The improvement of sodium dodecyl sulfate on the electrospinning of gelatin O/W emulsions for production of core-shell nanofibers

In this work, different concentrations of sodium dodecyl sulfate (SDS) were applied to improve the electrospinning performance of gelatin-stabilized emulsions. With the increase of SDS content, the average droplet size of emulsions became smaller and the uniformity improved. Besides, the addition of SDS could increase the apparent viscosity and viscoelasticity of the emulsion via inducing extensive association of gelatin molecules. These changes presented a positive impact on the morphology and structure of the electrospun fibers. By concentration optimization, the core-shell nanofibers were successfully fabricated with the assist of 1% (w/v) SDS with a beadless and uniform structure. Especially, the SDS crosslinking could also prevent the gelling of gelatin solution at the needle via changing the protein conformation, thereby improving the spinnability of gelatin solution with continuity. However, further increasing the SDS concentration to 2% (w/v) would cause conglutination between fibers and agglomeration of oil phase. It was due to the increased viscous resistance of emulsion resulting in insufficient jet stretching at high concentration of SDS. Finally, the gelatin nanofibers showed an enhanced structural stability under the crosslinking of SDS during 15-d storage. Hence, this study presents a practical strategy for the fabrication of bio-based nano-carriers.