Photosensitizer-immunotherapy integrated microneedles for preventing tumor recurrence and metastasis

Microneedles-based tumor therapy has obtained much focus in both biomedical research and clinical applications, while their efficient and synergetic strategy with minimal adverse effects remains highly expected. Herein, we develop a novel photosensitizer-immunotherapy integrated microneedles (MNs) with the required functions to prevent breast cancer recurrence and metastasis after surgery. Utilizing the enhanced penetration capability of MNs, the nanophotosensitizers with significant photodynamic and photothermal effects can be precisely targeted delivered and aggregated in the deep residual tumor tissue. Besides, with the hyperthermia of infrared ray (NIR) irradiation, the penetrated MNs can melt to release intrinsic photosensitizer in situ, achieving controllable drug release. As the reactive oxygen species and local hyperthermia generated from NIR-triggered nanophotosensitizers can induce the immunogenic death of residual cancer cells and evoke DCs maturation for system immunity, the proposed MNs can effectively protect against local tumor relapse and distant metastasis synergy with immune checkpoint inhibitors in the murine model. Thus, we believe that the photosensitizer-immunotherapy integrated MNs hold great potential for clinical translation.