探討微針貼片作為細胞載體在細胞治療上之應用

Abstract

細胞治療被應用於治療各種疾病並促進修復受損的組織。如何將細胞傳遞到受損組織的部位是細胞治療中至關重要的一個步驟。細胞必須被準確地傳遞到目標部位並且停留在受損的組織附近以修復受損的組織。在幹細胞治療中,將細胞直接注射到受損的組織中是目前最常見的方法。但是這種方法有一些缺點,例如:有發生感染的風險、注射過程中會產生疼痛感使得病人的接受度低、細胞液可能從注射的部位洩漏出來及細胞因為在注射的過程當中的擠壓而造成存活率降低等等。除了透過針筒直接注射外,細胞亦可藉由細胞載體傳遞到受損的組織。這種細胞傳遞方式被稱作幹細胞傳遞系統 (stem cells delivery system)。微針陣列是一種微創經皮輸送系統。這種裝置可以穿透皮膚的角質層將大分子的藥物傳送到皮膚中並且進入皮膚的微循環系統。在本研究中,我們製作了兩種不同類型的微針陣列貼片-實心和中空微針陣列貼片。實心微針是利用兩階段的微成型法 (micromolding) 製作而成,細胞可以直接裝載在微針陣列上並將其傳遞到目標組織中。我們使用膠原蛋白水膠當作組織模擬物來進行細胞傳遞實驗。經由微針陣列細胞傳遞系統,細胞可以被很有效率地傳遞到組織模擬物上,細胞傳遞率大約 83.2%。這些結果顯示實心微針陣列貼片可以非常有效率地傳遞細胞。利用微成型法可以成功地製作出具有微結構的中空微針陣列,經由調整雷射的功率和不同的設計圖形可以控制中空微針陣列的微結構。細胞可以很容易地裝載到中空微針陣列上。本研究的結果顯示中空微針陣列具有良好的生物相容性並且可以成功地將細胞傳遞到去細胞的組織中。本研究證實了細胞可以透過中空微針陣列貼片將細胞有效地傳遞並且滲透到組織中,被傳遞的細胞會均勻的分布並在組織中增生。我們同時將兩種細胞 (角膜上皮細胞 corneal epithelial cells 和角膜細胞 corneal keratocytes) 裝載到中空微針貼片上並傳遞到去細胞的角膜組織中,經過 7 天的培養後,角膜上皮細胞分布在角膜組織的表層,角膜細胞則分布在角膜組織的內層。這個結果顯示細胞傳遞到組織後,會慢慢地移動到特定的部位進行組織重建。本研究開發了一種可以有效地將細胞傳遞到組織的新型微創式細胞傳遞系統-微針陣列貼片, 在細胞治療的應用上有非常大的發展潛力。

Cell therapy is used to treat various diseases and to repair injuries. Cell delivery is a crucial process that delivers cells to target sites. Cells must be precisely delivered to a target site and the cells that are delivered must be localized to the target site to repair damaged tissue. For stem cell therapy, the most convenient method of cell delivery involves directly injecting cells into damaged tissue. But it has drawbacks, such as the risk of infection, low patient compliance due to pain at injection, leakage of cell suspensions from the injection site and cell damage during injection. Other strategies use carriers to transplant stem cells into damaged tissue. These are termed, stem cell delivery systems (SCDSs). Micro-needle arrays are minimally invasive transdermal delivery systems. The devices can pass through the stratum corneum barrier and deliver macromolecules into the skin. They can also access the microcirculation system in the skin. In this study, we fabricate two types of microneedle array patch: solid and hollow microneedle array patches. The solid PMMA micro-needle is fabricated using a two-stage micro-molding method. Cells are seeded on the micro-needle arrays and then transferred into the target tissue. Collagen hydrogel is used as a model biomimetic tissue. Cells are efficiently delivered to regions of interest, collagen hydrogel, by using this system. The delivery rate is about 83.2%. This demonstrates that microneedle arrays allow very efficient delivery of cells. Hollow microneedle arrays with various microstructures are successfully fabricated by micromolding, where their microstructure can be controlled by the laser power and the drawing pattern. The cells are easily loaded on top of hollow microneedles. The results show that PMMA hollow microneedles have good biocompatibility and the cells can be successfully delivered to the acellular tissue. This study confirms that the cells can be effectively delivered and penetrate into tissue by a hollow microneedle patch. The delivered cells proliferate and distribute evenly in the tissue. Two types of cells (corneal epithelial cells and corneal keratocytes) are loaded on the hollow microneedle array patches simultaneously, then deliver to the decellularized cornea. After 7 days, epithelial cells are located on the surface of the cornea and keratocytes are located in the surface and stroma of the cornea. This result shows that the delivered cells migrate to the specific regions and rebuild the tissue. The microneedle array patch provides a minimally invasive route for effectively delivering cells into tissue. This novel strategy has potential application for cell therapy.