Manganese dioxide (MnO2) based nanomaterials for cancer therapies and theranostics

Today, cancer still poses a serious threat to human, but there is no exact cure. Therefore, exploring to accomplish high therapeutic performance is a challenging and urgent task. Since the nanoparticles unique properties were discovered, they have displayed promising potential for more effective therapies and have been widely used in photodynamic therapy (PDT) and radiation therapy (RT). However, some special properties of the tumour microenvironment (TME) have seriously affected the therapeutic outcomes, so the modulation of the TME becomes critical. Manganese dioxide (MnO₂), as a transition metal oxide, has been widely used in biomedical fields with special physical and chemical properties, especially in regulating the TME. Furthermore, MnO₂ has widely applications in various cancer treatments, such as PDT, chemodynamic therapy (CDT), immunotherapy, and some specific collaborative treatment. Herein, we reviewed the recent applications of MnO₂ modified nanomaterials in tumour therapies and theranostics, including TME regulation, controlled drug loading/delivery/release, and imaging.