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Updated: Jul 10, 2026
The Importance of Correct Protein Concentration for Kinetics and Affinity Determination in Structure-function Analysis
Published on: March 18, 2010
History dependence of protein adsorption kinetics
C Calonder1, Y Tie, P R Van Tassel
1Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA.
Abstract:
The behavior of proteins at biological and synthetic interfaces is often characterized by a strong history dependence caused by long relaxation times or irreversible transitions. In this work, we introduce the rate of adsorption as a means to systematically quantify the extent, and identify the underlying causes, of history dependence. We use multistep kinetic experiments in which the i'th step is an exposure of a Si(Ti)O(2) surface to a flowing fibronectin or cytochrome c solution of concentration c(i) for a time t(i) (c(i) = 0 corresponds to a rinse) and measure the protein adsorption by optical waveguide light mode spectroscopy. The rate of adsorption is sensitive to the structure of the adsorbed layer, and we observe it to greatly increase, for a given adsorbed density, when going from a first to a subsequent adsorption step. This increase is most pronounced when the duration of the initial adsorption step is long. We attribute these observations to the gradual and irreversible formation of protein clusters or locally ordered structures and use them to explain previous underestimates of kinetic data by mesoscopic model descriptions. A thorough understanding of these complex postadsorption events, and their impact on history dependence, is essential for many physiological and biotechnological processes. Optical waveguide lightmode spectroscopy is a promising technique for their macroscopic quantification.
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