人體中的膽結石是非常常見的生物礦化例子。現今在世界上，幾乎就有數以千萬計的患者。人體中的膽結石總共有三種類型：膽固醇膽結石、黑色膽色素結石以及棕色膽色素結石，但又以膽固醇膽結石最常發生在人體中。而膽固醇結石幾乎由膽固醇結晶和碳酸鈣結晶所組成。經過廣泛文獻閱覽後，我們發現並沒有太多明確的研究以及文獻記載關於膽固醇(cholesterol)和碳酸鈣之間的相互作用。所以在本文中主要有三個重要的目標用來研究出膽固醇在於人體中的功能性。 首先，利用初步溶劑篩選程序來篩選膽固醇，包含溶解度(solubility)、多型晶體(polymorph)、晶體外貌(crystal habit)、以及結晶度(crystallinity)的資料會被建立成工程資料庫。而一種簡略但快速且只需要少量樣品的篩選方法也會在本文中加以介紹。第二，人工膽汁的組成將會描述的更詳盡以及利用大量的儀器分析來建立複合脂質系統完整的結構分析。第三，結合碳酸鈣的結晶學和過飽和人工膽汁系統來模擬人體中膽結石的形成機制，以及利用晶體外貌(crystal habit)、多型晶體(polymorph)、結晶動力學(crystallization kinetic)和碳酸鈣晶體的組成的分析來探討脂質和鈣離子之間的交互作用。藉著利用這些資料可以更明確的加以瞭解膽固醇膽結石在人體中的起因。除此之外，我們還發現 (1)卵磷脂本身具有誘發vaterite的形成或延緩vaterite轉換成calcite。 (2)複雜脂質系統中的微觀結構能夠控制碳酸鈣的結晶過程 (3)膽固醇的結晶能夠藉由誘發複雜脂質系統的不穩定所形成，且整個膽結石形成過程會變成自動催化的系統 (4)人體中膽汁內的成份，例如:鈣離子、膽鹽、碳酸根離子、溶菌酶以及膽固醇，都具有能力使複雜脂質系統不穩定化。 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
