Directional anneal-casting strategy enables mechanically enhanced biomimetic hydrogel for ligament reconstruction

Artificial ligaments play a crucial role in replacing injured natural ligaments and facilitating rehabilitation. However, existing artificial ligaments lack real-time strain monitoring capability, which limits personalized rehabilitation guidance. Here, we develop a highly biomimetic and intelligent electronic hydrogel ligament (IEHL) based on polyvinyl alcohol/sodium alginate through a universal directional anneal-casting (DAC) strategy. This innovative approach creates aligned microstructures that overcome conventional hydrogels' limitations of poor structural integrity and inadequate mechanical properties. The IEHL exhibits integrated bionics of microstructure, mechanical parameters and water content closely matching natural ligaments. The efficacy of the IEHL in stabilizing knee joint and monitoring movements is validated through in vivo models, and a wireless monitoring system is developed to detect and analyze ligament strain characteristics in real-time. This IEHL provides a superior intraoperative replacement strategy and quantitative guidance for post-surgical rehabilitation.