Surface modification of biomaterials to control adhesion of cells.

The layer-by-layer technique was used to build-up polyelectrolyte multilayers (PEMs) composed of heparin, an anionic glycosaminoglycan (GAG) and chitosan, a cationic biodegradable polysaccharide on model biomaterial surfaces. The surface coatings shall control adhesion of cells and thus their subsequent proliferation and differentiation. PEMs were characterized physicochemically by static contact angle and quartz crystal microbalance (QCM) measurements. Variations in procedure parameters such as the pH value of the solutions were crucial to the formation process and surface properties in terms of wettability and mass increase. Cell-surface interactions were studied with human fibroblast on PEMs. It was found that the pH value of solutions had a strong impact on cell adhesion making surfaces extremely cytophobic or moderately cytophilic. Adsorption of fibronectin to the terminal heparin layer could be used to increase cell adhesion in a concentration-dependent manner.