Frequency upconversion luminescence (FUCL) based on hot-band absorption has attracted considerable attention in bioimaging and
phototherapy fields for deep-seated
cancer treatment. Photoimmunotherapy, a promising therapeutic approach induced by
photodynamic therapy (
PDT), can selectively kill
cancer cells, reverse the immunosuppressive system, boost host immune response, and elicit durable antitumor immunity. To date, few near-infrared organic
photosensitizers for photodynamic
immunotherapy have been reported based on hot-band absorption. Herein, we report an upconversion luminescent
phthalocyanine photosensitizer PdPc(OBu)8 with anti-Stokes emission at 748 nm and highly efficient
singlet oxygen generation with hot-band absorption at 808 nm. Taking advantage of nanoliposomes, FUCL
phthalocyanine nano-
photosensitizers (
PdPc NPs) were obtained to reduce the aggregation-caused quenching and improve water solubility and biocompatibility.
PdPc NPs could be effectively accumulated in
tumor tissues through
intravenous administration, causing FUCL-induced
PDT under 808 nm irradiation. Considering its finite immune responses and
tumor ablation after
PDT, a combination of
PdPc NP-based
PDT with checkpoint inhibitors (anti-PD-L1) for near-infrared photoimmunotherapy has been used to potentiate the antitumor efficacy that could simultaneously ablate primary
tumors and inhibit the progression of distant
tumors. This study can promote the development of upconversion-based
PDT combined with
immunotherapy for
tumor precision
therapy.