Adsorption Dynamics and Self-Assembled L-cysteine on Au(100)

As the only amino acid with a functional thiol group, L - cysteine offers a strong perspective both for binding to gold and other metals, and for gentle immobilization of biomolecules. Binding to single - crystal, atomically planar surfaces offers the additional perspective that bound L - cysteine can be structurally mapped at the single - molecule level . In this work, we have followed the adsorption of L - cysteine on single - crystal Au(100) by measuring the electrode potential dynamics during the adsorption process. In situ STM revealed the structure of the self - assembled ordered layers. The molecular assemblies were studied through simulated STM image contrast based on density functional theory (DFT) including solvation effects. The adsorption kinetics showed clearly a complex pattern with at least one intermediate state. The modelling disclosed details of the interaction of all functional groups with the Au(100) - substrate.