Getting nerve cells to grow in the lab can be a challenge. But when it works, the result can be a thing of beauty for both science and art. What you see growing in the Petri dish shown above are nerve cells from an embryonic rat. On the bottom left is a dorsal root ganglion (dark purple), which is a cluster of sensory nerve bodies normally found just outside the spinal cord. To the right are the nuclei (light purple) and axons (green) of motor neurons, which are the nerve cells involved in forming key signaling networks.
Laura Struzyna, a graduate student in the lab of NIH grantee D. Kacy Cullen at the University of Pennsylvania’s Perelman School of Medicine, Philadelphia, is using laboratory-grown nerve cells in her efforts to learn how to bioengineer nerve grafts. The hope is this work will one day lead to grafts that can be used to treat people whose nerves have been damaged by car accidents or other traumatic injuries.
Here’s how the process currently works. After growing the cells in a Petri dish, Struzyna transfers them into a custom-built microdevice called a “mechanobioreactor.” There, the cells continue to grow for several days, while a small built-in motor applies controlled mechanical tension to the axons and progressively elongates them a few microns or more. (A micron is one millionth of a meter.) The goal is to prepare these cultured neurons for transplantation into an injured area, where their unusually long axons will stand out and attract nearby regenerating nerve cells.