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Improved initial osteoblast's functions on amino-functionalized titanium surfaces

Barbara J. Nebe 1Frank Lüthen 1Birgit Finke 2Karsten Schröder 2Claudia Bergemann 1Joachim Rychly 1Rainer Bader 3Andreas Ohl 2

1. University of Rostock, Dept. of Internal Medicine, Schillingallee 69, Rostock 18057, Germany
2. Institute of Low Temperature Plasma Physics (INP), Jahnstraße 19, Greifswald 17489, Germany
3. University of Rostock, Dept. of Orthopaedics, Doberaner Str. 142, Rostock 18055, Germany


Adhesion and spreading of cells on biomaterials are integrin-mediated processes. But recent findings indicate a key role of the matrix substance hyaluronan (HA) in interface interactions [Zimmermann E et al. 2002]. Because HA is a negatively charged molecule we assume that a biomaterial surface with an opposed charge could boost the cell's first contact to the surface until cells synthesize matrix proteins on its own to mediate the fundamental integrin contact. Polished titanium cp (Ra 0.19µm) was coated with a thin layer of a plasma polymer with amino-groups (Ti PPA). For this purpose, allylamine was polymerized with a microwave excited, pulsed, low pressure, gas-discharge plasma. Collagen was immobilized on Ti PPA with PEG-DA. Human osteoblasts MG-63 were cultured in serum-free DMEM to avoid masking of the coated surface with adsorbed proteins. Adhesion and cell cycle phases were calculated by flow cytometry. Time dependent spreading of cells and stained actin cytoskeleton were measured using confocal microscopy. For quantification of gene expression of osteogenic markers, we used a real-time TaqMan RT-PCR assay.
Ti PPA is significantly advantageous concerning initial adhesion and spreading during the first hours of cell's contact to the surface. The proliferation of osteoblasts is positively influenced. Otherwise there is only a slight effect on gene expression of the differentiation markers alkaline phosphatase, collagen I and bone sialoprotein. Therefore, future experiments are directed on the focus if the advantage in the initial contact phase of cells on amino- functionalized titanium is still to be detect on the level of differentiated cell function like protein expression and mineralization. Our results demonstrate that functionalization of titanium with positively charged amino-groups is sufficient enough to significantly improve initial steps of the cellular contact to the material surface.


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Presentation: Keynote lecture at E-MRS Fall Meeting 2006, Symposium J, by Barbara J. Nebe
See On-line Journal of E-MRS Fall Meeting 2006

Submitted: 2006-05-26 07:44
Revised:   2009-06-07 00:44