Adsorption of disulfide-modified polyacrylamides to gold and silver surfaces as cushions for polymer-supported lipid bilayers

作者：Munro JC; Frank CW^*

来源：Polymer, 2003, 44(20): 6335-6344.

DOI：10.1016/S0032-3861(03)00659-1

• lipopolymer
• polymer adsorption
• quartz crystal microbalance

Inclusion of a polymer cushion between a lipid bilayer membrane and solid surface has been suggested as a means to provide a soft, deformable layer that will allow for transmembrane protein insertion and mobility. In this study, we evaluate the properties of a disulfide- and lipid-modified polyacrylamide polymer cushion. High molecular weight random copolymers with various degrees of disulfide and lipid substitution were synthesized. X-ray photoelectron spectroscopy (XPS) was used to determine quantitatively the percentage of disulfide groups bound to gold and silver surfaces. A quartz crystal microbalance with dissipation (QCM-D) was used to study the adsorption process and resulting film properties in situ. The presence of backbone-surface interactions leads to a competition between physisorption of the acrylamide backbone and chemisorption of the disulfide side-chains. This competition limits the degree of chemisorption to gold and silver surfaces. For a polyacrylamide with 10 mol% disulfide side-chains, 78% of the side-chains covalently bind to silver and only 41% bind to gold. The undesired physisorption of the acrylamide backbone leads to adsorption of the homopolymer itself. In addition, film thicknesses, as indicated by both XPS and QCM-D, are limited to 15-30 Angstrom. The QCM-D results for all films indicate the fort-nation of relatively rigid films, rather than the soft, deformable films desired for a lipid membrane polymer cushion.

• 出版日期2003-9