Graduate School of Life Science, ‡Faculty of Advanced Life Science, §Global Station for Soft Matter, Global Institution for Collaborative Research and Education (GI-CoRE), and ∥Department of High Toughness Hydrogels for Cartilage Application, Center for Innovation and Business Promotion, Hokkaido University , Sapporo 001-0021, Japan.
ACS Nano. 2017 Dec 26;11(12):12103-12110. doi: 10.1021/acsnano.7b04942. Epub 2017 Oct 31.
Bone tissues possess excellent mechanical properties such as compatibility between strength and flexibility and load bearing owing to the hybridization of organic/inorganic matters with anisotropic structure. To synthetically mimic such an anisotropic structure of natural organic/inorganic hybrid materials, we carried out hydroxyapatite (HAp) mineralization in stretched tough double network (DN) hydrogels. Anisotropic mineralization of HAp took place in stretched hydrogels, as revealed by high brightness synchrotron X-ray scattering and transmission electron microscopic observation. The c-axis of mineralized HAp aligned along the stretching direction, and the orientation degree S calculated from scattering profiles increased with increasing in the elongation ratio λ of the DN gel, and S at λ = 4 became comparable to that of rabbit tibial bones. The morphology of HAp polycrystal gradually changed from spherical to unidirectional rod-like shape with increased elongation ratio. A possible mechanism for the anisotropic mineralization is proposed, which would be one of the keys to develop mechanically anisotropic organic/inorganic hybrid materials.
骨组织具有优异的机械性能，如强度和柔韧性以及承载能力之间的兼容性，这归因于有机/无机物质与各向异性结构的杂交。为了综合模拟天然有机/无机杂化材料的各向异性结构，我们在拉伸坚韧的双网络（DN）水凝胶中进行了羟基磷灰石（HAp）矿化。高亮度同步加速器 X 射线散射和透射电子显微镜观察表明，HAp 在拉伸水凝胶中发生各向异性矿化。从散射图谱计算出的取向度 S 随着 DN 凝胶伸长比 λ 的增加而增加，并且 λ = 4 时的 S 可与兔胫骨相媲美。HAp 多晶的形态逐渐从球形变为各向异性的棒状，随着伸长比的增加而变化。提出了各向异性矿化的可能机制，这可能是开发具有各向异性机械性能的有机/无机杂化材料的关键之一。
