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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 24: Poster Session I

CPP 24.34: Poster

Montag, 16. März 2020, 17:30–19:30, P3

Protein adsorption at the solid-liquid interface tuned by the choice of trivalent cations — •Nina Conzelmann, Madeleine Fries, Fajun Zhang, and Frank Schreiber — University of Tübingen, Germany

In biological processes, such as cell adhesion, protein adsorption at solid-liquid interfaces plays a crucial role since it is often observed as one of the first steps. Our study focuses on the effect of trivalent cations (La⁺³, Y⁺³) on globular proteins such as bovine serum albumin (BSA) which exhibits a rich phase behavior including reentrant condensation between two critical salt concentrations (c*, c**) and liquid-liquid phase separation [1]. Ellipsometry and quartz crystal microbalance were used to investigate the effect of increasing amounts of salt on the protein-interface system. The interaction of BSA with net-negatively charged surfaces like SiO₂ is dominated by electrostatic repulsion and minimum protein adsorption. First, an increasing amount of absorbed protein on the surface was observed while increasing salt concentration. Then, in the regime II, the thickness of absorbed protein reaches a maximum. At high salt concentrations, the adsorbed layer first decreases and then approaches a constant value. This behavior can be explained by using the ion-activated patchy interactions model [2]. Both salts used show the same overall adsorption trend, yet the absolute adsorbed amount in regime II (c*<c<c**) differs. The difference in regime II for LaCl₃ and YCl₃ is caused by LaCl₃ having weaker effective attractive protein-protein interactions.

[1] Matsarskaia et al, PCCP (2018); [2] Fries et al, PRL (2017)