Heterojunction engineered bioactive chlorella for cascade promoted cancer therapy

The hypoxic tumor microenvironment is one of most major hurdles restraining the anti-tumor efficiency of photodynamic therapy (PDT). Herein, active photosynthetic Chlorophyceae (Chlorella, Chl) functionalized with black phosphorus nanosheets (BPNSs) through polyaspartic acid (PASP) and Fe3+ mediating Lego building method are utilized for photocatalyzed oxygen-evolving to realize photosynthesis enhanced synergistic photodynamic/chemodynamic/immune therapy. The Chl cells with inherent photosynthesis and distinct me-tabolites are able to ameliorate tumor hypoxia, enhance immune cells infiltration, and stimulate the proliferation and maturation of immune cells. BPNSs loaded on the surface of Chl cells construct a type-II heterojunction with the chlorophyll in Chl cells, which improves the conversion efficiency of light through thoroughly separating photo-excited electrons and holes for O-1(2) generation and O-2 evolution, respectively. Additionally, the lock be-tween Lego bricks , Fe3+, can both consume glutathione (GSH) and catalyze Fenton reaction with H2O2 to generate .OH, mediating chemodynamic therapy (CDT). Moreover, Chl@BP-Fe also exhibited high biocompat-ibility and potential biodegradability, guaranteeing high potential for clinic applications of this synergistic photodynamic/chemodynamic/immune therapy.

Automated summary

This study explores a new approach of utilizing active photosynthetic Chlorella functionalized with black phosphorus nanosheets for enhanced photodynamic therapy. The functionalized Chlorella improves tumor hypoxia and enhances immune cell activity and proliferation through photosynthesis. Additionally, the black phosphorus nanosheets improve the conversion efficiency of light and mediate chemodynamic therapy. The synergistic therapy shows high biocompatibility and potential biodegradability, suggesting promising clinical applications.