| dc.description.abstract | Gallstone in humans is a very commonly seen example of biomineralization. There are almost tens of millions of patients in the world. Three types of gallstones occur in humans: cholesterol gallstones and two kinds of pigments stones (brown and black pigment stones), but cholesterol gallstones are the most common in humans. Cholesterol gallstones are almost composed of cholesterol anhydrous or monohydrate crystals and calcium carbonate. After studying an extensive of references, there are no specific researches on the link between cholesterol crystallization and calcium carbonate crystallization. So, three important goals in this thesis are performed to find out the cholesterol functions in humans. Firstly, an engineering data bank of solubility, polymorphism, crystal habits and crystallinity by solvent screening for cholesterol monohydrate was established and a robust, miniature solvent screening method was introduced. Secondly, composition of model bile was described in detailed and a wide selection of instruments was used to analyze the structure of complex lipid system. Thirdly, crystallization of calcium carbonate and a supersaturated model bile system was utilized and to study the interactions among lipids and calcium ions by analyzing the crystal habits, polymorphism, crystallization kinetic and composition of cholesterol anhydrous and monohydrate crystals and calcium carbonate crystals from different conditions. By answering these questions, we will more specific understand biomineration in humans. Besides, we also found:
(1) Lecithin was capable of inducing the formation of vaterite or slowing down the vaterite to calcite transformation.
(2) Microstructure of complex lipid system could control the crystallization of calcium carbonate.
(3) Crystallization of cholesterol could be induced by the destabilization of complex lipid system and became an auto-catalytic process in gallstone formation.
(4) Biliary components in human, such as calcium ions, bile salts, bicarbonate ions, lysozyme and cholesterol were capable of destabilizing the complex lipid system
| en_US |