磷酸鈣礦物於幾丁聚醣薄膜之相位調控

Different Mineral Phases of Calcium Phosphate Deposited within Chitosan Membranes

蔡佳怡(Chia-Yi Tsai)

指導教授 ： 陳振中

國立臺灣大學/理學院/化學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.01926

摘要

組織工程學近年來應用在牙周病治療領域的技術越來越廣泛與成熟，其中引導骨（組織）再生術於齒槽骨細胞的生長和牙周組織的修復極具發展的潛力。本研究利用幾丁聚醣來製備多孔薄膜作為引導骨再生膜的基材。　幾丁聚醣是天然聚合物，具有良好的生物相容性、生物降解性，還有特殊的骨傳導性以及抑菌性防止細菌感染。　為了加速骨細胞的增生，我們利用浸泡擴散的系統與直接沉澱法在膜上礦化磷酸鈣，欲藉由鈣離子的釋放來促進骨細胞的分化，並且提升膜的機械性質。我們利用XRD、TEM、SEM以及固態核磁共振等技術追蹤磷酸鈣的礦化過程，觀察到鹼性環境下隨著礦化時間增加（一天內），磷酸鈣由非晶相磷酸鈣（ACP）轉變成熱力學最穩定的氫氧基磷灰石（HAp），其中氫氧基磷灰石是人體牙齒和骨頭最常見的無機礦物，非晶相磷酸鈣則是各種結晶相磷酸鈣的前驅物，在各項研究ACP已被證實具有比HAp更好的生物降解性及骨傳導性。　我們也藉由添加胺基酸小分子來調控HAp不同的形貌生成，不同的浸泡系統亦可以調控不同晶相生成，比起一般計量下共沉澱法製備的ACP，我們在膜上礦化出的ACP可在水溶液中穩定達七天。利用一系列的NMR實驗，結果顯示ACP的穩定性與併入其結構中或包覆在表面的碳酸鈣含量有關。

關鍵字

幾丁聚醣 ； 氫氧基磷灰石 ； 非晶相磷酸鈣 ； 牙周病 ； 引導組織再生術 ； 固態核磁共振 ； 共沉澱法

並列摘要

The techniques of tissue engineering have been well established and widely applied to the treatment of periodontitis recently. In particular, Guided Bone Regeneration (GBR) has promising potential for periodontal tissues recovering. In this work, we prepared chitosan membranes as a scaffold for GBR applications. Chitosan, a naturally occurring polymer, is biocompatible, biodegradable , and osteoconductive. It has an inherent antimicrobial activity to suppress bacterial invasion. To accelerate bone regeneration and enhance mechanical properties, calcium phosphate was mineralized within the chitosan membrane via soaking (diffusion) and co-precipitation. The mineralization process was investigated by XRD, IR, TEM, SEM, and solid state NMR. All data indicated that the phase transformation pathway follows the order from amorphous calcium phosphate (ACP) to hydroxyapatite (HAp). HAp is the major inorganic component of bones and teeth, whereas ACP is the precursor of many crystalline calcium phosphates. It is well known that ACP has better osteoconductivity and biodegradability than HAp. The ACP synthesized on the chitosan membrane has revealed a higher stability in aqueous solution (< 7 days) than those collected by centrifuge from solution. Our results reveal that the unexpected stability of ACP is provided for by the calcium carbonate incorporated into the core structure of ACP, and calcium carbonate that in close vicinity to ACP may also have considerable effect on the stability of ACP.

並列關鍵字

chitosan ； hydroxyapatite (HAp) ； amorphous calcium phosphate (ACP) ； periodontitis, Guided Bone Regeneration (GBR) ； solid-state NMR ； co-precipitation

參考文獻

1. Nanci, A. & Bosshardt, D. D. Structure of periodontal tissues in health and disease. Periodontol. 2000 40, 11–28 (2006).

2. Pihlstrom, B. L., Michalowicz, B. S. & Johnson, N. W. Periodontal diseases. Lancet 366, 1809–1820 (2005).

3. Taba, M., Jin, Q., Sugai, J. V. & Giannobile, W. V. Current concepts in periodontal bioengineering. Orthod. Craniofac. Res. 8, 292–302 (2005).

4. Chen, F.-M. & Jin, Y. Periodontal Tissue Engineering and Regeneration: Current Approaches and Expanding Opportunities. Tissue Eng. Part B Rev. 16, 219–255 (2009).

5. Chen, F.-M. et al. A review on endogenous regenerative technology in periodontal regenerative medicine. Biomaterials 31, 7892–7927 (2010).