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 0.5 Sb 1.5 Te 3 /CaO 2 nanosheets, BST/CaO 2 NSs) with self-built-in electric field facilitated charge separation is fabricated. Upon exposure to TME, the CaO 2 coating undergoes rapid hydrolysis, releasing Ca 2+ , H 2 O 2 , and heat. The resulting temperature difference on the BST NSs initiates a thermoelectric effect, driving reactive oxygen species production. H 2 O 2 not only serves as a substrate supplement for ROS generation but also dysregulates Ca 2+ channels, preventing Ca 2+ efflux. This further exacerbates calcium overload-mediated therapy. Additionally, Ca 2+ promotes DC maturation and tumor antigen presentation, facilitating immunotherapy. It is worth noting that the CaO 2 NP coating hydrolyzes very slowly in normal cells, releasing Ca 2+ and O 2 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. The exogenous excitation requirement and electron-hole pair recombination are the key factors limiting the application of catalytic therapies. Here, the authors address these limitations by designing a tumor microenvironment-specific self-triggered thermoelectric nanoheterojunction with a self-built-in electric field that facilitates charge separation for cancer treatment.