| dc.description.abstract | Nowadays, as the concept of health awareness rises, biomedical engineering has been brought to public attention. Therefore, tissue engineering has become one of the hottest research topics. It combines with additive manufacturing to become 3D bioprinting technology, which not only solves the manufacturing of complex scaffold but mimics the natural extracellular matrix to provide a good living environment for cells.
Common Bioprinter used to manufacture scaffold with single printing mode, if it manufactures complex skin structures, such as burned skin and chronic ulcerated skin that epidermis and dermis are damaged. It is difficult to mimic the real appearance and also make tissues grow worse. Therefore, the purpose of this research is to integrate two different printing methods on bioprinter and choose the appropriate deposition method according to different structural characteristics to meet the needs of complex scaffolds. In terms of hardware, a multi-nozzle exchange module including pneumatic extrusion and micro-valve inkjet is developed.
Moreover, the average deviation value of the two nozzles superimposed printing is verified to ensure the accuracy of alignment that meets the complex scaffold requirements. In terms of software, the C# programming language is used to control the exchange process, height calibration, and temperature monitoring to achieve the purpose of machine automation.
In this research, a thermosensitive composite hydrogel composed of Gelatin and Pluronic F-127 was used as a bio-ink, and the overall printing temperature was controlled at 37°C for future cell culture experiments. In the aspect of the nozzle, a compact heating sleeve has been developed, which can instantly monitor the temperature of the needle and the ambient temperature of the deposition level to prevent the nozzle from clogging and maintain the rheological properties of the material. In addition to studying the printing parameters of different printing methods, this study also used pneumatic extrusion to deposit 25 layers of about 2.5mm high scaffold to mimic dermal tissue, and use a microscope to measure the diameter of the scaffold hole is about 0.1mm. Furthermore, use the microvalve to deposit bioink
with 0.5mm high on the surface of the scaffold to mimic the epidermal tissue, and finally produce a 3mm high skin scaffold. If the bio-ink containing cells is printed in the future, it will not only make the cells more uniform, but also more simulation to become a skin structure. | en_US |