| dc.description.abstract | 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. | en_US |