| 摘要: | 背景:
傳統組織工程是將細胞種植在預先成型的支架上，透過體外培養的方式再添加適當生長因子，最終成為具有功能性的器官或是組織，進而用於修補或取代受傷的器官。儘管現在組織工程的技術很成熟，但鑒於身體器官結構的高度複雜性，且受限於預先成型的支架結構，最終製造出來的器官無法精確地模擬受損器官的形狀和位置，限制了其發展。近年來，3D 生物列印利用數位化定位技術，便能控制材料堆疊於想要的位置，最後製作出客製化組織工程產品，進而解決傳統組織工程在支架上的限制。
目的:
本研究的目的是建造一套雷射誘導前向細胞列印系統(簡稱LIFT 系統)，由於LIFT 系統可利用雷射光精準地沉降細胞或是生物材料至想要的列印位置，因此是一種具有高度空間解析度的雷射輔助三維生物列印技術。系統建造完成後，我們將評估此系統的最佳化列印條件，並且將此系統應用於小範圍的精準細胞列印上。
材料與方法:
LIFT 是利用聚焦的雷射光束對細胞懸浮液加熱進而形成蒸氣氣泡，進而形成一個噴流結構並將列印樣本呈現液滴狀列印至預定位置的基材表面。建立一個雷射細胞列印系統需要多方面的考量，例如:雷射的種類、雷射光聚焦能力、如何控制列印圖案以及影像系統等。系統建構完成後，藉由調整雷射光強度、曝光時間、能量吸收層的厚度，找出最佳化的細胞列印條件。最後，本研究將利用LIFT 技術進行客製化列印以及細胞列印，並且評估列印後細胞的存活率和雷射光對細胞的傷害。
結果:
根據雷射細胞列印系統的需求，本研究最終選用波長830 nm 的近紅外光連續式雷射光源和20倍顯微鏡物鏡將雷射光聚焦在提供版的能量吸收層上。實驗中，使用金當作能量吸收層，結果顯示，在雷射強度為93 mW，雷射作用時間為8 秒，列印高度為0.7 mm，金膜厚度為16 nm，生物墨水厚度為25 μm 時，此系統有較好的列印品質和成功率，此外，系統也已經具有客製化列印和細胞列印的功能，但細胞存活率還需要提升。
結論:
本研究已經成功地建造雷射誘導前向細胞列印系統，並且已經找到較好列印品質和成功率的條件，未來將繼續尋找更好的列印條件以及解決所遇到的問題，以達到高精準度的細胞列印，期待未來可用於組織工程或是再生醫學上。
Background:
Traditional tissue engineering was to seed cells on the preformed scaffold along with suitable growth factors that stimulated tissue formation and cultured in vitro to
form functional substitutes that can repair or replace damaged tissues or organs. However, in view of high complexity of the organ and tissue, seeding cells on the
preformed scaffold cannot control over cell position and tissue architecture, which had the inability to mimic the complex microstructures of biological tissues. Fortunately, 3D bioprinting can deposit biomaterials in a desired location by using programmed-positioning technology and finally create customized tissue engineering products. It showed a promise to bridge the divergence between artificially engineered tissue constructs and native tissues.
Aims:
The aim of this study was to develop a laser induced forward transfer (LIFT) bioprinting system that could deposit cells in a controlled and precise way. After construction, the suitable printing condition was evaluated in order to achieve the ability of cell bioprinting. We hoped this technology can apply in accurate printing of cells in a small range area.
Materials and Methods:
A LIFT bioprinting system was to let laser highly focus on the energy-absorbing layer of ribbon, to generate evaporation and to produce a small droplet. Constructing a laser cell printing system required many considerations, such as the type of laser, the ability to focus laser light, how to control printing patterns, and imaging systems. After construction, we firstly calibrated the system. And, we found out the suitable energy-absorbing layer and optimal printing condition by adjusting the laser power, exposure time, and energy-absorbing layer thickness. Finally, this system applied in cells printing. We evaluated the cell viability and damage induced by laser after printing.
Results:
According to considerations and requirements for cell bioprinting, we finally selected the 830nm near- infrared continuous wave laser and applied a microscope objective to highly focus the laser beam in the LIFT system. In this study, thin gold film was used as the energy-absorbing layer for LIFT bioprinting. The results showed that when the laser power was 93 mW, the laser exposure time was 8 seconds, the direc-twriting height was 0.7 mm, the gold film thickness was 16 nm, and the bioink thickness was 25 μm, the LIFT system has an effective quality and high printing success rate. In addition, the system had the ability of customized pattern and cell printing. But the cell survival needed to be improved.
Conclusions:
We have successfully constructed LIFT bioprinting system and found out the conditions of better printing performance and success rate. We will continue to look for the best printing conditions and solve problems encountered in the future. We hope this bioprinting technology can provide potential for tissue engineering or regenerative medicine. |
