Figure 3.

FTIR spectra of the freeze-dried electrogelled silk: untreated (top dashed) and glutaraldehyde-crosslinked (bottom solid) in the 3500 ~ 2800 cm⁻¹ range. The principle IR bands and their assignments are summarized in the inset.^26,27 The chemically crosslinked silk e-gel exhibits a decrease in the intensity of the 2972 cm⁻¹ CH₃ asymmetric stretching vibration band suggesting the involvement of the side chain methyl groups in the crosslinking. Similar results were obtained on the vortex-induced and spontaneously formed silk gels (Figure S1).