Green synthesis of broccoli-derived carbon quantum dots as effective photosensitizers for the PDT effect testified in the model of mutant Caenorhabditis elegans .

The clinical application of photodynamic therapy (PDT) is still limited because of the drawbacks of the traditional photosensitizers, such as low singlet oxygen ( 1 O 2 ) quantum yield and the problem of photobleaching. Herein, carbon quantum dots (CQDs) derived from broccoli natural biomass as a carbon source were fabricated via a simple hydrothermal method and showed outstanding PDT ability as an effective photodynamic agent tested in Caenorhabditis elegans ( C. elegans ) models. The as-prepared broccoli-derived CQDs (BCQDs) showed excellent water solubility and optical properties and could generate singlet oxygen ( 1 O 2 ) effectively under irradiated light with a wavelength of 660 nm. The in vivo experiment revealed that the PDT efficiency of the BCQDs was dependent on the induction of germline apoptosis through the cep-1 / p53 pathway. Further investigation confirmed the DNA damage of the worm by the BCQDs after sufficient light irradiation, which was tested by measuring the egl-1 -fold induction in hus-1 (op244), and cep-1 (w40) mutants that have a loss of function in the genes involved in DNA damage response such as hus-1 (DNA checkpoint gene) and cep-1 / p53 (tumor suppressor). The lack of germline apoptosis in the loss of function mutants egl-1 (n487), hus-1 (op244), and cep-1 (w40) exposed to light irradiation compared with the control proved the necessity of these genes in DNA damage-induced germline apoptosis. Therefore, this work has not only provided a new photodynamic agent but also introduced C. elegans as an easy and high-throughput model for the rapid evaluation of the efficiency of PDT.