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Past Winner
2003 E.W.R. Steacie Memorial Fellowship

Molly Shoichet

Chemical Engineering

University of Toronto

Molly Shoichet
Molly Shoichet

A Canadian scientist has made a small but vital step toward providing clinicians with the ability to reverse spinal cord injury. Dr. Molly Shoichet, an associate professor of chemical engineering at the University of Toronto, and winner of a 2003 NSERC E.W.R. Steacie Memorial Fellowship, recently demonstrated that an artificial bridge constructed across a break in the spinal cord can serve as a conduit for new nerve cells originating in the brain.

"What's most exciting about this work is that we determined that some of the new nerve cells or axons that were growing in our rats were drawing from the brain. The reason that's so exciting is that you can get tissue growing. But you also want to get the right tissue. And in this case it's the cells in the brain that are regenerating their axons," says Dr. Shoichet, of the as yet unpublished research.

In the recent experiment, customized tubes developed in Dr. Shoichet's lab were spliced into the severed spinal cords of paraplegic rats. The tubes were infused with neural growth factors. The combination sparked the growth of new nerve tissue, and most importantly, tests showed that this new spinal cord nerve tissue provided some functional benefit, albeit slight.

Dr. Shoichet, holder of the Canada Research Chair in Tissue Engineering at the University of Toronto, is one of a rare new breed of scientists who are combining chemistry, biology and engineering to create the emerging fields of tissue engineering and regenerative medicine. An expert in the creation and modification of polymers, Dr. Shoichet's work focuses on perhaps the most vexing of tissue engineering questions: spinal cord regeneration. Bone, skin and even peripheral nerves regenerate spontaneously. So why not the nerves of the spinal cord?

"That's the central question," says Dr. Shoichet. "My lab approaches the problem from an engineering perspective, as opposed to a neurosurgical or biological perspective. Engineers are trained to solve problems. The challenge with this problem is that it's ill-defined. So we're looking for solutions that will help us better define the problem."

Her research at the University of Toronto since 1995 has methodically teased apart the problem and shown the way forward in two clearly engineering-inspired ways: bridges and communications equipment.

Dr. Shoichet has used her materials science expertise to design specialized tiny tubes that mimic spinal cord tissue in structure and feel. These tubes act as bridges, providing both support and direction, over which spinal cord nerves can regenerate.

In collaboration with biologists, she has also helped clarify the role of what could be considered molecular "smell" in guiding spinal nerve cell growth. Her experiments have shown that spinal cord nerve cell regeneration is in part guided by specific concentration gradients of chemicals in the tissue.

Her recent rat spinal cord regeneration results were based on combining these two approaches.

During her Steacie research, Dr. Shoichet will continue to develop new biodegradable tissue bridges that will be eroded by the nerve cells they inspire to grow. Her lab is also working on a less invasive way to deliver a sustained concentration gradient of neural growth factor using an injectable polymer.

"It looks like we're going in the right direction, but there's still so much to do," says Dr. Shoichet. "My goal is to make an impact and have a therapeutic strategy available for spinal cord injury patients. Every step from improved bladder control to walking would be significant. And if I don't believe it's all possible, who will?"