Mn-ZIF nanozymes kill tumors by generating hydroxyl radical as well as reversing the tumor microenvironment.

Tumor tissues are well known for their unique high hydrogen peroxide (HO) microenvironment. How to exploit this tumor microenvironment for tumor cell killing is a question. In this study, a Mn-doped metal-organic framework (Mn-ZIF) was constructed. It possesses good peroxidase (POD) activity, which can oxidize tumor-localized HO into hydroxyl radicals (·OH), that possesses the ability to directly kill tumor cells. More surprisingly, experiments the researchers not only observed the tumor-killing effect of Mn-ZIF, but also found it changes in macrophage phenotype in the tumor region. There was an increase in macrophage polarization towards the M1 subtype. This suggests that the tumor-killing effect of Mn-ZIF not only comes from its POD activity, but also regulates the immune microenvironment in the tumor region. In conclusion, the preparation of Mn-ZIF provides a new way for comprehensive tumor therapy.