Crystallization of calcium carbonate under the influences of casein and magnesium ions

Various proteins and molecules are involved in the crystallization pathways of biomineralization. The present study investigated the involvement of casein and magnesium ions in the crystallization of calcium carbonate (CaCO₃). The calcium carbonate crystals obtained under the control of casein and magnesium ions were characterized by various techniques such as XRD and FTIR. Results showed that the morphology of the CaCO₃ crystals was significantly affected by casein and magnesium ions. The secondary structure of casein proteins and the size of casein micelles play important roles in the morphological construction of CaCO₃ crystals. Magnesium ions can directly interact with CaCO₃ crystals to affect the morphology. Magnesium ions are also indirectly involved in the casein assisted CaCO₃ mineralization by affecting the size of casein micelles to regulate the CaCO₃ mineralization. This work may not only provide insight into natural biomineralization process, but also be helpful in designing and synthesizing novel functional materials.