Rheology-directed design of multifunctional human-like skin materials for extrusion-based 3D bioprinting combining bioadhesion, bacteriostatic, and wound repair.

Severe skin injuries require printable biomaterials that combine tissue adhesion, infection-control potential, and wound-repair compatibility. In this study, a gelatin/tannic acid/hyaluronic acid/elastin hydrogel precursor was developed using a rheology-directed design strategy for extrusion-based 3D printing. Rheological tests showed that the precursor ink exhibited controllable shear-thinning behavior, thixotropic recovery, and yield-stress characteristics suitable for extrusion at 25 °C, which corresponds to the ambient printing environment rather than physiological temperature. EDC/NHS secondary crosslinking was introduced to improve post-printing structural stability; however, the rheological stability of the post-crosslinked network at physiological temperature, approximately 37 °C, requires further systematic evaluation. The optimized formulation showed tissue adhesion,in vitrobacteriostatic activity againstE. coliandS. aureus, and preliminary wound-closure potential in a non-infected mouse wound model. These results suggest that rheology-directed formulation design may support the development of printable bioadhesive hydrogel dressings, while further studies are needed to validate post-crosslinked mechanical stability, post-printing cell viability, and infection-control efficacy in infected wound models.