3D printing and electrospinning dual-scale polycaprolactone scaffolds with low density and oriented fibres to promote cell alignment

Complex and hierarchically functionalised scaffolds composed of micro and nanoscale structures is a key goal in tissue engineering. The combination of 3D printing and electrospinning enables the fabrication of these multi-scale structures. This study presents a polycaprolactone 3D printed and electrospun scaffold with multiple mesh layers and fibre densities. The results show successful fabrication of a dual-scale scaffold with the 3D printed scaffold acting as a gap collector with the printed microfibres as the electrodes and the pores a series of insulating gaps resulting in aligned nanofibres. The electrospun fibres are highly aligned perpendicular to the direction of the printed fibre and form aligned meshes within the pores of the scaffold. Mechanical testing showed no significant difference between the number of mesh layers whilst the hydrophobicity of the scaffold increased with increasing fibre density. Biological results indicate that increasing the number of mesh layers improves cell proliferation, migration and adhesion. The aligned nanofibres within the microscale pores allowed enhanced cell bridging and cell alignment which was not observed in the 3D printed only scaffold. These results demonstrate a facile method of incorporating low-density and aligned fibres within a 3D printed scaffold and is a promising development in multi-scale hierarchical scaffolds where alignment of cells can be desirable.