Three-dimensional porous bioscaffolds for bone tissue regeneration: fabrication via adaptive foam reticulation and freeze casting techniques, characterization, and cell study.

Highly interconnected and 3D porous bioactive hydroxyapatite (HAP) and Bioglass scaffolds have been fabricated by an adaptive version of camphene based foam reticulation (ARM) and camphene freeze casting (CFC) methods. Controlled sublimation of camphene during freeze casting at -78°C produced process optimized bioscaffolds with open, uniform, and interconnected porous structures. HAP and Bioglass scaffolds with desired porosity, pore size, and microtopography were successfully fabricated using polyurethane foam templates of appropriate structures. Macropores of 50-1100 μm with microporosity of 1-10 μm, known to facilitate cell adhesion and proliferation, were obtained. Compressive yield strength of 0.8 MPa close to the upper range of cancellous bone was achieved. The mean compressive strength of HAP scaffolds compared favorably with the theoretical model of porosity variation with strength and was higher than reported values. The nature of pore development, morphology, porosity, crystal structure, chemical composition, and thermal behavior were characterized using scanning electron and optical microscopy, X-ray diffraction, thermal analysis, and mercury porosimetry. These scaffolds are suited for nonstructural graft and were not cytotoxic in vitro when osteoblast-like MG63 cells were cultured with the HAP constructs. The cells attached indicated by cell metabolic activity by resazurin assay and spread well when cultured on the surface of the materials.