Electrospinning of Polycaprolactone for Tendon Regeneration

Electrospinning of Polycaprolactone for Tendon Regeneration L. A. Bosworth, S. J. Eichhorn, S. DownesTendons are primarily composed of collagen type I fibres and tendon cells. The fibres mainly run along the length of the tendon axis and form part of the extracellular matrix (ECM). The tendon cells lie amongst these fibres in relatively few numbers and assist the turnover of the ECM. Tendons have great flexibility and elasticity, but their main function is to provide sufficient tensile strength. This is achieved by the parallel alignment of collagen fibres to one another along the direction of applied load. Should the tendon degenerate and rupture the healed tissue is no longer as mechanically strong. This is because the formed scar tissue is composed of collagen type III, a mechanically weaker structure compared to collagen type I. Consequently the scarred tendon is prone to re-rupture. This leads on to the need for artificially created tendons to be fabricated for implantation. The purpose of this research is to develop a technique capable of producing an artificial scaffold that closely mimics natural tendon in terms of structure, composition and mechanical properties.Electrospinning is a relatively simple method capable of producing fibres with long lengths and diameters ranging from microscopic to nanoscopic. The process utilises an electric field to produce a jet of charged polymer that is deposited onto a metallic target collector. Deposition can be controlled by rotation of the target to produce organised fibres or left stationary to create a random network. This method has been chosen because of its ease of fabrication, and its ability to construct the scaffold in such a way that it can closely resemble the original tendon.Polycaprolactone is the material polymer to be used as it is both biocompatible and bioresorbable. One of the benefits of using this polyester is its slower rate of degradation compared to other biopolymers - allowing the seeded tendon cells the time needed to produce significant amounts of ECM, required to withstand the loads exerted on the tendon. Other ideal characteristics are its low levels of toxicity, and excellent mechanical properties in terms of tensile strength and flexibility.Research to date has mainly focused on determining the ideal electrospinning parameters necessary to produce bead-free, nanoscopic fibres.