In-situ NO release and conversion for highly efficient synergistic gas therapy and phototherapy

In this paper, simple nitrated carbon dots (CDs-NO) were prepared as NO donor as well as photosensitizer to integrate gas therapy and phototherapy therapy into one nanoparticle. Firstly, carbon nanodots (CDs) were synthesized by using methylene blue (MB) as carbon source via hydrothermal strategy with H2SO4 as oxidization and dehydration (carbonization) agent. On account of the aromas property and the present heteroatom of MB, as-synthesized CDs possess great NIR-II harvest and photothermal conversion ability (29.7 %). To take advantage of the abundant incoming –OH, nitration treatment is performed to obtain CDs-NO, which produces NO gas under the stimuli of glutathione (GSH) and hyperpyrexia. The consumption of GSH also benefits to the elevation of intracellular oxidative stress. Under NIR-II (1064 nm) irradiation, the generated ROS would combine with NO in-situ to form ONOO− radicals, which possess the higher cytotoxicity to cancer cells. The short distance between ROS and NO makes sure the quick conversion and high utilization of NO. The synergistic NO therapy and photo-thermal/dynamic therapy not only reveals remarkable therapeutic effect for tumor bearing mice but also arouses immune response for metastasis inhibition efficiently.