Biomimetic Strain-Stiffening in Chitosan Self-Healing Hydrogels

Abstract

The strain-stiffening and self-healing capabilities of biological tissues enable them to preserve the structures and functions from deformation and damage. However, biodegradable hydrogel materials with both of these biomimetic characteristics have not been explored. Here, a series of strain-stiffened, self-healing hydrogels are developed through dynamic imine crosslinking of semiflexible O-carboxymethyl chitosan (main chain) and flexible dibenzaldehyde-terminated telechelic poly(ethylene glycol) (crosslinker). The biomimetic hydrogels can be reversibly stiffened to resist the deformation and can even recover to their original state after repeated damages. The mechanical properties and stiffening responses of the hydrogels are tailored by varying the component contents (1−3%) and the crosslinker length (4 or 8 kDa). A combinatorial system of in situ coherent small-angle X-ray scattering with rheological testing is developed to investigate the network structures (in sizes 1.5−160 nm) of hydrogels under shear strains and reveals that the strain-stiffening originates from the fibrous chitosan network with poly(ethylene glycol) crosslinking fixation. The biomimetic hydrogels with biocompatibility and biodegradability promote wound healing. The study provides an insight into the nanoscale design of biomimetic strain-stiffening self-healing hydrogels for biomedical applications.

Novel Trends in Hydrogel Development for Biomedical Applications: A Review

“…Moreover, in vivo experiment results confirm the ability of CTS-based hydrogels to accelerate tissue regeneration to reduce inflammation and facilitate wound healing [ 102 , 103 ]. Current trends in CTS-based hydrogels for biomedical applications focus on the improvement of CTS performance and properties, from cross-linking strategies [ 99 , 100 , 101 , 188 ] to blending [ 189 , 190 , 191 ] and functionalization of CTS structure [ 192 , 193 ].…”

Synthetic strain-stiffening hydrogels towards mechanical adaptability

“…When the shear strain increases to 650%, the hydrogel can still maintain its integrity, and the storage and loss moduli increase by an order of magnitude. Compared with semi- 48 17.0 1.3 r1.5 33 1C Agarose hydrogels 89 330.0 12.0 0.9 5.1 mg mL À1 PIC hydrogels 90 200.0 10.0 1.3 37 1C PDA gels 91 200.0 20.0 1.0 15 mg mL À1 Polyisocyanopeptide hydrogels 92 400.0 10.0 1.5 50 1C NFs 4.0 0.7 1.5 25 1C Polyisocyanopeptide 44 105.0 10.2 None 10-3 rad s À1 CC/DP hydrogels 93 1000.0 900.0 1.4 25 1C…”

Current Self-Healing Binders for Energetic Composite Material Applications

“…The intrinsic self-healing process is generally based on the dissociation and rearrangement of dynamic covalent or non-covalent bonds in materials, which can be spontaneous or driven by external stimuli (heat, light, pH, etc.). Dynamic covalent bonds include Diels–Alder bonds [ 18 , 19 , 20 ], disulfide bonds [ 21 , 22 , 23 ], acyl semicarbazides (ASCZ) [ 24 ], acylhydrazone bonds [ 25 , 26 , 27 ], imine bonds [ 28 , 29 , 30 ], borate ester bonds [ 31 , 32 , 33 ], diselenide bonds [ 34 , 35 , 36 ], etc. Dynamic non-covalent bonds include hydrogen bonds [ 37 , 38 , 39 ], metal–ligand coordination [ 40 , 41 , 42 ], host–guest interactions [ 43 , 44 , 45 ], donor–acceptor interactions [ 46 , 47 , 48 ], ionic bonds [ 49 , 50 , 51 ], etc.…”