Bipolar Electrochemical Analysis of Chirality in Complex Media through Miniaturized Stereoselective Light-Emitting Systems

Environmentally relevant contaminants endowed with chirality may include pharmaceutical compounds, flame retardants, perfluoroalkyl chemicals, pesticides, and polychlorinated biphenyls. Despite having similar physicochemical properties, enantiomers may differ in their biochemical interactions with enzymes, receptors, and other chiral molecules leading to different biological responses. In this work, we have designed a wireless miniaturized stereoselective light-emitting system able to qualitatively detect a chiral contaminant (3,4-dihydroxyphenylalanine, DOPA) dissolved in reduced volumes (in the microliters range), through bipolar electrochemistry. The diastereomeric environment was created by mixing the enantiomers of an inherently chiral inductor endowed with helical shape (7,8-dipropyltetrathia[7]helicene) and the chiral probe (DOPA) in micro-solutions of a commercial ionic liquid. The synergy between the inductor, the applied electric field, and the chiral pollutant was transduced by the light emission produced from a miniaturized light-emitting diode (LED) exploited in such an approach as a bipolar electrode.