The aim of this research study is the preparation and characterization of graded glass—ceramic scaffolds that are able to mimic the structure of the natural bone tissue, formed by cortical and cancellous bone. The material chosen for the scaffolds preparation is a glass belonging to the system SiO 2—P2O5—CaO—MgO—Na 2O—K2O (CEL2). The glass was synthesized by a conventional melting—quenching route, ground, and sieved to obtain powders of specific size. The scaffolds were fabricated using different methods: polyethylene burn-off, sponge replication, a glazing-like technique, and combinations of these methods. The scaffolds were characterized through morphological observations, density measurements, volumetric shrinkage, mechanical tests, and in vitro bioactivity tests. The features of the scaffolds prepared using the different methods were compared in terms of morphological structure, pores content, and mechanical strength. The proposed scaffolds effectively mimic the cancellous/cortical bone system in terms of structure, porosity, and mechanical strength, and they exhibit a highly bioactive behavior. Therefore, these graded grafts have a great potential for biomedical applications and can be successfully proposed for the substitution of load-bearing bone portions.
Bonfield, W. ( 1984). Elasticity and Viscoelasticity of Cortical Bone, In: Hastings, G.W. and Ducheyne, P. (eds), Natural and Living Biomaterials, p. 43, Boca Raton, Florida, CRC Press .
2.
Van Audekercke, R. and Martens, M. ( 1984). Mechanical Properties of Cancellous Bone, In: Hastings, G.W. and Ducheyne, P. (eds), Natural and Living Biomaterials, p. 89, Boca Raton, Florida, CRC Press.
3.
Cowin, S.C. ( 1984). The Mechanical Properties of Cancellous Bone, In: Cowin, S.C. (ed.), Bone Mechanics, p. 130, Boca Raton, Florida, CRC Press.
4.
Thompson, J.D. and Hench, L.L. (1998). Mechanical Properties of Bioactive Glasses, Glass-ceramics and Composites, J. Eng. Med., 212: 127-136.
5.
Goldstein, S.A. (1987). The Mechanical Properties of Trabecular Bone: Dependence on Anatomic Location and Function, J. Biomech., 20: 1055-1061.
6.
Schlickewei, W. and Schlickewei , S. (2007). The Use of Bone Substitutes in the Treatment of Bone Defects - The Clinical View and History, Macromol. Symp., 253: 10-23.
7.
Hoop, S.G., Dahners, L.G. and Gilbert, J.A. ( 1989). Study of the Mechanical Strength of Long Bone Defects Treated with Various Bone Autograft Substitutes: An Experimental Investigation in the Rabbit, J. Orthop. Res., 7: 579-584.
8.
Ries, M.D., Gomez, M.A., Eckhoff, D.G., Lewis, D.A., Brodie, M.R. and Wiedel, J.D. ( 1994). An In Vitro Study of Proximal Femoral Allograft Strains in Revision Hip Arthroplasty, Med. Eng. Phys., 16: 292-296.
9.
Jones, J. and Hench, L.L. ( 2003). Regeneration of Trabecular Bone using Porous Ceramics, Curr. Opin. Solid State Mater. Sci., 7: 301-307.
10.
Ozawa, N., Negami, S., Odaka, T., Morii, T. and Koshino, T. ( 1989). Histological Observations on Tissue Reaction of the Rat Calcaneal Tendon to Sintered Hydroxyapatite, J. Mater. Sci. Lett., 8: 869-871.
11.
LeGeros, R.Z. (1993). Biodegradation and Bioresorption of Calcium Phosphate Ceramics, Clin. Mater., 14: 65-88.
12.
LeGeros, R.Z. , Lin, S., Rohanizadeh, R., Mijares, D. and LeGeros, J.P. (2003). Biphasic Calcium Phosphate Bioceramics: Preparation, Properties and Applications, J. Mater. Sci.: Mater. Med., 14: 201-209.
13.
Thomson, R.C. , Yaszemski, M.J., Powers, J.M. and Mikos, A.G. (1998). Hydroxyapatite Fiber Reinforced Poly(α-hydroxy ester) Foams for Bone Regeneration, Biomaterials, 19: 1935-1943.
14.
