Optimizing a self-healing gelatin/aldehyde-modified xanthan gum hydrogel for extrusion-based 3D printing in biomedical applications

Printable hydrogels with inherent self-healing capabilities hold significant promise as bioinks for tissue repair in biomedical applications. These user-friendly hydrogels, designed to provide structural support, offer advantages such as accelerated ink preparation, uniform cell dispersion, and the maintenance of predetermined shapes and microstructures during the printing process without the need for additional stimuli. This study introduces the synthesis of 3D printable polysaccharide self-healable hydrogels through the covalent crosslinking of aldehyde- modified xanthan gum (AXG) and gelatin (Gel) via Schiff base reactions. The self-healing capacity of the hydrogel is substantiated through macroscopic observations, rheological recovery assessments, and compression measurements. The optimized Gel-AXG hydrogel (11.3 % (wt/vol) AXG to 5.7 % Gel (wt/vol)) exhibits outstanding characteristics, including exceptional integrity, well-defined pore morphology with an average pore size of approximately 123 mu m, thixotropic behavior, shear-thinning characteristics, and notable self-healing properties, achieving a high healing efficiency (HE) of approximately 88 %. Notably, this hydrogel exhibits self-recovery at 37 degrees C without the need for external stimuli. Additionally, it demonstrates commendable printability and biocompatibility. In a comparative analysis of different printing tips, the use of a 27G tip is found to enhance printing accuracy and pattern fidelity when compared to patterns produced with a 22G tip. Overall, this research introduces a self-healing and printable hydrogel that holds promise as an ink for 3D bioprinting applications.