The black TiO 2 nanoparticles are synthesized via a facile calcination method combined with an in-situ controllable solid-state reaction approach. The results indicate that the photocatalyst with a narrow band gap of ~ 2.32 eV extends the photoresponse to visible light and near infrared region. And thus more reactive oxygen species can be obtained to induce the cell-killing under 808 nm light triggering. The as-obtained black TiO 2 nanoparticles exhibiting low toxicity, good biocompatibility and high anticancer effect in vitro, is demonstrated as efficient photosensitizers for phototherapy to kill the bladder cancer cells. These findings suggest that the facile synthetic black TiO 2 nanomaterials will have broad application in biomedicine.
Hui Yu,Qing Wang,Xinmiao Zhang,Aliya Tiemuer,Jing Wang,Yuanyuan Zhang,Xiaolian Sun,Yi Liu
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.