Porous Bioactive 3-D Glass Fiber Scaffolds for Tissue Engineering Applications Manufactured by Sintering Technique

In this study novel osteoconductive porous scaffolds were manufactured by sinte ring bioactive glass fibers with diameter of 100 μm and length of 3 mm. The relative porosity of the scaffolds and siz e of the pores in structure can be controlled by altering the sinteri ng temperature. By increasing the sintering temperature from 690 °C to 740 °C the relative porosity is decreased from 80% to 5 % by volume and mean pore size values are decreased from 420 μm to 125 μm. By sintering technique the porosity and pore sizes of the scaffold can be controlled and this e nables the manufacture of porous scaffolds with tailor made characteristics. Introduction Hench and colleagues first introduced bioactive glasses in l969. Since that time numerous clinical studies have demonstrated that bioactive glasses perform well e.g. as artificial bone graft materials. By now bioactive glasses have mainly been used in their particul te form, but there is interest to expand the diversity of bioactive glass devices. Numerous studies hav demonstrated that it is advantageous for an artificial bone filler material to have sufficient porosit y t allow bone ingrowth. The interconnection between the pores and optimal pore size are also c riteria which optimal bone filler should full fill. Brink and colleagues found that new bioactive glasses in the system Na 2O K2O MgO CaO B2O3 P2O5 SiO2 have large working range and this allows the manufacturing of fibers from these glasses. Also further heat treatments ar e possible with these glasses, so that bioactivity of the materials is retained [1]. The aim of this study was to manufacture porous networks by sinter ing bioactive glass fibers. From the obtained 3-D scaffolds the total porosity and mean pore size values were further characterized. Materials and Methods The composition of the bioactive glass 13-93 used in this study was as follows; 6 wt-% Na2O; 12 wt-% K2O; 5 wt-% MgO; 20 wt-% CaO; 4 wt-% P 2O5 ; and 53 wt-% of SiO2. Glass fibers, with mean diameter of 100 μm, were manufactured from the glass by melt spinning [2]. The fibe rs w re further chopped into a length of 3 mm and then placed into a cylindri cal ceramic mould with diameter of 12 mm and height of 15 mm. The mould containing the chopped fi bers was then placed into a heated furnace for 45 minutes. The sintering temperatures used (one sample for each temperature) were as follows; 690 °C, 700 °C, 710 °C, 720 °C, 730 °C and 740 °C. From the obtained rigid networks, the relative porosity and pore size distribut ion were characterized. The specimens were first cast into epoxy and sections with two-dimens onal (2-D) image were achieved by polishing the samples. From the 2-D images the ratio of the g lass and epoxy was measured to Key Engineering Materials Online: 2003-05-15 ISSN: 1662-9795, Vols. 240-242, pp 237-240 doi:10.4028/www.scientific. net/KEM.240-242.237 © 2003 Trans Tech Publications Ltd, Switzerland 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 Trans Tech Publications Ltd, www.scientific. net. (Semanticscholar.org-13/03/20,21:20:36) obtain relative porosity value. From each sample three sections wer e analysed. The 2-D images were further used to estimate pore sizes in scaffold. All the por s bigger that 100 μm in networks were identified as elliptical areas and the diameters of the ellipses were measured by using microscope (Smaertscope flash, Optical Gaging Products Inc.) a nd image analysis software (Image tool 2.0, UTH SCSA). The mean pore size values were identified for samples sintered at different temperatures. Scanning electron microscope (Jeol T100, Japan) was used to view sc affold.