Diffusion and adsorption of proteins in a model pore in the surface forces apparatus

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 110; no. 2; pp. 119 - 127
• Main Authors: Palkar, S.A., Lenhoff, A.M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.05.1996; Elsevier
• Subjects: Adsorption; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Hindered diffusion; Lysozyme; Multiple beam interferometry; Porous materials; Protein; Restricted transport; Solid-liquid interface; Surface forces apparatus; Surface physical chemistry; Restricted transport; Multiple beam interferometry; Adsorption; Hindered diffusion; Surface forces apparatus; Lysozyme; Protein; Liquid solid interface; Transport properties; Enzyme; Liquid solid adsorption; Pore structure; Organic adsorbate; Inorganic adsorbent; Experimental study; Porous material; Mass transfer; Proteins; Pore size; Glycosidases; Concentration effect; Surface properties; Hydrolases; Diffusion; O-Glycosidases; Mica; Interferometry
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/0927-7757(95)03435-8

When the energetic interactions between proteins and pore surfaces are favorable, both hindered diffusion and adsorption govern the overall transport rates in fine pores. To study these effects, we have used the narrow gap between mica surfaces in a surface forces apparatus (SFA) as a model slit-like pore that has a well-characterized geometry and surface chemistry. The optical technique of multiple beam interferometry used in the SFA for measuring surface separations also provides a means for determining protein concentrations inside the pore. The results obtained show the effect of ionic strength on the net transport rates for lysozyme diffusing in a mica-bounded pore, a consequence of the influence of electrolyte screening on the extent of adsorption. It is also seen how adsorption on opposing surfaces leads to pore blockage once the pore size decreases to 2–3 times the molecular diameter. Although quantitative determination of hindrance effects is potentially also possible using the method, an improved method for acquisition of the interferometry data must first be implemented.