Fig. 9.
Hysteresis-based enzyme detection using a graphene–nanoparticle hybrid sensor. (a) Graphene–nanoparticle hybrid devices for enzyme sensing. (b) Chemical structure of the functional polypeptide linker molecule. (c) Fabrication process of the hybrid biosensor. Fabrication of the graphene channel between the Au electrodes (i). Functionalization of the graphene surface with hydrophilic molecules (ii). Assembly of the functional peptide linker molecules and AuNPs on the polypeptide layer (iii). (d) Change in VDirac under various periods of exposure to a 1 µM solution of carboxypeptidase B in PBS, 1 mM PBS solution and 1 mM solution of BSA in PBS. Reproduced from ref. 58 with permission from Wiley.