DFT Investigation of Graphene Nanoribbon As a Potential Nanobiosensor for Tyrosine Amino Acid

We investigated (2,2) graphene nanoribbon (GNR) as a nanobiosensor for tyrosine (C9H11NO3) amino acid detection using density functional theory (DFT) calculations. The geometric, energetic, and electronic properties, which include the bond length, charge, adsorption energies, HOMO energies, Fermi level energies, LUMO energies, energy gaps, work functions, dipole moments and reactivity descriptors were calculated by DFT/B3LYP with 6-31G(d) basis set for the GNR in free mode and interacted with the tyrosine (Tyr) molecule. The molecular electrostatic potential and the electron density surfaces have been constructed. Moreover, we used orbital analysis counting the density of states (DOS) to finding out the possible orbital hybridization of these hybrid structures. Based on the results, it was found that GNR shows high reactivity toward Tyr, and, in the favorable state, the calculated adsorption energy is about 2.610 eV. It is shown that the electronic properties of GNR are strongly sensitive to the presence of Tyr molecule. Therefore, we believe that these hybrid structures of nanobiosensors are able to sense the smallest amino acid constructing block of proteins, and the GNRs have the potential to be used in sensor devices.