Adsorption of proteins onto surfaces containing end-attached oligo(ethylene oxide): a model system using self-assembled monolayers

Abstract

This paper reports a study of the adsorption of four proteins-fibrinogen, lysozyme, pyruvate kinase, and RNAse A-to self-assembled monolayers (SAMs) on gold. The SAMs examined were derived from thiols of the structure HS(CH 2 ) 10 R, where R was CH 3 , CH 2 OH, and oligo(ethylene oxide). Monolayers that contained a sufficiently large mole fraction of alkanethiolate groups terminated in oligo(ethylene oxide) chains resisted the kinetically irreversible, nonspecific adsorption of all four proteins. Longer chains of oligo(ethylene oxide) were resistant at lower mole fractions in the monolayer. Resistance to the adsorption of proteins increased with the length of the oligo(ethylene oxide) chain: the smallest mole fraction of chains that prevented adsorption was proportional to n -0.4 , where n represents the number of ethylene oxide units per chain