Using water to control electrospun Polycaprolactone fibre morphology for soft tissue engineering

Control of the properties of electrospun polycaprolactone can be achieved by adjusting the acetic acid:water ratio used to dissolve and electrospin the polymer. In this work, we studied the effect of using up to 15 wt% water in the solvent mixture. Solution conductivity and viscosity and fibre morphology vary dramatically with water content and solution age. Two days after initial solution preparation, electrospinning yields regular fibres for a water content of 0 wt% and 5 wt%, irregular fibres for a 10 wt% water content and irregular and fused fibres for a 15 wt% water content. Fibres with the highest crystallinity (60%) were obtained from solutions containing 5 wt% water while the highest elastic modulus (8.6 ± 1.4 MPa) and tensile stress (4.3 ± 0.3 MPa) pertain to fibres obtained from solutions containing 10 wt% water. Enzymatic fibre degradation is faster the higher the water content in the precursor solution. Adhesion ratio of human foetal fibroblasts was highest on scaffolds obtained from precursor solutions containing 0 wt% water. Cell population increases for all scaffolds and populations quickly become equivalent, with no statistically significant differences between them. Cells exhibit a more extended morphology on the 5 wt% scaffold and a more compact morphology on the 0 wt% scaffold. In summary, a small water content in the solvent allows a significant control over fibre diameter, scaffold properties and the production of scaffolds that support cell adhesion and proliferation. This strategy can be used in soft tissue engineering to influence cell behaviour and the degradation rate of the scaffolds.