Tumor microenvironment-activated single-atom platinum nanozyme with HO self-supplement and O-evolving for tumor-specific cascade catalysis chemodynamic and chemoradiotherapy.

Nanozyme-based tumor collaborative catalytic therapy has attracted a great deal of attention in recent years. However, their cooperative outcome remains a great challenge due to the unique characteristics of tumor microenvironment (TME), such as insufficient endogenous hydrogen peroxide (HO) level, hypoxia, and overexpressed intracellular glutathione (GSH). Herein, a TME-activated atomic-level engineered PtNC single-atom nanozyme (PtNC-SAzyme) is fabricated to induce the "butterfly effect" of reactive oxygen species (ROS) through facilitating intracellular HO cycle accumulation and GSH deprivation as well as X-ray deposition for ROS-involving CDT and O-dependent chemoradiotherapy.