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The mechanical mismatch between soft hydrated tissues and sutures has become a common negative impact on wound healing process. A novel method of coating multilayer polymer shells is thus reported to improve the mechanical performance of hydrogel sutures. It is suitable for tissue patching and shows advantages of convenient, efficient, and biosafety. Specifically, a precursor hydrogel (Cu@CMC) consisted of carboxymethyl chitosan and copper modified by carbon dots was used as the inner sheath, and then bonding the precursor hydrogel sheath with toughening polyethylene glycol network by anchoring sites composited from rigid chitosan shell integrated a whole structure. Subsequently, the whole system was soaked with EtOH, and rapid dehydration of EtOH was used to accelerate the entanglement process between the two coatings by constricting the molecular chains. Finally, an ideal suture (Cu-fiber) with both toughness and rigidness was obtained. The data showed that the tensile strength and biosafety of the hydrogel sutures prepared by the new strategy were significantly improved, and the skin, liver and vessel of rodents can be sutured without secondary damage. Moreover, it can inhibit inflammation response and promote the healing process of skin wound, indicating that the Cu-fiber will become a great candidate for tissue patching. [ABSTRACT FROM AUTHOR]

The treatment of traumatic spinal cord injury (SCI) remains challenging as the neuron regeneration is impaired by irregular cavity and apoptosis. An injectable in situ gelling hydrogel is therefore developed for the local delivery of cannabidiol (CBD) through a novel method based on polyelectrolyte (PEC) interaction of sodium carboxymethylcellulose (CMC) and chitosan (CS). It can be injected into the spinal cord cavity with a 26-gauge syringe before gelation, and gelled after 110 ± 10 s. Of note, the in-situ forming hydrogel has mechanical properties similar to spinal cord. Moreover, the CBD-loaded hydrogels sustain delivery of CBD for up to 72 h, resulting in reducing apoptosis in SCI by enhancing mitochondrial biogenesis. Importantly, the CBD-loaded hydrogels raise neurogenesis more than pure hydrogels both in vivo and in vitro, further achieving significant recovery of motor and urinary function in SCI rats. Thus, it suggested that CMC/CS/CBD hydrogels could be used as promising biomaterials for tissue engineering and SCI. CBD-loaded CMC/CS PEC hydrogels with injectable and in situ gelling are developed. It can be injected into the injury site to perfectly match the lesion cavity. Moreover, the hydrogels can enhance mitochondrial biogenesis, inhibit apoptosis and promote neurogenesis, thus achieving significant locomotor and urinary function restoration in SCI rats. [Display omitted] • A cannabidiol-loaded hydrogel (CMC/CS/CBD) was fabricated as a novel material for treatment of spinal cord injury. • The CMC/CS/CBD hydrogel significantlypromotes the recovery of motor and urinary function in SCI rats. • The CMC/CS/CBD hydrogel not only shows good injectability, in-situ gelling, and biocompatibility but also acts as a drug carrier. • The CMC/CS/CBD hydrogel significantly promoted filopodia extension of neural stem cells • The CMC/CS/CBD hydrogel promotes spinal cord injury repair by upregulating of PGC-1α/NRF2 pathway [ABSTRACT FROM AUTHOR]