Chlorella-derived natural photosynthetic system for in situ energy metabolism enhancement in cardiomyocytes

Myocardial ischemia (MI), caused by insufficient blood supply, is a pathological condition where cardiomyocytes lack oxygen and energy supply. Herein, we developed a natural photosynthetic system (HCU) consisting of chlorella pyrenoidosa (C. pyre), hyaluronic acid methacryloyl (HAMA) and degradable upconversion nanoparticles (UCNPs, NaCeF4:Yb,Tm,Zr). Upon near-infrared irradiation, HCU was photo-crosslinked in situ, thereby facilitating C. pyre photosynthetic oxygen generation within the myocardium. Concurrently, cytochrome c oxidase (CCO) in mitochondria was activated to enhance electron transport along the respiratory chain, synergistically boosting cardiac energy metabolism. Consequently, the ATP levels were elevated, and the hypoxic microenvironment was mitigated. In MI mouse models, echocardiography readings returned to normal levels, and the infarct size was significantly reduced following a 7-day treatment with HCU. Based on the photosynthetic system, this study proposes an in situ oxygen and energy metabolic regulation strategy for MI, holding certain inspiration for other ischemia diseases. Myocardial ischemia is a pathological condition where cardiomyocytes lack oxygen and energy supply. Here, Cheng et al. develop a photosynthetic system consisting of Chlorella pyrenoidosa (C. pyre) and upconversion nanoparticles encapsulated in a hydrogel, which upon exposure to near-infrared light, enables oxygen production by C. pyre to alleviate the hypoxic myocardial environment.