Effect of Process Parameters on the Characteristics of Porous Calcium Phosphate Ceramics for Bone Tissue Scaffolds

Abstract

: Porous hydroxyapatite (HA) has already been widely used as a bone substitute due to its similarity with the mineral part of the bone. In this work, cylindrical tablets with micro and macro porosity were produced from stoichiometric and deficient hydroxyapatites by using naphthalene as porosifier agent. The influence of the processing parameters such as Ca/P ratio of start material, calcination temperature, and naphthalene content on the characteristics of porous calcium phosphate tablets was evaluated. Three mineral phases—HA, α‐TCP (α tri‐calcium phosphate), and β‐TCP (β tricalcium phos‐phate)—with variable contents were identified by x‐ray diffraction (XRD) and Fourier‐transformed infrared spectroscopy (FT‐IR). Image analysis and density measurements were used to characterize sample porosity. As expected, the total porosity of the calcinated material is not dependent on the stoichiometry of the precursor hydroxyapatite. For calcium‐deficient hydroxyapatite, the increase in naphthalene content contributes to stabilize α‐TCP phase, altering the relative phases content.

Diffusion in Musculoskeletal Tissue Engineering Scaffolds: Design Issues Related to Porosity, Permeability, Architecture, and Nutrient Mixing

“…3 Porosity values may also be derived from scanning electron microscopy of cross-sections of scaffolds. 10,11,39,42,51,73,98,102,113,126 Two-dimensional images and image analysis can yield the pore to polymer area, which is then extrapolated to 3D to obtain estimates of porosity.…”

“…A simpler method used to obtain the porosity of a scaffold also requires the use of its density, 38,41,73,92 and is referred to by some as gravimetry. 65 Once the dimensions and mass of the scaffold are measured, the density (d) of the porous structure is obtained from d = m/v, where m is the mass and v the volume of the porous structure.…”

Advances in Regenerative Medicine

“…In the bone tissue engineering, for instance, pores are necessary to allow migration and proliferation of osteoblasts and mesenchymal cells, as well as vascularization (Gauthier, Bouler et al 1998;Boyde, Corsi et al 1999;Lu, Flautre et al 1999;Chang, Lee et al 2000;Hollister, Maddox et al 2002;De Oliveira, De Aguiar et al 2003;Karageorgiou and Kaplan 2005;Mastrogiacomo, Scaglione et al 2006). In addition, macroporosity has a strong impact on the amount of newly formed bone tissue; moreover, a porous surface may improve mechanical interlocking between the implant biomaterial and the surrounding natural bone.…”

Cell-Biomaterial Interactions Reproducing a Niche

“…During this phase, as soon cells are addressed towards their differentiative fate, it may be beneficial for a biomaterial to provide adequate space (porosity) and appropriate surface to foster and direct new tissue formation. In the bone tissue engineering, for instance, pores are necessary to allow migration and proliferation of osteoblasts and mesenchymal cells, as well as vascularization (Gauthier, Bouler et al 1998;Boyde, Corsi et al 1999;Lu, Flautre et al 1999;Chang, Lee et al 2000;Hollister, Maddox et al 2002;De Oliveira, De Aguiar et al 2003;Karageorgiou and Kaplan 2005;Mastrogiacomo, Scaglione et al 2006). In addition, macroporosity has a strong impact on the amount of newly formed bone tissue; moreover, a porous surface may improve mechanical interlocking between the implant biomaterial and the surrounding natural bone.…”