Upconversion Nanoparticles Hybridized Cyanobacterial Cells for Near‐Infrared Mediated Photosynthesis and Enhanced Photodynamic Therapy.

The hypoxic hallmark of tumor has aroused substantial burdens on a variety of therapeutic modalities including photodynamic therapy (PDT). Recently, biological oxygen evolution enabled by photosynthetic cyanobacterial cells has emerged as one of the most advanced and promising tissue oxygenation strategies, which is particularly beneficial for in situ tumor‐PDT. Herein, a near infrared‐driven PDT platform based on the photosynthetic cyanobacterial cells hybridized with photosensitizer rose bengal (RB)‐loaded upconversion nanoparticles, named as UR‐Cyan cells, is reported. Upon the irradiation of 980 nm laser and its upconversions to shorter wavelengths, the formulated UR‐Cyan cells are both photosynthetically active for oxygen production and photosensitive for the subsequent singlet oxygen generation by the photosensitizer, resulting in enhanced and sustainable PDT efficacy against tumor cells/tissues. The present design offers a practical approach to conquer the hypoxic burden of PDT operations against a wide range of pathological lesions with excellent biocompatibility and clinical promises. [ABSTRACT FROM AUTHOR]