Permeability of porous gelcast scaffolds for bone tissue engineering

• Published in: Journal of porous materials 2010-10, Vol.17 (5), p.615-627
• Main Authors: Innocentini, M. D. M., Faleiros, R. K., Pisani, R., Thijs, I., Luyten, J., Mullens, S.
• Format: Article
• Language: English
• Subjects: Catalysis; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Physical Chemistry
• ISSN: 1380-2224; 1573-4854
• DOI: 10.1007/s10934-009-9331-2

The permeability of metallic and ceramic open-cell foams prepared by the gelcasting technique was assessed by fitting of Forchheimer’s equation to experimental pressure drop curves. The ceramic composition was based on pure hydroxyapatite, while the metallic composition was based on titanium metal. Experimental Darcian ( k 1 ) and non-Darcian ( k 2 ) permeability constants displayed values in the range 0.40–3.24 × 10 −9 m 2 and 3.11–175.8 × 10 −6 m respectively. Tortuosity was evaluated by gas diffusion experiments and ranged from 1.67 to 3.60, with porosity between 72 and 81% and average hydraulic pore size between 325 and 473 μm. Such features were compared to data reported in the literature for cancellous bones and synthetic scaffolds for bone graft. A detailed discussion concerning the limitations of Darcy’s law for fitting laboratory data and for predicting fluid flow through scaffolds in real biomedical applications is also performed. Pore size was obtained by image analysis and was also derived from permeation-absorption-diffusion experiments. In both cases, values were within the range expected for porous scaffolds applications.