Silk Nanofibers as Robust and Versatile Emulsifiers

Peptides have been extensively studied as emulsifiers due to their sequence and size control, biocompatibility, versatility, and stabilizing capacity. However, cost and mass production remain the challenges for broader utility for these emulsifiers. Here we demonstrate the utility of silk fibroin nanofibers as emulsifiers, with superior functions to the more traditional peptide emulsifiers. This silk nanofiber system is universal for different oil phases with various polarities and demonstrates control of microcapsule size through tuning the ratio of silk fibroin nanofiber solutions to oils. Besides the improved stabilizing capacity to peptides, these silk fibroin nanofibers endow additional stability to the emulsions formed under high salt concentration and low pH. Highly efficient encapsulation of biomarkers through interfacial networks suggests potential applications in therapeutics, food, and cosmetics. Compared to peptide emulsifiers, these silk fibroin nanofibers offer advantages in terms of cost, purification, and production scale, without compromising biocompatibility, stabilizing capacity, and versatility.