Development Of Super-tough And Self-healing Hydrogel Based On Biological Tissue Materials

Tissue engineering is a rapidly emerging and emerging interdisciplinary subject in the field of biomedical engineering.The core is the application of biologically active raw materials to construct artificial tissues in vitro to promote the repair or regeneration of human tissues and organs by engineering principles and methods.Hydrogel is a hydrophilic polymer network that has become a widely used biological tissue engineering material due to its high water content and excellent biocompatibility.Among them,the single-network hydrogel has a limited application range due to poor mechanical properties.The double-network hydrogel compounded by the two polymers has excellent mechanical properties,but is easily broken after deformation or repeated deformation,and the complexity curing principle and large number of preparation steps which is not conducive to processing and molding.Therefore,the development of a composite double-network hydrogel with spontaneous healing function,and its low-cost,rapid preparation,can greatly expand the application range and practical value of dual-network hydrogel in the field of tissue materials engineering.In this paper,we have innovatively synthesized a polyacrylamide-alginic acid double-network hydrogel with self-healing ability.The new formulation of the dual-network hydrogel has excellent stretchability and toughness,the maximum draw ratio can be 46 times,and the maximum toughness can reach 200 KPa.More importantly,this new dual-network hydrogel has a very high self-healing ability,and it can be repaired spontaneously by cutting it into several pieces and placing it in a humid environment.Even if it is dried and ground to pulverize,it can be quickly and spontaneously recovered by adding water,and its tensile properties can be restored to 100%.Moreover,the self-healing regeneration after pulverization can be cycled several times.The double-network hydrogel regenerated every time also maintains an elongation of about 40 times.We performed detailed characterization and analysis of the control parameters in the preparation of hydrogels and self-healing experiments,such as the pH of the prepolymer,the polymer ratio,temperature,reaction time,we found that when pH=3,Mechanical properties such as stretchability and toughness reach amaximum,while temperature only accelerates the gelation time and has no significant effect on the mechanical properties of the resulting gel.Through experimental analysis,we also found that the initial gelation of the hydrogel is based on the covalent bond of the amide bond and the hydrogen bond network,while the self-healing is based on the cleavage and reformation of hydrogen bonds.The self-healing double-network hydrogel prepared in this paper is superior to the general physical gel,and its self-healing speed is fast,it can be healed and regenerated in multiple cycles,and it can be repaired in time without damage,even in severe crushing.After standing for a long time,it can still maintain self-healing regeneration ability.These superior features also give the ease of processing and storage compared to conventional dual-network hydrogels.Finally,we use this new self-healing regenerative dual-network hydrogel for applications such as hydrophilic glues,material repair agents,and bio-printing inks.