Superparamagnetic Graphene Quantum Dot as a Dual-Modality Contrast Agent for Confocal Fluorescence Microscopy and Magnetomotive OCT

A magnetic graphene quantum dot (MGQD) nanoparticle, synthesized by hydrothermally reducing and cutting graphene oxide-iron oxide sheet, was demonstrated to possess the capabilities of simultaneous confocal fluorescence and magnetomotive OCT imaging. This MGQD shows low toxicity, significant tunable blue fluorescence and superparamagnetism, which can thus be used as a dual-modality contrast agent for confocal fluorescence microscopy (CFM) and magnetomotive OCT (MMOCT). The feasibility of applying MGQD as a tracer of cells is shown by imaging and visualizing MGQD labelled cells using CFM and our in-house MMOCT. Since MMOCT and CFM can offer anatomical structure and intracellular details respectively, the MGQD for cell tracking could provide a more comprehensive diagnosis.