Light triggered oxygen-affording engines for repeated hypoxia-resistant photodynamic therapy.

Hypoxia is the trickiest barrier for oncotherapy, which can cause the resistance of various tumor treatments, even promote cancer progression and metastasis, especially in the treatment of photodynamic therapy (PDT). Therefore, alleviating tumor hypoxia would be a favorable modality to improve PDT treatment. In this study, we designed an innovative biological oxygen-evolving material, autotrophic light-triggered green affording‑oxygen engine (ALGAE), which could perform an on-off switchable and inexhaustible oxygen generation triggered by the same irradiation of PDT with good biocompatibility and degradability. And the hypoxia-resistant PDT induced by ALGAE could successfully eradicate tumors and avoid tumor metastasis. The ALGAE system could be standby in a long period for efficient oxygen-affording around tumors, which not only dramatically alleviated tumor hypoxia but also achieved a high-efficiency and repetitive PDT treatments. Furthermore, the innovative biological oxygen-affording engine described in the study presents a new class of oxygen-generating material for hypoxia-resistant cancer therapy.