Fig. 4
Effect of surface-coated gold NPs with different surface coatings and diameters on Aβ1-40 aggregate morphology. Aβ1–40 monomer diluted to 40 μM in 40 mM Tris–HCl (pH 8.0) was aggregated alone (control, panels a, d) or in the presence of 200 pM citrate-coated (panel b), PAH-coated (panel c), CTAB-coated (panel e), or PAA-coated (panel g) NPs 18 nm in diameter. Additionally, monomer was aggregated in the presence of 200 pM PAA-coated NPs exhibiting diameters of 8 nm (panel f) or 40 nm (panel h). Monomer aggregation was induced by continuous agitation, and the control reaction was monitored periodically via ThT fluorescence. Upon evidence of equilibrium, samples were gridded and visualized by TEM. Results are representative of 2 independent experiments. Images are shown relative to a scale bar of 500 nm at 100,000x (panels a-c, e-g) or 75,000x (panels d, h) magnification