Light-Triggered Bismuth-Based Nanosphere as a Dual-Inductive Nanomedicine for Antitumor Immunotherapy

The immunosuppressive microenvironment of the tumor is an important factor that seriously affects the effect of tumor immunotherapy. Programmed cell death, including apoptosis and necroptosis, has shed light on antitumor therapy and could synergistically activate the antitumor immunity. Herein, S-doped bismuth oxide lychee-like nanospheres (BiOSSs) are presented to realize apoptosis- and necroptosis-mediated tumor treatment strategies. Under laser irradiation, BiOSS demonstrated exceptional capabilities in reactive oxygen species generation and heat production. After BiOSS-triggered antitumor phototherapy, the characteristic markers of apoptosis and necroptosis were significantly changed and the cell membrane was damaged. Moreover, BiOSS-induced apoptosis/necroptosis could result in an immune response and obtain exciting treatment effects. The flow cytometry results revealed that costimulatory molecules CD86 and CD80 expressions in dendritic cells (DCs) were increased after BiOSS-triggered apoptosis/necroptosis, indicating DC maturation, further promoting the activation of CD8+ cytotoxic T lymphocytes, finally inhibiting tumor lung metastasis. Overall, BiOSS-triggered phototherapy shows a strategy for antitumor immunotherapy with exciting potential for clinical application.