Graphene Oxide-mediated Fluorescence Quenching of Green Fluorescent Protein for Biomedical Applications

We investigated the fluorescence property of green fluorescent protein (GFP) with graphene oxide (GO) for both non-covalent and covalent interactions. The mechanism of GO-mediated quenching of GFP fluorescence is the combination of both static and dynamic quenching. Although GFP exhibits two absorption bands with similar fluorescence emission spectra, the quenching efficiency of the two absorption bands from non-covalent immobilization were differentone with absorption at 460 nm, showing a higher fluorescence resonance transfer efficiency than the other absorption at 395 nm. We determined the apparent Stern-Volmer quenching constant (K-app) of GFP for GO to be 2.6 x 10(-7) mL/g. However, GFP fluorescence disappeared upon covalent immobilization on GO.