| Natural cartilage acts as storage,cushioning and lubrication in the joint cavity.In recent years,multi-network hydrogels have been able to mimic the structure of natural cartilage tissue,which can maintain structural integrity under large mechanical deformation and sustained tension and compression due to their good energy dissipation mechanism.This overcomes the bottleneck of traditional hydrogels in terms of mechanical properties,so multi-network hydrogels have attracted extensive attention in the field of tissue engineering.However,during the regeneration and repair of cartilage tissue,hydrogel materials must also exhibit good lubricating properties to reduce the wear between bone tissues.In addition,when hydrogel is used as an artificial cartilage scaffold material,immune rejection during transplantation and the survival rate of chondrocytes in the matrix must be considered.Therefore,preparing low friction/high toughness hydrogels with good biocompatibility remains a challenge.The present work reports a rapid orthogonal photoreactive 3D-printing strategy to prepare high-performance multi-network hydrogels.This orthogonal ruthenium photochemistry helps the achievement of multiple chemical reactions for the one-step formation of multi-networks in customizable low-friction tough hydrogels（CLFTHs）in seconds.Rational component design enables them to have excellent mechanical performances and load-bearing capacity at the level of megapascal.And the further Ca2+-crosslinking treatment greatly improves their mechanical properties.When the critical strain is 300%,the tensile performance of CLFTHs can reach 6.4 MPa,and the toughness can reach 10.85 MJ m-3.In addition,the lubrication property is easily regulated by varying the content of chelating monomers to adjust the Young’s moduli of CLFTHs.As a potential cartilage tissue replacement material,the design strategy of high cross-linking density enables the friction coefficient of CLFTHs to perform better in cartilage scaffold materials,which can reduce the wear between cartilage implants and bone,and make the material have long-term use value.Rapid photochemical reactions can be combined with 3D printing technology to achieve customizable material structures.The artificial cartilage scaffold prepared by 3D printing technology still maintains good mechanical stability and wear resistance in long-term cyclic motion.In addition,the excellent biocompatibility of CLFTHs can promote cell attachment and proliferation,and significantly inhibit bacterial growth,so that it can avoid immune rejection in clinical trials of cartilage tissue engineering. |
