Effect of electrospinning parameters on the mechanical and morphological characteristics of small diameter PCL tissue engineered blood vessel scaffolds having distinct micro and nano fibre populations – A DOE approach

Abstract

Electrospinning is a widely used technique in tissue engineered blood vessel (TEBV) scaffold research. Successful TEBV scaffolds must be produced in a way that balances tissue-like mechanical characteristics with morphologies that promote cellularity by supporting cell attachment whilst also permitting cell infiltration. Electrospun tubular poly (ε-caprolactone) (PCL) scaffolds combining interspersed nano and micro fibre morphologies have shown promise in this regard. A comprehensive design of experiments (DOE) approach examines the effect of production parameters on the mechanical and morphological properties of small diameter PCL vascular scaffolds created using a single-step electrospinning process and comprised of multi-modal fibre populations. Mechanical properties of the vessels are assessed using a modified uniaxial ringlet tensile test method while morphological properties, including mean fibre diameter, degree of fibre alignment and porosity, are also captured.Regression analysis showed that a diverse range of mechanical properties could be achieved through the careful adjustment of processing conditions. Constructs with a broad range of ultimate tensile strengths (~4–10 MPa) and Young's moduli (~1.5–3 MPa) were prepared. The speed of the rotating collector system was found to be a dominant factor influencing both the mechanical and morphological attributes of the fabricated scaffolds. Several other main effects and interactions terms were found to influence the scaffold attributes, including degree of fibre orientation and mean fibre diameter.The potential applicability of particular tubular scaffolds for vascular applications were then evaluated by comparison with literature obtained mechanical property values for human coronary arteries and the great saphenous vein. This study demonstrates an important step towards a readily available and tailorable set of multi-modal PCL scaffold designs for further biological and clinical investigation.