Functionalization of graphene oxide quantum dots for anticancer drug delivery

Abstract

Graphene quantum dots (GQDs) have a wide range of applications in biomedical applications, particularly anticancer drug delivery. In this study, graphene oxide quantum dots conjugated with glucosamine and boric acid (GOQDs-GlcN-BA) with and without doxorubicin (DOX) were investigated for cancer therapy for the first time in the literature. The nanocomposite contained 4 w/w boron according to the ICP analysis. Furthermore, the size of the nanocomposites ranged between 15 and 51 nm. DOX loading efficiencies of GOQDs-GlcN-DOX and GOQDs-GlcN-BA-DOX were 57% and 90%, respectively. Only 8% of DOX release occurred from GOQDs-GlcN-DOX in acidic environment and 5% of drug released at neutral pH, whereas BA addition in the nano -composite increased DOX release up to 20% at 5.5 pH and 10% at 7.4 pH in 96 h. GOQD-GlcN-BA-DOX exhibited more cytotoxicity against MCF-7 cells compared to GOQD-GlcN-DOX. Cellular internalization of GOQD-GlcN-BA-DOX in MCF-7 was higher than it was observed for GOQDs-GlcN-DOX owing to sialic acid-BA interaction on cell surface. This work shows the incorporation of BA to the nanocomposite enhanced the loading and release of DOX, with higher cellular internalization, thus superior potential for anticancer drug delivery.