AVS 47th International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI-TuM

Paper BI-TuM7
Assessment of Fibronectin Conformation Adsorbed to Polytetrafluoroethylene Surfaces from Serum Protein Mixtures and Correlation to Support of Cell Attachment in Culture

Tuesday, October 3, 2000, 10:20 am, Room 202

Session: Protein-Surface Interactions
Presenter: D.W. Grainger, Colorado State University
Authors: D.W. Grainger, Colorado State University
G. Pavon-Djavid, Universite Paris, France
V. Migonney, Universite Paris, France
M. Josefowicz, Universite Paris, France
Correspondent: Click to Email
Fluoropolymer surfaces in biotechnology applications are notorious for tightly adsorbing proteins that do not support cell attachment. Reasons for this remain confusing but surround both the population and conformation of proteins adsorbed competitively from physiological milieu that do not interact with cell adhesion receptors. In this study, polytetrafluoroethylene (PTFE) surfaces were exposed to buffered aqueous solutions containing radio labeled (@super 125@I) human fibronectin (Fn), fibronectin:serum albumin (BSA) binary mixtures of various ratios, or whole human plasma dilutions (one hour). Total adsorbed fibronectin and albumin following rinsing were quantified on PTFE. @super 125@I-labeled monoclonal antibodies against either the fibronectin cell adhesion (containing the RGDS integrin recognition motif) or the fibronectin amino terminal domains were used to probe accessibility of each of these fibronectin regions post-adsorption. Human umbilical vein endothelial cells (HUVECs) were then cultured on PTFE surfaces pre-exposed to each of these protein adsorption conditions and compared to identical conditions on tissue culture polystyrene (TCPS) controls. Fibronectin adsorption to PTFE is dependent upon the concentration of albumin co-adsorbing from solution: albumin out-competes fibronectin for PTFE surface sites even at elevated nonphysiological Fn:HSA ratios. Antibodies against Fn do not readily recognize Fn adsorbed on PTFE as the HSA co-adsorption concentration in either binary mixtures or in plasma increases, indicating albumin masking of adsorbed Fn. At higher Fn:HSA ratios, albumin co-adsorption actually improves anti-Fn antibody recognition of adsorbed Fn. HUVEC attachment efficiency to PTFE after protein adsorption correlates with amounts of Fn adsorbed and levels of anti-Fn antibody recognition of Fn on PTFE, linking cell attachment to integrin recognition of adsorbed Fn density and Fn adsorbed conformation on PTFE surfaces.