製備可調控微結構之中空微針陣列於細胞傳遞之應用

Abstract

微針是以微米等級的針穿透過皮膚表皮製造出微通道，並以無痛、微創的方式進行藥物傳遞。利用該微通道，可以克服經皮吸收所面臨傳遞的藥物的限制，其必須是脂溶性且小分子藥物才可透過皮膚角質層的屏障。微針的優點是可以避免藥物在通過體內時受到肝臟腸胃等的代謝、減少感染的風險、以無痛且微創的方式以增加患者使用上的依從性，並且可以延長藥物釋放。微針又分為固體微針、藥物塗層微針，中空微針、可降解微針以及水膠微針。其中中空微針具有夾帶物質進行傳送的優勢，但因結構相較於其他類型微針較為複雜，也因此在製程上產生的成本高、步驟繁瑣、無法進行量產等等的限制。細胞療法為藥物治療外的一種治療方式，用以恢復體內受損及缺失的細胞及組織。目前，該療法主要以針劑注射的方式將細胞傳遞到體內。該方法除了會面臨傳統針劑所面臨到的限制，以針劑進行細胞注射也會造成細胞聚集，無法有足夠空間進行生長。因此在綜合上述兩者優缺點，本研究以聚二甲基矽氧烷(Polydimethylsiloxane, PDMS)做為材料，利用雷射雕刻機在聚二甲基矽氧烷上進行雕刻，製作出可調控微結構的中空微針陣列之模具。利用聚丙烯酸甲酯(Polymethylmethacrylate, PMMA)成功製作出不同微結構之中空微針陣列。接著將不同種類之細胞培養於中空微針陣列之上，利用MTT Assay測試細胞培養於中空微針上的細胞活性，且利用Live/Dead染色測試材料之生物相容性並觀察細胞於中空微針上的貼附情況。結果顯示PMMA中空微針具有良好的生物相容性，且在電子顯微鏡的照射觀察下，貼附於中空微針上的細胞仍可保持原本的細胞型態。同時，將此中空微針作為細胞傳遞之載體，針對依序以凍融、洗滌劑及生物酶的綜合去細胞處理程序所製備的去細胞支架，進行細胞傳遞。並證實細胞經由中空微針載體可有效傳遞並且生長。

Microneedles are micro-scale needles that pierce into epidermis of skin to create micro-channel for drug delivery in a painless, minimally invasive way. With this micro-channel, we can address the limitation of transdermal method, which is the molecule of the drug must be small and oil-soluble to penetrate the stratum corneum barrier. The advantages of microneedles are avoiding drug degradation in stomach and liver, reducing the risk of infection, improving patient compliance due to minimal skin trauma, less pain, and sustaining drug release. The current types of microneedles include solid microneedles, coated microneedles, hollow microneedles, degradable microneedles, and hydro-forming microneedles. Cellular therapy is one of therapeutic medical therapy, which involves culturing and modifying cells in an in vitro sterilized environment. The cells will deliver to the body to restore damaged or missing cells and tissues in the body. Nowadays, the therapy mainly delivers the cells to the body by injection. In addition, there are some limitations by traditional injection. For example, the injection has a risk of infection, the patient's compliance is low due to pain at injection, and injections could also cause cells are no room for growth. Therefore, in combining the advantages and disadvantages of the above two, in this study, polydimethylsiloxane (PDMS) was used as a material, engraved by laser engraving machine, to produce a hollow microneedle array mold. Polymethylmethacrylate (PMMA) was then used for filling, polymerization and demolding. Hollow microneedle arrays with different microstructures were successfully fabricated. The cells were cultured on the hollow microneedles. We used MTT Assay to test cell viability and the biocompatibility of the material. Then we used Live/Dead Staining to test the survival rate of the cells and we also observed the attachment of the cells on the hollow microneedles. The results show that PMMA hollow microneedles have good biocompatibility and the cells can be successfully attached to the microstructure of hollow microneedles. At the same time, the hollow microneedles were used as a carrier for cell delivery, and the cells were delivered to acellular tissue scaffolds prepared by a comprehensive acellular processing program in sequence of freeze-thaw, detergent and biological enzyme. This study confirmed that the cells can effectively enter the tissue via hollow microneedle carrier and growth well.