Xenogeneic bone properties prepared by calcination and freeze-dried methods / 中国组织工程研究

ABSTRACT

BACKGROUND:Xenogeneic bone structure and biological characteristics are similar to human bone tissue, and the xenogeneic bone has a decreased antigenicity after physicochemical treatment, with a natural porous structure and rich source, and can be kept for a long time, which is considered to be an effective way to solve the shortage of the autogenous bone and al ograft bone. OBJECTIVE:To compare the physical and chemical properties of xenogenic bone materials prepared by two different methods. METHODS:Sheep cancellous bone treated with chemical method was placed into the muffle furnace at 1 000 ℃for 2 hours to prepare calcined bone. Another cancellous bone was placed into an 80 ℃ refrigerator for 4 weeks and then placed into a vacuum instrument to prepare freeze-dried bone. Cancellous bone rinsed with ultra-pure water served as controls. RESULTS AND CONCLUSION: Three groups of samples retained three-dimensional porous structure which similar with human bone tissue under microscopic observation. The framework was stil intact, with a smal pore of 55-650μm and high porosity of 65%-80%. For the calcined bone, the toughness was decreased and the brittleness increased significantly, but the freeze-dried bone had a little changes in the mechanical properties. Through diffraction analysis, hydroxyapatite was the main composition of the three groups. However, there was a smal amount ofβ-tricalcium phosphate in the calcined bone. Spectrum analysis confirmed that calcium and phosphorus content in these three groups were al close to the human body. The results suggest the cancellous bone treated with these two methods is similar to human bone structure, and the major elements are close to the body. In addition, the cancellous bone after processing has enough smal pore and higher porosity. However, calcination process has a more influence on the mechanical property of scaffold materials, and the freeze-dried bone has a little change but the antigen cannot be completely removed that can reach the basic requirements.