Folic acid conjugated capecitabine capped green synthesized fluorescent carbon dots as a targeted nano-delivery system for colorectal cancer

Herein, we have developed folic acid conjugated capecitabine capped passivated carbon dots (CAP-FA-CDPs) for colorectal cancer targeting. Carbon dots were synthesized via a microwave treatment of the Buchnania lanzan leaf extract and PEG6000 was used as a surface passivating agent. The developed system has shown an acidic pH (pH 5.0) dependent drug release of 84.57% after 72 h. In an in vitro cytotoxicity study, CDPs showed almost no toxicity to the HT-29 colorectal cancer cells with the viability rate of 96.03%. However, the viability of HT-29 cells significantly dropped to 24.4% in CAP-FA-CDPs treated group, only after 36 h of incubation. A cellular uptake study showed an efficient internalization of CAP-FA-CDPs systems by HT-29 cells expected via folic acid-folate receptor (ligand-receptor) interaction. Greater reactive oxygen species (ROS) generation further confirmed the successful cellular uptake of the CAP-FA-CDPs. Finally, flow cytometry analysis clearly showed the apoptotic potential of the CAP-FA-CDPs conjugated system on HT-29 cells where live cells significantly decreased to 21.4% and apoptotic cells increased to 77.2%. Thus, the presently developed CAP-FA-CDPs nano delivery system offers a promising strategy for targeted and effective drug delivery in colorectal cancer.