When a man's cancerous prostate gland is removed, the fragile cavernous nerve is often damaged when it is crushed or pulled during surgery. Once the nerve is damaged, smooth muscle cells quickly begin to die in the penis. The consequent scarring prevents the smooth muscle from relaxing and allowing blood to flow into its tissue to become erect.

"Once the smooth muscle starts to die off, you don't get an erection or you get less of an erection," Podlasek said. "The muscle damage is irreversible, so it's essential to heal the damaged nerve as quickly as possible."

Her goal is to regenerate the nerve more quickly to reduce the damage downstream in the penis. "When the nerve is functional, you get normal erectile function," she said. "It's two pieces to a puzzle."

For the current study, Podlasek combined sonic hedgehog with a nanofiber gel designed by study coauthor Samuel I. Stupp, the Board of Trustees Professor of Chemistry, Materials Science and Engineering, and Medicine at Northwestern. The gel traps the protein as it self-assembles into linear nanofibers, which resemble slender threads made out of gel. Podlasek applied the nanofibers to crushed cavernous nerves in rats. When she examined the nerves six weeks later, they had regenerated twice as fast as they would have on their own.

In previous research, Podlasek saw a 63 percent decrease in smooth muscle cell death in the penis when sonic hedgehog was restored to injured cavernous nerves. Also in previous research, she found that decreasing sonic hedgehog in the penis caused smooth muscle cells to die.

Source: Northwestern University