Aligned electrospun nanofibers specify the direction of dorsal root ganglia neurite growth.

Nerve injury, a significant cause of disability, may be treated more effectively using nerve guidance channels containing longitudinally aligned fibers. Aligned, electrospun nanofibers direct the neurite growth of immor- talized neural stem cells, demonstrating potential for directing regenerating neurites. However, no study of neu- rite guidance on these fibers has yet been performed with primary neurons. Here, we examined neurites from dorsal root ganglia explants on electrospun poly-L-lactate nano- fibers of high, intermediate, and random alignment. On aligned fibers, neurites grew radially outward from the ganglia and turned to follow the fibers upon contact. Neurite guidance was robust, with neurites never leaving the fibers to grow on the surrounding cover slip. To com- pare the alignment of neurites to that of the nanofiber substrates, Fourier methods were used to quantify the alignment. Neurite alignment, however striking, was infe- rior to fiber alignment on all but the randomly aligned fibers. Neurites on highly aligned substrates were 20 and 16% longer than neurites on random and intermediate fibers, respectively. Schwann cells on fibers assumed a very narrow morphology compared to those on the sur- rounding coverslip. The robust neurite guidance demon- strated here is a significant step toward the use of aligned, electrospun nanofibers for nerve regeneration. 2007 Wiley Periodicals, Inc. J Biomed Mater Res 83A: 636-645, 2007