AVS 50th International Symposium
    Biomaterial Interfaces Monday Sessions
       Session BI-MoM

Paper BI-MoM8
Nanoscale Control of ECM Proteins for Cell Adhesion

Monday, November 3, 2003, 10:40 am, Room 307

Session: Protein-Surface Interactions
Presenter: S. Chen, University of Washington
Authors: H. Wang, University of Washington
L. Liu, University of Washington
S. Chen, University of Washington
T. Barker, University of Washington
H. Sage, University of Washington
B.D. Ratner, University of Washington
S. Jiang, University of Washington
Correspondent: Click to Email
Osteopontin (OPN) is an important extracellular matrix protein shown to function in wound healing, inflammation and foreign body reaction and has been identified as a potential target for engineered biomaterials. The secreted protein acidic and rich in cystein (SPARC/osteonectin/BM-40) is associated with events characterized by changes in cell shape and mobility. In the work, we first report control of OPN orientation and conformation on charged self-assembled monolayers (SAMs) for cell adhesion. Our atomic force microscope (AFM) results show that the amount of adsorbed OPN on -COOH surface is slightly less than that on -NH2 surface. Results from in vitro cell adhesion assays show that on NH2 surface BAEC adhesion and spreading are more. By comparing these results, it is suggested that the orientation/conformation of OPN on -NH2 positively charged surface is more favorable for cell interactions than on -COOH negatively charged surface. Second, AFM is used to image the binding of OPN onto individual triple-helical collagen I monomer on freshly cleaved mica for the first time. We also use anti-OPN antibody to assist for better visualization. Analysis of AFM results clearly shows binding patterns of OPN to collagen I. Finally, the interactions of SPARC with ECM proteins, such as collagen I and fibronectin, are characterized and quantified using AFM and surface plasma resonance (SPR). Cell culture and adhesion assays are used to study SPARC as a modulator of the adhesive process of cells seeded on ECM proteins. The influence of SPARC-collagen I interaction is studied using smooth muscle cells while the influence of SPARC-fibronectin interaction is studied using endothelial cells.