Transmission electron microscope (TEM) analyses

Aβ_1–42 solutions for TEM analysis were prepared under the same conditions as the ThT binding assay. Aβ_1–42 fibril formation was visualized by TEM as previously reported [25, 26]. The blank, control, and MSX (500 μg/mL) treated samples (5 μL each) were placed onto a 200 mesh carbon-coated copper TEM grid (Ted Pella Inc., Redding, CA, USA) for 2 min. The excess fluid was removed by filter paper and 5% uranyl acetate (10 μL) was placed onto the grid for 2 min. Aβ_1–42 fibril formation was imaged using a Joel Corp. (Peabody, MA, USA) JEM 2100 TEM with a LaB6 illumination filament operating at 200 kV.