In-situ extrusion 3D printing with tea polyphenol crosslinking for Hyaluronic acid sodium salt -based composite hydrogel scaffolds.

High-performance hydrogel biomaterials hold considerable promise for advanced wound care. However, the suboptimal mechanical properties of conventional hydrogel materials limit their practical application. In this study, Hyaluronic acid sodium salt (HA), xanthan gum (XG), and N-acryloyl-glycinamide (NAGA) hydrogels with porous structures were successfully fabricated using in-situ extrusion 3D printing technology, and a functionalization strategy involving tea polyphenol (TP) immersion was proposed to enhance material properties through additional hydrogen bonding. Systematic optimization of TP concentration and immersion time led to significant improvements in the resulting hydrogel: tensile strain increased from 95 % to 266 %, tensile stress improved 6.8-fold, and compressive stress increased 10-fold, with an elastic modulus of 0.68 MPa and toughness of 1.2 MJ/m³ . Furthermore, TP-treated hydrogels exhibited excellent biocompatibility and strong antioxidant activity and antibacterial activity. This study provides a simple yet effective secondary functionalization approach for enhancing the performance of 3D-printed hydrogels, offering a promising approach for multifunctional hydrogel biomaterials with integrated mechanical strength and biocompatibility. These findings open new avenues for advanced wound care systems and personalized medicine applications.