Inorganic/organic biocomposite cryogels for regeneration of bony tissues.

The present work focuses on the physical, mechanical and in vitro properties of porous inorganic/organic biocomposite scaffolds of polyvinyl alcohol-tetraethylorthosilicate-alginate-calcium oxide (PTAC). These scaffolds are prepared by means of cryogelation technology and are intended for bone tissue engineering applications. The biocomposite cryogels have much more favorable physical and biological properties compared to the previous work of our group on the same composition in the form of pellets and foams. The optimized and heat-treated PTAC biocomposite cryogels show homogenous porosity and good mechanical properties and also exhibit the formation of a hydroxyapatite-like layer on their surface on coming in contact with simulated body fluid (SBF). Furthermore, the biocomposite cryogels showed good biocompatibility with L929 fibroblasts. Also, the influence of pre-soaking in SBF to that of non-soaked scaffolds was compared in terms of proliferation of MG-63 osteoblast-like osteosarcoma cells on these scaffolds and it was found that the pre-soaking caused a decrease in cell proliferation. Finally, the response of human osteoblasts on these scaffolds was analyzed by MTT assay, scanning electron microscopy, energy dispersive X-ray spectroscopy and micro X-ray computing tomography. The cells revealed good biocompatibility with the biocomposite cryogels and were mostly present as cell sheets on the surface with thick bundles of collagenous extracellular matrix during initial period of incubation. During later phases, the formation of calcium phosphate-like mineral deposits was observed on the surface of the cryogels suggesting a high potential of the biocomposite cryogels towards bone regeneration. Therefore, the PTAC biocomposite cryogels, due to their favorable properties and high biocompatibility with human osteoblasts can be suggested as potential scaffolds for bone tissue engineering applications.