An engineering-reinforced extracellular vesicle-integrated hydrogel with an ROS-responsive release pattern mitigates spinal cord injury

Sci Adv. 2025 Apr 4;11(14):eads3398. doi: 10.1126/sciadv.ads3398. Epub 2025 Apr 2.

Abstract

The local delivery of mesenchymal stem cell-derived extracellular vesicles (EVs) via hydrogel has emerged as an effective approach for spinal cord injury (SCI) treatment. However, achieving on-demand release of EVs from hydrogel to address dynamically changing pathology remains challenging. Here, we used a series of engineering methods to further enhance EVs' efficacy and optimize their release pattern from hydrogel. Specifically, the pro-angiogenic, neurotrophic, and anti-inflammatory effects of EVs were reinforced through three-dimensional culture and dexamethasone (Dxm) encapsulation. Then, the prepared Dxm-loaded 3EVs (3EVs-Dxm) were membrane modified with ortho-dihydroxy groups (-2OH) and formed an EV-integrated hydrogel (3EVs-Dxm-Gel) via the cross-link with phenylboronic acid-modified hyaluronic acid and tannic acid. The phenylboronic acid ester in 3EVs-Dxm-Gel enabled effective immobilization and reactive oxygen species-responsive release of EVs. Topical injection of 3EVs-Dxm-Gel in SCI rats notably mitigated injury severity and promoted functional recovery, which may offer opportunities for EV-based therapeutics in central nervous system injury.

MeSH terms

  • Animals
  • Dexamethasone / administration & dosage
  • Dexamethasone / chemistry
  • Dexamethasone / pharmacology
  • Disease Models, Animal
  • Drug Liberation
  • Extracellular Vesicles* / chemistry
  • Extracellular Vesicles* / metabolism
  • Hydrogels* / chemistry
  • Mesenchymal Stem Cells / cytology
  • Mesenchymal Stem Cells / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Reactive Oxygen Species* / metabolism
  • Spinal Cord Injuries* / drug therapy
  • Spinal Cord Injuries* / metabolism
  • Spinal Cord Injuries* / pathology
  • Spinal Cord Injuries* / therapy

Substances

  • Hydrogels
  • Reactive Oxygen Species
  • Dexamethasone