Lessons from a Challenging System: Accurate Adsorption Free Energies at the Amino Acid/ZnO Interface

We undertake steps to overcome four challenges that have hindered the understanding of ZnO/biomolecule interfaces at atomic scale: parametrization a classical force field, ZnO surface termination and amino acid protonation state in methanol, convergence enhanced sampling molecular dynamics simulations. predict adsorption free energies for histidine, serine, cysteine, tryptophan remarkable agreement with experimental measurements obtained via novel indicator-displacement assay. Adsorption is driven by direct surface/amino-acid interactions mediated terminal hydroxyl groups stabilized strongly structured methanol solvation shells.