Fig. 3

BSB and MCAAD-3 exhibited different affinities for amyloid plaques vs. background parenchyma. Plaques in both 5xFAD mouse and human AD brain were efficiently stained with both probes at nanomolar concentrations, with fluorescence intensity reaching a plateau at ≈ 100 nM. Interestingly, plaques from sporadic human AD had the highest affinity exhibiting substantial staining even at 5 nM (B,D). While background parenchyma required higher probe concentrations which did not plateau even at 1µM, this background exhibited a higher affinity in AD cases compared to non-AD controls (dashed plots in B and D). Finally, BSB stained plaques much more effectively at the lowest concentration from sporadic AD (sAD) cases compared to familial AD (fAD). Error bars indicate SEM