Since individual fascicle dimensions are on the order of microns, which is ~1000 times smaller than typical scaffolds, the role of the channel size on Schwann cell migration and axonal growth remains poorly understood especially for channels smaller than 200 μm. While a variety of synthetic and biopolymers, such as collagen, polycaprolactone, polyglycolic acid, poly-DL-lactide-co-caprolactone (PLCL), and polyvinyl alcohol (PVA), have been explored as scaffold materials, geometry of these devices remains largely limited to simple cylindrical lumens with millimeter dimensions. Nerve guidance scaffolds promoting axonal growth may in future provide therapeutic alternatives to autografts. For complete nerve transections with gap distances greater than 4 cm, functional recovery becomes highly unlikely even with surgical intervention. While ubiquitous in clinic, this method is limited by the availability of donor tissue, and poses a risk of secondary co-morbidity and neuroma formation. Autografting of the donor tissue is commonly used for injuries greater than 2 cm. The common PNS surgical intervention for small-gap injuries, fascicular neurorrhaphy that sutures the ends of the proximal and distal nerve stumps together, adequately restores function only in ~50% of patients. While spontaneous recovery can occur for small-gap injuries (less than 2 cm), regeneration across larger injuries is impeded by a combination of factors including immune response, scarring, poor support cell repopulation, and neuronal death. Following PNS injury, regenerating axons from the proximal nerve stump have to span the injury site and reconnect with the distal targets. Injuries to the peripheral nervous system (PNS) affect a broad population globally and often result in life-long disabilities in 60% of the patients due to the limited regenerative ability of neural tissue. Our findings indicate that fiber drawing provides a scalable and versatile strategy for producing nerve guidance channels capable of controlling direction and accelerating the rate of axonal growth. Our approach enabled straightforward integration of microscopic topography at the scale of nerve fascicles within the scaffold cores, which led to accelerated Schwann cell migration, as well as neurite growth and alignment. Using isolated whole dorsal root ganglia as an in vitro model system we have identified key features enhancing nerve growth within these fiber scaffolds.
![dropping scaffold drawing dropping scaffold drawing](https://www.avontus.com/wp-content/uploads/SGSBridge.jpg)
We have employed fiber drawing to engineer a wide spectrum of polymer-based neural scaffolds with varied geometries and core sizes.
![dropping scaffold drawing dropping scaffold drawing](https://smartscaffolder-rcg73ewp.stackpathdns.com/wp-content/uploads/2017/09/4.jpg)
Despite substantial evidence for the influence of scaffold geometry and dimensions on the rate of axonal growth, systematic evaluation of these parameters remains a challenge due to limitations in materials processing.
![dropping scaffold drawing dropping scaffold drawing](http://patentimages.storage.googleapis.com/US6702509B2/US06702509-20040309-D00001.png)
Synthetic neural scaffolds hold promise to eventually replace nerve autografts for tissue repair following peripheral nerve injury.