Effect of Serine and Arginine on the Phase Transition from Amorphous CaCO₃ and CaCO₃·6H₂O to Calcite Film

Abstract

Calcium carbonate, ubiquitous throughout nature, is one of the most biologically significant minerals. It is known that the organic matrix of biological materials controls the phase transition of CaCO₃, but much remains undiscovered regarding its pathway from an amorphous to crystalline solid. In this study, examination of the initial formation of CaCO₃ films has been proposed as a new methodology to identify the phase transition of CaCO₃. We have identified a significant role for both serine and arginine in the synthesis of CaCO₃ and have found them to be important for the stabilization of amorphous calcium carbonate and CaCO₃·6H₂O. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy have been used for the identification of crystalline phase and surface structure. This study presents information useful for understanding the phase transition of CaCO₃ and the function of organic molecules in the formation of biological materials.