Injectable and Self-Healing Chitosan Hydrogel Based on Imine Bonds: Design and Therapeutic Applications.

Yanshuang Xu,Lihua Fu,Qiaomei Chen,Yongsan Li,Lei Tao,Yen Wei

doi:10.3390/ijms19082198

Abstract

Biological tissues can automatically repair themselves after damage. Examples include skin, muscle, soft tissue, etc. Inspired by these living tissues, numerous self-healing hydrogels have been developed recently. Chitosan-based self-healing hydrogels constructed via dynamic imine bonds have been widely studied due to their simple preparation, good biocompatibility, and automatic reparability under physiological conditions. In this mini-review, we highlighted chitosan-based self-healing hydrogels based on dynamic imine chemistry, and provided an overview of the preparation of these hydrogels and their bioapplications in cell therapy, tumor therapy, and wound healing.

Highlights

Hydrogels are a family of soft matters which have the three-dimensional polymeric network and contain large proportion of water [1,2,3]
The development of self-healing hydrogels constructed by dynamic covalent bonds has been booming
We specially focused on self-healing hydrogels obtained from the derivatives of chitosan and PEG, and introduce their synthetic strategies, mechanical properties and biological applications in cell therapy, tumor therapy, and wound healing

Summary

Introduction

Hydrogels are a family of soft matters which have the three-dimensional polymeric network and contain large proportion of water [1,2,3]. Self-healing hydrogels can be injected as numerous solid fragments, the fragments coaleIsnct.eJ. .AAftfetrerddepeprorotetcetcitoinon, t,htehebebneznazladledheyhdyede uunniitt wwaass iinnttrroodduucceedd ttoo ppoollyy((EEOO--ccoo--GGllyy))tthhrroouugghhtthheerreeaacctitoionnbbeetwtweeeennththeefrfereeehyhdyrdorxoyxmymetehtyhlyglrgoruopusps aanndd 44--ffoorrmmyybbeennzzooiicc aacciidd. EPGE-GB-ABAwawsapsropdroudceudcebdy bcoyncjuongajutignagting 4-4f-ofromrmyybbeennzzooiiccaacciidd ttoo tthhee tteerrmmiinnaall hhyyddrrooxxyylloofffofouur-ra-ramrmPPEGEGvivaiacacrabrobdoiidmiiimdeidceoucpoulinpglinregarcetiaocntion sismimilailrartotoththeepprereppaarraattiioonnooff DDFF PPEEGG,, aass pprreesseenntteeddininFFigiguurere3a3.a. The nature of imine bonds rendered the CMC/PEG-BA hydrogels with outstanding self-healing perfTohrme naantcuer. Hydrogel was suspended, indicating high self-healing efficiency and mechanical strength. The self-healing process of the cut surfaces was monitored by optical microscopy. A “mobile phase” was necessary at the damaged interface, where the imine bonds cleaved and the free aldehyde and amine groups exposed. The newly-formed imine bonds connected the cut surfaces together This crack healing experiment revealed that dynamic reaction rather than the simple adhesion took place at the interfaces of broken hydrogels

Biological Applications

Cell Therapy

Tumor Therapy

Summary and Outlook