Fabrication of Porous Hydroxyapatite-Gelatin Composite Scaffolds for Bone Tissue Engineering

Background: engineering new bone tissue with cells and a synthetic extracellular matrix represents a new approach for the regeneration of mineralized tissues compared with the transplantation of bone (autografts or allografts). Methods: in this study, to mimic the mineral and organic component of natural bone, hydroxapatite (HA) and gelatin (GEL) composite scaffolds were prepared. The raw materials were first compounded and the resulting composite were molded into cylindrical shape. Using solvent-casting method combined with freeze drying process, it is possible to produce scaffolds with mechanical and structural properties close to natural trabecular bone. Glutaraldehyde (GA) was used as cross linking agent. The chemical bonding and the microstructure were investigated by Fourier Transform Infra Red (FT-IR), Scanning Electron Microscopy (SEM) and Light microscopy. Results: it was observed that the prepared scaffold has an open, interconnected porous structure with a pore size of 80-400 mµ , which is suitable for osteoblast cell proliferation. The mechanical properties of different weight fraction of HA (30, 40, and 50 wt%) was assessed and it was found that the GEL/HA with ratio of 50wt% HA has the compressive modulus of ~10 Giga Pascal (GPa), the ultimate compressive stress of ~32 Mega Pascal (MPa) and the elongation of ~3MPa similar to that of trabecular bone. The porosity and the apparent density of 50wt% HA scaffold were calculated and it was found that the addition of HA content can reduce the water absorption and the porosity. Since GA is cytotoxin, sodium bisulfite was used as GA discharger. The biological responses of scaffolds carried out by L929 fibroblast cell culture and it was observed that fibroblast cells partially proliferated and covered scaffold surface, 48h after seeding. Conclusion: these results demonstrate that the manufactured scaffolds are suitable candidate for trabecular bone tissue engineering.