Michael Mullins
Professor of Chemical Engineering
Director of Center for Fundamental and Applied Research in
Nanostructured and Lightweight Materials
Michigan Technological University
Houghton, Michigan

Nerve Guidance Conduits Utilizing Aligned Electrospun Fibers
Synthesis and /InVitro/ Studies

Conditions for electrospinning aligned poly-L-lactic acid (PLLA) fibers for nerve growth applications have been examined, using a modified electrospinning method in conjunction with a rotating electrode to collect the fibers.    Dense, highly aligned fields of PLLA fibers in the micron to sub-micron range have been collected and used to study neuronal outgrowth /in vitro /using chick embryonic stage nine dorsal root ganglion neurons (E0 chick DGRs).  Fiber morphology and neuronal outgrowth were studied using scanning electron microscopy (SEM) and fluorescent upright microscopy with appropriate cell staining.  It is  shown that the outgrowth of neurites was guided along the aligned fibers, and the density of outgrowth is proportional to the fiber density.  The results show that the aligned PLLA fibers are a promising material to promote nerve regeneration win a directed manner.  To test these scaffolding materials /in vivo/, we have subsequently prepared a unique multi layered 3 -dimensional conduit that maintains the fiber alignment , and similarly promotes directed neuronal outgrowth.   The further design and  testing of these implantable scaffolds in animal models is underway in conjunction with the Johns Hopkins International Center for Spinal Cord Injury to determine the promise of this approach for organizing and guiding nerve regeneration following spinal cord or peripheral nerve injury.