Department of Material Science and Engineering, Pohang University of Science and Technology (POSTECH), Nam-gu, Pohang, Korea.
Tissue Eng Part C Methods. 2010 Oct;16(5):1059-68. doi: 10.1089/ten.TEC.2009.0759.
Synchrotron X-ray bioimaging was successfully carried out to observe bone regeneration by a novel artificial bone substitute of bioactive MegaGen Synthetic Bone (MGSB) and hyaluronate (HA) hydrogels. A biphasic calcium phosphate of MGSB was prepared by chemical precipitation method, with a porous spherical morphology. On the basis of the fact that HA plays important roles in bone regeneration and promotes the differentiation, vascularization, and migration of stem cells, HA-cystamine (CYS) hydrogels with cleavable disulfide linkages were prepared to supply HA continuously for effective bone regeneration by their controlled degradation in vivo. Among seven different samples using Bio-OSS®, MGSB, and/or several kinds of HA hydrogels, MGSB/HA-CYS hydrogels resulted in the most significant bone regeneration in the calvarial critical bone defect of New Zealand white rabbits. Histological and histomorphometric analyses revealed that the bone regeneration by MGSB/HA-CYS hydrogels was as high as 43%, occupying 71% of the bone defect area with MGSB in the form of a calvarial bone plate in 4 weeks. After that, MGSB was bioabsorbed and replaced gradually with regenerated bones as observed in 8 weeks. Synchrotron X-ray imaging clearly confirmed the effective bone regeneration by MGSB/HA-CYS hydrogels, showing three-dimensional micron-scale morphologies of regenerated bones interconnected with MGSB. In addition, sequential nondestructive synchrotron X-ray tomographic analysis results from anterior to posterior of the samples were well matched with the histomorphometric analysis results. The clinically feasible artificial bone substitutes of MGSB/HA-CYS hydrogels will be investigated further for various bone tissue engineering applications using the synchrotron X-ray bioimaging systems.
利用新型生物活性 MegaGen 合成骨（MGSB）和透明质酸（HA）水凝胶成功进行了同步加速器 X 射线生物成像，以观察骨再生情况。采用化学沉淀法制备了具有多孔球形形态的 MGSB 双相磷酸钙。鉴于 HA 在骨再生中发挥重要作用并促进干细胞的分化、血管生成和迁移，制备了具有可裂解二硫键的 HA-胱胺（CYS）水凝胶，通过其在体内的可控降解来持续供应 HA，从而实现有效的骨再生。在使用 Bio-OSS®、MGSB 和/或几种 HA 水凝胶的七种不同样本中，MGSB/HA-CYS 水凝胶在新西兰白兔颅骨临界骨缺损中导致了最显著的骨再生。组织学和组织形态计量学分析表明，MGSB/HA-CYS 水凝胶的骨再生率高达 43%，在 4 周时占据了骨缺损区域的 71%，其中 MGSB 以颅骨骨板的形式存在。之后，MGSB 被生物吸收，并在 8 周时逐渐被再生骨取代。同步加速器 X 射线成像清楚地证实了 MGSB/HA-CYS 水凝胶的有效骨再生，显示了与 MGSB 相互连接的再生骨的三维微米级形态。此外，从样本的前向后进行的连续非破坏性同步加速器 X 射线层析分析结果与组织形态计量学分析结果非常吻合。将进一步使用同步加速器 X 射线生物成像系统对 MGSB/HA-CYS 水凝胶这种具有临床可行性的人工骨替代品进行各种骨组织工程应用的研究。
