Hydrogel scaffolds in the treatment of spinal cord injury: a review

Abstract

Spinal cord injury (SCI) is a disease of the central nervous system often caused by accidents, and its prognosis is unsatisfactory, with long-term adverse effects on patients’ lives. The key to its treatment lies in the improvement of the microenvironment at the injury and the reconstruction of axons, and tissue repair is a promising therapeutic strategy. Hydrogel is a three-dimensional mesh structure with high water content, which has the advantages of biocompatibility, degradability, and adjustability, and can be used to fill pathological defects by injectable flowing hydrophilic material in situ to accurately adapt to the size and shape of the injury. Hydrogels mimic the natural extracellular matrix for cell colonization, guide axon extension, and act as a biological scaffold, which can be used as an excellent carrier to participate in the treatment of SCI. The addition of different materials to make composite hydrogel scaffolds can further enhance their performance in all aspects. In this paper, we introduce several typical composite hydrogels and review the research progress of hydrogel for SCI to provide a reference for the clinical application of hydrogel therapy for SCI.

Injectable Hydrogels for Nervous Tissue Repair—A Brief Review

“…Spinal cord injury is a very debilitating condition, which can result in partial or total paralysis, and places a considerable economic, physical, and emotional burden on patients and their families [ 55 , 56 ]. The current treatment for spinal cord injury includes the surgical decompression of the injured segments and the administration of steroids, which neutralize acute inflammation and decrease swelling to further reduce compression on any remaining neurons [ 57 , 58 ].…”

“…Also, scaffolds must possess suitable mechanical properties that support cells and tissues and promote controlled drug delivery [ 115 ]. These scaffolds must provide hydrogels with three-dimensional polymer structures for neuronal regeneration and axonal extension that would help promote cell adhesion, growth, proliferation, and migration [ 56 , 98 ].…”

Hydrogel-encapsulated extracellular vesicles for the regeneration of spinal cord injury

“…They can be tailored to mimic the native tissue microenvironment and provide structural support for cells during regeneration. Additionally, hybrid hydrogels combine both natural and synthetic components to harness the advantages of both materials, offering enhanced mechanical properties while maintaining biocompatibility ( Cai et al, 2023 ). These compositions can provide a biocompatible structure for tissue engineering and biomedical applications such as SCI treatment ( Riedelová-Reicheltová et al, 2016 ).…”

“…As mentioned previously, hydrogels result from crosslinking polymers through chemical, physical, or enzymatic approaches. While chemical crosslinking is difficult to change, physical crosslinking is reversible, and the state of physical crosslinking might change in response to external conditions ( Cai et al, 2023 ). Crosslinking methods affect the physical properties of the hydrogel, such as stiffness.…”

“…Soft hydrogels loaded with exosomes showed better nerve repair compared with stiff hydrogels through the quick release of exosomes ( Liu et al, 2022 ). In this regard, smart hydrogels are physically cross-linked hydrogels capable of responding to external stimuli, including changes in temperature, light, electrical signaling, and pH in the environment ( Cai et al, 2023 ). These smart hydrogels have been used in tissue engineering, drug and cell delivery, and the promotion of tissue repair by regulating the tissue microenvironment.…”