Strong, Self‐Healing, Biocompatible Aramid Nanofiber‐Reinforced Hydrogels for 3D Printing

ABSTRACT Combining self‐healing hydrogels with 3D printing enables the fabrication of complex hydrogel structures that can recover from damage and extend their functional lifespan, making them promising materials for artificial tissues. However, low mechanical strength continues to limit their applications. Here, we address this challenge by synthesizing polyvinyl alcohol/polyacrylic acid hydrogels reinforced with aramid nanofibers (ANF) for 3D printing. ANF, derived from poly (p‐phenylene terephthalamide) via deprotonation, was added into a semi‐interpenetrating polymer network hydrogel cross‐linked by poly (ethylene glycol) diacrylate and photopolymerized using water‐soluble (2, 4, 6‐trimethylbenzoyl) diphenylphosphine oxide nanoparticles. The resulting ANF‐enhanced hydrogels exhibited significant improvements in tensile strength (0.32 ± 0.02 MPa), elastic modulus (0.075 ± 0.008 MPa), and energy dissipation (126.46 ± 10.02 kJ/m 3 ), while maintaining at least 30% self‐healing efficiency through hydrogen‐bond‐mediated interfacial recovery. Leveraging digital light processing 3D printing, we fabricated intricate hydrogel architectures, such as meniscus‐shaped structures, with enhanced tensile strength (0.41 ± 0.01 MPa) and self‐healing efficiency (> 50%). Cryo‐SEM and ATR‐FTIR analyses revealed that ANF induces phase separation and hydrogen bonding, reinforcing the hydrogel network. Biocompatibility studies indicate low cytotoxicity after ANF incorporation. This strategy provides an effective route to reinforce and toughen 3D‐printed self‐healing hydrogels for biomedical applications.