Electrospinning and dual crosslinking of water-soluble silk fibroin modified with glycidyl methacrylate

The water solubility of silk fibroin (SF) was significantly improved by introducing glycidyl methacrylate (GMA) into the reactive side chains (-NH2, -OH, -COOH) of SF. The degree of methacrylation (DM) of SF-GMA varied with the amount of GMA added to the SF solution and confirmed by proton nuclear magnetic resonance spectra. In addition, the pH of SF/GMA solution changed with the GMA amount and the reaction time, and thus the main reactive groups of SF changed. GMA-modified SF ultrathin fibers (SF-GMA UFs) were prepared by eco-friendly electrospinning process using distilled water as a spinning solvent. The water-soluble SF-GMA UFs were treated with an aqueous ethanol solution to insolubilize them by a structural transformation from random coils to β-sheets. This was confirmed by attenuated total reflectance infrared spectroscopy. Furthermore, chemical crosslinking was applied to improve the water resistance by increasing the crosslinking density of SF-GMA UFs. The dual-crosslinked SF-GMA UFs will be suitable for tissue engineering fields, such as wound dressings and scaffolds.