Biocompatible Fluorescent\nGraphene Oxide Quantum Dots\nfor Imaging of Drosophila melanogaster

Developing reliable biocompatible bioimaging agents is\nparamount\nfor diagnosing critical diseases and disorders early through oral\ningestion of fluorescent probes to image living organisms. Here, we\nprepared fluorescent, water-dispersed graphene oxide quantum dots <i>via</i> pyrolysis of a Glycyrrhiza glabra root in the water medium using a cost-effective and environmentally\nbenign method to enable Drosophila melanogaster, an organism analogous to the human genome, to be imaged alive.\nThe prepared graphene oxide quantum dots demonstrated a 2.6 nm diameter\nand 0.36 nm graphitic spacing with carboxylic acid, carbonyl, and\nhydroxyl functionalities. The selected area electron diffraction image\nanalysis reveals a series of bright circular patterns that confirm\nthe crystalline nature of the graphene oxide quantum dots. Raman and\nX-ray diffraction analyses also validate the crystallinity nature\nof prepared materials. The graphene oxide quantum dots exhibited blue\nfluorescence under ultraviolet-light irradiation with excitation-dependent\nemission properties from blue to red emission. The synthesized graphene\noxide quantum dots consistently fluoresce in the larva-fed graphene\noxide quantum dots without exhibiting toxicity. The current study\nevaluates the toxic effect of synthesized fluorescent graphene quantum\ndots by examining several screening and staining methods on D. melanogaster, a fruit fly, as a model.