Bandgap-Tunable CeO_x@MnO_x Heterojunction for Modulable Sonodynamic and Chemodynamic Tumor Therapy.

Abstract

Sonodynamic therapy (SDT) has emerged as a promising non-invasive anticancer strategy with deep tissue penetration. However, conventional sonosensitizers often exhibit limited efficacy, largely due to wide bandgaps that promote rapid electron-hole recombination and poor tumor microenvironment responsiveness. To overcome these limitations, we designed a series of CeO_x@MnO_x heterojunction nanomaterials (CM-1, CM-2, CM-3 and CM-4) with tunable content of MnO_x. Heterojunction engineering effectively modulated the inner structure, narrowed the bandgaps and suppressed charge recombination under ultrasound. Therefore, the sonodynamic performance can be manipulated upon changing the contents. As one of the heterojunction with markedly excellent performance, CM-3 has been proved to possess the narrowest bandgap and optimal activity. Additionally, CM-3 exhibited chemodynamic function, catalyzing H₂O₂ to produce •OH and O₂, which alleviated hypoxia and depleted glutathione for synergistic chemodynamic therapy. This work presents a novel nanotheranostic platform and establishes a basis for applying heterojunction band engineering in biomedicine.