Aggregation of amyloid-β peptides is a hallmark of Alzheimer's disease. Since the aggregation is driven by early 'aggregation seeds', detection of the seeds is a promising approach for diagnostics. The aggregation can be monitored by Thioflavin T that binds to beta sheet-rich structures and in turn increases its fluorescence.
Brain homogenates of wild type mice and APP23 mice which are prone to amyloid-β aggregation were incubated with Thioflavin T. The fluorescence intensity of these reactions was detected every 30 min after 30 s of shaking and over a period of 2-3 days. In homogenates from wild-type mice, fluorescence signal increased later than in homogenates from APP23 mice. This reflects the higher seeding activity in APP23 brain tissue.
The assay was read, incubated and shaken with a FLUOstar® Omega microplate reader which might be the basis for replacing time- and labor-intensive in vivo studies.