Nanoparticle Phototherapy in the Era of Cancer Immunotherapy

Phototherapy, including photodynamic therapy and photothermal therapy, exploits light to activate photo-reactions that kill cancer cells. Recent studies show that phototherapy can not only kill irradiated tumor cells, but also elicit a tumor specific immune response. This phenomenon breaks the limitations of conventional phototherapy, and has reinvigorated phototherapy-related research in the era of cancer immunotherapy. Nanoparticles play essential roles in this new campaign for allowing simultaneous delivery of photo-reactive agents and immune modulators. Some nanoparticles are potent adjuvants on their own and can augment anticancer immunity to fight off tumor relapse and metastasis. In this review, we summarize recent advances on exploiting nanoparticle-based photodynamic therapy and photothermal therapy for cancer immunotherapy, with an emphasis on nanoplatform design and functions.