Aza-BODIPY: improved synthesis and interaction with soluble Aβ1-42 oligomers.

Dye-binding assays that are used to evaluate anti-aggregation ability of small molecule inhibitors towards amyloids are known to be prone to false-positive effects due to spectral overlaps between the dye and the inhibitor. Aza-BODIPY dye, which has both excitation and emission maxima above 600nm, exhibits a significant increase in its fluorescence intensity in the presence of soluble oligomers of Aβ1-42. These results indicate that aza-BODIPY could serve as a near-IR probe for detecting conformational changes of Aβ1-42 soluble oligomers in vitro, and it should eliminate false-positive effects that are associated with currently utilized thioflavin T-based dyes. In addition, a facile synthesis of aza-BODIPY has been developed, which might further expand the applications of this dye.