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Plasma-assisted amino functionalized titanium - a surface for enhanced osteoblast functionality
|Birgit Finke 1, Frank Lüthen 2, Karsten Schröder 1, Barbara J. Nebe 2, Claudia Bergemann 2, Rainer Bader 2, Joachim Rychly 2, Andreas Ohl 1|
1. Institute of Low Temperature Plasma Physics (INP), Jahnstraße 19, Greifswald 17489, Germany
Titanium and its alloys are widespread applied in bone replacement. It is well known, that the behaviour of osteoblasts is determined by the surface characteristics like roughness and oxide composition. In more detail, surface properties control the adhesion of biomolecules, which induce a cellular response. Hyaluronan (HyA) could be a key substance for the design of the interface between implant and osteoblasts. HyA is a negatively charged molecule, which will preferably adsorb to a positively charged titanium surface. Therefore, a thin plasma polymerized film with positively charged amino groups is fixed at the titanium surface. The polished metal surface was activated by a low pressure oxygen plasma for the fixation of an about 50-100 nm thin layer of a plasma-polymerized allylamine. Therefore, a microwave-excited pulsed plasma was applied at a pressure of 50 Pa. Collagen coupling was applied to compare cell adhesion to the plasma polymer with cell response to ECM molecules.The coated surface was analyzed by XPS, FTIR, Zeta potential and contact angle measurements.Plasma polymerization only partially sustains the structure of the allylamine molecule. The nitrogen concentration at the film surface is N/C=25 % and therewith near the theoretical value of a chemically polymerized film (N/C=33 %). Amino groups are present, confirmed by Zeta potential, FTIR, and chemical derivatization XPS measurements. The film properties differ from chemically polymerized allylamine in oxygen content and nitriles, verified by XPS and FTIR spectra. Contact angle measurements demonstrate a medium hydrophilic film surface advantageous for cell adhesion. Osteoblast cell adhesion on allylamine plasma polymer coated titanium surfaces was superior to covalent coupled collagen.
Presentation: Oral at E-MRS Fall Meeting 2006, Symposium J, by Karsten Schröder
See On-line Journal of E-MRS Fall Meeting 2006
Submitted: 2006-05-15 18:02 Revised: 2009-06-07 00:44