Titanium alloy scaffold with controlled internal architecture as an osteoblast carrier to repair rabbit defects

Objective To evaluate effects of titanium alloy scaffolds with controlled internal architecture as an osteoblast carrier on bone response in models of rabbit defects. Methods Electron beam melting process was utilized to fabricate porous titanium alloy scaffolds with fully interconnected and controlled internal pore architecture. After osteoblasts were seeded on the scaffolds and cultured for up to 7 days, the growth of rabbit osteoblasts on the scaffolds was observed by scanning electron microscopy. The experiment was conducted in 4 groups to evaluate the bone formation in vivo: group A (cell/scaffold composite), group B (scaffold only), group C (left empty) and group D (autogenous bone implant) . The scaffolds were transplanted into the rabbit defects after cultured in vitro for 7 days. The animals were sacrificed at 4, 8, and 12 weeks after implantation. Bone formation in the scaffolds was investigated by gross observation, histology and histomorphometry of non-decalcified sections and fluorochrome markers. Results Confluent cell layers could be observed on the scaffold surface and in the internal pores after 7 days of incubation in vitro. New bone growth and revascularization could be observed not only at the margins of the scaffolds, but also inside the central pores of the scaffolds after 12 weeks. New bone formed along the controlled internal channels of the scaffolds. The scaffolds were filled fully with the new bone tissue and blood vessels. More extensive new bone formation was found to originate from the host bone towards the implant in group A than in group B (P ＜0. 05) . Conclusions The controlled scaffolds are well biocompatible enough to accelerate healing of rabbit defects and new bone formation. The controlled honeycomb-like architecture may guide and promote the formation of mineralized tissue. Key words: Scaffold; Titanium; Bone defect; Electron beam melting