Xigeng, M., Tan, D.M., Jian, L., Yin, X. and Crawford, R. ( 2008). Mechanical and Biological Properties of Hydroxyapatite/Tricalcium Phosphate Scaffolds Coated with Poly(lactic-co-glycolic acid), Acta Biomater., 4: 638-645.
15.
Hench, L.L. and Anderson, O. ( 1993). Bioactive Glasses, In: Hench, L.L. and Wilson, J. (eds), An Introduction to Bioceramics, p. 41, Singapore, World Scientific.
16.
Hench, L.L. (1998). Bioactive Materials: The Potential for Tissue Regeneration, J. Mater. Biomed. Res. , 41: 511-518.
17.
Jones, J.R. , Ehrenfried, L.M. and Hench, L.L. (2006). Optimising Bioactive Glass Scaffolds for Bone Tissue Engineering, Biomaterials , 27: 964-973.
18.
Vitale-Brovarone, C., Verné, E. and Appendino, P. (2006). Macroporous Bioactive Glass-ceramic Scaffolds for Tissue Engineering, J. Mater. Sci.: Mater. Med., 17: 1069-1078.
19.
Vitale-Brovarone, C., Verné, E., Robiglio, L., Appendino, P., Bassi, F., Martinasso, G., Muzio, G. and Canuto, R. (2007). Development of Glass-ceramic Scaffolds for Bone Tissue Engineering: Characterisation, Proliferation of Human Osteoblasts and Nodule Formation, Acta Biomater., 3: 199-208.
20.
Vitale-Brovarone, C., Verné, E., Robiglio, L., Martinasso, G., Canuto, R.A. and Muzio, G. (2008). Biocompatible Glass-ceramic Materials for Bone Substitution, J. Mater. Sci.: Mater. Med. , 19: 471-478.
21.
Vitale-Brovarone, C., Baino, F. and Verné , E. (2009). High Strength Bioactive Glass-ceramic Scaffolds for Bone Regeneration, J. Mater. Sci.: Mater. Med., 20: 643-653.
22.
Adachi, T., Osako, Y., Tanaka, M., Hojo, M. and Hollister, S.J. ( 2006). Framework for Optimal Design of Porous Scaffold Microstructure by Computational Simulation of Bone Regeneration, Biomaterials , 27: 3964-3972.
23.
Livingston, T. , Ducheyne, P. and Garino, J. (2002). In Vivo Evaluation of a Bioactive Scaffold for Bone Tissue Engineering, J. Biomed. Mater. Res., 62: 1-13.
24.
De Aza, P.N. , Luklinska, Z.B., Santos, C., Guitian, F. and De Aza, S. (2003). Mechanism of Bone-like Formation on a Bioactive Implant In Vivo, Biomaterials, 24: 1437-1445.
25.
Schwarts, Z. and Boyan, B.D. ( 1994). Characterization of Microrough Bioactive Glasses: Surface Reactions and Osteoblast Responses, J. Cell. Biochem., 56: 340-347.
26.
Lyckfeldt, O. and Ferreira, J.M. (1998). Processing of Porous Ceramics by Starch Consolidation, J. Eur. Ceramic Soc., 18: 131-140.
27.
Vitale-Brovarone, C., Di Nunzio, S., Bretcanu, O. and Verné , E. (2004). Macroporous Glass-ceramics Materials with Bioactive Properties, J. Mater. Sci. Mater. Med., 15: 209-217.
28.
Tampieri, A. , Celotti, G., Sprio, S., Delcogliano, A. and Franzese, S. (2001). Porosity-graded Hydroxyapatite Ceramics to Replace Natural Bone, Biomaterials, 22: 1365-1370.
29.
Hsu, Y.H. , Turner, I.G. and Miles, A.W. (2008). Fabrication of Porous Bioceramics with Porosity Gradients Similar to the Bimodal Structure of Cortical and Cancellous Bone, J. Mater. Sci.: Mater. Med., 18: 2251-2256.
30.
Kokubo, T. and Takadama, H. ( 2006). How Useful is SBF in Predicting In Vivo Bone Bioactivity?Biomaterials, 27: 2907-2915.
31.
Gibson, L.J. and Ashby, M.F. ( 1999). Cellular Solids: Structure and Properties, 2nd edn, p. 117, Oxford, Pergamon.
