Protein-Resistant Poly(ethylene oxide)-Grafted Surfaces: Chain Density-Dependent Multiple Mechanisms of Action

• DOI: 10.1021/la702310t
• Publication Date: 2008-01-25T10:01:01Z
• Authors: Larry D. Unsworth; Heather Sheardown; John L. Brash
• Keywords: Protein Adsorption; Chain (unit); Side chain

A clear understanding of the mechanisms responsible for protein-resistant nature end-tethered poly(ethylene oxide) (PEO) surfaces remains elusive. barrier to improved is fact that many factors involved (chain length, chain density, hydration, conformation, and distal chemistry) are inherently correlated. We hypothesize that, by comparing systems variable but precisely known it should be possible gain additional insight into effects other factors. To evaluate this hypothesis, chain-end-thiolated PEOs were chemisorbed gold-coated silicon wafers such a range densities was obtained. Three different investigated: hydroxy-terminated chains molecular weight 600 (600-OH), methoxy-terminated 750 (750-OCH3), 2000 (2000-OCH3). In situ null ellipsometry used determine PEO chemisorption kinetics, ultimate densities, protein adsorption adsorbed quantities. With approach, ascertain chemistry (-OH, -OCH3), layer hydration on adsorption. The data obtained suggested properties related density (conformational freedom, hydration) main determinants resistance at up critical value ∼0.5 chain/nm2; value, minimum PEOs. For hydroxyl-terminated PEO, leveled off value. Thus appears major determinant greater than