Self-triggered thermoelectric nanoheterojunction for cancer catalytic and immunotherapy

The exogenous excitation requirement and electron-hole recombination are the key elements limiting the application of catalytic therapies. Here a tumor microenvironment (TME)-specific self-triggered thermoelectric nanoheterojunction (Bi_0.5Sb_1.5Te₃/CaO₂ nanosheets, BST/CaO₂ NSs) with self-built-in electric field facilitated charge separation is fabricated. Upon exposure to TME, the CaO₂ coating undergoes rapid hydrolysis, releasing Ca²⁺, H₂O₂, and heat. The resulting temperature difference on the BST NSs initiates a thermoelectric effect, driving reactive oxygen species production. H₂O₂ not only serves as a substrate supplement for ROS generation but also dysregulates Ca²⁺ channels, preventing Ca²⁺ efflux. This further exacerbates calcium overload-mediated therapy. Additionally, Ca²⁺ promotes DC maturation and tumor antigen presentation, facilitating immunotherapy. It is worth noting that the CaO₂ NP coating hydrolyzes very slowly in normal cells, releasing Ca²⁺ and O₂ without causing any adverse effects. Tumor-specific self-triggered thermoelectric nanoheterojunction combined catalytic therapy, ion interference therapy, and immunotherapy exhibit excellent antitumor performance in female mice.