Core-shell structured PEO/HA nanofibers could be produced from electric field inducing phase separation during the electrospinning progress. Hyaluronic acid (HA) molecules could move along the opposite direction of the electric field under the electrostatic force, which induced phase separation from PEO to form the core layer of nanofibers. The morphology of core-shell nanofibers was supported using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Thermal analysis and X-ray diffraction (XRD) results showed that the fibers had good thermal stability and HA hindered the crystallization of the PEO. The presence of PEO on the surface was also verified by X-ray photoelectron spectroscopy (XPS) analysis as further evidence of core-shell formation during the process of electrospinning. Methylthiazolydiphenyl-tetrazolium bromide (MTT) assay was employed to investigate the toxic and cytocompatibility with the aim of demonstrating the possible application for tissue engineering scaffolds. Furthermore, In vitro cytotoxicity against fibroblasts cells culture demonstrated the nanofibers as scaffolds were biocompatible and nontoxic. (C) 2015 Elsevier Ltd. All rights reserved.