Polowczyk Izabela, Bastrzyk Anna, Fiedot Marta
Faculty of Chemistry, Wroclaw University of Science and Technology, Norwida 4/6, 50-373 Wroclaw, Poland.
Faculty of Microsystem Electronics and Photonics, Wroclaw University of Science and Technology, Janiszewskiego 11/17, 50-372 Wroclaw, Poland.
Materials (Basel). 2016 Nov 22;9(11):944. doi: 10.3390/ma9110944.
Calcium carbonate is an important component in exoskeletons of many organisms. The synthesis of calcium carbonate was performed by mixing dimethyl carbonate and an aqueous solution of calcium chloride dihydrate. The precipitation product was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) measurements. In addition, the turbidity of the reaction solution was acquired to monitor the kinetics of the calcium carbonate structure's growth in the investigated system. In this study, samples of CaCO₃ particles obtained with individual proteins, such as ovalbumin, lysozyme, and a mixture of the proteins, were characterized and compared with a control sample, i.e., synthesized without proteins. The obtained data indicated that the addition of ovalbumin to the reaction changed the morphology of crystals from rhombohedral to 'stack-like' structures. Lysozyme, however, did not affect the morphology of calcium carbonate, yet the presence of the protein mixture led to the creation of more complex composites in which the calcium carbonate crystals were constructed in protein matrices formed by the ovalbumin-lysozyme interaction. It was also observed that in the protein mixture, ovalbumin has a major influence on the CaCO₃ formation through a strong interaction with calcium ions, which leads to the coalescence and creation of a steric barrier reducing particle growth. The authors proposed a mechanism of calcium carbonate grain growth in the presence of both proteins, taking into account the interaction of calcium ions with the protein.
碳酸钙是许多生物体外骨骼中的重要成分。通过将碳酸二甲酯与二水合氯化钙水溶液混合来进行碳酸钙的合成。通过扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X射线衍射（XRD）和傅里叶变换红外光谱（FTIR）测量对沉淀产物进行表征。此外，获取反应溶液的浊度以监测所研究体系中碳酸钙结构生长的动力学。在本研究中，对用单个蛋白质（如卵清蛋白、溶菌酶）以及蛋白质混合物获得的碳酸钙颗粒样品进行了表征，并与对照样品（即无蛋白质合成的样品）进行了比较。所得数据表明，向反应中添加卵清蛋白会使晶体形态从菱面体变为“堆叠状”结构。然而，溶菌酶并未影响碳酸钙的形态，但蛋白质混合物的存在导致形成了更复杂的复合材料，其中碳酸钙晶体构建在由卵清蛋白 - 溶菌酶相互作用形成的蛋白质基质中。还观察到，在蛋白质混合物中，卵清蛋白通过与钙离子的强相互作用对碳酸钙的形成有主要影响，这导致聚结并形成空间位垒，从而减少颗粒生长。作者考虑到钙离子与蛋白质的相互作用，提出了在两种蛋白质存在下碳酸钙晶粒生长的机制。
