Overcoming ROS Resistance of Photodynamic Therapy with Self‐Assembled Nano‐Prodrugs for Efficient Triple‐Negative Breast Cancer

Abstract Triple‐negative breast cancer (TNBC) is endowed with a highly aggressive nature that results in distant metastases and high recurrence rates, yet limited success is realized in traditional chemotherapy. Activatable photosensitizers (PSs) may provide an effective and non‐invasive strategy to induce TNBC cell death in a precise way by offering stimuli‐responsive reactive oxygen species (ROS). However, the toxicity of ROS is often mitigated and even devitalized by the instinctive behavior of ROS resistance in TNBC cells. To address this issue, herein a small molecular self‐assembly nano‐prodrug is presented to co‐deliver an activatable PS and ROS resistance inhibitor. In TNBC cells, the overexpressed glutathione can disassemble the nano‐prodrug, thereby releasing ROS resistance inhibitor and activating the PS for photodynamic therapy and fluorescence imaging. A hybrid membrane coating‐assisted nanoparticle formation strategy is further demonstrated for efficient inhibition of tumor growth and distant metastases on both subcutaneous and orthotopic TNBC mice models.