Physical characterization of an electrospun nerve wrap to enhance nerve regeneration

Marina Manoraj (1,3), Katelyn Chan (2,3), Kasra Tajdaran (2,3), Tessa Gordon (3,4), Gregory Borschel (2,3,4)

1. Department of Chemical Engineering, McMaster University

2. Institute of Biomaterials and Biomedical Engineering, University of Toronto

3. Division of Plastic and Reconstructive Surgery, The Hospital for Sick Children

4. Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Toronto

Peripheral nerve regeneration is often slow and incomplete following injury, despite advances in microsurgical techniques. FK506 is an FDA-approved immunosuppressant with neurotrophic properties. A poly(lactic-co-glycolic) acid (PLGA) microsphere and fibrin gel system for FK506 encapsulation has shown successful local and sustained delivery of FK506 to enhance peripheral nerve regeneration in rats. However, this system can be made more clinically feasible by simplifying the manufacturing process and reducing the number of components involved. Our aim is to create a nerve wrap, applied around a micro-sutured nerve repair site, that releases FK506 to enhance nerve regeneration following injury. Co-axial electrospinning was employed to form core-shell nanofibers with an outer shell of PLGA that protects the inner shell of PLGA and FK506 from burst release of the drug. After analyzing the fibres using scanning electron microscopy and ImageJ software, it was determined that the fibres were smooth, indicating mechanical stability. The mean fibre diameters and porosity with or without FK506 were not significantly different across groups, suggesting that FK506 does not alter fibre morphology. The fibres are easily synthesized and contain components from only two different FDA categories (e.g. the polymer(s) and FK506). Therefore, this process has the potential to be more easily achieve FDA approval and be upscaled for commercial production and clinical use.