A graphene quantum dot@Fe3O4@SiO2 based nanoprobe for drug delivery sensing and dual-modal fluorescence and MRI imaging in cancer cells

Abstract

A novel graphene quantum dot (GQD)@Fe₃O₄@SiO₂ based nanoprobe was reported for targeted drug delivery, sensing, dual-modal imaging and therapy. Carboxyl-terminated GQD (C-GQD) was firstly conjugated with Fe₃O₄@SiO₂ and then functionalized with cancer targeting molecule folic acid (FA). DOX drug molecules were then loaded on GQD surface of Fe₃O₄@SiO₂@GQD-FA nanoprobe via pi-pi stacking, which resulted in Fe₃O₄@SiO₂@GQD-FA/DOX conjugates based on a FRET mechanism with GQD as donor molecules and DOX as acceptor molecules. Meanwhile, we successfully performed in vitro MRI and fluorescence imaging of living Hela cells and monitored intracellular drug release process using this Fe₃O₄@SiO₂@GQD-FA/DOX nanoprobe. Cell viability study demonstrated the low cytotoxicity of Fe₃O₄@SiO₂@GQD-FA nanocarrier and the enhanced therapeutic efficacy of Fe₃O₄@SiO₂@GQD-FA/DOX nanoprobe for cancer cells. This luminomagnetic nanoprobe will be a potential platform for cancer accurate diagnosis and therapy.

Keywords: Cell imaging; Drug delivery sensing; Fluorescence resonance energy transfer (FRET); Graphene quantum dots (GQDs); Magnetic resonance imaging (MRI).