Biomineralization of varied calcium carbonate crystals by the synergistic effect of silk fibroin/magnesium ions in a microbial system

Abstract

The influence of silk fibroin (SF) and magnesium ions (Mg²⁺) on calcium carbonate (CaCO₃) bio-mineralization has been investigated. However, the morphology of CaCO₃ controlled by the synergistic effect of SF and magnesium ions has not been reported in microbial mineralization systems. Here, we provide novel experimental insights into the role of SF and Mg²⁺ in the crystallization of CaCO₃ in microbial mineralization systems. The morphology and crystallization of CaCO₃ aggregates are affected by the self-assembly of SF molecules and the inhibition of Mg²⁺. This combination promoted the growth of a novel, rod-like superstructure of calcite crystals by aggregating/assembling behavior and crystallization kinetics. In addition, prism-shaped and hemispherical CaCO₃ crystal superstructures were obtained in the presence of Mg²⁺ and SF, respectively. Furthermore, CaCO₃ crystals with well-defined morphologies and polymorphs can be obtained by regulating the crystallization conditions (mineralization time and the amount of the additives). The above system has potential applications in the design and preparation of numerous inorganic materials with novel morphologies and specific textures.