A Protein‐Responsive Chromophore Based on Squaraine and Its Application to Visual Protein Detection on a Gel for SDS‐PAGE

Dying to know: A visual protein indicator based on squaraine is responsible for a profound color change upon binding to protein in solution, from light pink for the dye alone to deep purple for the dye⋅BSA complex (see picture; BSA: bovine serum albumin). The detection limit for BSA is 2 μg mL−1, which is about five times higher than that with Coomassie Brilliant Blue as the dye.