From the BBC:

The researchers injected the blind hamsters at the site of their injury with a solution containing synthetically made peptides - miniscule molecules measuring just five nanometres long.

Once inside the hamster’s brain, the peptides spontaneously arranged into a scaffold-like criss-cross of nanofibres, which bridged the gap between the severed nerves.

The scientists discovered that brain tissue in the hamsters knitted together across the molecular scaffold, while also preventing scar tissue from forming.

Importantly, the newly formed brain tissue enabled the brain nerves to re-grow, restoring vision in the injured hamsters.

“We made a cut, put the material in, and then we looked at the brain over different time points,” explained Dr Rutledge Ellis-Behnke, a neuroscientist at MIT and lead author on the paper.

“The first thing we saw was that the brain had started to heal itself in the first 24 hours. We had never seen that before - so that was very surprising.”