Krogstad Daniel V, Wang Dongbo, Lin-Gibson Sheng
Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States.
Biomacromolecules. 2015 May 11;16(5):1550-5. doi: 10.1021/bm501725t. Epub 2015 May 1.
Bone is an important material to study due to its exceptional mechanical properties and relevance with respect to hard tissue regeneration and repair. A significant effort has been directed toward understanding the bone formation process and the production of synthetic bone mimicking materials. Here, the formation and structural evolution of calcium phosphate (CaP) was investigated in the presence of relatively high concentrations of calcium, phosphate, and polyaspartic acid (pAsp) using dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryo-TEM). The incipient CaP aggregates were comprised of spherical nanoparticles (diameter ≈ 3-4 nm); they became preferentially aligned over time and eventually transformed into nanorods. The nanorods remained stable in suspension with no signs of further aggregation for at least four months. Detailed cryo-TEM suggested that the CaP nanorods formed through an oriented attachment mechanism. These results show that the reaction concentration greatly influences the mechanism and final properties of CaP. Mechanistic insights gained from this study will facilitate better design and fabrication of bioinspired materials.
由于骨骼具有卓越的力学性能以及与硬组织再生和修复的相关性，它是一种重要的研究材料。人们已经付出了巨大努力来了解骨形成过程以及合成骨模拟材料的制备。在此，使用动态光散射（DLS）和低温透射电子显微镜（cryo-TEM），在相对高浓度的钙、磷酸盐和聚天冬氨酸（pAsp）存在的情况下，研究了磷酸钙（CaP）的形成和结构演变。初始的CaP聚集体由球形纳米颗粒（直径约3 - 4 nm）组成；随着时间的推移，它们优先排列，最终转变为纳米棒。纳米棒在悬浮液中保持稳定，至少四个月没有进一步聚集的迹象。详细的低温透射电子显微镜研究表明，CaP纳米棒是通过定向附着机制形成的。这些结果表明，反应浓度对CaP的形成机制和最终性能有很大影响。从这项研究中获得的机理见解将有助于更好地设计和制造仿生材料。
