Detection of protein conformational changes with multilayer graphene nanopore sensors.

Detecting conformational change in protein or peptide is imperative in understanding their dynamic function and diagnosing diseases. Existing techniques either rely on ensemble average that lacks the necessary sensitivity or require florescence labeling. Here we propose to discriminate between different protein conformations with multiple layers of graphene nanopore sensors by measuring the effect of protein-produced electrostatic potential (EP) on electric transport. Using conformations of the octapeptide Angiotensin II obtained through molecular dynamics simulations, we show that the EP critically depends on the geometries of constituent atoms and each conformation carries a unique EP signature. We then, using quantum transport simulations, reveal that these characteristic EP profiles cause distinctive modulation to electric charge densities of the graphene nanopores, leading to distinguishable changes in conductivity. Our results open the potential of label-free, single-molecule, and real-time detection of protein conformational changes.