Fogorvosi szemle, 2005 (98. évfolyam, 1-6. szám)

2005-04-01 / 2. szám

84

FOGORVOSI SZEMLE ■ 98. évf. 2. sz. 2005.

K. TURZÓ, I.K. PELSŐCZI, C. GERGELY*, A. FAZEKAS, F. CUISINIER*

Department of Dentistry and Oral Surgery, University of Szeged, Flungary, *INSERM U595, Université Louis Pasteur Strasbourg, France

STRUCTURAL CHARACTERIZATION OF POLYELECTROLYTE MULTILAYERS BY ATOMIC FORCE MICROSCOPE

Objectives: Chemical modification of biomaterial surface with polyelectrolyte self-assembled films is a promising method for their bio-functionalisation to achieve improved biointegration. Methods: Poly-L-lysine (PLL) and poly-L-glutamic acid (PGA) polyelectrolyte (PE) films were deposited onto titanium and silica substrates by sequential adsorption methods in two ways: build-up either in situ, in the liquid cell of the atomic force microscope (AFM) or by an automatic immersion technique (dry samples). In this way possible differences of film surface characteristic between in situ and immersion build-up method were investigated which is an important aspect of industrial applicability. Results: The autoassembled layers were adsorbed in an irreversible way

on both substrates and the films reveal granular pattern up to 10 bilayers, independent of the buildup procedure used. The grain diameters are between 200 and 400 nm for both substrates. However the PE films deposited on the two substrates show a different behaviour with increasing number of layer. The stability in time of films composed by 8 bilayers is almost the same for the two substrates. In case of titanium a better stability in time can be observed and the films obtained by the ex situ and in situ methods revealed similar behaviour. In case of silica at the 6th bilayer a significant decrease of the film roughness occurs. Upon rehydration of dry samples both on silica and titanium surface the roughness values reach the values measured in situ. The stability and rehydration capability of PLL/PGA multilayer coatings built on titanium by immersion is of prime importance for their biomedical use. In case of PE films built on titanium substrate a significant pH effect can be observed. The AFM proved to be a valuable method for visualizing even protein molecules like fibronectin.

Acknowledgment: This work was supported by the SIMI-NAS Project of the 5th FWPofthe European Commission (GRD3-200T61801). Keywords: osseointegration, titanium implants, surface modification, self-assembled films, atomic force microscopy, fibronectin