Binding affinities and adhesion phenomena of binding peptides at the interface to zinc oxide

Peptide sequences can selectively bind to inorganic substrates in a process similar to the concept of molecular recognition. Here we focused on zinc oxide as an important representative of functional oxides and identified binding peptides with an affinity for different ZnO facets. Five peptides were selected and their conformational ensemble (macrostate) and sensitivity to adsorption were characterised via circular dichroism (CD) spectroscopy. The microstates within their conformational ensembles are accessed by enhanced sampling simulations. To quantify the free energies of adsorption, an optically sectioned indicator displacement assay (O-IDA) was adapted to the peptide/ZnO interface and compared to the results of single molecule force spectroscopy (SMFS), leading to a good agreement between the two approaches.