Controlled Molecular Motion for Spinal Cord Repair

Northwestern University researchers have developed a new injectable therapy that harnesses "dancing molecules" to reverse paralysis and repair tissue after severe spinal cord injuries. The new injectable therapy is based on nanofibers. It is described in a paper published in Science.

The therapy has been tested on paralyzed laboratory mice with severe spinal cord injuries. The researchers administered a single injection to tissues surrounding the spinal cords of the paralyzed mice. Just four weeks later, the animals regained the ability to walk.

"Our research aims to find a therapy that can prevent individuals from becoming paralyzed after major trauma or disease," said research leader Samuel Stupp, who led the study. "Currently, there are no therapeutics that trigger spinal cord regeneration. I wanted to make a difference on the outcomes of spinal cord injury and to tackle this problem, given the tremendous impact it could have on the lives of patients.”

The new therapy dramatically improved severely injured spinal cords in five ways:

1. Regenerated the severed extensions of neurons, called axons
2. Diminished scar tissue, which can create a physical barrier to regeneration and repair
3. Reformed myelin, the insulating layer of axons around cells that is important in transmitting electrical signals efficiently
4. Formed functional blood vessels to deliver nutrients to cells at the injury site
5. Increased survival of motor neurons

How does the new therapy work? A synthetic material is injected as a liquid. It gels into structures of nanofibers that mimic the shape of the spinal cord. And the researchers have been able to control the collective motion of more than 100,000 molecules within the nanofibers.

Once connected to cells, the moving molecules trigger signals that promote spinal cord repair. The synthetic signals are short chains of amino acids that survive for weeks. The molecules move, "dance," or even leap temporarily out of these structures. And this enables them to connect more effectively with the cells. 

"Given that cells themselves and their receptors are in constant motion, you can imagine that molecules moving more rapidly would encounter these receptors more often," explained Stupp. "If the molecules are sluggish and not as 'social,' they may never come into contact with the cells."

"We are going straight to the FDA to start the process of getting this new therapy approved for use in human patients, who currently have very few treatment options," announced Stupp.

The new therapy could be used to prevent paralysis after major trauma or from diseases. The researchers are persuaded that the underlying technique of controlling and leveraging molecular motion can be applied to other medical cases such as neurodegenerative diseases and stroke. The “fundamental discovery about controlling the motion of molecular assemblies to enhance cell signaling could be applied universally across biomedical targets," concluded Stupp.