Figure 3

(a) Bright field optical micrograph of AIPs (Amyloid Inspired Peptides) network, directly self-assembled on the SOM substrate by air-drying a peptide solution. (b) A wide-field SERS video sequence is recorded at the same location and resulting images are used to reconstruct an image of the self-assembled AIP network. Due to high SERS sensitivity, residual peptide presence on the surface complicates resolution of individual peptide nanofibers. A well-separated, thin peptide nano-bundle (highlighted by arrows) is used to plot the line profile. (see Supplementary Video 4). (c) The peptide bundle is observed to be approximately 30 nm in diameter (solid line), a width smaller than the diffraction limited resolution (represented by dashed line). (d) During wide-field SERS video imaging of AIPs, SERS spectra were simultaneously recorded from a spot located at the center. Amide VI (630–750 cm⁻¹), Amide V (700–750 cm⁻¹), Amide III (1230–1300 cm⁻¹), Amide II (~1550 cm⁻¹) and Amide I (1600–1700 cm⁻¹) bands associated with peptide backbone structure and side chain composition can be identified in the spectra. δ, in plane bending vibration; ν, stretching vibrations. Scale bars are 1 μm wide.