Effect of humidity on melt electrospun polycaprolactone scaffolds

Direct write melt electrospinning is an additive manufacturing technique used to produce 3D polymer scaffolds for tissue engineering applications. It is similar to conventional 3D printing by layering 2D patterns to build up an object, but uses a high-electric potential to draw out fibres into micron-scale diameters with great precision. Direct write melt electrospinning is related to a well-established fabrication technique, solution electrospinning, but extrudes a melted polymer in a controlled manner rather than a polymer solution. The effect of environmental conditions such as humidity has been extensively studied in the context of solution electrospinning; however, there is a lack of similar studies for direct write melt electrospinning. In this study, melt electrospun polycaprolactone scaffolds were produced with 90 degree cross-hatch architecture at three specific humidity [H2O/air (g/kg)] levels, low (0.74 g/kg), standard (8.94 g/kg), and elevated (11.26 g/kg). Micro-computed tomography and scanning electron microscopic analysis was performed on the scaffolds to investigate the degree to which humidity affects inter-layer ordering, fibre diameter consistency, and fibre surface morphology. Results indicated that humidity does not play a significant role in affecting these scaffold parameters during fabrication within the levels investigated.