Engineering regenerated nanosilk to efficiently stabilize pickering emulsions

A simple and efficient method of preparing regenerated nanosilk (RNS) has been developed based on fast dissolution of silk fibroin in 85 wt% aqueous phosphoric acid (PA) followed by coagulation in acetone. Compared with the previously reported methods to prepare RNS, this method used the non-toxic, non-volitle and costeffective PA as the solvent and by-passed the time-consuming dialysis process typically required. Selfassembly of silk fibroin molecular chains during the regeneration process led to dominance of the folded beta-sheet secondary structure, which avoided the unstable structure transitions of RNS as emulsifiers during actual use. The as prepared RNS was further employed to stabilize the Pickering emulsions. Smaller RNS, higher RNS loading, and lower oil/water (O/W) ratio favored the formation of more stable emulsions. The prepared emulsions were stable for more than one month and were insensitive to environmental stresses such as heating and high ionic strength, but responsive to pH changes. Overall, a simple and efficient method was proposed to prepare RNS with tunable properties and great potential for application in food and cosmetic formula.