Fig. 2: Bulk Fourier Transform Infrared spectroscopy (FTIR) analysis of supramolecular silk fibroin assembly states.

a Amide I region IR-spectra showing overlap of monomers released from nanocompartments (blue) and monomers within the nanocompartments (orange). The analysis confirms the re-folding event in protein monomers upon nanospherical assembly disintegration. b Amide I FTIR spectra of silk fibroin monomers, nanocompartments, and nanofibrils. c Comparative analysis of the secondary structure of (b) with the band positions of the β-sheets at 1610–1635 cm–1, anti-parallel β-sheets at 1690–1705 cm–1, random coil and α-helixes at 1635–1665 cm–1, and β-turns at 1665–1690 cm–1. Source data are provided as a Source Data file.