Label-free electrochemiluminescent enantioselective sensor for distinguishing between chiral metallosupramolecular complexes.

Chiral molecular recognition of DNA is important for rational drug design and for developing structural probes of DNA conformation. Developing a convenient and inexpensive assay for sensitive and selective identification of DNA-specific binding compounds with rapid, easy manipulation is in ever-increasing demand. Here, we present a "turn-on" and label-free electrochemiluminescent (ECL) biosensor for distinguishing chiral metallosupramolecular complexes based on DNA three-way junction formation selectively induced by the analyte. The fabricated ECL sensor shows excellent performance in the chiral discrimination of two enantiomers with an enantioselective recognition ratio of up to 4.4. More importantly, as a "turn-on" detection system, the ECL chiral sensor does not suffer from false positives and limited signal range of "signal-off" systems. Therefore, this concept may provide a new insight into the design of efficient sensors for distinguishing chiral molecules and for investigating the interactions between DNA and small molecules.