Development of a Path-to-Follow Nozzle for Ultraviolet-Assisted Three-Dimensional Bioprinting Technology

Ultraviolet-assisted three-dimensional bioprinting (UV-3DP) combines tissue engineering and extruding-based additive manufacturing. Photocrosslinking is performed by irradiating a specific area with UV light. The cells laden in the scaffold may be irradiated repeatedly, increasing the probability of damage and death. In this study, a path-to-follow nozzle with the following two characteristics was developed. First, the UV light was focused onto a spot with an objective microscope lens to reduce the illumination range; second, a gear set was used to control the rotation angle of the barrel such that the material extruded by the nozzle was always in front of the UV focus spot. As a result, the scaffold material underwent crosslinking in extremely small areas after exposure to the subsequent focus UV light. This study used gelatin methacryloyl (GelMA) hydrogel as the scaffold material. After conducting basic experiments to determine the GelMA material composition suitable for UV-3DP, we analyzed the printing results at the turning point and successfully printed two-layer square and circular scaffolds.