生物矿化的模拟与仿生合成

【作者】 黄方志；

【导师】 沈玉华；

【作者基本信息】 安徽大学 ， 无机化学， 2004， 硕士

【摘要】 本论文分三部分：第一部分羟基磷灰石仿生材料的制备与表征；第二部分胆汁的成分与存在状态及其与胆结石形成关系的研究；第三部分胆结石的体外模拟研究。主要内容如下： 1．采用溶胶-凝胶法，在聚乙二醇作为化学添加剂的作用下，成功地合成了羟基磷灰石纳米棒，通过纳米粒度及Zeta电位大小与分布的测定、FT-IR、XRD和TEM等测试方法对其进行了表征，同时考查了不同种类化学添加剂对水分散体系中羟基磷灰石颗粒稳定性的影响。结果表明，在羟基磷灰石纳米棒的制备过程中聚乙二醇起了诱导与调控作用；NaCl、KCI以及十二烷基磺酸钠添加剂的加入使得悬浮液中的羟基磷灰石纳米棒明显较纯水分散体系中的稳定。论文还根据羟基磷灰石纳米棒的强吸附性能，进一步合成了葡聚糖／羟基磷灰石和聚乙二醇／羟基磷灰石纳米复合材料。 2．通过Zeta电位的测定、颗粒粒度分析、FT-IR和UV-vis光谱等研究方法对胆石病人胆汁及离心后的上层清液进行了研究。结果表明病人的胆汁是一个非均匀体系，处于相对不稳定状态；离心后的胆汁聚沉物主要含有胆固醇、蛋白、磷脂、胆红素及其钙盐等物质，与该病人胆石核心的主要成分非常相似，说明这些物质在胆结石的成核过程中起了主要作用；胆汁中磷脂类囊泡的破坏以及一些难溶性钙盐的生成是影响胆汁稳定性及胆石形成的主要因素。 3．在N₂保护和敞开体系两类不同的反应环境中，分别研究了纯水溶液、葡聚糖水溶液和聚乙二醇水溶液中胆红素钙晶体的成核与生长情况。结果显示，在N₂保护的上述三种体系中不能形成结晶态的胆红素钙固体；而只有在敞开体系中，空气中CO₂的参与以及葡聚糖和聚乙二醇的诱导作用下才导致胆红素钙／碳酸钙复合晶体的形成。 4．在敞开体系中，用DPPC单分子膜为模拟体系研究了色素型胆结石的主要成分胆红素钙与另一重要组成碳酸钙的晶体成核与生长情况。发现在DPPC单分子膜的作用下，碳酸钙晶体在102面优先取向生长形成方解石型晶体，亚相中不同浓度的葡聚糖调控了形态各异的碳酸钙晶体在气／液界面上形成，只有在亚相含葡聚糖浓度为0.04％的胆红素钙过饱和溶液的气／液界面上才有与碳酸钙复合的胆红素钙晶体生成，表明胆红素钙在通常条件下很难形成晶体，生物分子的安徽大学申请硕士学位论文诱导和碳酸钙结晶的析出有利于胆红素钙晶体的形成，它们在人体中可能是胆结石的促进剂。更多还原

【Abstract】 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.更多还原