title: Effect of biomaterial surface properties on fibronectin-alpha5beta1 integrin interaction and cellular attachment.
abstract: The ability of fibronectin (Fn) to mediate cell adhesion through binding to alpha(5)beta(1) integrins is dependent on the conditions of its adsorption to the surface. Using a model system of alkylsilane SAMs with different functional groups (X=OH, COOH, NH(2) and CH(3)) and an erythroleukemia cell line expressing a single integrin (alpha(5)beta(1)), the effect of surface properties on the cellular adhesion with adsorbed Fn layers was investigated. (125)I-labeled Fn, a modified biochemical cross-linking/extraction technique and a spinning disc apparatus were combined to quantify the Fn adsorption, integrin binding and adhesion strength, respectively. This methodology allows for a binding equilibrium analysis that more closely reflects cellular adhesion found in stable tissue constructs in vivo. Differences in detachment strength and integrin binding were explained in terms of changes in the adhesion constant (psi, related to affinity) and binding efficiency of the adsorbed Fn for the alpha(5)beta(1) integrins (CH(3) approximately NH(2)<COOH approximately OH) and the resulting average bond strength. Fn interacted more strongly with alpha(5)beta(1) integrins when adsorbed on COOH vs. OH surfaces suggesting that negative charge may be a critical component of inducing efficient cellular adhesion. As evident by the low psi values, Fn adsorbed on NH(2) and CH(3) surfaces interacted inefficiently with alpha(5)beta(1) integrins and also possessed significant non-specific components to adhesion. Lastly, comparison of cellular adhesion to Fn adsorbed onto smooth and rough surfaces showed that nano-scale roughness altered cellular adhesion by increasing the surface density of adsorbed Fn.
authors.affiliation: Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA. markhl@alumni.upenn.edu
authors.forename: Mark H
authors.initials: MH
authors.lastname: Lee
authors.forename: Paul
authors.initials: P
authors.lastname: Ducheyne
authors.forename: Laura
authors.initials: L
authors.lastname: Lynch
authors.forename: David
authors.initials: D
authors.lastname: Boettiger
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Composto
mesh_terms: D001672:Biocompatible Materials / Q000494:pharmacology*; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D003432:Cross-Linking Reagents / Q000494:pharmacology; D005353:Fibronectins / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D039081:Integrin alpha5beta1 / Q000187:drug effects* / Q000378:metabolism; D012821:Silanes / Q000494:pharmacology*; D013388:Succinimides / Q000494:pharmacology; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D005353:Fibronectins; D039081:Integrin alpha5beta1; D012821:Silanes; D013388:Succinimides; C035759:3,3'-dithiobis(sulfosuccinimidyl propionate)