β-Cyclodextrin-Decorated Carbon Dots Serve as Nanocarriers for Targeted Drug Delivery and Controlled Release

A novel nanocarrier for targeted delivery of anti-cancer drug doxorubicin (DOX) was fabricated with carbon dots (CDots) as the matrix. Fluorescent CDots capable of targeting folate receptor-positive cells first conjugate with boric acid and then couple with -CD to produce the nanocarrier -CD/CDots. DOX was encapsulated into the cavity of -CD providing a maximum loading ratio of 27.3% at pH7.4. Benefiting from pH-sensitive dissociation of DOX/-CD inclusion complex and the cleavage of the bonding between boric acid and -CD, pH-triggered release of drugs was realized, with an 82% release of the loaded drug at pH5.0. Meanwhile, the fluorescence resonance energy transfer (FRET) occurs between CDots (donor) and DOX (acceptor), which may potentially facilitate monitoring/tracing of the drug delivery process. In vitro results further demonstrated the targeting capability of the nanocarrier towards folate receptor-positive cells. Moreover, confocal microscopy results, in accordance with that of flow cytometry analysis, confirmed the efficient intracellular uptake of DOX--CD/CDots and sustained release of DOX. This makes DOX--CD/CDots promising as biocompatible and multifunctional nanomedicine for targeted delivery, controlled release and real time monitoring/tracing of drugs.