Signal amplification and detection via a supramolecular allosteric catalyst

The design of a supramolecular allosteric catalyst system for catalytic signal amplification and detection is presented. The catalyst was switched "on" by the introduction of an analyte that also behaves as an allosteric activator. Concentrations of Cl- ions as low as 800 nM were catalytically amplified and detected. The signal was transduced via a pH-sensitive fluorescent probe and observed visually using a laboratory, handheld UV lamp and by spectrophotometry. Furthermore, the allosteric effect was quantified using gas chromatography for a range of Cl- concentrations. This three-part detection scheme involving analyte binding, allosteric catalyst activation, and signal transduction represents a new approach to small-molecule detection. Copyright © 2005 American Chemical Society.