Fabrication and Characterization of Gelatin/Zein/Thymol Nanofibers by Electro-blown Spinning

Abstract

In this study, gelatin/zein/thymol nanofibers were fabricated by electro-blown spinning technique, and its microscopic morphology and diameter distribution were characterized by scanning electron microscopy (SEM). The interaction between protein and thymol was studied by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy, and thermal analysis techniques in order to elucidate the changes in macroscopic performance such as mechanical properties and water vapor permeability (WVP) as well as antioxidant activity and antimicrobial property. Compared with traditional electrospinning, the yield of nanofibers was increased by 10.0 times using electro-blown spinning, and the feeding rate was increased from 1.0 to 10.0 mL/h. The diameter of gelatin/zein/thymol nanofibers showed an upward trend with increasing thymol loading (0%, 0.1%, 0.5%, and 1.0%). FTIR spectroscopy showed that thymol interacted with protein through hydrogen bonding, and no characteristic diffraction peak for thymol was observed in the XRD profile, indicating that thymol was uniformly distributed in the nanofibers. Nanofibers encapsulated with 0.5% thymol showed better WVP than thymol-free nanofibers, indicating that due to its hydrophobicity, thymol could prevent water molecules from passing through the nanofibers. Tensile tests showed that the addition of thymol significantly increased the elastic modulus of the nanofibers, but had no significant effect on the tensile strength or elongation at break. The antioxidant capacity of the nanofibers, as determined by radical scavenging and metal ion reducing assay, was correlated with the concentration of thymol. The nanofibers had potent antimicrobial effect against Escherichia coli and Staphylococcus aureus as evaluated by the zone of inhibition method.

Keywords

• electro-blown spinning; thymol; nanofibers