photo by Marci Hersh Ravi Bellamkonda ( right) holds a hydrogel while graduate student Mahesh Dodla looks on.

"We are focused on a new generation of biomimetically inspired hydrogels that could bridge the gap between peripheral nerves that do not spontaneously recover from injury," said Ravi Bellamkonda, the lead researcher and professor in the department of biomedical engineering at CWRU.

The research, conducted at CWRU's biomaterials cell and tissue engineering lab, is the work of Bellamkonda, Dominique Durand and Gerald Saidel, both professors in the department of biomedical engineering. The project is funded by a new $1.8 million grant from the National Institutes of Health.

The researchers are developing a three-dimensional hydrogel that serves as a scaffold that can support and guide the direction of regenerating nerve fibers like a paved three-dimensional pathway.

"The hydrogel is 99 percent water, and we will incorporate growth-promoting proteins on an increasing gradient that we expect to provide the directional cues nerves require to regenerate properly," Bellamkonda said. "This seemingly minor function will solve a major shortcoming of the current generation of hydrogels being developed."

The CWRU researchers plan to evaluate the new material and treatment approach in an animal model. The procedure is not currently being used in patients. The team plans to compare this new method to nerve grafting, the current standard treatment for peripheral nerve damage in which nerves are taken from a donor site on the patient's body.

"Because nerve grafting only offers a 50 percent rate of full recovery and harvesting those nerve segments can result in sensory loss or pain at the donor site, we believe that polymer guidance channels that will be filled with our hydrogel matrices are an essential bioengineering solution that can offer a real treatment alternative," Bellamkonda said. "Compared to conventional nerve grafting, this method has the potential to reduce pain by eliminating the need for a donor site and to eliminate other common problems with the procedure, such as the lack of necessary nerve segments. Patients could experience less scarring and a higher full recovery rate."

Bellamkonda and his research team are looking into the fabrication and characterization of the hydrogel. They have devised a mathematical scheme to layer gels so that each consecutive layer contains a higher concentration of LN-1, a glycoprotein that enhances the attachment of neural cells, and a method to smooth the transition between layers by using controlled local heating that removes the stark interface between layers. Bellamkonda's laboratory also has developed a technique that allows the researchers to generate gradients of proteins called neurotrophic factors within the hydrogels.

"We need this new hydrogel to promote regeneration of a severed nerve stump across a large gap to help it go further to make necessary connections to muscle and other organs," Bellamkonda said. "Our current funding from the National Institutes of Health provides the necessary support for this project and brings us closer to a viable treatment option."

The researchers said they are confident that their hydrogel holds promise for clinical neurologists and others in the medical field that strive to improve the therapeutic outcome for those who suffer from peripheral nerve damage.