An injectable gel developed at Duke University prompted stroke-damaged mouse brains to repair themselves, growing new blood vessels and nerve fibers and largely restoring the animals’ ability to move.
A scaffold made of tiny hydrogel beads
The team led by Professor Tatiana Segura and first author Shangjing Xin used a material called MAPS (microporous annealed particle scaffolds). It is built from microscopic hydrogel particles annealed together into a sponge-like structure with open spaces between them. Injected into the cavity left behind by a stroke, the scaffold acts as scaffolding into which the body’s own cells can migrate and rebuild tissue.
IL-4 and C1q steer the immune response
The key was loading the gel with extracellular vesicles from astrocytes, the brain’s support cells. Activated by the two signaling molecules IL-4 and C1q, these vesicles recruited immune cells from the bloodstream into the injured region. This controlled inflammatory response kick-started regeneration rather than hindering it, the researchers report in the journal Cell Biomaterials.
Matching healthy animals after eight weeks
- On a grid-walking test measuring forelimb coordination, treated mice performed on par with healthy controls after eight weeks.
- New blood vessels formed throughout the stroke cavity.
- More axons, the fibers essential for neurons to communicate, grew in and around the injured area.
So far the results come only from mice given a direct brain injection. Before any move to humans, safety and effectiveness must be tested in larger animal models, and the vesicles, currently sourced from rat astrocytes, will need to be replaced with human alternatives.
Sources: Duke University / ScienceDaily · Cell Biomaterials (Sept 3, 2026)
