3D‐Printed Hierarchically Porous Hydrogel Scaffolds with Enhanced Shape Fidelity and Structural Durability via Network‐Assisted Freeze‐Thaw (NAFT) Processing

Abstract Regenerating strong, load‐bearing tissues such as cartilage requires scaffolds that replicate both the multiscale architecture and mechanical resilience of the native extracellular matrix (ECM). Hydrogels are promising ECM analogs due to their high water content and tunable chemistry; however, most lack sufficient 3D printability and/or mechanical robustness, restricting their use in precision‐engineered, mechanically demanding applications. While approaches such as rheological modification and double‐network formation have addressed these challenges individually, integrating high‐resolution printability with strong mechanical performance in a single hydrogel system remains challenging. Here, a printable hydrogel platform is presented, composed of poly(vinyl alcohol) (PVA) and polyacrylamide (PAM), with carbomer added to improve shear‐thinning behavior and enable direct ink writing (DIW) with microscale resolution. A network‐assisted freeze‐thaw (NAFT) process induces nanoscale porosity, enhances tensile strength by ≈10‐fold, and confers high compressive resilience (maintained at 80% strain for over 200 cycles), without compromising the printed architecture's shape fidelity. The resulting hydrogels demonstrate a coefficient of friction (COF, µ) comparable to native porcine cartilage and support ≈97.9% chondrocyte viability along with 3D cellular proliferation. Finally, patient‐specific cartilage implants are fabricated from MRI data using mechanically optimized scaffold designs, demonstrating the clinical potential of this customizable hydrogel platform for load‐bearing tissue repair.