Injectable Hydrogel with Ultrafast In Situ Reforming Properties

Shearing-thinning injectable hydrogels, with a fixed 3D network structure, have significant potential for application in soft and hard tissue defect repair, drug delivery, wound dressings, etc. However, these hydrogels often exhibit poor in situ reforming ability in wet and underwater environments. In this study, a hydrogel with ultrafast in situ reforming ability in wet and underwater environments is prepared using modified sodium alginate-polyvinyl alcohol-dopamine. This hydrogel, with a double dynamic chemical crosslinking network, exhibits good in situ and ex situ self-healing abilities owing to the wet adhesion property of dopamine and the underwater rebuilding property of borate ester bonds. The strength of in situ self-healing is restored to 90.1% and 110.2% of the original strength and that of ex situ self-healing is restored to 101.3% and 123.9% of the original strength after 6 min of healing in water and phosphate buffer solution environments, respectively. The in situ reforming efficiency of the hydrogel is reported to be 86.6% within 5 min of being injected into the liquid environment owing to the contribution of in situ self-healing and ex situ self-healing. In addition, the proposed hydrogel has good cell compatibility. Therefore, it can be widely used as a biomaterial.