Simulation Of Biological Mineralization And Biomimetic Synthesis

The dissertation consists of three parts, which include the biomimetic synthesis and characterization of hydroxyapatite, the relationship between the property change of patient bile and the formation of gallstone, and the simulation study of gallstone formation outside organism.1. Regular hydroxyapatite nanorods were synthesized by sol-gel method using polyethylene glycol (PEG) as chemical additive and determined by FT-IR, XRD and TEM. The results showed that PEG induced the formation of HAP nanorods during the sol-gel process. The varieties of the zeta potentials indicated that the dispersibilities of HAP nanorods were better in the suspensions containing sodium chlorine, kalium chlorine than in the pure water systems owing to the changes of the nanoparticles electric double layers. And the dispersibility of HAP nanorods would be further enhanced in the suspensions by adding sodium dodecyl sulfonate due to the presence of multiple interactions. Two kinds of homogeneously distributed polymer complexes (dextran/HAP and PEG/HAP) were produced according to the adsorption behaviors of HAP nanorods.2. The patient bile and its centrifugate were studied by particle size analysis and zeta potential determination, FTIR spectra, UV-vis spectra. The result showed that the patient bile was in a heterogenetic and unstable state. The composition of the precipitates was mainly phospholipid, cholesterol, protein, bilirubin, calcium bilirubinate and so on, which was much close to that of the core of the patient gallstone. The property change of cholesterol/phospholipid vesicles and the produce of the undissolvable calcium salt in the patient bile had crucial influence on the stability of the patient bile, which played important roles in the core-formation and initial growth of gallstone.3. The crystal growth of calcium bilirubinate was studied in pure water, dextran and polyethylene glycol aqueous solutions with the protection of N2 or in the open system. It was found that the amorphism calcium bilirubinate produced in the three different systems with the safeguards of N2 as well as in pure water of the open systems. But the multiple crystalloids of calcium bilirubinate were induced by dextran and polyethylene glycol in the open systems because carbon dioxide participated.4. DPPC monolayers were used as templates to induce calcium bilirubinate and calcium carbonate crystallite in the air ambience. The results showed that calcitecrystallized on the (102) axis at the interface of air/water, which could be rationalized in term of the lattice match between monolayers and crystal. The morphologies of calcites varied as the change of the concentration of dextran in the subphases. The crystalloids of calcium bilirubinate only formed together with calcite beneath the DPPC monolayer when subphase contained dextran with the concentration of 0.04% (wt) and supersaturated calcium bilirubinate solution. The results suggested that some biomolecules and calcium carbonate were helpful to the crystal growth of calcium bilirubinate and might accelerate the formation of pigment gallstone.