Drug-Derived Carbon Dots with Red Light Emission and Low Side Effects for Targeting Fluorescence Imaging and Potential Treatment of Liver Cancer

The carbon dots synthesized using the drug function retention strategy not only possess the inherent characteristics of low toxicity and high biocompatibility but also retain the properties of their precursor, thereby exhibiting significant potential in the field of cancer treatment. The red light-emitting carbon dots, 5-FICD, were synthesized through a simple method employing the anticancer drug 5-fluorouracil (5-FU) and the phototherapeutic agent indocyanine green (ICG). The retained characteristics of ICG enable 5-FICD to selectively accumulate in liver cancer cells. Under light irradiation, 5-FICD emits vivid red fluorescence, effectively illuminating the intracellular environment and simultaneously inducing photothermal and photodynamic effects. In comparison to 5-FU, 5-FICD exhibited significantly reduced cytotoxicity toward normal cells, exhibiting almost negligible toxic side effects at a concentration of 200 μg/mL; conversely, it displayed markedly enhanced cytotoxicity against liver cancer cells, resulting in an apoptosis rate of liver cancer cells treated with 5-FICD reaching as high as 85.93%. The three-dimensional tumor spheroid experiments also confirmed the highly effective therapeutic effect of 5-FICD. The synthesis of drug-derived carbon dots, employing the strategy of function retention, introduces a synthetic path for precise targeting of hepatocellular carcinoma in the synthesis of diagnostic and therapeutic agents.