Electrospun Nanofibers for Anterior Cruciate Ligament Reconstruction: Effect of Draw Ratio on Enzymatic Degradation Rate

D. Brennan, J. Posselt, E. Wagner, V. Beachley
Rowan University,
United States

Keywords: electrospinning, nanofiber, scaffold

Summary:

Fibers with submicron diameters exhibit large surface area to volume ratio, flexibility, high mesh porosity, and increasing tensile strength with decreasing diameter; making them useful in developing technologies such as high-performance tissue scaffolds. One specific application in need of a stronger nanofiber materials is a graft for anterior cruciate ligament (ACL) repair. ACL rupture is one of the most common knee injuries; approximately 200,000 tears are reported annually and 85% require surgery due to the limited self-healing capacity of the ligament. The most common repair strategies utilize either an autograft or allograft of tendon, however; these procedures suffer from complications such as pathogen transmission and limited graft supply. Electrospinning is a simple manufacturing method which produces fibers with nanoscale diameters and biomimetic structure which promote cell adhesion and guide proliferation. However, electrospun nanofibers are weaker than natural load bearing tissue, due to the lack of a drawing process to align polymer chains within the fiber. Furthermore, the degradation rate of load bearing scaffolds should be sufficiently slow to allow the formation of new tissue without critical loss of mechanical strength. A method of simultaneously electrospinning and drawing is developed and used to produce sheets of aligned nanofibers. This study investigates the effect of post-drawing on electrospun nanofiber and enzymatic degradation rate. We hypothesize there is an inverse relationship between post-drawing ratio and degradation rate; where drawn fibers samples will degrade at a slower rate and maintain a higher degree of mechanical integrity compared to undrawn fibers.