Energies Exploration for Glycine Molecule Supported on Zinc Oxide Clusters: Computational and Experimental Study

Density functional theory calculations of 0D (zero-dimensional) metal oxide nanomaterials and protein amino acids have been used to evaluate the disease progression for biosensing applications. In this study, the interaction of glycine with ZnO clusters was evaluated, incorporating a van der Waals correction. Glycine was rotated to interact with the nanoparticles at different active sites. Binding and cohesion energies, the density of states, and charge transfer were calculated for each system. The results indicate that glycine interacting with the ZnO(3) cluster in the XZ-plane exhibits greater stability due to higher binding and cohesion energies. A higher charge transfer was also observed for this interaction. Furthermore, the density of state analysis shows a significant decrease in all band gaps, indicating a reduction in the cluster's semiconductive behavior. To experimentally validate this interaction, atomic force microscopy (AFM) was performed as a proof of concept. A silicon contact tip in pinpoint mode was used with ZnO nanoparticles and a functionalized silicon wafer containing glycine. The AFM results confirm the binding affinity between glycine and ZnO nanoparticles.