生物可降解性溫感型PEG-PLGA-PEG / HA複合材料之體內相容性研究

An in-vivo biocompatibility study of biodegradable and thermosensitive PEG-PLGA-PEG / HA composites

賴玫君(Mei-Chun Lai)

指導教授 ： ARRAY(0xc855fc4)

中原大學/理學院/化學研究所/博士(2009年)

https://doi.org/10.6840/CYCU.2009.00873

摘要

本研究之目的在於分別利用開環聚合方式和化學共沉澱法，合成具有溫度敏感性之團聯型高分子聚合物 (PEG-PLGA-PEG) 以及氫氧基磷灰石，利用漩渦混合器將兩者混摻製成可降解性之溫感型複合骨水泥，並添加骨形成蛋白質 (BMP-2) 期望藉此促進骨誘導性，接著利用針筒將材料植入老鼠皮下，植入後在不同的時間點 (四週及八週時) 將材料取出，藉由組織切片觀察此材料對於骨生長之影響。
在材料鑑定與特性量測方面，利用核磁共振光譜儀 (NMR) 及傅利葉轉換紅外線光譜儀 (FTIR) 對有機高分子 PEG-PLGA-PEG進行結構鑑定。而 PEG-PLGA-PEG 及 PEG-PLGA-PEG / HA 複合材之溫度敏感性及體外降解行為，則利用黏度計及體外降解實驗量測。至於無機氫氧基磷灰石的鑑定則是利用X-ray繞射儀 (XRD)、能量散佈分析儀 (SEM-EDS) 及感應耦合電漿原子放射光譜儀 (ICP-AES) 判斷其結構正確性，實驗結果顯示在2θ角為25.8°處出現的波峰是氫氧基磷灰石主要的特徵峰，而其鈣/磷比亦與天然骨頭之成分相近。其次，在探討複合骨材之生物相容性應用方面，利用注射幫浦進行評估以了解材料在不同溫度之注射難易性，最後，在動物實驗方面則將四種材料 (PEG-PLGA-PEG、HA錠片、PEG-PLGA-PEG / HA 複合骨水泥、PEG-PLGA-PEG / HA / BMP-2複合骨水泥) 分別植入老鼠皮下八週，以了解骨細胞生長之情況。結果顯示：具骨誘導性之BMP-2 的添加可提升PEG-PLGA-PEG / HA 複合骨材注射至老鼠體內後之骨細胞及纖維母細胞的生長，此結果可由光學顯微鏡觀察之。因此由實驗結果所得到的結論是：在PEG-PLGA-PEG / HA複合骨水泥中添加少量的 (如：0.01wt%) 骨促進劑BMP-2，可製備出一具有較佳骨誘導效果的材料。

關鍵字

開環聚合法 ； 溫度敏感性 ； 化學共沉澱法 ； 生物相容性 ； 骨形成蛋白質 ； 生物降解性

並列摘要

The present study is aimed to observe osteogenesis in-vivo when a composite hydrogel of biodegradable thermosensitive poly(ethylene glycol) - block poly(lactide-co-glycolide) - block poly(ethylene glycol) triblock copolymer (PEG-PLGA-PEG) and hydroxyapatite (HA) is injected subcutaneously. The composite hydrogel was also mixed with recombinant bone morphologenesis protein 2 (BMP-2) for the osteoinduction. PEG-PLGA-PEG was synthesized using ring opening polymerization technique whereas HA was synthesized in a chemical co-precipitation method. The hydrogel was formed by vortexing predetermined amount of PEG-PLGA-PEG and HA and injected into skin throught a syringe in rat. Tissue sections at various time point post injection were prepared and In-vivo biocompatibility of injected materials was evaluated accordingly.
In the part of chemical synthesis of PEG-PLGA-PEG, the structure was determined by 1H nuclear magnetic resonance spectrophotometer and Fourier-transform infrared spectrum. The thermosensitivity and in-vitro degradation of PEG-PLGA-PEG and its composites with HA were studied by following the viscometer of hydrogels and in-vitro degradation test, respectively. On the other hand, the crystal structure of HA was measured by powder X-ray diffraction, scanning electron microscope - energy dispersive spectrometer and inductively coupled plasma atomic emission spectrometry, respectively. Results show that 2-theta degree appeared a peak at 25.8° which is the obviously characteristic peak of HA and the Ca/P ratio is close to composition of nature bone. Secondly, the quantitative assessment of the injectability of composite hydrogel was conducted using in syringe. Finally, In-vivo injection of the composite hydrogels (PEG-PLGA-PEG hydrogel, HA disc, composite hydrogel of PEG-PLGA-PEG and HA, PEG-PLGA-PEG, HA and BMP-2 composite hydrogel) under skin of the rat was conducted for a research period of 8 weeks. Results demonstrated that osteoinductive BMP-2 can be injected through biocompatible hydrogel of PEG-PLGA-PEG and HA. The biocompatibility of materials can be observed by the optical microscope. After eight weeks, fibroblasts not only grow but also osteocytes. The adding bone morphogenetic proteins-2 can be clearly observed more of osteocytes. Then conclusion is the as-prepared composite hydrogel of PEG-PLGA-PEG and HA, with small additive amount (e.g. 0.01 wt%) of BMP-2 as bone promoter, is a suitable material for osteoinduction.

並列關鍵字

ring-opening polymerization ； chemical co-precipitation ； thermosensitivity ； biocompatibility ； biodegradable ； bone morphogenetic proteins

參考文獻

[13] 廖阿全，PEG/PLGA/PEG水膠高分子的製備與其藥物釋放的研究，國立台灣大學醫學工程研究所/碩士論文 (2004)。

[30] 張淑真，水熱法合成氫氧基磷灰石之研究，中原大學/化學所/碩士論文 (1993)。

[41] 史中，夏毅然 “移植骨生成細胞預防年齡增長後骨質流失效果及機轉的骨組織型態學研究” ，中華口腔顎面外科雜誌，March 2004。

[50] 葉獻彬，生物可降解性聚乳酸高分子之合成與降解性質探討，國立陽明大學/醫學工程研究所/碩士論文 (2000)。

[1] 施威任，奈米級氫氧基磷灰石之合成及燒結，國立成功大學/材料科學及工程學系/博士論文 (2006)。