Orienting neurite growth in electrospun fibrous neural conduits

In cases where direct suture of two nerve stumps is not feasible, generally a scaffold is required to bridge the gap and guide nerve regeneration. The scaffold used in nerve tissue engineering applications requires optimal guidance effect, mechanical strength, and cellular compatibility. A number of studies suggest that fibrous scaffolds can potentially be used for nerve regeneration, as the aligned fibers can provide the guidance effect for axonal growth and the fibrous structure mimics the nerve microenvironment. A practical method to fabricate the fibrous nerve conduit with structural guidance cue for neurite growth will improve its potential application in neural tissue engineering. In this study, fibrous tubular scaffolds were fabricated using an electrospinning technique. The fibrous conduit was composed of aligned fibers in the interior layer and randomly oriented fibers in the exterior layer. In order to investigate the fiber diameter on neurite extension and directional growth, fibers with different diameter in the subcellular size range were fabricated and the neurite growth on these fibers was investigated. We observed that PC12 cells' neurites showed similar parallel growth on the aligned fibers irrespective of fiber diameter. Neurite length on aligned fibers, with fiber diameters of 3.7 +/- 0.5 microm and 5.9 +/- 0.9 microm, was significantly longer than neurite length on randomly oriented fibers. This study showed that electrospinning provides a practical solution to fabricate fibrous nerve conduit by controlling the conduit inner diameter and fiber alignment and, hence, potentially improves the application of the conduit in neural regeneration.