Mn-rich oxide/persistent luminescence nanoparticles achieve light-free generation of singlet oxygen and hydroxyl radicals for responsive imaging and tumor treatment.

X-ray excited persistent luminescence (XEPL) imaging has attracted increasing attention in biomedical imaging due to elimination of autofluorescence, high signal-to-noise ratio and repeatable activation with high penetration. However, optical imaging still suffers from limited for high spatial resolution. Herein, we report Mn-rich manganese oxide (MnO)-coated chromium-doped zinc gallogermanate (ZGGO) nanoparticles (Mn-ZGGOs). Enhanced XEPL and magnetic resonance (MR) imaging were investigated by the decomposition of MnO shell in the environment of tumors. We also evaluated the tumor cell-killing mechanism by detection of reactive oxygen (ROS), lipid peroxidation and mitochondrial membrane potential changes . Furthermore, the biodistribution, imaging and therapy were studied by U87MG tumor-bearing mice. In the tumor region, the MnO shell is quickly decomposed to produce Mn and oxygen (O) to directly generate singlet oxygen (O). The resulting Mn transforms endogenous HO into highly toxic hydroxyl radical (·OH) via a Fenton-like reaction. The Mn ions and ZGGOs also exhibit excellent T-weighted magnetic resonance (MR) imaging and ultrasensitive XEPL imaging in tumors. Both the responsive dual-mode imaging and simultaneous self-supplied O for the production of O and oxygen-independent ·OH in tumors allow for more accurate diagnosis of deep tumors and more efficient inhibition of tumor growth without external activation energy.