NIR-triggered photodynamic therapy via antigen-capturing upconversion nanoparticle enhances cancer immunotherapy
Meng Wang,a,b Lu Wang,a Benqing, Zhou,a,b Feifan Zhou,b Wei R. Chen*a
a Biophotonics Research Laboratory, Center of Interdisciplinary Biomedical Education and Research, College of Mathematics and Science, University of Central Oklahoma, Oklahoma, 73034, USA
b Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
Photodynamic therapy (PDT) as a promising cancer treatment strategy has the ability to induce antitumor immune responses. However, conventional PDT using photosensitizers activated by visible light has limited penetration depth, which attenuates severely the effectiveness of induced immune responses. We developed an NIR-triggered antigen-capturing nano-photosensitizer, using upconversion nanoparticles (NPs), indocyanine green (ICG), Rose Bangel (RB), a photosensitizer, and maleimides (mal) for cancer treatment. NP/ICG/RB-mal can be used not only for photodynamic therapy, but also for cancer immunotherapy though in situ tumor-associated antigens capturing. With ICG, NP/ICG/RB-mal increases the UCNP emission intensity to achieve higher PDT efficiency and, at the same time, enhances photothermal therapy (PTT). Tumor-associated antigens arising from the PDT/PTT can further be captured by NP/ICG/RB-mal in situ, and delivered to antigen-presenting cells (APCs) to induce a tumor-specific immune response. As a result, a remarkable in vivo synergistic therapeutic effect is achieved using NP/ICG/RB-mal under laser irradiation in treating metastatic tumors.