An Asymmetric Near-Infrared-Triggered Nanoplatform for Self-Supplying Oxygen to Enhance Photodynamic Therapy with Real-Time Apoptosis Monitoring

Breast cancer poses a serious threat to the health of women. Although photodynamic therapy (PDT) has the advantages of being a minimally invasive treatment, its efficacy is limited by the shallow tissue penetration depth of visible light, hypoxia in the tumor microenvironment, and lack of real-time treatment monitoring. Herein, we designed an asymmetric nanocomposite material (UCNP@MOF@Pt-mSiO2-Ac-DEVDK-TAMRA). This material uses UCNPs as its core to convert deeply penetrating near-infrared light into visible red and green light. The metal–organic framework (MOF) grown on the UCNP surface acts as a photosensitizer, absorbing red light to efficiently generate reactive oxygen species (ROS) for PDT. Pt nanoparticles loaded on one side via mSiO2 catalytically decompose endogenous H2O2 in the tumor to produce O2, alleviating hypoxia and enhancing PDT efficacy. Moreover, treatment-induced apoptosis activates Caspase-3, which cleaves a specific peptide sequence, leading to the “turn-on” of green emission from the UCNPs and enabling real-time visual feedback on the therapeutic response. In vitro cell experiments have shown that the nanoplatform has good biocompatibility, efficient cell uptake ability, excellent oxygen production, and ROS generation performance and can effectively induce the apoptosis of 4T1 cells and synchronously monitor Caspase-3 activity, providing ideas for the development of integrated antitumor strategies for diagnosis and treatment.