Abstract
OBJECTIVES: Carbon dots (CDs) are one of the most promising carbon-based materials in bioimaging and drug/gene delivery applications. In this study, we have attempted to study the drug carrying capacity of highly fluorescent CDs for delivery of doxorubicin (DOX) and investigate the therapeutic activity of the CDs-DOX drug delivery system. MATERIALS AND METHODS: Carbon dots were synthesized by means of a hydrothermal approach with mixing citric acid and ethylenediamine. The properties of CDs were characterized in respects of spectral property, zeta potential, particle morphology and chemical composition. The drug loading efficiency (DLE) and release profile of CDs-DOX were determined by a fluorescence spectrophotometer. We investigated the cellular toxicity and pharmaceutical activity of CDs and CDs-DOX in L929 cells and MCF-7 cells by the CCK-8 assay. We also studied the cellular uptake of CDs-DOX with the methods of confocal microscopy and flow cytometry. In addition, the effect of CDs-DOX on cell apoptosis was assessed by flow cytometry. RESULTS: The obtained CDs possessed good biocompatibility and showed a potential capacity of promoting proliferation. DOX was successfully conjugated to CDs through electrostatic interaction, and the results of the DLE and loading content (DLC) suggested a relatively high drug loading capacity of CDs. Compared with free DOX, the CDs-DOX complex had a higher cellular uptake and better anti-tumour efficacy on MCF-7 cells. CONCLUSIONS: The results of this study indicated that the CDs-DOX drug delivery system had a potential value in cancer chemotherapeutic application.