Crystal Growth Mechanism of Vaterite in the Systems Containing Charged Synthetic Poly(Amino Acids)
Crystal Growth Mechanism of Vaterite in the Systems Containing Charged Synthetic Poly(Amino Acids)
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DOI：
10.5562/cca3290
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发表时间：
2017-12
影响因子：
0.3
通讯作者：
B. N. Džakula;G. Falini;D. Kralj
中科院分区：
文献类型：
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作者：
B. N. Džakula;G. Falini;D. Kralj
可负离子化的聚-L-谷氨酸（pGlu）和聚-L-天冬氨酸（pAsp），被视为参与生物矿化过程的天然酸性大分子的类似物，被用作碳酸钙沉淀系统中的添加剂，以研究它们与球霰石微晶的相互作用。聚-L-赖氨酸（pLys），一种可正离子化的聚（氨基酸），也被使用以阐明侧链电荷的影响。发现球霰石的生长动力学呈抛物线状，这表明生长单元整合到球霰石晶体表面的螺旋台阶是速率决定机制。少量pGlu和pAsp的存在抑制了晶体生长。在这两种酸性大分子的最高浓度下，观察到指数速率定律，这表明表面成核是速率控制机制。在所应用浓度范围内添加pLys对球霰石的晶体生长没有显著影响。因此，动力学结果，经形态学观察证实，指出了所选多肽侧链的负电荷在与矿物平面的界面相互作用中的重要性。
Negatively ionisable poly-L-glutamic acid (pGlu) and poly-L-aspartic acid (pAsp), considered as analogues of the naturally occurring acidic macromolecules involved in biomineralization processes, were used as additives in the calcium carbonate precipitation systems in order to investigate their interactions with the vaterite crystallites. Poly-L-lysine (pLys), a positively ionisable poly(amino acid), was also used in order to elucidate the impact of the side chain charge. The growth kinetics of vaterite was found parabolic, indicating that the integration of growth units into the spiral step at the vaterite crystal surfaces is the rate-determining mechanism. The presence of small amounts of pGlu and pAsp inhibited the crystal growth. At the highest concentrations of both acidic macromolecules the exponential rate law was observed, which indicates the surface nucleation as the rate controlling mechanism. The addition of pLys in the range of applied concentrations did not significantly influence the crystal growth of the vaterite. Thus, the kinetic results, corroborated by morphological observations, pointed out to the significance of the negative charge of the side chains of selected polypeptides in the interfacial interactions with mineral planes.