Protein repellant silicone surfaces by covalent immobilization of poly(ethylene oxide)

Polydimethylsiloxane elastomers were surface modified with passivating polyethylene oxide (PEO) polymers of different molecular weights, both monofunctional and bifunctional. Following the introduction of Si-H groups on the surfaces by acid-catalyzed equilibration in the presence of polymethylhydrosiloxane, the PEO was linked by platinum-catalyzed hydrosilylation. ATR-FTIR, X-ray photoelectron spectroscopy (XPS) and water contact angle results confirmed that the PEO was successfully grafted to the silicone rubber. Atomic force microscopy and XPS suggested that surface coverage with PEO was very high on the modified surfaces but not complete. The protein-resistant properties of the PEO-modified surfaces were demonstrated by measuring the adsorption of fibrinogen from both buffer and plasma. Fibrinogen adsorption from buffer to the PEO-modified surfaces was reduced by more than 90% compared with controls.