Ruan Qichao, Liberman David, Zhang Yuzheng, Ren Dongni, Zhang Yunpeng, Nutt Steven, Moradian-Oldak Janet
Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, Los Angeles, California 90033, United States.
Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 3651 Watt Way, Los Angeles, California 90089, United States.
ACS Biomater Sci Eng. 2016 Jun 13;2(6):1049-1058. doi: 10.1021/acsbiomaterials.6b00164. Epub 2016 May 24.
Bioinspired synthesis of hierarchically structured calcium phosphate (CaP) material is a highly promising strategy for developing improved bone substitute materials. However, synthesis of CaP materials with outstanding mechanical properties still remains an ongoing challenge. Inspired by the formation of lamellar structure in nacre, we designed an organic matrix composed of chitosan and cis-butenediolic acid (maleic acid, MAc) that could assemble into a layered complex and further guide the mineralization of monetite crystals, resulting in the formation of organized and parallel arrays of monetite platelets with a brick-and-mortar structure. Using the layered monetite-chitosan composite as a precursor, we were able to synthesize hydroxyapatite (HAp) with multiscale hierarchically ordered structure via a topotactic phase transformation process. On the nanoscale, needlelike HAp crystallites assembled into organized bundles that aligned to form highly oriented plates on the microscale. On the large-scale level, these plates with different crystal orientations were stacked together to form a layered structure. The organized structures and composite feature yielded CaP materials with improved mechanical properties close to those of bone. Our study introduces a biomimetic approach that may be practical for the design of advanced, mechanically robust materials for biomedical applications.
受生物启发合成具有层次结构的磷酸钙（CaP）材料是开发改良骨替代材料的一种极具前景的策略。然而，合成具有优异机械性能的CaP材料仍然是一个持续存在的挑战。受珍珠层中层状结构形成的启发，我们设计了一种由壳聚糖和顺丁烯二酸（马来酸，MAc）组成的有机基质，该基质可以组装成层状复合物，并进一步引导透钙磷石晶体矿化，从而形成具有砖石结构的透钙磷石片晶的有序平行排列。以层状透钙磷石-壳聚糖复合物为前驱体，我们能够通过拓扑相变过程合成具有多尺度层次有序结构的羟基磷灰石（HAp）。在纳米尺度上，针状HAp微晶组装成有序的束状结构，在微米尺度上排列形成高度取向的薄片。在宏观尺度上，这些具有不同晶体取向的薄片堆叠在一起形成层状结构。这种有序结构和复合特性使得CaP材料的机械性能得到改善，接近骨的机械性能。我们的研究引入了一种仿生方法，该方法对于设计用于生物医学应用的先进、机械坚固的材料可能具有实际意义。
