Defect-rich sonosensitizers based on CeO2 with Schottky heterojunctions for boosting sonodynamic/chemodynamic synergistic therapy

Abstract

Sonodynamic therapy (SDT) has been recognized as a promising treatment for cancer due to its advantages of superior specificity, non-invasiveness, and deep tissue penetration. However, the antitumor effect of SDT remains restricted by the limited generation of reactive oxygen species (ROS) due to the lack of highly efficient sonosensitizers. In this work, we developed the novel sonosensitizer Pt/CeO_2−xS_x by constructing oxygen defects through S doping and Pt loading in situ. Large amounts of oxygen defects have been obtained by S doping, endowing Pt/CeO_2−xS_x with the ability to suppress electron–hole recombination, further promoting ROS production. Moreover, the introduction of Pt nanoparticles can not only produce oxygen in situ for relieving hypoxia but also form a Schottky heterojunction with CeO_2−xS_x for further inhibiting electron–hole recombination. In addition, Pt/CeO_2−xS_x could effectively deplete overexpressed glutathione (GSH) via redox reactions, amplifying oxidative stress in the tumor microenvironment (TME). Combined with the excellent POD-mimetic activity, Pt/CeO_2−xS_x can achieve highly efficient synergistic therapy of SDT and chemodynamic therapy (CDT). All these findings demonstrated that Pt/CeO_2−xS_x has great potential for cancer therapy, and this work provides a promising direction for designing and constructing efficient sonosensitizers.