Design and evaluation of high-viscosity gelatin / polyacrylamide / sodium alginate triple-network hydrogels for 3D printing: fluid dynamics simulation and experimental method

Extrusion-based 3D printing technology enables the precise design and fabrication of hydrogel scaffolds, demonstrating great potential for tissue repair applications. However, the addition of rheological modifiers or adjustment of the printing environment is often required to achieve successful scaffold formation. In this study, we developed a high-viscosity gelatin/acrylamide/sodium alginate (Gel/AM/SA) hydrogel ink that allows direct high-precision printing of triple-network hydrogel scaffolds. Our results show that the addition of SA significantly increased ink viscosity and yield stress, thereby reducing deposition deformation and improving printing accuracy. Our fabricated gelatin/polyacrylamide/sodium alginate (Gel/PAM/SA) scaffolds exhibited excellent mechanical properties, with a compressive strength of 3.69 MPa and a compressive modulus of 496 kPa. Moreover, the Gel/PAM/SA scaffold demonstrated long-term stability in the biological environment, with a weight loss rate of only 41.79 % after 28 days of degradation. The scaffold showed good cell compatibility and the cell adhesion rate on the scaffold reached 88.3 % after 1 day of culture. This study underscores the ability of Gel/AM/SA ink to fabricate scaffolds with complex shapes and structures at high fidelity, offering new avenues for biomedical applications.