Figure 3: Fluorescence microscope images of Aβ40 protofibrils and fibrils labeled with the R-γ-Fe2O3 nanoparticles. Single staining by adding 8% (w/ wAβ40) of the γ-Fe2O3-R nanoparticles to the protofibrils (A1) and fibrils (B2) formed after 88 h and 120 h, respectively; double staining by adding 8% (w/ wAβ40) of the R- γ-Fe2O3 nanoparticles and ThT to the fibrils formed after 120 h (C1). A2, B2 and C2 corresponding to the optical images of A1, B1 and C1, respectively.