Using electrospun scaffolds for tendon repair

Electrospinning has become a popular technique in the field of biomaterials and tissue engineering as 3D structures can be easily created. With architectures similar to the extracellular matrix, electrospinning has been investigated for a wide range of tissues, including; bone, heart valves, trachea and tendons1.Being load-bearing tissues, tendons are susceptible to wear-and-tear and even spontaneous rupture, which then requires medical intervention. Autologous tendon tissue is used when a segmental repair or reconstruction is required. Whilst this repair is classed as the ‘gold standard’, it is not without several disadvantages – secondary sites of tissue morbidity are created which could prolong patient rehabilitation time and there is an increased risk of infection; and an adequate source of tendon tissue for autografting cannot be guaranteed. Therefore there remains an unmet clinical need and biomaterials are being investigated as a potential solution. A synthetic scaffold for tendon repair needs to incorporate the following factors in its design: (1) resemble the natural tissue structure, (2) be biocompatible and promote appropriate tissue healing, (3) provide sufficient mechanical strength to support new tissue formation and withstand applied forces, and (4) degrade at a rate which allows a smooth transfer of load without premature failure or accumulation of by-products.Poly(ε-caprolactone) (PCL) is a readily electrospinnable polymer and the alignment of emitted fibres can be controlled and further manipulated to create 3D yarn structures, which resemble the tertiary layer of the natural tendon hierarchy2. Material properties, such as tensile strength, can be tailored3 and the scaffolds are capable of supporting cell adhesion, proliferation and their orientation4,5. Implantation of scaffolds into the superficial digital flexor tendon of mice hind-paws yielded encouraging results with minimal inflammatory reaction and observation of cell infiltration into the scaffold and collagen deposition over a 12-month period.This research demonstrates the on-going development of electrospun scaffolds as a potential medical device for the treatment of tendon injuries.With special thanks to Dr Sarah Cartmell and Prof Sandra Downes for guidance and supervision, and acknowledgement of financial support from EPSRC, the UMIP Premier Fund, Regener8 and MRC-DPFS. References:1 ‘Electrospinning for Tissue Regeneration’, Edited by LA Bosworth and S Downes, Woodhead Publishing, Cambridge. 2011.2 ‘Tissue Repair Scaffold’, PCT/GB2009/002874, Inventors; S Downes and LA Bosworth. 3 Bosworth LA, ‘Electrospinning for tendon regeneration’, in Electrospinning for Tissue Regeneration, Woodhead Publishing, Cambridge. 2011;p148-167.4 Bosworth LA, Alam N, Wong JK, Downes S, ‘Investigation of 2D and 3D electrospun scaffolds intended for tendon repair’. Journal of Materials Science: Materials in Medicine. 2013; 24(6):1605-1614.5 Bosworth LA, Rathbone SR, Downes S, Cartmell SH, ‘Cyclical loading of electrospun scaffolds affects Mesenchymal stem cell response’. European Cells and Materials, Vol. 23. Suppl. 4, 2012 (page 1).