Persistent luminescence phosphor as <i>in-vivo</i> light source for tumoral cyanobacterial photosynthetic oxygenation and photodynamic therapy.

Chang, Meiqi; Feng, Wei; Ding, Li; Zhang, Hongguang; Dong, Caihong; Chen, Yu; Shi, Jianlin · Bioact Mater · 2022

basic_science · Level V

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Abstract

Tumor oxygenation level has been regarded as an attractive target to elevate the efficiency of photodynamic therapy (PDT). Cyanobacterial photosynthesis-mediated reversal of tumor hypoxia could enable an oxygen-boosted PDT, but is limited by scant penetration depth and efficiency of external light. Herein, aiming at the dual purposes of reducing biological toxicity induced by long-term light irradiation and alleviating hypoxia, we here introduce a novel-designed CaAl<sub>2</sub>O<sub>4</sub>:Eu,Nd blue persistent luminescence material (PLM) as the <i>in vivo</i> light source after pre-excited <i>in vitro</i>. The ingenious construction of blue-emitting PLM with "optical battery" characteristics activates cyanobacterial cells and verteporfin simultaneously, which performs the successive oxygen supply and singlet oxygen generation without the long-term external excitation, resulting in the modulated tumor hypoxic microenvironment and enhanced photodynamic tumor proliferation inhibition efficiency. Both <i>in vitro</i> cellular assessment and <i>in vivo</i> tumor evaluation results affirm the advantages of self-produced oxygen PDT system and evidence the notable antineoplastic outcome. This work develops an irradiation-free photosynthetic bacteria-based PDT platform for the optimization of both oxygen production capacity and light utilization efficiency in cancer treatment, which is expected to promote the clinical progress of microbial-based photonic therapy.