Fig. 3: Aβ₄₂ fibrils sensing of LS7 in solutions.

A Fluorescence signal ratio of LSs before and after binding to Aβ fibrils. B Fluorescence spectra of LS7 reacted with 0–100 μΜ Aβ₄₂ fibers. C Linearly fluorescence response of LS7 to 0–100 μM Aβ₄₂. D Fluorescence intensities of LS7 (10 μM) at 936 nm against time after addition Aβ₄₂ (40, 60, and 100 μM). E LS7 (0–10 μM) displaces ThT from the ThT/Aβ aggregation complex and forms the LS7/Aβ aggregation complex. F Specificity test for LS7 and various: (1–3) 500 μM Cu²⁺, Fe²⁺, K⁺; (4–6); 50 μM H₂O₂, HOCl, ONOO⁻; (7–10) 500 μM L-phenylalanine, glycine, lysine, serine; (11–14) 500 μM trypsin, hyaluronidase, glucose oxidase, horseradish peroxidase; (15–16) 300 μM BSA, HAS; (17) LS7 only; (18)100 μM Aβ₄₂ fibers. All the above experiments were performed in PBS (pH 7.4, 10 mM) at 37 °C, λ_ex = 808 nm, λ_em = 1000–1700 nm. For (A, C, F), data are presented as mean ± SD (n = 3 independent experiments).