Tetraphenylethylene-based glycoconjugate as a fluorescence "turn-on" sensor for cholera toxin.

Tetraphenylethylene (TPE)-based glycoconjugates were easily synthesized by copper(I)-catalyzed "click reactions" between propargyl-attached TPE and azido-functionalized sugars. The TPE compound bearing lactosyl moieties (Lac-TPE) was found to be a fluorescence "turn-on" sensor for cholera toxin by virtue of aggregation-induced emission characteristics of the TPE motif owing to the specific interaction of lactose with the cholera toxin B subunit, whilst a cellobiose-functionalized TPE derivative did not show any response to the toxin. Therefore, Lac-TPE shows promising applications in the detection of cholera toxin, as well as in the investigation of carbohydrate-protein interaction.