ELECTROKINETIC CHARACTERIZATION OF HYDROPHILIC POLYMER-COATINGS OF BIOTECHNICAL SIGNIFICANCE

Analytical microparticle electrophoresis was used to characterize vari ous polymer coatings known to control protein adsorption and related p henomena of biotechnical significance. The electrophoretic mobility of polystyrene latex microspheres and the electro-osmosis associated wit h quartz capillaries were characterized over the pH range 2-11. Such c haracterization provides information related to surface modification. Aminopropylsilane and mercaptopropylsilane were shown to be effective sublayers for covalent attachment of hydrophilic polymers to quartz gl ass surfaces. Poly(ethylenimine) was similarly verified as an effectiv e sublayer for polystyrene latex. Polymer coatings based on poly(ethyl ene glycol) and three polysaccharides, dextran, ethyl(hydroxyethyl)cel lulose, and hydroxypropylcellulose, were found to reduce capillary ele ctro-osmosis and microsphere electrophoretic mobility significantly ov er a broad pH range. This reduction corresponds to the ability of thes e coatings to reduce protein adsorption and control surface wetting by aqueous polymer two-phase systems.