Fluorescent Light‐up Probe for the Detection of Protein Aggregates

A fluorescent dye was decorated with water‐soluble pyridinium groups in order to be applied in the detection of cyclodextrins or DNA. The dye displays an enhancement of its emission intensity when the internal rotations are restricted due to the formation of an inclusion complex with cyclodextrins or upon interaction with DNA. In vivo, the fluorescent probe can stain protein aggregates with a selectivity comparable to the widely used Proteostat®. Let′s light up the world: A water‐soluble fluorescent probe was prepared that displays an enhancement of its emission intensity upon stiffening of its backbone and successfully detects γ‐cyclodextrins and DNA in vitro. In cells, it selectively stains protein aggregates when those are present.