Biomineralization Of CaCO₃ Induced By Ordered Polypeptide Molecular Films

In recent years, further understanding of the structure of mineralized tissues and the mechanism of mineralization in natural biomaterials provides a theoretical basis for the biomimetic design and synthesis of materials and devices with special structures and functions. Study on oriented mineral crystal growth induced by LB technology has become a hot topic. In biomineralization process, organisms can exert great control over mineral deposition from the solution phase by using biomolecules templates. The biomineralization field has highlighted the possibilities of materials synthesis based on molecular interactions between Supermolecular organic assemblies and inorganic materials. In the biological system, biomacromolecular structures composed of lipid, protein et al are intimately associated with mineral phases and serve vital roles in their crystallization and play an important function in the process of the biomineralization. In this process, natural organisms can deposit an oriented crystal from the aqueous solutions under ambient conditions. Now it has been recognized that one promising approach of producing fine single-crystalline is to mimic the biomineralization processes occurring in natural organisms.Langmuir monolayer and LB film are widely used organic templates due to its specific structure advantages in the study of biomimetic mineralization. In this work, the crystallization of CaCO₃ was studied through LB technology under polypeptide molecular films. The results are characterized by AFM, TEM, SEM and XRD. Our work included three sections as followed:(1) Calcite crystals growth induced by polyβ-benzyl L-aspartate (PBA) Langmuir monolayerWe studied the influence and control of the polyβ-benzyl L-aspartate (PBA) Langmuir monolayer on the nucleation and growth of calcium carbonate. Calcium carbonate crystals with clear edge and petal-like crystal morphology were obtained under the PBA Langmuir monolayer. XRD results show that the crystal phase was calcite with orientated growth along (104) and (208) planes. AFM, TEM and SEM observations show the morphology change of calcite. Our results suggest that PBA Langmuir monolayer used as a template can induce and manipulate the nucleation and growth of calcium carbonate with various morphology and specific crystal orientation.(2) Growth of hollow calcite crystals induced by polyβ-benzyl L-aspartate (PBA) LB filmLB film is one of the most widely used organic templates due to its specific structure advantages in the study of biomimetic mineralization. In this chapter, we studied the influence and control of the polyβ-benzyl aspartate (PBA) LB film on the nucleation and oriented growth process of calcium carbonate. XRD results show that the crystals grow only along the (104) face, which indicates calcite has a well orientation; SEM results show the growing process of calcite crystal with clear edge and hollow and disk-like crystal morphology. Our results suggest that PBA Langmuir film can be used as a template to induce and regulate the calcium carbonate to crystallize with special orientations and complex morphologies.(3) Calcite crystals growth induced by poly-DL-alanine (PDLA) Langmuir monolayerWe studied the influence and control of the poly-DL-alanine (PDLA) Langmuir monolayer on the nucleation and oriented growth process of calcium carbonate. XRD results show that the crystals grow only along the (104) and (208) faces, which indicates calcite has a well orientation; AFM, TEM and SEM results show the growing process of calcite crystal with clear edge and petal-like crystal morphology. Our results suggest that PDLA Langmuir monolayer can be used as a template to induce and regulate the calcium carbonate to crystallize with special orientations and complex morphologies.