Dissolution at the nanoscale: Self-preservation of biominerals
Dissolution at the nanoscale: Self-preservation of biominerals
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DOI：
10.1002/anie.200353652
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发表时间：
2004-01-01
影响因子：
16.6
通讯作者：
Nancollas, GH
中科院分区：
文献类型：
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作者：
Tang, RK;Wang, LJ;Nancollas, GH
尽管贝壳、骨骼和牙齿等天然材料具有复杂的层次结构，但它们的基本组成单元通常在纳米尺寸范围内[1-6]，以确保最佳的物理和生物功能。[5-7]我们发现这种纳米结构优化也赋予了生物材料显著的动态保存特性。一般认为，矿物的溶解是一种自发反应，其中所有固相都可以溶解在不饱和的溶液中。然而，已经发现脱矿反应实际上涉及分子水平上依赖于颗粒大小的能量控制临界条件。[8-10]这表明，当晶体的尺寸落在某一临界值范围内时，晶体的溶解可能被抑制甚至抑制——通常是在纳米尺度上。因此，这些纳米结构的生物矿物可以抵抗溶解，因为它们的大小，可以保持相对稳定的生物环境，即使后者可能是不饱和的。这一来自大自然的新教训丰富了我们对纳米结构材料和生物脱矿的理解。牙齿表面的牙釉质层是最坚硬的生物组织之一。[4,11,12]在本通讯中，珐琅质被选为纳米脱矿的例子，因为它是高度矿化的，表现出接近纯合成磷灰石的特征，约97%的矿物相和约3%的水和有机基质。[11-13]在牙釉质显著溶解之前的扫描电子显微照片（SEM）（图1a）显示牙釉质组织良好
Despite the complicated hierarchical structures of natural materials such as shells, bones, and teeth, their basic building blocks are generally in the nanometer size range [1–6] to ensure optimum physical and biological functions.[5–7] Herein we reveal that this nanostructural optimization also confers on the biomaterials remarkable characteristics of dynamic preservation. Generally, dissolution of minerals is regarded as a spontaneous reaction in which all the solid phase can be dissolved in undersaturated solutions. However, it has been found that demineralization reactions actually involve particle-size-dependent critical conditions of energetic control at the molecular level.[8–10] It suggests that the dissolution of crystallites may be inhibited or even suppressed when their sizes fall into the same range as that of a certain critical value—always at a nanoscale level. Therefore, these nanostructured biominerals can be resistant to dissolution on account of their sizes and can remain relatively stable in the biological milieux even though the latter may be undersaturated. This new lesson from nature enriches our understanding of nanostructured materials and biological demineralization.Enamel layers at tooth surfaces are among the hardest biological tissues.[4, 11, 12] In this Communication, enamel is selected as an example in the context of nanodemineralization since it is highly mineralized and exhibits features that are close to pure synthetic apatites with about 97% mineral phase and about 3% water and organic matrix.[11–13] Scanning electron micrographs (SEM) of enamel surfaces prior to significant dissolution (Figure 1a) show the well-organized