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

Paper BI-TuM5
Protein Adsorption to Plasma Functionalized Surfaces Using Surface Plasmon Resonance Spectroscopy and Atomic Force Microscopy

Tuesday, October 3, 2000, 9:40 am, Room 202

Session: Protein-Surface Interactions
Presenter: M.T. van Os, University of Twente
Authors: M.T. van Os, University of Twente
A.T.A. Jenkins, Max Planck Inst. for Polymer Res.
M. Péter, University of Twente
R. Förch, Max Planck Inst. for Polymer Res.
R.B. Timmons, The Univ. of Texas at Arlington
W. Knoll, Max Planck Inst. for Polymer Res.
G.J. Vancso, University of Twente
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Plasma modification provides a powerful tool to tailor the surface properties of materials. Surface characteristics such as wettability, chemistry and morphology are known to influence protein adsorption, and the subsequent attachment and spreading of cells on biomaterials. To improve the understanding of protein-surface interactions we functionalized gold and silicon surfaces with amino or ether groups, using radio frequency plasma polymerization of ethylenediamine, allylamine, cycloheptylamine and di(ethyleneglycol)vinylether (EO2V). The functional group density at the surface was controlled by using different monomers or by variation of the input power during the plasma deposition. The adsorption of the proteins fibrinogen, bovine serum albumin and immunoglobulin G to these surfaces was measured in situ with surface plasmon resonace spectroscopy. The tenacity of the protein adsorption on the different substrates was also measured, after removing elutable protein with 1% sodium dodecyl sulfate (SDS) solution. After drying, the protein layers were studied by tapping mode atomic force microscopy (TM-AFM). The results obtained show that both the protein adsorption to and the retention on the surfaces are affected greatly by the surface functionalities. All the amine functionalized surfaces showed a high affinity toward the proteins, and thin dense layers of adsorbed protein remained on these surfaces, even after rinsing with SDS solution. A large contrast in protein affinity was observed between the EO2V films polymerized at different power input conditions. A dramatic reduction in both initial adsorption and retention of all proteins was observed on these films with decreasing power. The low degree of cross-linking, as well as the high retention of ether content during the polymerization of EO2V under low power input conditions is thought to result in the production of biologically non-fouling surfaces.