Extrusion 3D Printing Processes and Performance Evaluation of GelMA/LPN/MC Hydrogel

Extrusion 3D printing hydrogels for tissue repair is a research hotspot in recent years. However, the high-fidelity hydrogel printing process is still inseparable from the complex cross-linking strategy, which greatly increases the difficulty of printing and limits the application of hydrogel in the field of tissue engineering. A hydrogel that can be printed at room temperature is prepared, and high-fidelity printing can be achieved without any auxiliary cross-linking during the printing process. The hydrogel is composed of gelatin methacrylate (GelMA), Laponite (LPN) and methylcellulose (MC).The extrusion test screened out the proportion of composite materials suitable for printing, and the process test investigated the effects of extrusion speed and nozzle movement speed on the continuity of the filament and the line width of the microfilament. When the inner diameter of the nozzle is 400 μm, the conditions for GelMA/LPN/MC hydrogel to achieve smooth silk-out (φ400-600 μm) are the extrusion speed of 8.6-13 mm/h and the printing speed of 6-10 mm/s. Rheological results show that the addition of LPN and MC grants the material excellent shear-thinning properties, enabling it to print at room temperature and maintain a stable structure. The compression test shows that changing the crosslinking time can increase the compressive modulus of the composite hydrogel by 5 times and the compressive strength by 3 times. Cell test showed that GelMA/LPN/MC hydrogel has good biocompatibility. © 2022 Editorial Office of Chinese Journal of Mechanical Engineering. All rights reserved.