Effects on Interfacial Properties and Cell Adhesion of Surface Modification by Pectic Hairy Regions Marco Morra,* Clara Cassinelli, and Giovanna Cascardo Nobil Bio Ricerche, Str. S. Rocco 36, 14018 Villafranca d’Asti, Italy Marie-Danielle Nagel Universite ´ de Technologie de Compie ` gne, UMR 6600 Domaine Biomate ´ riaux-Biocompatibilite ´ , Centre de Recherches de Royallieu, Compie ` gne, France Claudio Della Volpe, Stefano Siboni, Devid Maniglio, and Marco Brugnara Department of Materials Engineering and Industrial Technologies, University of Trento, Trento, Italy Giacomo Ceccone Institute for Health and Consumer Protection, European Commission Joint Research Center, Ispra, Italy Henk A. Schols Laboratory of Food Chemistry, Wageningen University, Wageningen, The Netherlands Peter Ulvskov Biotechnology Group, Danish Institute of Agricultural Sciences Frederiksberg, Denmark Received March 19, 2004; Revised Manuscript Received July 31, 2004 Polystyrene Petri dishes, aminated by a plasma deposition process, were surface modified by the covalent linking of two different enzymatically modified hairy regions (HRs) from pectin containing, for example, rhamnogalacturonan-I and xylogalacturonan structural elements. The two polysaccharide preparations share the same structural elements of apple pectin, but the relative amounts and lengths of the neutral side chains present differ. Surface analysis by X-ray photoelectron spectroscopy, contact angle measurement, and atomic force microscope (AFM) force-separation curves was used to characterize the effects on surface chemistry and interfacial forces of the surface modification process. Cell adhesion experiments using continuous L-929 fibroblasts and primary aortic smooth muscle cells were performed to evaluate the effect of the polysaccharide nature on cell adhesion. Results show that immobilization of the HR affects the interfacial field of forces and the cell behavior: “equilibrium” contact angles, obtained by a recently introduced vibrational approach, decrease after HR immobilization reaching a value close to 20°. AFM force-separation curves show a more extended (or softer) interface in the case of the HR bearing longer side chains. Accordingly, depending on the HR preparation, cells shifted from spread morphology and adhesion behavior quantitatively comparable to that observed on conventional tissue culture polystyrene to rounded morphology and significantly lower adhesion. These data show that engineering of plant pectins can be a valuable tool to prepare novel and finely tuned polysaccharides having different chemico-physical and biological properties, to be used in the surface modification of medical devices and materials. Surface modification of medical materials and devices by polysaccharides is presently a topic of great interest, both at a fundamental and applied level. 1,2 Recent literature actually shows that this field is undergoing significant advancement and evolution. Except for heparin, whose widespread use as a coating in blood-contacting devices exploits a specific interaction, 3-6 hydrophilic polysaccharides, such as dextran, have long been used as “bio-passive” materials, because of their extensive hydration and low protein adsorption proper- ties. 7,9 Naturally occurring alginate and hyaluronan have been used mostly because of their favorable physical properties, primarily extensive hydration, in wound healing and post- surgery applications. 10-12 Contrary to this biopassive sce- nario, recent advancements stress the biological and bioactive 2094 Biomacromolecules 2004, 5, 2094-2104 10.1021/bm049834q CCC: $27.50 © 2004 American Chemical Society Published on Web 09/25/2004