Cell infiltration and vascularization in porous nanoyarn scaffolds prepared by dynamic liquid electrospinning

A novel electrospun nanoyarn scaffold, aimed to improve cell infiltration and vascularization, as well as guide cell behaviors by its biomimetic structure, was fabricated for tissue engineering. Electrospun nanofibers were deposited and twisted into yarns in a water vortex before collecting on a rotating mandrel to form a nanoyarn scaffold. Field emission-scanning electronic microscope (FE-SEM) images revealed that the scaffold, composed of aligned nanoyarns (24 micro m) which were composed of a bundle of nanofibers, created a porous structure which may be conducive to cellular infiltration. Thus, we hypothesized that the biomimetic nanoyarn will have a positive influence on cell proliferation and morphology. Pig iliac endothelial cells (PIECs) and MC3T3-E1 pre-osteoblastic cells cultured on the nanoyarn scaffolds showed significantly higher proliferation rates than that on traditional electrospun nanofiber scaffolds. Histological analysis demonstrated that cells infiltrate throughout the nanoyarn scaffolds over a 10-day period, however, no cell infiltration was observed on the nanofiber scaffolds. Moreover, confocal microscopy images indicated that both PIECs and MC3T3-E1 pre-osteoblastic cells cultured on the nanoyarn scaffolds exhibit an extremely elongated morphology compared to the flattened morphology when cells were cultured on electrospun nanofiber scaffolds or tissue culture plates. Furthermore, complex capillary-like structures were observed when PIECs cultured on the nanoyarn scaffold for 7 days, indicating that the nanoyarns provide templates and topographical cues for the assembly of PIECs and the promotion of a capillary network in vitro. In conclusion, the positive cellular interactions on the nanoyarn scaffold demonstrate potential application for use in tissue engineering.