Bioinspired Conductive Hydrogel with Ultrahigh Toughness and Stable Antiswelling Properties for Articular Cartilage Replacement

The fabrication of bionic articular cartilage has been a hot topic because many people are suffering from cartilage degeneration. Among various substitute materials, the biocompatible and low-frictional PVA-based hydrogels have revealed their special potential to replace the natural cartilage. However, the porous nature of most hydrogels is prone to inevitable swelling or degradation in liquid environments, limiting their talent in practical clinical application of tissue engineering. Herein, we designed and prepared a bioinspired hydrogel by combining two cost-effect and biocompatible materials, poly(vinyl alcohol) (PVA) and sodium phytate (PANa), which could have superstrong toughness and long-term antiswelling properties in different solutions. The strong hydrogen bonds between PANa and PVA, together with the crystalline microphases of PVA chains, played the major role in offering the physical cross-linking points to give the PVA–PANa gel a dense porous structure. Meanwhile, a compressing process was introduced to the PVA–PANa complex to further strengthen its mechanical properties. Moreover, the introduction of PANa could endow the PVA–PANa gel with good conductivity, which has exhibited a highly sensitive and stable response in strain sensing. This innovative preparation of the high-strength, antiswelling, and conductive hydrogel will open a promising avenue for producing implantable smart biomaterials.