Platelet-derived exosomes hybrid liposomes facilitate uninterrupted singlet oxygen generation to enhance breast cancer immunotherapy

The development of strategies to maintain the long-term presence of reactive oxygen species in tumor sites remains an urgent issue to be addressed. Here, we design platelet exosome hybrid liposome nanovesicles (named platelet-derived exosome hybrid liposomes co-loaded with DPDPy and chloroperoxidase [DCHL]) co-loading aggregation-induced emission (AIE) photosensitizers and chloroperoxidases to facilitate uninterrupted singlet oxygen (1O2) generation for enhancing breast cancer immunotherapy. When DCHL enters tumor cells, it lyses under external laser irradiation, thus releasing AIE photosensitizers (DPDPy) and chloroperoxidase. Subsequently, chloroperoxidase utilizes hydrogen peroxide (H2O2) and chloride to synthesize HClO, and, as a second step, HClO reacts with H2O2 to form 1O2. Therefore, uninterrupted 1O2 generation is achieved. The experimental results show that DCHL plus light can lead to systemic immune response, increase the proportion of central memory T cells and tumor-infiltrating T cells, and thereby delay tumor recurrence and rechallenge. Overall, the DCHL system provides a good idea for the design of tumor treatment system.