Key Engineering Materials Vols. 361-363 (2008) pp. 1111-1114 online at http://www.scientific.net © (2008) Trans Tech Publications, Switzerland

Preliminary Results of in vitro Study of Cell Growth in a 45S5 Bioactive Glass as Bone Substitute using Scanning Electron and Confocal Microscopies. R. Maksoud1, a, L. Lefevbre2, b, L. Heinrich1, c, L. Gremillard2, d, J. Chevalier2, e, D.J. Hartmann1, f 1

Université de Lyon, Unité « Réparation Tissulaire, Interactions Biologiques et Biomatériaux » (RTI2B), ISPB-Faculté de Pharmacie, 8 av. Rockefeller 69373 Lyon Cx 08, France 2

INSA-LYON, UMR CNRS 5510-MATEIS, bat. Blaise Pascal, 20 av. Albert Einstein, 69621 Villeurbanne, France a

[email protected], [email protected], [email protected], [email protected], e [email protected], [email protected]

c

Keywords: bone substitute; porous bioglass; cell culture; scanning electron microscopy; confocal microscopy.

Abstract. The aim of this study was to evaluate the cytocompatibility, cell ingrowth and extracellular matrix deposition of a newly developed porous bioactive glass as a bone substitute. Two types of bioactive glass, different in their pore size (75 and 20 ppi, resp. ~350 and ~1200 µm), were used in this study. The materials were seeded with human osteoblastic (MG63) and fibroblastic (M-228 F01 and M-191 F01) cell lines. The cells were visualized by two techniques, scanning electron microscopy and confocal microscopy. For confocal microscopy cell nuclei were labeled with propidium iodide (IP) and the extracellular matrix components (type I collagen and osteocalcin) by specific antibodies. Cells and matrix were visualized by fluorescence. The bioactive glass used in this study was shown to be non cytotoxic. Cell growth and colonization at the surface and in the depth of the material were observed. Extracellular matrix deposition was also demonstrated which proved the proper biofunctionality of the biomaterial. Scanning electron microscope allowed us to visualize cells at a high magnification at the surface of the bioglass and evidenced that the biomaterials were covered by a sheet of cells with their matrix; on the other hand, confocal microscopy permitted us to observe cell ingrowth and matrix deposition within the depth of the substitute. We showed that extracellular matrix was synthesized mainly in the upper levels where the cell population was the most confluent. In summary, this porous bioglass appears promising for bone substitution. Introduction Nowadays, due either to pathologies or trauma, many tissues in human have to be repaired, restored or replaced. As far as bone is concerned, several grafting techniques are possible, autografts, allografts or xenografts. One advantage of autograft is that there is no immune reaction. However the patient endures pain and this procedure requires two surgical operations. The two other types of graft imply to take a piece of bone from a foreign mammalian (human or animal) and to place it into the patient. This method can induce immune response or transmission of diseases. Since 1988, it was proven that organ and tissue grafts could be contaminated, in particular by HIV during the asymptomatic phase [1, 2]. Security considerations lead scientists to consider the use of “artificial” bone [3]. Among these materials bioceramics based on hydroxyapatite and tricalcium phosphate or dense bioactive glass have been used as bone substitute in orthopaedic, craniofacial and oral surgeries. Since 1970, calcium phosphate systems, in particular hydroxyapatite, have been the subject of intensive investigation for medical implants, because they are usually bioactive and can bind directly to bone. Their usually low mechanical strength limited their use in clinical All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of the publisher: Trans Tech Publications Ltd, Switzerland, www.ttp.net. (ID: 193.48.219.8-17/09/07,10:29:13)