Effect of Flow on Human Serum Albumin Adsorption to Self-Assembled Monolayers of Varying Packing Density

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• 作者：Eugene J. Choi ; Mark D. Foster ; Susan Daly ; Robert Tilton ; Todd Przybycien ; Charles F. Majkrzak ; Peter Witte ; and Henning Menzel
• 刊名：Langmuir
• 出版年：2003
• 出版时间：June 24, 2003
• 年：2003
• 卷：19
• 期：13
• 页码：5464 - 5474
• 全文大小：143K
• 年卷期：v.19,no.13(June 24, 2003)
• ISSN：1520-5827

文摘

Adsorption of human serum albumin (HSA) to self-assembled monolayers (SAMs) of different packingdensities under dynamic conditions was investigated in situ using optical reflectometry and neutronreflectometry. When optical reflectometry was used, it was observed that HSA has a greater apparentsteady-state surface concentration and higher initial rate of adsorption on a less densely packed SAM thanon a densely packed SAM. These results are consistent with the contention that HSA specifically bindsto the loosely packed chains. Changes in the morphology of an adsorbed protein layer with the impositionof continuing flow during adsorption were studied for the first time using neutron reflectometry. HSAinterpenetrates the less densely packed SAM but sits on top of the densely packed SAM when adsorbingunder persistent flow or without persistent flow. However, the orientation of the adsorbed moleculeschanges with the details of the flow. In the absence of persistent flow, a side-on orientation prevails. Theadsorbed layers are thicker when adsorbed under persistent flow, consistent with a reasonably uniformtilting of the molecules up away from the surface. The variation in the adsorption tenacity on the SAMswith an alkyl chain packing density is greater when the adsorbed layer structure is equilibrated underquiescent conditions than when the adsorbed layer is subjected to continuing flow.