Advances in Synthesis and Applications of Self-Healing Hydrogels

Abstract

Background: Hydrogels, a type of three-dimensional (3-D) crosslinked network of polymers containing a high water concentration, have been receiving increasing attention in recent years. Self-healing hydrogels, which can return to their original structure and function after physical damage, are especially attractive. Some selfhealable hydrogels have several kinds of properties such as injectability, adhesiveness, and conductivity, which enable them to be used in the manufacturing of drug/cell delivery vehicles, glues, electronic devices, and so on. Main Body: This review will focus on the synthesis and applications of self-healing hydrogels. Their repair mechanisms and potential applications in pharmaceutical, biomedical, and other areas will be introduced. Conclusion: Self-healing hydrogels are used in various fields because of their ability to recover. The prospect of self-healing hydrogels is promising, and they may be further developed for various applications.

A Facile Strategy for Synergistic Integration of Dynamic Covalent Bonds and Hydrogen Bonds to Surmount the Tradeoff between Mechanical Property and Self‐Healing Capacity of Hydrogels

“…[ 6,8–12 ] Therefore, it is of great significance to design and develop self‐healable hydrogels, especially the autonomous self‐healing hydrogels that can automatically repair damages without any external diagnosis or intervention. [ 9,10,13 ]…”

“…Despite the great progress achieved previously, one of the long‐standing challenges in the field of intrinsic self‐healing hydrogels is to resolve the tradeoff between the mechanical property and self‐healing capacity. [ 7,10,13,16 ] Apparently, the unstable and highly reversible noncovalent or dynamic covalent bonds behind self‐healable systems conflict with the high mechanical performances that typically company with stable and strong intermolecular bonds. In addition, the mobility and dynamics of polymer chains within the hydrogel matrix play a key role in ensuring self‐healing.…”

Hydrogel Properties and Their Impact on Regenerative Medicine and Tissue Engineering

“…Several factors may be considered when specifying the physical or chemical properties that affect self-healing. Wang et al divide these mechanisms into physical and chemical [ 63 ]; Tu et al specify this classification, calling physical mechanisms noncovalent and chemical mechanisms covalent [ 64 ]; while Fan et al look at the classification much more comprehensively and divide the mechanisms into intrinsic and extrinsic [ 65 ]. The classification of self-healing mechanisms is summarized in Table 2 and is presented in Figure 3 .…”

“…In this process, the functional group of one compound, called the ‘guest’, is enclosed within the chemical group of the other compound, called the ‘host’. The most widely used hosts are cyclodextrins, crown ethers, calixarenes, pillararenes, and cucurbiturils [ 65 ]. Zhu et al presented a thermosensitive HG consisting of poly( N -isopropylcrylamide) (PNIPAM), adamantyl as guest and cyclodextrin as host [ 72 ].…”

Charge-Mediated Co-assembly of Amphiphilic Peptide and Antibiotics Into Supramolecular Hydrogel With Antibacterial Activity

“…Unfortunately, the hydrated environment of hydrogels could also improve the proliferation of bacteria adhered to the surgical sites ( Schierholz and Beuth, 2001 ). Therefore, antibacterial agents such as antibiotics, metal particles, and cationic polymers with inherent antibacterial capability are usually incorporated into hydrogel networks to endow them with antibacterial activity ( Li et al, 2018 ; Fan et al, 2020 ; Zhao et al, 2020 ). In the past few years, several polymers with bacteria membrane-destroying characteristic have been also developed to construct antibacterial hydrogels to inhibit surgical site infections ( Salick et al, 2009 ; Liu et al, 2012 ; Giano et al, 2014 ; Wang et al, 2019 ).…”