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標題: | 調控磷酸鈣成礦路徑之研究 Modulation of the Mineralization Pathway of Calcium Phosphate |
作者: | NIEN-FANG TSAI 蔡念舫 |
指導教授: | 陳振中(Jerry Chun Chung Chan) |
關鍵字: | 生物礦化,磷酸八鈣,羥基磷灰石,固態核磁共振,唾液蛋白, biomineralization,octacalcium calcium phosphate (OCP),hydroxyapatite (HAp),solid-state NMR,statherin, |
出版年 : | 2018 |
學位: | 博士 |
摘要: | 本論文利用LipoCaP系統來模擬生物礦物於細胞、囊泡或細胞間介質中的礦化過程,發現以微脂體作為限制空間時,其內部初期生成的磷酸鈣礦物為無晶形磷酸鈣(ACP),爾後發生相轉變形成羥基磷灰石(HAp)。加入鎂離子於LipoCaP系統來調控磷酸鈣礦化的實驗中,證實適量的鎂離子能有效穩定無晶形結構。 本論文的第四章中利用氨氣擴散產生pH梯度來進行礦化,並加入微脂體調控磷酸鈣礦化過程,成功於聚丙烯材質的離心管表面製備出厚度為10 um、面積達平方公分等級的磷酸鈣薄片。透過31P固態核磁共振和同幅光源粉末繞射鑑定,發現薄片包含ACP和磷酸八鈣(OCP)兩種磷酸鈣晶相,且薄片中OCP相轉變為HAp的過程受到抑制,使OCP能穩定存在於pH高於9.0的鹼性環境數天。將薄片在pH 12.0的磷酸鹽緩衝液中進一步培養,促使其相轉變為HAp,並藉由一系列不同交叉極化(CP)接觸時間的異核相關(HETCOR)固態核磁共振實驗分析礦物晶相,證實相變轉化途徑為 ACP/ OCP → HAp。 唾液中的statherin能抑制口腔中磷酸鈣的生成,目前已有許多關於HAp與statherin或其胜肽片段SN15相互作用的研究,本論文的第五章中,利用直接混合產生共沈澱的方式製備含SN15胜肽片段的無晶形磷酸鈣礦物,在沒有特殊的磷酸鈣面向下,探討SN15胜肽片段與磷酸鈣的交互作用力。 Calcium phosphate is the major inorganic ingredient in bone and teeth minerals. There are many different crystalline phases associated with calcium phosphate including brushite, monetite, octacalcium phosphate (OCP), and hydroxyapatite (HAp). It is of great interest to study the phase transformation pathway of calcium phosphate under carefully controlled conditions. The growth of bone minerals in vivo occurs in confined space such as cellular vesicles and extracellular matrix. We investigated the mineralization process of calcium phosphate within phospholipid bilayer vesicles (liposomes) and confirmed the transformation pathway as follows: ACP (amorphous calcium phosphate) → HAp. By adding magnesium to the LipoCaP system, we found that magnesium can stabilize the amorphous phase of minerals. In this study, the formation of calcium phosphate in the presence of phosphatidylcholine (PC) was carried out under a pH gradient created by ammonia gas diffusion. We successfully prepared a thin film of calcium phosphate on the polypropylene surface. The thickness of the film was about 10m and the lateral dimensions were in the length scale of millimeter. 31P solid-state NMR and powder III X-ray diffraction revealed that the thin film comprised ACP and OCP, and the OCP phase was stable under alkaline condition for several days, indicating that the phase transformation process, from OCP to HAp, was suppressed. Further incubation in a phosphate buffer of pH 12.0 led to the formation of HAp. By a series of solid-state NMR experiments, viz., cross-polarization (CP) based heteronuclear correlation (HETCOR) with variable contact time, we concluded that the phase transformation pathway occurred by the sequence of ACP/ OCP → HAp. Statherin is an active inhibitor of calcium phosphate precipitation in the oral cavity. The interaction between HAp and statherin or its fragment derived from the N-terminal 15 amino acids (SN15) has been widely studied. In this study, the ACP sample was precipitated in the presence of an SN15 peptide fragment to study the interaction of SN15 with amorphous calcium phosphate. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/77796 |
DOI: | 10.6342/NTU201801439 |
全文授權: | 有償授權 |
電子全文公開日期: | 2023-07-23 |
顯示於系所單位: | 化學系 |
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