Triple-Jump Photodynamic Theranostics: MnO2 Combined Upconversion Nanoplatforms Involving a Type-I Photosensitizer with Aggregation-Induced Emission Characteristics for Potent Cancer Treatment

The development of multifunctional nanoplatforms has been recognized as a promising strategy for potent photodynamic theranostics. Aggregation-induced emission (AIE) photosensitizers undergoing Type-I reactive oxygen species (ROS) generation pathway appear as potential candidates due to their capability of hypoxia-tolerance, efficient ROS production, and fluorescence imaging navigation. To further improve their performance, a facile and universal method of constructing a type of glutathione (GSH)-depleting and near-infrared (NIR)-regulated nanoplatform for dual-modal imaging-guided photodynamic therapy (PDT) is presented. The nanoplatforms are obtained through the coprecipitation process involving upconversion nanoparticles (UCNPs) and AIE-active photosensitizers, followed by in situ generation of MnO2 as the outer shell. The introduction of UCNPs actualizes the NIR-activation of AIE-active photosensitizers to produce center dot OH as a Type-I ROS. Intracellular upregulated GSH-responsive decomposition of the MnO2 shell to Mn2+ realizes GSH-depletion, which is a distinctive approach for elevating intracellular center dot OH. Meanwhile, the generated Mn2+ can implement T-1-weighted magnetic resonance imaging (MRI) in specific tumor sites, and mediate the conversion of intracellular H2O2 to center dot OH. These outputs reveal a triple-jump center dot OH production, and this approach brings about distinguished performance in FLI-MRI-guided PDT with high-efficacy, which presents great potential for future clinical translations.