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 SFGMA 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 b-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. (C) 2020 Elsevier Ltd. All rights reserved.