2344
Coating Polystyrene Particles by Adsorption of
Hydrophobically Modified Dextran
C . Fournier, M. Leonard,* I. Le Coq-Leonard, and E . Dellacherie
L CPM, URA C NRS 494, ENSIC B.P. 4 51, 54001 Nancy, France
Received March 14, 1995. I n Final Form: May 22, 1995@
I n order to decrease their hydrophobicity and thus t o reduce the protein adsorption at their surface, polystyrene-divinylbenzene (PS-DVB) particles have been coated with dextran. To favor its adsorption, the polysaccharide was previously substituted with low concentrations of phenoxy groups. The amount of dextran adsorbed onto the PS-DVB surface was examined as a function of the polymer concentration, and various samples of beads, differing in surface dextran concentration, were prepared. The adsorbed polymeric layer was then chemically cross-linked and its stability was checked in the presence of sodium dodecyl sulfate. The hydrophiliccharacter of the various resulting beads was evaluated toward the adsorption ofbovine serum albumin, a stronglyhydrophobic protein. By this study, the conditionsfor coating polystyrene particles were optimized and the dextran layer was shown t o greatly reduce the nonspecific adsorption of proteins.
I. Introduction
Polymer adsorption a t solid-liquid interfaces is a widely studied phenomenon as connected with many important processes including colloidal stabilization, flocculation, adhesion, or coating.
T he reduction of protein adsorption by coating hydrophobic surfaces is of significant importance for many biomedical and biotechnological applications. Particularly, there is a n increasing interest in the use of polystyrene particles for liquid chromatography of biological molecules. These materials exhibit excellent mechanical properties and a good chemical stability over a large range of pH.IJ However, to use this packing material for the chromatography of proteins, it is essential to make the bead surface