Multimodal Imaging of Protein Aggregates

Prior to lap shear testing, all laps were photographed using a digital camera (16 MP resolution). Polarized optical microscopy was performed on selected samples using an Olympus SZX10 microscope, with the illumination, exposure and gain settings remaining unchanged across all images. A slight overexposure enabled the visualization of the fractures, while highlighting differences in birefringence patterns across the samples. Scanning electron microscopy images were recorded using a Zeiss Sigma VP field emission scanning electron microscope at 1.6 kV and working distance of ca. 7 mm. The monomeric HEWLs, their amyloids, and short amyloids were imaged by AFM (Bruker ICON3), with the samples being prepared from ∼0.05 mg mL⁻¹ suspensions deposited on freshly cleaved mica substrates. The ChNCs were imaged by AFM using a JPK-Bruker NanoWizard IV XP on freshly cleaved mica. The length and width of the ChNCs were corrected for tip convolution according to previous work.^{26 (link)}