含水非晶碳酸钙的仿生矿化研究

生物成因矿物的形成过程通常是通过先沉积非晶前驱体，进而转变形成某一种结晶相的途径来实现的。对生物成因碳酸钙而言，普遍认为其非晶的前驱体相是在生物有机大分子和无机离子共同作用下形成的。在阴离子柠檬酸根存在的情况下，仿生合成了非晶碳酸钙（Amorphous calcium carbonate，ACC），运用场发射扫描电子显微镜（FESEM）、X-射线衍射（XRD）、傅里叶红外光谱（FTIR）和热重-差热分析（TG-DTA）等实验手段进行了分析并观测了非晶碳酸钙后续转变。结果显示，多羧基的阴离子能够诱导形成非晶碳酸钙，并且这些非晶碳酸钙具有与生物成因非晶碳酸钙类似的组成。这可能指示与生物矿化相关的生物大分子，特别是一些富含极性羧基大分子能够诱导碳酸钙矿物非晶态前驱体相的形成，同时也能暂时稳定这些非晶前驱体相。

Hydrous Amorphous Calcium Carbonate: A Biomimetic Mineralization Study

A common route  to  form biogenic minerals during biomineralization  is  that  the  initial deposit of  transient amorphous precursor phases and subsequent transformation into one of more stable crystalline phases. In terms of biogenic calcium carbonate minerals, amorphous precursor phase is generally considered to be formed under the joint regulation of biological macromolecules and  inorganic  ions.  In  this work, amorphous calcium carbonate  (ACC) was synthesized  in  the presence of citrate anions by a biomimetic mineralization process. Structure and morphology of the synthesized ACC and the subsequently products from the ACC transformed were characterized using a wide range of techniques, including field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier infrared spectroscopy (IR) and thermal gravity analysis-differential thermal analysis (TG-DTA). The results showed that the multi-carbonate anions could induce the formation of ACC which had a similar composition to biogenic hydrous ACC. Therefore, our results suggest that some biomineralization-associated acidic biomacromolecules canalso induce the formation of biogenic ACC and transiently stabilize it.