Green synthesized cobalt doped graphene quantum dots derived from Boswellia serrata for dual ligand targeted bioimaging and delivery of exemestane

Major objective of hydrothermal method is to achieve the synthesis of Cobalt doped Graphene quantum dots (Co-GQDs) using natural precursor (Boswellia serrata gum resin). The Co-GQDs were surface engineered with folic acid (FA) and hyaluronic acid (HA) to enable dual targeting module (Co-GQDFH), followed by loading of the anticancer drug Exemestane (EXE@Co-GQDs). The nanosized, crystallite structure with high luminescence intensity was maintained after functionalization and drug loading process was assessed from preliminary physicochemical analysis. The EXE@Co-GQDFH forms complex via passive loading approach and achieves and entrapment efficiency of 68.58%. The in-vitro drug release study shows extended release of EXE from the surface functionalized Co-GQDFH for 24 h and releases (~ 88%) maximum encapsulated drug. The dose dependent toxicity was observed for EXE@Co-GQDFH (49.5 µg/ml) on MCF-7 cell breast cancer cell types while IC50 value was comparable to 5-Fluorouracil. The fluorescent Co-GQD shows high bioimaging and cellular uptake efficiency in MCF-7 cells. The surface conjugation with FA and HA on Co-GQDs shows enhanced activity with zone of inhibition was found to be 25 mm while the Co-GQD shows 20 mm suggest conjugation improved the antimicrobial effect. Radical scavenging activity was also demonstrated, with Co-GQDs showing 77.92% and EXE@Co-GQDs was 59.02% DPPH inhibition. These results suggest that surface-engineered Co-GQDs offer a multidentate nanoplatform for targeted delivery, imaging, and therapy in breast cancer applications.