Self‐healing and conductivity of chitosan‐based hydrogels formed by the migration of ferric ions

Abstract

The currently reported self-healing hydrogels have problems of low mechanical strength, single performance, and poor self-healing efficiency, which greatly limit their applications. Here, through adding N-carboxyethyl chitosan to acrylic-Fe 3+ system, the self-healing physically crosslinked hydrogels were prepared via in situ free radical polymerization, which have excellent self-healing ability and mechanical properties. The maximum tensile strength and elongation at break of the hydrogels can reach up to 280 KPa and 1900%, respectively. Owing to the reversibility of coordination, self-healing efficiency of the hydrogels can reach 98% in 2.5 h. Moreover, the hydrogels also have good conductivity due to the migration of Fe 3+ . This strategy can broaden the applications of chitosan-based self-healing hydrogels.Since the metal coordination has multiple coordination points, it can form hydrogels with high strength and self-healing ability. Metal ions, like Fe 3+ , Zn 2+ , Cu 2+ , can form strong coordination with some groups, such as OH, COOH, NH 2. 32-34 The ionicAdditional Supporting Information may be found in the online version of this article.

Thermoresponsive and Conductive Chitosan-Polyurethane Biocompatible Thin Films with Potential Coating Application

“…The different roughness between the control group and DCDFs could be attributed to the presence of DCP. The addition of the positively charged DCP may produce an ionic reaction with negatively charged CEC and negatively charged DAPU and facilitate the more homogeneous crosslinking for networks of DCDFs [36]. The control groups used in all the following experiments were the non-DCP-containing films.…”

Polysaccharide-Based In Situ Self-Healing Hydrogels for Tissue Engineering Applications

“…Nevertheless, multiple coordination bridges established by coordination metals are a promising way to add a second reversible network to covalently crosslink hydrogels, and thus, to gain high mechanical stability as well as an efficient self-repairing ability. Typically, chemically crosslinked hydrogels are obtained by in situ polymerization of poly (acrylic acid), polyacrylamide or their copolymers that are also coordinated with metallic cations like Fe 3+ to add physical crosslinking points due to electrostatic interactions to the polymerized networks [ 106 ]. As aforementioned, the use of synthetic polymers for biomedical research is limited and, therefore, in situ hydrogels with self-healing properties based on polysaccharides are increasingly investigated.…”

“…As aforementioned, chitosan is one of the most used biopolymers for the development of hydrogels based on polysaccharides. For example, double-crosslinked chitosan hydrogels were prepared by combining the in situ free-radical polymerization of acrylic acid monomer and reversible coordinative interactions between water soluble chitosan and Fe 3+ ions that provide a hydrogel with good mechanical properties and ability to self-repair [ 106 ]. The results showed that in situ hydrogels based on chitosan had excellent efficiency for self-repair (98%) and were able to achieve total self-repair in just 2.5 h ( Figure 6 ).…”

“…( c ) Self-healed hydrogel after healing for 2.5 h and ( d ) stretching of self-healed hydrogel. Reprinted from self-healing and conductivity of chitosan-based hydrogels formed by the migration of ferric ions [ 106 ]. Copyright © 2020 Wiley Periodicals, Inc.…”

Highly Adhesive, Conductive, and Self-Healing Hydrogel with Triple Cross-Linking Inspired by Mussel and DNA for Wound Adhesion and Human Motion Sensing

“…Many new materials have been used for rapid wound closure in emergency situations, including fibrin glue, gelatin, collagen, oxidized cellulose, peptides, polymers, and hydrogels. − Among these materials, hydrogels are widely used in tissue repair, wound closure, and other aspects. Polymer hydrogels are a promising option due to their soft properties similar to the extracellular matrix, adjustable physical and chemical properties, and the ability to adapt to a variety of wound shapes. − The self-healing hydrogel can repair itself quickly when cracks appear under force, which ensures the overall mechanical properties of the hydrogel. − However, most conventional hydrogels lack the ability to adhere to moist tissues because the water molecules in the hydrogels tend to reduce the surface energy of the matrix, weakening the ability of the hydrogels to adhere to tissues. Therefore, it is desirable to develop viscous hydrogels that act as hemostatic agents while promoting the healing process at the wound site.…”