電刺激或力學刺激施加於導電高分子支架在軟骨組織工程上之應用

Abstract

軟骨是受損後難以自我修復的組織，而選擇一個適當的材料和誘導細胞生長分化的環境可以加速軟骨修復的過程。本研究透過施加外部的電刺激或力學刺激於導電高分子PEDOT:PSS 支架上以加速促進人類脂肪幹細胞進行軟骨分化。與沒有施加刺激的組別做對照，有施加刺激的組別的軟骨特徵基因SOX9、COL2A1的表現量有顯著的上調；在免疫細胞化學螢光染色圖中也觀察到蛋白質SOX9和COL II 在受到刺激之後有較強的螢光訊號，與基因表現的結果趨勢相符。 在力學刺激實驗當中，我們透過模擬的方式將改變材料應變的施力模式量化成支架的應力響應。模擬出的應力響應中，應力峰值會隨著時間逐漸下降而趨近定值，且應力出現負值，說明有拉伸的應力產生。這個量化應力響應的方法將有助於組織工程施加力學刺激實驗中不同材料的施力條件選擇，並且可以根據細胞行為的結果最佳化施加的應力條件。這些研究成果在未來將有助於軟骨修復以及組織工程當中力學刺激的相關研究。

Cartilage is a tissue that is difficult to repair itself after damage, and choosing an appropriate material and an environment that induces cell growth or differentiation could accelerate the process of cartilage repair. In this study, the chondrogenic differentiation of human adipose stem cells (hASCs) was promoted by applying external electrical stimulation (ES) or mechanical stimulation (MS) on the conductive polymer PEDOT:PSS scaffold. Compared with the group without stimulation, the expression levels of chondrogenic characteristic genes, SOX9 and COL2A1, in the stimulation group were significantly up-regulated; SOX9 and COL II proteins were also observed with stronger fluorescent intensity in the immunocytochemistry (ICC) fluorescence staining images, which was consistent with the trend of gene expression results. In MS experiment, the strain excitation exerted on the scaffold was transformed into stress response by means of simulation. In the simulated stress response, stress peak would gradually decrease with time and approach a constant value, and the negative value of the stress represents the generation of tensile stress. This method of quantifying the stress response could facilitate the selection of applying MS conditions for different materials in tissue engineering, and the applied stress conditions could further be optimized. These findings could contribute to the research on cartilage repair and mechanical stimulation in tissue engineering in the future.