Growth and structure in abalone shell
Growth and structure in abalone shell
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DOI：
10.1016/j.msea.2004.06.072
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发表时间：
2005-01-15
期刊：
影响因子：
6.4
通讯作者：
Meyers, MA
中科院分区：
文献类型：
--
作者：
Lin, A;Meyers, MA
研究了鲍鱼壳中文石型碳酸钙的生长和自组装。这是通过对实验室生长的扁平珍珠样品和珍珠贝壳的横截面切片进行仔细检查来完成的。对测序组装有了进一步的了解。已经证实，复合物的文石组分的生长是通过文石晶体的连续成核和通过蛋白质介导的机制的阻止而发生的;它以“圣诞树模式”发生[Nature 49（1994）371]。它表明，蛋白质层几乎是不存在的板在同一平面上邻接（沿着侧表面的瓷砖）。这表明了一种机制的c轴文石生长停滞的蛋白质层的沉积约20-30 μ m的周期性激活，并确定文石血小板的厚度，这是非常恒定的（0.5 μ m）。测量了壳直径为10、50和200 mm的动物的血小板大小，发现其大小是恒定的。整个生长过程用结合文石中生长速度各向异性的参数（V-c，沿沿着c轴的速度，和V-ab，基面中的速度）来表示。实验室饲养的鲍鱼和自然生长的鲍鱼的比较表明，生长受蛋白质饱和度的调节。自然生长的鲍鱼呈现出中胚层（生长带），间距约为0.3毫米;有人认为，它们是由于季节性的摄食模式中断造成的，产生了更厚的（约10 -20微米）蛋白质层。这些中间层在机械性能中起着关键作用，并且是强大的裂纹偏转器。有机层间的粘塑性变形是导致抗拉强度显著提高的主要原因。(C)2004 Elsevier B. V.保留所有权利。
The growth and self-assembly of aragonitic calcium carbonate found in the shell of abalone (Haliotis) is described. This was accomplished through the close examination of laboratory-grown flat pearl samples and cross-sectional slices of the nacreous shell. Further understanding of the sequenced assembly has been obtained. It has been confirmed that the growth of the aragonite component of the composite occurs by the successive nucleation of aragonite crystals and their arrest by means of a protein-mediated mechanism; it takes place in the "Christmas-tree pattern" [Nature 49 (1994) 371]. It is shown that the protein layer is virtually absent where plates on a same plane abut (along lateral surfaces of tiles). This suggests a mechanism of c-axis aragonite growth arrest by the deposition of a protein layer of approximately 20-30 m that is periodically activated and determines the thickness of the aragonite platelets, which are remarkably constant (0.5 mum). This platelet size was measured for animals with shell diameters of 10, 50, and 200 mm and was found to be constant. The overall growth process is expressed in terms of parameters incorporating the anisotropy of growth velocity in aragonite (V-c, the velocity along c axis, and V-ab, the velocity in basal plane). Comparison of laboratory-raised and naturally-grown abalone indicates growth regulated by the level of proteinaceous saturation. Naturally-grown abalone exhibits mesolayers (growth bands) similar to0.3 mm apart; it is proposed that they result from seasonal interruptions in feeding patterns, creating thicker (similar to10-20 mum) layers of protein. These mesolayers play a critical role in the mechanical properties, and are powerful crack deflectors. The viscoplastic deformation of the organic inter-tile layers is responsible for the significant improvement of tensile strength over the tensile strength of monolithic aragonite. (C) 2004 Elsevier B.V. All rights reserved.