| 摘要: | 由於心肌的再生能力有限，在遭逢嚴重損傷後無法自行修復，因此細胞療法被指出具有促進心臟組織修補的潛力。然而心肌的動態環境難以複製，因此細胞在體外擴增時常失去應有功能。基於此，我們將開發具有高拉伸性的導電基材來同時對細胞進行電和拉伸刺激，並導入溫敏性高分子讓刺激誘導後的細胞得以層狀脫附。我們將評估該複合薄膜在拉伸過程中的電導率，以確定適用的應變範圍，，也會以循環拉伸測試其可靠性，並確認溫控操作時細胞層可以被完整取下且維持其細胞活性及功能性。此複合薄膜將被組裝至生物反應器，藉此對細胞同時進行拉伸及電刺激。因為細胞可藉其骨架接受環境誘導，所以預期這兩種物理刺激的組合能產生協同作用來促進細胞朝向心肌分化。最後我們將驗證接受誘導的細胞治療心肌梗死之可行性。由於拉伸和電的處理可促進心肌細胞的生成及分化，且層狀脫附的細胞能維持細胞間的聯結並保有ECM的完整，因此細胞存活率及訊息傳遞應可大為提高，預期除了能促進受損部位的修復，且可與原生心肌的收縮耦聯避免心律失調，達到恢復心臟功能的目的。除了在組織工程的應用外，此反應器亦可作為體外培養之觀察平台，以了解肌肉相關疾病的致病機轉，進而提升對於如肌肉萎縮症等的治療和藥物開發。 ;In Taiwan, cardiovascular disease is the second among the top ten leading causes of death. Following significant injury such as myocardial infarction, the myocardium has limited regenerative potential. Therefore, cell therapy has been investigated to promote the repair of damaged heart tissues. However, cells expanded ex vivo always lose their functions and cannot couple to the host tissue because static culture condition is too far from dynamic cardiac environment. Consequently, we would like to develop a bioreactor to achieve a mature tissue-engineered myocardium in vitro. To electrically and mechanically treat cells simultaneously, a conductive substrate with high stretchability is essentially demanded. Polypyrrole (PPy) will be deposited onto elastic polydimethylsiloxane (PDMS) to form a conductive stretchable substrate. In addition, thermo-sensitive poly (N-isoproylacrylamide) (PNIPAAm) will be grafted on the surface, by which intact engineered cell sheets can be completely detached through temperature regulation. The conductivity of PNIPAAm-PPy/PDMS constructs during stretching will be evaluated to determine their applicable strain range, and the cyclic stretching will also be performed to ensure their reliability. Furthermore, detached cell sheets will be examined of their viability and cardiac properties. Once the PNIPAAm-PPy/PDMS constructs are successfully fabricated, they will be utilized for bioreactor application. A 3-layered device will be manufactured by computer numerical control (CNC) processing. When cells are seeded on this bioreactor, they can be mechanically and/or electrically stimulated. Because cytoskeleton is sensitive to environmental cues, it is expected that the combination of these two physical stimulations can synergistically control cell morphology. Regarding to the cardiomyogensis, mechanical and electrical treatments can both mimic the environmental cues in myocardium, and thus cell differentiation toward cardiac phenotype should be highly promoted. Finally, we will further validate the feasibility of engineered cell sheets on healing myocardial infarction. Comparing to untreated cardiac cells, mechanically and electrically treated cells should be highly promoted of their myogenesis. In addition, the cell sheet method preserve cell-cell interaction and cell-ECM linage, thus their communication and survival rates should be highly improved, which may facilitate electrical coupling to the native myocardium without arrhythmia. Through echocardiography analysis, these engineered cell sheets should significantly heal myocardial infarction and recover heart function. In addition to promote myogensis for tissue engineering application, this device can also be used as an disease model to understand the etiology of muscle disease such as Duchene muscular dystrophy, by which the clinical treatment and drug development can be highly promoted. |
