Supramolecular hybrids of carbon dots with doxorubicin: synthesis, stability and cellular trafficking

Supramolecular hybrids of carbon dots (CDs) and doxorubicin (Dox) were successfully prepared via p-p stacking and electrostatic interactions. The hybrids were characterized by the changes in size, morphology and zeta potential, and further validated by the absorption and photoluminescence spectra. A binding constant of 63 L g(-1) between CDs and Dox was calculated from the Stern-Volmer plot. The hybrids between CDs and Dox (CDs-Dox) showed pH-dependent drug loading and release behaviors in aqueous solution. The poor stability of CDs-Dox in fetal bovine serum (FBS) solution led to the rapid separation of Dox and CDs, facilitating the release of Dox and its entrance into cellular nuclei as revealed by confocal laser scanning microscopy (CLSM). After being coated with polydopamine (CDs-Dox@PDA), the stability of the hybrids in cell culture media was enhanced, as supported by the slow release of Dox in living cells. This work highlights the potential of using CDs to synthesize functional nanoparticles through supramolecular interactions.