Experimental Study On The Absorption Of The Bio-derived Bone Scaffolds

[Backgrounds and objectives]Tissue engineering is the application of the principle and method of engineering science and life sciences based on the understanding of relationship between structure and function in normal tissue, and the development of biological substitutes to repair, maintain, or improve physiological function.This research is to investigate the techniques of preparating bone bio-derived materials as scaffolds,make clear their essential features in vitro and in vivo, to evaluate the prospect of this bone scaffold in tissue engineering, to provide theoretical basis for it further developing and exploration.[Methods] Xenogenic column-shaped compact bones underwent defatted, selectively-deproteined,antigen-digested, half of the amount of all products were partially demineralized(demineralization rate: 30%); All the products were sealed, after freeze-drying , in packets and sterilized. Their surface topographic features were examined, and their mechanical properties were tested. Then two kinds of materials were implanted into tibia bone defects inxenogenic animal models. By the technology of the medical imagining, histology, fluoroscopy, scanning electronical microscopy, the behaviors and rules in degradation of implants were observed and investigated periodically, finally the features in scaffold were evaluated comprehensively.[ Results ] Both the partially demineralized bone scaffolds and the non-demineralized bone scaffolds, to some extent, possess natural three-dimensions porous structure, the porosity of surface of the former were improved comparision with the latter, while biomechanical properties of them remain no significant difference. The 5th month postoperation, the absorption rate of the partially demineralized bone scaffolds was slow than that of the non-demineralized bone scaffolds, the absorption rate of the segment located in the cavitas medullaris was faster than that were inlayed to the cortex. The 7th month postoperation,the segment of the non-demineralized bone scaffolds in the cavitas medullaris were virtually disappearing. While the minorities of the segment, in the cavitas medullaris, of the partially demineralized bone scaffolds, had still been into existence. The others were growing porosy. The 9th month postoperation, there was no bone scaffolds in the cavitas medullaris. The bone scaffolds which were layed into host bones had been integrated and into fusion. However, under the microscopy, there were certain traces of the partially demineralized bone scaffolds, through which identification comes. By contrast, the non-demineralized bone scaffolds had vanished.[Conclusion] Both the partially demineralized bone scaffolds and the non-demineralized bone scaffolds, though, possessing the properties which meet the essential needs of extracellular scaffolds for bone tissue engineering,they own their characteristics. The span of their aborbption are longer than that are expected, what's more, the span of the degradation aborbption of the partially demineralized bone scaffolds is longer than that of the non-demineralized bone scaffolds. They are hoped to further better their characters, by various ways,such as porosity, strength,plasticity, et al, to perform their missons in the field of bone tissue engineering.