Wingender Brian, Azuma Masashi, Krywka Christina, Zaslansky Paul, Boyle John, Deymier Alix
Biomedical Engineering, UConn Health, Farmington, CT, USA.
Helmholtz-Zentrum Geesthacht, Zentrum für Material - und Küstenforschung GmbH, Geesthacht, Germany.
Acta Biomater. 2021 Mar 1;122:377-386. doi: 10.1016/j.actbio.2021.01.002. Epub 2021 Jan 11.
Bone mineral comprises nanoparticles of carbonate-substituted bioapatite similar to hydroxylapatite. Yet mechanical values of macroscopic-sized geological hydroxylapatite are often used to model bone properties due to a lack of experimental data for bioapatite. Here, we investigated the effects of carbonate substitution and hydration on biomimetic apatite response to load using in situ hydrostatic pressure loading and synchrotron x-ray diffraction. We find that increasing carbonate levels reduced the bulk modulus and elastic strain ratio. Elastic constants, determined using computational optimization techniques, revealed that compliance values and elastic moduli decreased with increasing carbonate content, likely a result of decreased bond strength due to CO substitution and Ca loss. Hydration environment had no clear effects on the elastic properties likely due to dissolution and reprecipitation processes modifying the crystal structure organization. These results reinforce the need to consider carbonate composition when selecting mechanical properties and provide robust data for carbonate-substituted apatite stiffness.
骨矿物质由类似于羟基磷灰石的碳酸盐取代生物磷灰石纳米颗粒组成。然而，由于缺乏生物磷灰石的实验数据，宏观尺寸的地质羟基磷灰石的力学值常被用于模拟骨特性。在此，我们使用原位静水压力加载和同步加速器X射线衍射研究了碳酸盐取代和水化对仿生磷灰石载荷响应的影响。我们发现，增加碳酸盐含量会降低体积模量和弹性应变比。使用计算优化技术确定的弹性常数表明，随着碳酸盐含量的增加，柔度值和弹性模量会降低，这可能是由于CO取代和Ca损失导致键强度降低的结果。水化环境对弹性性能没有明显影响，这可能是由于溶解和再沉淀过程改变了晶体结构组织。这些结果强化了在选择力学性能时考虑碳酸盐组成的必要性，并为碳酸盐取代磷灰石的刚度提供了可靠数据。
