Iowa State University (ISU) researchers have created a new way to design and fabricate microfibers that support cell growth and could be useful tools for reconnecting nerves and regenerating other damaged tissues.

The ISU researchers have developed an approach that uses microfluidic fabrication methods to pump polycaprolactone (PCL) through tiny channels to produce microfibers. Hydrodynamic forces are employed to influence the orientation of molecules for the fabrication of the fiber structures, which have different properties along different directions.

The fibers are 2.6 to 36.5 millionths of a meter in diameter, and both their shapes and surface patterns can be controlled. They’re also flexible, biocompatible and biodegradable.The microfibers designed and fabricated by ISU researchers. Image credit: Christopher Gannon.“Neural stem cells on our polymer fibers could survive, differentiate and grow,” says Nastaran Hashemi, assistant professor of mechanical engineering. “These new fibrous platforms could also be used for cell alignment, which is important in applications such as guiding nerve cell growth, engineered neurobiological systems and regenerating blood vessels, tendons and muscle tissue."

In their study, the researchers demonstrated that neural stem cells were able to attach and align on the microfiber scaffold. "Cell death was minimal," the researchers report, and cell proliferation was affected by changing the features of the fibrous scaffold.

The researchers believe their technology could be a tool that helps bioengineers find ways to regenerate nerve cells. By mimicking the microenvironment of the nervous system, regeneration can be enhanced due to biological and chemical cues in the environment, they say. In addition, the PCL fibers can be applied in the regeneration of other tissues, such as muscles and blood vessels.

According to Hashemi, the Office of Naval Research is supporting the project because it wants to learn more about traumatic brain injury. “We are interested in understanding how shock waves created by blows to the head can create microbubbles that collapse near the nerve cells, or neurons, in the brain and damage them,” she says.

The researchers are now working to build a microfiber scaffold to support the cells and allow them to survive for the Navy’s studies of brain injuries.

“Our approach to fiber fabrication is unique,” Hashemi says. “There is no high voltage, high pressure or high temperatures. And so one day I think we can encapsulate cells within our fibers without damaging them.”