Stopping scars

Following spinal cord injury the body can produce cells called astrocytes.

Astrocytes lead to scarring and hinder injury repair, which can cause paralysis.

Stupp and colleagues have shown that their scaffold directs cell differentiation so that neural progenitor cells become neurons and not astrocytes.

The scaffold contains nanofibers made of molecules called peptide amphiphiles.

Normally, the molecules repel each other and remain liquid, but positively charged molecules such as the calcium in living tissue causes them to clump together.

They clump in such a way that they self-assemble into porous tubes about five nanometers wide and several hundred nanometers long.

Directing cells

To encourage neuron growth, Stupp and colleagues added a biological "signal" to the mix.

When their peptide amphiphiles self-assemble into nanofibers, they present on their surface a sequence of five amino acids known to promote neuron growth.

"This was all done by design," says Stupp.

When the peptide amphiphiles were placed in solution and combined with neural progenitor cells, the researchers found that the molecules formed nanofiber scaffolds that led the cells to become neurons.

When they injected a solution of the molecules into the site of spinal cord injury in a laboratory rat, they found that it formed a scaffolding gel upon contact with the tissue.

The scaffold is designed to disintegrate after four to six weeks.

By Dwayne Hunter - Betterhumans Staff