Adsorption of blood proteins on glow-discharge-modified polyurethane membranes

Polyurethanes are a class of polymers that have a wide range of application s in the medical field although their blood compatibility still needs impro vement. In order to obtain medical purity, this study prepared membrane-for m polyurethanes from toluene 2,4-diisocyanate (TDI) and poly(propylene ethy lene glycol) without the addition of any ingredients such as solvents, cata lysts, or chain extenders. The aim was to increase surface hydrophilicity a nd improve blood compatibility. Therefore, the prepared membranes were modi fied by treatment with oxygen or argon plasmas. Characterizations of the sa mples were achieved by contact-angle and water-uptake studies as well as fr om atomic force microscope (AFM) pictures. It was found that oxygen-modifie d samples were more hydrophilic than argon-modified samples. The AFM images showed that surface roughness increased with plasma treatment. The protein adsorption experiments carried out with single protein solutions demonstra ted that the adsorption of bovine serum albumin and fibrinogen decreased dr astically by increasing the applied power and exposure time of the glow dis charge. A similar decrease in the adsorption of protein was also observed f or human blood proteins. The alterations of the conformational structures o f the adsorbed proteins were examined by fluorescence spectrophotometry. Si milar spectra with the same maximum wavelength were observed for native and desorbed proteins. These results showed that no denaturation of the protei ns occurred upon adsorption on the surfaces of the prepared membranes. (C) 2001 John Wiley & Sons, Inc.