Synthetic Aβ Homologue Preparation and Aggregation

Synthetic Aβ homologues were dissolved to 1 mM in hexafluoro-isopropanol (HFIP; Sigma Chemical Co., St. Louis, MO), a pre-treatment that breaks down β-sheet structures and disrupts hydrophobic forces leading to monodisperse Aβ preparations [34 (link)]. Following lyophilization to remove HFIP, peptides were subsequently solubilized in deionized water and added to an equal volume of a 2× concentrated phosphate-buffered saline (PBS), pH 7.4, to a final concentration of 1 mg/ml in 1 × PBS. Peptides, in the presence or absence of 100 µM TUDCA (Sigma), were either incubated at 37°C for up to 48 h for the aggregation studies or diluted into culture media at the required concentration for the toxicity experiments. For the aggregation studies, structural properties were assessed by Western blot analysis, circular dichroism (CD) spectroscopy and Thioflavin T binding.