The Existence Of Organic Matrix Of Calcium Carbonate Biomineralization

The biomineralization is quite different from the common mineral crystallization in nature. The mineral crystallization is regulated by the organic matrix that the biology excretes, then the organic matrix can induce the inorganic materials to crystallize and grow. The organic matrix can be defined for the local area face and interface constituted by organism component, it is the medium of biomineralization, also come to a decision the mineral pellets space orientation and construction. The activation spot of organism matrix' interface decides the minerals turning process to crystallize according to the sequence through constitution, construction and appearance three aspect, in each position of crystallization, the interaction of molecule and molecule regiment has many-sides highly adaptability. As a result, in the identical apparatus of the same kind living beings, the construction, appearance and distribution of biominerals are able to obtain the exact repetition, the inorganic crystals of living beings are wholly designed into ordered sequence that unities with organic macromolecule correlation, this is suggesting that in the living creature system certainly exist highly tight control mechanism of crystallization, growth and space organization. Among biominerals, calcium carbonates are most widespread in nature, the compositions of which include minor organic matrix in addition to inorganic materials. The organic matrix can be divided into two classes: water-soluble(SM) and water-insoluble(IM) matrix. SM is often rich in anionic groups such as carboxylate, phosphonate and sulphate groups and plays important role in regulating the crystallization of calcium carbonates. It is generally accepted that the control of organic matrix over CaCO₃ morphology and polymorphism is due to the molecular recognition between organic-inorganic interfacesuch as electrostatic attraction, Lattice geometery matching and stereochemical complimentary. At the negative charged interface between organic monolayer and inorganic phase, the electrostatic attraction results in the composition departure from lattice ion stoichiometry and pH lowering which are considered as the main factors to promote inorganic mineral nucleation. Lattice geometry matching and stereochemical complimentary between organic matrix and calcium carbonate effectively reduce the activation energy of nucleation of minerals along such matching faces to result in the oriented nucleation and growth of minerals. Though there is little understanding of detailed control mechanism of biogenic calcium carbonate by matrix, the research will shed lights on material science and provide new pathways to fabricate advanced organic-inorganic composite materials.In the dissertation, different organic matrix were used to regulate and control the growth progress of calcium carbonate under present conditions in our lab. Versatile morphologies and different polymorph of calcium carbonate were produced in our experiences, and the mechanisms of these results were investigated. The main information is followed.(1) Based on the basic principles of biomineralization, a novel aragonite (CaCOs) with specific morphology was synthesized under the control of 0 -cyclodextrin were used as the organic matrix. The obtained composite CaCC>3 with small amount of P -cyclodextrin were characterized by X-ray powder diffraction (XRD) analysis and scanning electronic microscopy (SEM). Furthermore, according to the results of Fourier transform infrared spectroscopy (FT-IR) and measurement of conductance ratios, the possible mechanism of the interaction between P -cyclodextrin and CaCO3 during the CaCC>3 formation process was discussed.(2) Based on the basic principles of biomineralization, CaCC>3 crystal that formedin some amino acids with different R-groups was studied, the influence of CaCC>3 biomineralization with different R-groups was studied too. It was found that some amino acids with different R-groups are able to change the template of CaCO3 crystal in pure aqueous-solution, calcium carbonate crystal of vaterite with higher energy is found in the amino acids, but calcite in pure aqueous-solution. The obtained composite CaCCb with small amount of some amino acids wim different R-groups were characterized by X-ray powder diffraction (XRD) analysis, scanning electronic microscopy (SEM% Fourier transform infrared spectroscopy (FT-IR) and measurement of conductance ratios.