Fig. 1: Multivariate effects of pH, ionic strength, and Zn²⁺ ions on Aβ₄₀ fibrillation.

The \({t}_{1/2}\) values of the fibrillation kinetics experiment of 10 µM Aβ₄₀ in 20 mM potassium phosphate buffer at various pH values (6.5, 6.8, 7.1, 7.4, 7.7, and 8) and NaCl concentrations (0, 0.0143, 0.0285, 0.0429, 0.0571, 0.0714, 0.0857, and 0.1 M), were derived from sigmoidal curve fitting of ThT aggregation kinetics data of each repeat in the absence or presence of 40 µM Zn²⁺ ions. A pH effects and B salt effects on the Aβ₄₀ fibrillation are shown separately for comparison (check text for details). All original ThT data were smoothed by choosing the Savitzky–Golay method with a points of Window from 5 to 30 using the Origin software before the aggregation halftime was extracted by sigmoidal curve fitting. The measurement variability is represented by error bars from the standard deviation of three replicas.