwaves to effectively execute MWDT for cancer. Under microwave irradiation, BTHSs exhibit a remarkable therapeutic effect and slight cytotoxicity. In terms of mechanism, the enhanced ROS production efficiency of BTHSs can be attributed to their unique hollow structure and the formation of a type-II heterojunction by the incorporation of BaTiO₃. The hollow structure increases the availability of active sites and enhances light scattering, while the BaTiO₃-TiO₂ heterojunction enhances the photocatalytic activity of TiO₂ through charge transfer and electron-hole separation. Overall, this study provides important insights into the design and optimization of sensitizers for MWDT applications.