CaO2 nanomedicines: a review of their emerging roles in cancer therapy

Abstract Metal peroxide-based nanomedicines have emerged as promising theranostic agents for cancer due to their multifunctional properties, including the generation of bioactive small molecules such as metal ions, H 2 O 2 , O 2 , and OH – . Among these metal peroxides, calcium peroxide (CaO 2 ) nanomedicines have attracted significant attention due to their facile synthesis and good biocompatibility. CaO 2 nanoparticles have been explored for cancer treatment through three main mechanisms: (1) the release of O 2 , which helps alleviate tumor hypoxia and enhances oxygen-dependent therapies such as chemotherapy, photodynamic therapy, and immunotherapy; (2) the generation of H 2 O 2 , a precursor for ·OH generation, which enables cancer chemodynamic therapy; and (3) the release of Ca 2+ ions, which induce calcium overload and promote cell apoptosis (called ion-interference therapy). This review provides a comprehensive summary of recent examples of CaO 2 nanoparticle-based cancer therapeutic strategies, as well as discusses the challenges and future directions in the development of CaO 2 nanomedicines for cancer treatment.