Butterfly Proboscis‐Inspired Water‐Welding Strategy for Hollow‐Walled Hydrogel 3D Stents With Ultrahigh Mechanical Support Capacity

Hydrogels have emerged as promising candidates for next-generation implantable biomedical stents. However, the scalable fabrication of hydrogel three-dimensional (3D) stents with sufficient mechanical support remains a major challenge, owing to the intrinsic flexibility of hydrogel materials. Here, inspired by the water-welding mechanism of the butterfly proboscis, we report a facile water-mediated welding strategy for sodium alginate (SA) films, which enables the assembly of fully integrated 3D stents using only water as the processing medium. The as-prepared solid-walled 3D stents can be seamlessly converted into hollow-walled architectures via a metal ion-induced asymmetric crosslinking followed by solvent exchange. Notably, the hollow-walled structure enables the mechanical support force five times that of solid-walled ones, rendering these hydrogel 3D stents highly attractive for biodegradable medical stents. This work provides a versatile and environmentally benign route to engineer 3D hydrogel stents, thereby advancing the development of advanced implantable biomedical devices.