Aβ42 Oligomer Preparation

Oligomeric Aβ₄₂ was prepared as previously described (An et al., 2013). Briefly, 1 mg of synthetic Aβ₄₂ peptide (American Peptide, Sunnyvale, CA, USA) was dissolved into 1 mL 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP; Sigma Aldrich, St. Louis, MO, USA). The solution was dried under a nitrogen stream and resuspended in 100% HFIP at a concentration of 1 mg/mL. The solution was sonicated in a bath sonicator for 5 min and dried under nitrogen stream. The solution was re-dissolved in 1 mL HFIP and dried for 2 h. The film was resuspended in 200 μL dimethyl sulfoxide (DMSO; Sigma Aldrich, St. Louis, MO, USA) to obtain a 1 mM Aβ₄₂ stock solution. For Aβ₄₂ treatment, 10 μL of 1 mM Aβ₄₂ was diluted with 1 mL DMEM media (final concentration, 10 μM) and incubated for 12 h at 37°C.