| AVS 64th International Symposium & Exhibition | |
| Biomaterial Interfaces Division | Thursday Sessions |
| Session BI+AS+SA-ThM |
| Session: | Characterisation of Biological and Biomaterial Surfaces |
| Presenter: | Markus Valtiner, TU Bergakademie Freiberg, Germany |
| Authors: | P. Stock, MPI for Iron Research, Germany J.I. Monroe, UC Santa Barbara T. Utzig, MPI for Iron Research, Germany D.J. Smith, UC Santa Barbara M.S. Shell, UC Santa Barbara M. Valtiner, TU Bergakademie Freiberg, Germany |
| Correspondent: | Click to Email |
Interactions between hydrophobic moieties steer ubiquitous processes in aqueous media, including the self-organization of biologic matter. Recent decades have seen tremendous progress in understanding these for macroscopic hydrophobic interfaces. Yet, it is still a challenge to experimentally measure hydrophobic interactions (HIs) at the single-molecule scale and thus to compare with theory.
Here, I will present a combined experimental–simulation approach to directly measure and quantify the sequence dependence and additivity of HIs in peptide systems at the single-molecule scale. We combined dynamic single-molecule force spectroscopy on model peptides with fully atomistic, both equilibrium and nonequilibrium, molecular dynamics (MD) simulations of the same systems. Specifically, we mutate a flexible (GS)5 peptide scaffold with increasing numbers of hydrophobic leucine monomers and measure the peptides’ desorption from hydrophobic self-assembled monolayer surfaces. Based on the analysis of nonequilibrium work-trajectories, we measure an interaction free energy that scales linearly with 3.0–3.4 kBT per leucine. In good agreement, simulations indicate a similar trend with 2.1 kBT per leucine, while also providing a detailed molecular view into HIs.
Our approach potentially provides a roadmap for directly extracting qualitative and quantitative single-molecule interactions at solid/liquid interfaces in a wide range of fields, including interactions at biointerfaces and adhesive interactions in industrial applications. In this context, I will finally discuss in detail how single molecule unbinding energy landscapes can be utilized to predict scenarios where a large number of molecules simultaneously interact, giving rise to adhesive failure under corrosive and wet conditions.
[1] S. Raman et al. in Nature Communications, 5(2014), 5539.
[2] T. Utzig et al. in Langmuir, 31(9) (2015), 2722.
[3] T. Utzig, P. Stock et al. in Angewandte Intl.(2016).
[4] P. Stock et al. in ACS Nano(2017), 11 (3), 2586.