| 摘要: | 三維生物列印是一門結合組織工程與積層製造的技術，利用生物墨水當作材料來堆積出生物組織的外形結構，並把細胞佈署在適當的位置進行培養，希望能複製出所需的組織或器官，以解決現今器官短缺的問題。在製造方面，積層製造技術擁有快速客製化的優勢，可製作出多孔性且複雜外型輪廓的組織工程支架，能促進材料中的細胞增殖與分化，誘導活體組織再生修復。
本研究以甲基丙烯酸酐化明膠(Gelatin Methacrylate, GelMA)作為目標材料，發展光交聯類型之三維生物列印技術。光交聯形式之三維生物列印常使用紫外光為光源，支架成形過程中經常因為長時間在紫外光下曝光而接收過多光能量，最終導致材料中的細胞病變或死亡。為了解決此問題，本研究設計一組路徑導引式噴頭，將紫外光使用顯微物鏡聚焦成一點，在焦點前方利用噴頭將生物墨水隨著預定位置擠出，隨後立即使其被交聯，並且利用C#Program撰寫一套演算法與人機介面。在光源的部分則設計了兩種模組，分別是利用單光子進行光交聯的UV-LED模組，以及雙光子吸收聚合的飛秒雷射模組。此外考慮到GelMA對溫度敏感度較高，因此在放置料桶的一端設計成加熱套的形式，可即時監控生物墨水的擠出溫度，來提升列印品質。
為了驗證此次設計之噴頭的列印可行度，本研究比對了演算法的路徑規劃與實際列印情況並討論之。從觀察轉角處列印情況可知，擠料線段雖符合指定路徑，但因材料的黏度較低，擠出線段容易流動而影響精度。在材料的部分，則利用不同重量百分比濃度的GelMA與光起始劑進行實驗，觀察UV-LED輸出功率與曝光時間的關係。結果表明，越高濃度的GelMA以及光起始劑所須曝光時間較短，但兩者的添加劑量皆有上限，且根據配方的不同，材料所需的固化能量值是固定的。最後再利用最佳比例12 wt%GelMA進行方形與圓形之簡易列印，初步成功列印出兩層結構。
;Three-dimensional bio-printing is a technology that combines tissue engineering and additive manufacturing. It uses biological ink to stack into the shape of biological tissue, and deploys the cells in an appropriate position for cultivation to solve the current shortage of organs. In manufacturing, additive manufacturing technology has the advantage of rapid customization. It can make tissue engineering scaffold with high porosity and complex shape. Also, it can promote cell proliferation and differentiation in the material, and induce tissue regeneration and repair.
In this study, methacrylic anhydride gelatin (GelMA) was used as the target material to develop photo-crosslinking of 3D bio-printing. The light source often uses UV light, so it often change or die because it receives too much energy from UV light for long time. In order to solve this problem, this study design the Path Guiding Nozzle. It can focus the UV light into a point using a microscopic objective lens, and push the bio-ink in the predetermined position by the nozzle. Then the material can be crosslinked. This study also develop algorithms and the user interface by C # Program. Two types of modules are designed on the light source, which are the UV-LED module that uses a single photon for photo-crosslinking, and the femtosecond laser modules that use two-photon polymerization. They can be focused into a point through the microscope objective and irradiate the material to produce cross-linking. In addition, the characteristics of GelMA are highly sensitive for temperature, so the end of the material container is designed as a heating jacket. It can monitor the temperature in real time to improve print quality.
In terms of printing feasibility, this study discusses the path of the algorithm and the results of printing. Although the line meets the target, it is less smooth and affects the accuracy due to the lower viscosity of the material. For materials, we find out the relationship between UV-LED output power and exposure time with GelMA and photoinitiator. Under the same power of UV, the results show that the higher the concentration of GelMA and the photoinitiator, the shorter the exposure time. However, there is an upper limit on the dosage of both. And the curing energy value is fixed by different settings. It successfully prints round and rectangular structures, the number of layers can reach two layers using 12 wt% GelMA. |
