Oriented Bioactive Glass (13-93) Scaffolds with Controllable Pore Size by Unidirectional Freezing of Camphene-Based Suspensions: Microstructure and Mechanical Response

Abstract

Scaffolds of 13-93 bioactive glass (composition 6.0 Na2O, 7.9 K2O, 7.7 MgO, 22.1 CaO, 1.7 P2O5, 54.6 SiO2 (mol.%)) containing oriented pores of controllable diameter were prepared by unidirectional freezing of camphene-based suspensions (10vol.% particles) on a cold substrate (−196°C or 3°C). By varying the annealing time (0-72h) to coarsen the camphene phase, constructs with the same porosity (86±1%) but with controllable pore diameters (15-160μm) were obtained after sublimation of the camphene. The pore diameters had a self-similar distribution that could be fitted by a diffusion-controlled coalescence model. Sintering (1h at 690°C) was accompanied by a decrease in porosity and pore diameter, the magnitude of which depended on the pore size of the green constructs, giving scaffolds with a porosity of 20-60% and average pore diameter of 6-120μm. The compressive stress vs. deformation response of the sintered scaffolds in the orientation direction was linear, followed by failure. The compressive strength and elastic modulus in the orientation direction varied from 180MPa and 25GPa (porosity=20%) to 16MPa and 4GPa (porosity=60%), respectively, which were 2-3 times larger than the values in the direction perpendicular to the orientation. The potential use of these 13-93 bioactive glass scaffolds for the repair of large defects in load-bearing bones, such as segmental defects in long bones, is discussed.

Department(s)

Nuclear Engineering and Radiation Science

Second Department

Materials Science and Engineering

Keywords and Phrases

Bioactive Glass; Scaffolds; Bone Repair; Unidirectional Freeze Casting; Camphene

International Standard Serial Number (ISSN)

1742-7061

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2011 Elsevier, All rights reserved.

Publication Date

01 Jan 2011

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