High-precision 3D printing of hydrogel: Material innovations, process breakthroughs, and translational applications in regenerative medicine

Hydrogels have emerged as pivotal materials in precision additive manufacturing due to their exceptional biocompatibility, tunable physicochemical properties, and hydration capabilities. This Review systematically examines cutting-edge fabrication strategies, including extrusion-based systems, photopolymerization techniques (stereolithography/digital light processing), and embedded 3D printing, with an emphasis on resolution enhancement through material rheology optimization and process innovation. Advanced material engineering approaches such as functional group modification [e.g., poly(ethylene glycol) diacrylate and gelatin methacryloyl] and hybrid network design are discussed to address mechanical-performance trade-offs and enable stimuli-responsive functionalities. This work highlights transformative biomedical applications spanning vascularized tissue constructs, patient-specific organ models, and smart wound dressings, while exploring emerging intersections with flexible electronics. Current limitations regarding multi-material compatibility, dynamic response stability, and clinical translation are critically analyzed, proposing synergistic development of intelligent manufacturing frameworks combining 4D printing and artificial intelligence-driven optimization for next-generation precision medicine.