Fluorescent carbon dots as carriers for intracellular doxorubicin delivery and track

This paper reported a simple pH-responsive fluorescent therapeutic drug delivery system of doxorubicin (DOX)-loaded carbon dots (CDs) for intracellular drug delivery and track in human gastric cancer cells. Drug loading efficiency of this system was 75.3 wt%. The drug release process of this system followed the first-degree drug delivery model, which was ideal for intravenous injection therapy of cancer. The carboxyl-rich CDs had almost no toxicity to human gastric cancer (MGC-803) and human gastric epithelial (GES-1) cells with the survival rates of over 90%. The CDs-DOX system had about a 2-fold inhibitory effect on MGC-803 cells growth compared to GES-1 cells according to the MTT assay. The cell imaging results showed that the CDs-DOX system could be internalized into the cells efficiently. The intracellular uptake and drug delivery efficiency of this system in GES-1 cells was about 30% of that in the MGC-803 cells. The fluorescent CDs enabled the optical labeling and tracking of the drug delivery process at least 48 h. Because of its specific drug delivery and fluorescence tracking properties, the multifunctional CDs-DOX system possesses potential applications in bioimaging, biolabeling and cancer therapy.