Structural Ordering of Interfacially Assembled Silk Fibroin-Like Peptides via Robust Intermolecular Hydrogen-Bonding Networks

The formation of strong intermolecular hydrogen-bonding networks among repeating key motifs, i.e., Glu-Ala motifs of silk fibroin proteins, providing excellent mechanical and biochemical properties, has gained broad attention in many fields. For example, in biosensing, they could be utilized as stable molecular scaffolds on layered nanomaterials such as MoS₂ for high-sensitivity targeting-molecule detection. However, understanding the characteristics of self-assembled fibroin-like proteins, i.e., concentration-/time-dependent morphological and structural changes, on the solids is still poor. Moreover, the repeating length of key motifs inducing the formation of hydrogen bonds, of peptide sequences in determining the nucleation and growth rates, and controlling molecular-scale features has not yet been explored. Thus, we utilized the synthetic fibroin-like peptides with sequences of NH₂–Y(GA)_n=3–5Y–COOH to investigate the morphological and structural characteristics, molecular orientations, and single molecule structures on MoS₂ under different time and concentration conditions. This work would expand potential applications using fibroin-like peptide-based nanodevices for biosensing and bioelectronics.