Preparation of Natural Multicompatible Silk Nanofibers by Green Deep Eutectic Solvent Treatment

Natural silk fibers consist of well-organized, sophisticated hierarchical architectures that contribute to the robust mechanical performance and functions of the fibers; thus, the direct extraction of silk nanofibers (SNFs) at a single level is a major challenge. Herein, a novel simple, environmentally friendly, and recyclable route was developed to directly downsize natural silks into SNFs via a green deep eutectic solvent (DES) system assisted by mild mechanical disintegration. SNFs with diameters ranging from 2.3 to 28 nm and lengths of 598 ± 308 nm were isolated at a high yield (over 70%) under optimal DES pretreatment conditions. On the basis of the inherent amphoteric properties of SNFs, the pH sensitivity and reversibility were explored to lighten the weight of SNF dispersions for storage and transport, and furthermore, the double adsorption properties of the SNFs might functionalize them for transparent anticounterfeiting devices. In addition, the nanodispersibility of the SNFs in organic solvents and the subsequent nanofiber-containing composite materials with hydrophobic polymer matrixes provide new prospects for wound dressing and porous scaffold materials in biomedical applications.