A conductive supramolecular hydrogel creates ideal endogenous niches to promote spinal cord injury repair

Bioactive Materials, 2022 · DOI: https://doi.org/10.1016/j.bioactmat.2021.11.032 · Published: January 1, 2022

Spinal Cord Injury Regenerative Medicine Biomedical

Simple Explanation

This study introduces a novel hydrogel, AGP3, designed to mimic the spinal cord's properties and promote its repair after injury. The hydrogel is made from agarose, gelatin, and polypyrrole, making it conductive and biocompatible. The AGP3 hydrogel can be injected into the injured area to fill the cavity and create a supportive environment for nerve regeneration. It encourages neural stem cells to differentiate into neurons and reduces the formation of scar tissue. Experiments showed that AGP3 hydrogel significantly improved motor function recovery in rats with spinal cord injuries. This suggests that AGP3 hydrogel has the potential to be a favorable biomaterial for SCI repair.

Study Duration

6 Weeks

Participants

Rats with induced spinal cord injury

Evidence Level

Level 2: Experimental study using in vitro and in vivo models

Key Findings

1
AGP3 hydrogel exhibits excellent biocompatibility, promoting neural stem cell differentiation towards neurons while inhibiting astrocyte over-proliferation.
2
In vivo implantation of AGP3 hydrogel effectively covered tissue defects, reduced injured cavity areas, and fostered a biocompatible microenvironment that supported endogenous neurogenesis over glial fibrosis formation.
3
RNA sequencing analysis revealed that AGP3 hydrogel significantly modulated the expression of neurogenesis-related genes through intracellular Ca2+ signaling cascades.

Research Summary

The study developed an Aga/Gel/PPy (AGP3) hydrogel with similar conductivity and modulus as the spinal cord. The physically crosslinked features made the AGP3 hydrogels injectable. In vitro cultures showed that the AGP3 hydrogel exhibited good biocompatibility, and accelerated formation and maturation of neurons whereas it inhibited over-proliferation of astrocytes. In vivo studies further showed that the hydrogel provided a biocompatible microenvironment for NSCs migration and differentiation, resulting in significant recovery of motor function.

Practical Implications

Therapeutic Potential

AGP3 hydrogel shows promise as a bioactive material for filling injured cavities, inhibiting glial scar formation, and promoting neurological function recovery after SCI.

Biomaterial Design

The supramolecular strategy can be used to design biological environment-adaptive functional materials with suitable porosity, modulus, and conductivity.

Neurogenesis Promotion

The AGP3 hydrogel can activate endogenous nerve regeneration of the spinal cord, rather than glial fibrosis formation, to construct a neural bridging network.

Study Limitations

1
The study was conducted on rats, and further research is needed to confirm the results in humans.
2
The long-term effects of the AGP3 hydrogel implantation are not fully understood.
3
The specific mechanisms of how AGP3 hydrogel modulates the expression of neurogenesis-related genes require further investigation.

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