Covalent attaching protein to graphene oxide via diimide-activated amidation

In this paper, graphene oxide nanosheets (GOS) are functionalized by bovine serum albumin (BSA) via diimide-activated amidation under ambient conditions. The obtained GOS–BSA conjugate is highly water-soluble. Results of atomic force microscopy (AFM), Raman spectra and Fourier transform infrared spectroscopy analysis confirm that GOS–BSA conjugate contains both GOS and BSA protein. AFM image shows that GOS are fully exfoliated. Results of cyclic volatammograms show that the protein in the GOS–BSA conjugate retains its bioactivity. The present method may also provide a way to synthesize graphene-based composites with other biomolecules.