Dresden 2014 – scientific programme
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BP: Fachverband Biologische Physik
BP 30: Biomaterials and Biopolymers I (joint CPP/BP)
BP 30.3: Talk
Wednesday, April 2, 2014, 15:45–16:00, ZEU 222
On the Relationship between Peptide Adsorption Resistance and Surface Contact Angle: A Combined Experimental and Simulation Single-Molecule Study — •Nadine Schwierz1, Dominik Horinek1, Susanne Liese2, Tobias Pirzer1, Bizan N. Balzer1, Thorsten Hugel1, and Roland R. Netz2 — 1Technische Universität München, Germany — 2Freie Universität Berlin, Germany
Controlling the adsorption of proteins and peptides at synthetic surfaces is the ultimate goal for designing biocompatible implants and fouling resistant surfaces. To gain a microscopic understanding of the transition between peptide adsorption and adsorption resistance, the force-induced desorption of single peptide chains is investigated in closely matched molecular dynamics simulations and atomic force microscopy experiments. In both simulations and experiments, the surfaces become adsorption resistant when their contact angle decreases below θ = 50°-60°, thus confirming the so-called Berg limit, established in the context of protein and cell adsorption.
Entropy/enthalpy decomposition of the simulation results reveals that the key discriminator between the adsorption of different residues on a hydrophobic monolayer is of entropic nature and thus is suggested to be linked to the hydrophobic effect. Peptide adsorption resistance is caused by the strongly bound water hydration layer and characterized by the simultaneous gain of both total entropy in the system and total number of hydrogen bonds between water, peptide, and surface. This mechanistic insight into peptide adsorption resistance might help to refine design principles for anti-fouling surfaces.