Revisiting Whitlockite, the Second Most Abundant Biomineral in Bone: Nanocrystal Synthesis in Physiologically Relevant Conditions and Biocompatibility Evaluation
Revisiting Whitlockite, the Second Most Abundant Biomineral in Bone: Nanocrystal Synthesis in Physiologically Relevant Conditions and Biocompatibility Evaluation
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DOI：
10.1021/nn405246h
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发表时间：
2014-01-01
期刊：
影响因子：
17.1
通讯作者：
Nam, Ki Tae
中科院分区：
文献类型：
--
作者：
Jang, Hae Lin;Jin, Kyoungsuk;Nam, Ki Tae
尽管whitlockite (WH: Ca18Mg2(HPO4)(2)（PO4)(12)）是活骨中含量第二丰富的无机物，但合成纯whitlockite (WH: Ca18Mg2(HPO4)(2)（PO4)(12)）仍然是一个挑战。虽然已经发表了一些关于在非均相中析出WH的报道，但到目前为止，不利用任何缓冲剂或各种其他离子的作用来合成WH仍然很困难。因此，相关的研究领域遇到了困难，没有得到充分的发展。在此，我们基于系统的方法，在三元Ca(OH)(2)-Mg(OH)(2)-H3PO4体系中开发了一种大规模合成纯WH纳米颗粒的方法。我们使用过量的Mg2+来阻碍羟基磷灰石(HAP: Ca-10(PO4)(6)（OH)(2)）的生长和其他动力学上有利的磷酸钙中间相的形成。此外，我们设计并研究了在pH 4.2以上最热稳定相HAP溶解所需的酸性pH条件下，WH的合成条件，并在WH的化学结构中加入HPO42-基团。我们证明了纯WH纳米颗粒可以在富Mg2+和酸性pH条件下沉淀，而不需要任何中间相。有趣的是，合成的纳米wh与HAP具有相当的生物相容性。我们的方法可以为研究水体系中其他重要的沉淀剂提供一个新的平台。
The synthesis of pure whitlockite (WH: Ca18Mg2(HPO4)(2)(PO4)(12)) has remained a challenge even though it is the second most abundant inorganic in living bone. Although a few reports about the precipitation of WH in heterogeneous phases have been published, to date, synthesizing WH without utilizing any effects of a buffer or various other ions remains difficult. Thus, the related research fields have encountered difficulties and have not been fully developed. Here, we developed a large-scale synthesis method for pure WH nanoparticles in a ternary Ca(OH)(2)-Mg(OH)(2)-H3PO4 system based on a systematic approach. We used excess Mg2+ to impede the growth of hydroxyapatite (HAP: Ca-10(PO4)(6)(OH)(2)) and the formation of other kinetically favored calcium phosphate intermediate phases. In addition, we designed and investigated the synthesis conditions of WH under the acidic pH conditions required to dissolve HAP, which is the most thermodynamically stable phase above pH 4.2, and to incorporate the HPO42- group into the chemical structure of WH. We demonstrated that pure WH nanoparticles can be precipitated under Mg2+-rich and acidic pH conditions without any intermediate phases. Interestingly, this synthesized nano-WH showed comparable biocompatibility with HAP. Our methodology for determining the synthesis conditions of WH could provide a new platform for investigating other important precipitants in aqueous systems.