Photo-oxidase carbon dot-based nanozyme for breast cancer theranostics under normoxia condition

Ultra-small histidine-functionalized carbon nanodots (His C-dots) with engineered modality as photo-oxidative nanozymes for cancer theranostics were prepared by one step microwave-assisted pyrolysis. The role of chemically embedded imidazole ring into nanoparticle aromatic domains was to enhance the absorbance, fluorescence, and phosphorescence intensities in aqueous solution at room temperature. It contributed to the increase of pyrrolic nitrogen, which was responsible for the higher oxygen adsorption and better photosensitization under visible irradiation. The ability of nanozyme as theranostics was demonstrated on illuminated with visible light B16-F10 mouse melanoma cells with high metastatic potential under normoxic condition. The inhibition of cell migration was measured by wound healing assay after scratching confluent monolayer of the breast cancer cells. The microscopic data revealed that the metastatic migration could be controlled by the applied nanozyme dosage, which was responsible for the production of singlet oxygen and the causing of effective photo-induced cytotoxicity. The biocompatibility of the illuminated His C-dots was proved on ATPase activity of intact mitochondria and sub-mitochondrial particles, on diamine oxidase activity of liver and kidney fractions in dark mode, MTT assay as well as on non-illuminated adenocarcinomic human alveolar basal epithelial cells (A549) and human liver cancer cells (HepG2). The satisfactory ability of the reported nanoparticles as fluorescence anticancer agents makes them a promising platform for the development of oxidize-mimicking nanozymes with application in the photodynamic therapy.