Visualization and Modeling of Protein Adsorption and Transport in DEAE‐ and DEAE‐Dextran‐Modified Bare Capillaries

Abstract

This article reports a microscopic method to directly visualize protein adsorption and transport in bare capillaries modified with ion exchange groups. Silica capillaries were coated with poly(vinyl alcohol) to eliminate nonspecific protein absorption and then functionalized with diethylaminoethyl (DEAE) and DEAE-dextran to prepare anion-exchange capillaries denoted as D-C and D-dex-C, respectively. Protein concentration profiles acquired from microscopic images were analyzed with a one-dimensional diffusion-adsorption model to determine adsorption capacities and effective diffusivities. It revealed that surface diffusion of bound protein on the capillary surface in D-Cs was negligible, but that of bound proteins markedly contributed to protein transfer in D-dex-Cs because of the chain delivery effect of charged dextran chains. The chain delivery was little affected by protein concentration, but significantly increased with ionic capacity. The research thus provided new insight into protein adsorption and transport behaviors on the surfaces modified with ion exchange groups of different structures.