以甲基纖維素補強明膠性質做為周邊神經修復導管之研究

Abstract

本實驗以甲基纖維素 (Methyl cellulose)經高碘酸鈉(Sodium periodate)氧化後與明膠(Gelatin)形成共聚物，發展出適合於神經修復的替代材料做為周邊神經再生導管的研究。實驗主要分為三大部分：材料氧化改質、材料性質分析及體外生物相容性(biocompatibility)的測試。首先在材料的氧化改質上，本研究利用過碘酸鈉於甲基纖維素的環狀結構上產生所需官能基在與明膠進行交聯(cross-link)，希望利用甲基纖維素降解緩慢及明膠良好的生物相容性，並且在不加入交聯劑(cross-linking agent)的情況下製備出一項嶄新的合成高分子。 第一階段，先製備不同氧化程度的甲基纖維素，希望藉由評估不同氧化度下材料性質的差異來製備出最適合神經再生的導管。 第二階段為材料性質的分析使用各種不同的儀器及方法來探討不同氧化度下各類性質的差異，首先，會利用富利葉紅外線光譜儀(FTIR)來進行官能基的定性測定，確認官能基生成後，進行材料改質的定性分析，希望以此分析了解不同條件下氧化程度的差異，分析後發現氧化劑濃度對於氧化度具有決定性的影響，同時進行交聯度分析藉以了解在加入明膠後材料所生成醛基(aldehyde group)與明膠上胺基(amine group)的反應程度差異，結果發現由於高分子間立體障礙(steric hinderance)的影響，因此，氧化度的大幅提升對於交聯度並未造成相對程度的影響。定性分析完成後，便進行降解性質的分析，有兩種測試方法相互對照後，發現本材料對於減緩降解速率上具有一定的幫助。由於甲基纖維素於37度下具有緩慢降解的特性，因此，對於延緩降解速率具有相當程度的幫助，接下來進行水接觸角分析(contact angle)，分析後我們發現經由交聯劑交聯過後的明膠薄膜較疏水(hydrophobic)，對於細胞貼附為一較不適宜的環境，相對於本研究所製備的材料其親水性(hydrophilic)佳，對於細胞貼附生長具有相當程度的幫助。 第三階段為生物體外生物相容性測試，藉由生物相容性測試後發現，本研究所製作出的材料，由於其親水特性因此對於細胞生長貼附具有正面幫助。此外，由細胞毒性(cytotoxicity)測試中發現，該材料對細胞不具有毒性，為一適合細胞生長貼附的材料。 總結，利用高碘酸鈉氧化後的甲基纖維素與明膠交聯過後的共聚物具有良好的型態物理化學性質以及生物相容性是一項極有淺力的一項新興材料。

In the study, the dialdehyde cellulose-gelatin was designed and fabricated for peripheral nerve regeneration. The methyl cellulose could successfully transferred into 2, 3-dialdehyde cellulose by using sodium periodate as an oxidant. The DAC-Gel membrane with different conditions was fabricated by controlling the concentration of sodium periodate and the reaction time. The biological stability of membrane was improved by cross-linking with gelatin. The physical-chemical properties and biocompatibility of DAC-Gel membrane were evaluated to ensure the potential viability of this novel co-polymer for peripheral nerve regeneration. To estimate the properties of the DAC-Gel membrane with different conditions, the methyl cellulose was oxidized by different concentration of sodium periodate. After oxidized, the dialdehyde cellulose with different degree of oxidation was fabricated. FTIR could further confirm the formation of aldehyde group and the quantification of aldehyde group showed that the concentration sodium periodate was the dominant factor to the degree of oxidation. Basic assessment of cross-linking degree showed that steric hinderance could be the factor to hinder cross-linking. According to the degradation test, the DAC-Gel membrane could prolong the degradation time and slow down the rate of degradation. The hydrophilic/hydrophobic surface after cross-linking was evaluated by water contact angle test. The DAC-Gel membrane was more hydrophilic than the Gel membrane using glutaraldehyde as a cross-linker. The biocompatibility was evaluated by WST-1 cell proliferation and LDH cytotoxicity. The DAC-Gel membrane provided an adaptable place for cell proliferation and the membrane using glycine to block the residual aldehyde group showed a low cytotoxicity. To sum up, the DAC-Gel membrane was a newly designed material and possessed great potential in the different application.