A dynamic and self-crosslinked polysaccharide hydrogel with autonomous self-healing ability

Abstract

Natural polymeric hydrogels with self-healing capability that can recover the functionalities and structures of gels after damage are extremely attractive due to their emerging applications in the biomedical field. Here we report a self-healable polymeric hydrogel by self-crosslinking two natural polymers acrylamide-modified chitin (AMC) containing amino groups and oxidized alginate containing dialdehyde groups. The generation of the self-crosslinked hydrogel relies on the dynamic covalent linkage through Schiff base between the polysaccharide chains. The self-healing capability of the crosslinked hydrogel depends on the molar ratio of AMC and oxidized alginate and the surrounding pH. Under certain circumstances, the damaged hydrogel shows a complete recovery and can be stretched to a favorable extent, which is seldom observed for polysaccharide self-healing hydrogel. Notably, we find that the self-healing ability can be "stored" by freeze-drying and "activated" by rehydration. In addition, we demonstrate that the hydrogel can be used as a soft template to guide the repair of inorganic materials like hydroxyapatite. We anticipate that this self-healable hydrogel consisting of biocompatible and biodegradable polysaccharides can be applied to various biomedical fields.

Flexible Polysaccharide Hydrogel with pH‐Regulated Recovery of Self‐Healing and Mechanical Properties

“…Constructing dynamic covalent bond in the network is one important strategy to prepare self‐healing hydrogel . Schiff base linkage (CHN) is one kind of dynamic covalent bonds formed between the aldehyde (CHO) and amino group (NH 2 ) . Owing to its intrinsic dynamic equilibrium, the Schiff base linkage could be regarded as a quasi‐covalent linkage.…”

Self‐Healing Polysaccharide Hydrogel Based on Dynamic Covalent Enamine Bonds

“…Schiff base is a dynamic covalent bond which could be effective formed between aldehyde groups and amino groups without external stimuli . Self‐healing polysaccharide hydrogel based on Schiff base had been reported to be an attractive method . However, most studies used the sodium periodate transform adjacent hydroxyl groups into a pair of aldehyde groups; this could lead to the sharp degradation of polysaccharide polymer, besides, complicated synthesis process makes it difficult to control.…”

Self-healing polysaccharide-based hydrogels as injectable carriers for neural stem cells

“…Therefore, self-healing hydrogels, which can automatically restore their integrity of network structures and functionalities after damages without the need of external interventions, have been explored to meet the needs of biomedical applications15161718. Currently, the self-healing injectable hydrogels, possessing the dual capabilities of self-healing and injection, are emerging as a new generation of multifunctional vehicles for cell therapy192021. Different from the conventional injectable hydrogels, self-healing injectable hydrogels can directly deliver cells via transplanting the cell-loaded hydrogel fragments which can self-heal into integral connected structures after filling a lesion site.…”