Kinetics and thermodynamics of protein adsorption: A theoretical approach
Abstract
The thermodynamics and kinetics of protein adsorption on bare surfaces as well as on surfaces with grafted polymers are studied using a molecular theoretical approach. The cases studied include adsorption of globular proteins, competitive adsorption from protein mixtures, adsorption with conformational change and surface-induced phase separation of proteins. For the case of competitive adsorption from a solution containing a mixture of large and small proteins, a variety of different adsoprtion patterns are observed depending upon the bulk composition, the protein-surface interaction and the size of proteins. It is found that the experimentally observed Vroman sequence is predicted in the case that the bulk solution is at a composition with an excess of the small protein, and that the interaction between the large protein and the surface is much larger than that of the small protein. For adsorption on surfaces with grafted polymers, the effects of changing polymer-surface interactions, polymer chain length, polymer segment volume and surface coverage of grafted polymers on controlling protein adsorption are studied. Our results show that the ability of the polymer layer to prevent protein adsorption at equilibrium is different from that during kinetics. Thermodynamically, increasing polymer-surface attraction, increasing surface coverage and using polymers with larger segments help to better reduce protein adsorption. Whereas changing polymer chain length has little effect on preventing protein adsorption when polymers are long enough. However, longer polymer chains, weaker polymer-surface interactions, higher surface coverage and larger segments are better at kinetically retarding protein adsorption. When studying phase separation of proteins, we found both the bulk concentration and the protein-surface interaction affect the coexistence of proteins with different densities on the surface.
Degree
Ph.D.
Advisors
Szleifer, Purdue University.
Subject Area
Chemistry
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