Effect of Fe3+ on the Silk Fibroin Regulated Direct Growth of Nacre-like Aragonite Hybrids

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• 作者：Guoqiang Lin ; Yiming Zhong ; Jiajia Zhong ; Zhengzhong Shao
• 刊名：Crystal Growth & Design
• 出版年：2015
• 出版时间：December 2, 2015
• 年：2015
• 卷：15
• 期：12
• 页码：5774-5780
• 全文大小：544K
• ISSN：1528-7505

文摘

Silk fibroin (SF), which has been used as an analogue of the silk-like proteins in studying the biomineralization process of calcium carbonate in vitro, shows a high preference for the formation of aragonite polymorph. In this study, Fe³⁺, which has been found with relatively high levels in the shells of marine mollusks, was introduced into the SF-regulated biomineralization system. The addition of Fe³⁺ into the SF aqueous solutions induced a conformational transition of SF from random coil to 尾-sheet. The promoted 尾-sheet structures provided Ca²⁺-binding sites for SF and, accordingly, enabled the formation of an amorphous calcium carbonate precursor. Such a precursor has an aligned parallel structure and acts as a template for the direct growth of aragonite. The corresponding aragonite products showed similar organic鈥搃norganic hierarchical structure to nacre building in vivo as well as higher thermal stability compared with that of the other Fe³⁺-free aragonite products in terms of the polymorph. It is indicated that Fe³⁺ plays multiple roles in this nacre-mimetic biomineralization process. By examining the coeffect of SF and Fe³⁺ as multiple additives, this study has provided a deeper understanding on the valuable contribution of Fe³⁺ in the nacre-mimetic system, which could facilitate the fabrication of similar synthetic materials with good mechanical performance from cheap abundant materials.