Multivalent Ion-Activated Protein Adsorption Reflecting Bulk Reentrant Behavior

Abstract

Protein adsorption at the solid-liquid interface is an important phenomenon that often can be observed as a first step in biological processes. Despite its inherent importance, still relatively little is known about the underlying microscopic mechanisms. Here, using multivalent ions, we demonstrate the control of the interactions and the corresponding adsorption of net-negatively charged proteins (bovine serum albumin) at a solid-liquid interface. This is demonstrated by ellipsometry and corroborated by neutron reflectivity and quartz-crystal microbalance experiments. We show that the reentrant condensation observed within the rich bulk phase behavior of the system featuring a nonmonotonic dependence of the second virial cofficient on salt concentration c_s is reflected in an intriguing way in the protein adsorption d(c_s) at the interface. Our findings are successfully described and understood by a model of ion-activated patchy interactions within the framework of classical density functional theory. In addition to the general challenge of connecting bulk and interface behavior, our work has implications for, inter alia, nucleation at interfaces.

5 pages, 3 Figures, accepted by Phys. Rev. Lett

References in corpus (4)

• Phase behaviour of a simple model of globular proteins
• A simple patchy colloid model for the phase behavior of lysozyme dispersions
• Control of pathways and yields of protein crystallization through the interplay of nonspecific and specific attractions
• The crystallization of asymmetric patchy models for globular proteins in solution

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• Like-charge polymer-membrane complexation mediated by multivalent cations: one-loop-dressed strong coupling theory
• Role of Entropy in Determining the Phase Behavior of Protein Solutions Induced by Multivalent Ions
• Orientational transition and complexation of DNA with anionic membranes: weak and intermediate electrostatic coupling
• The ion activated attractive patchy particles model and its application to the liquid-vapour phase transitions
• Integral equation study of effective attraction between like-charged particles mediated by cations: Comparison between IPY2 and HNC closures