Taking a step forward from the indicator spacer receptor (ISR) method
comprising covalent linkages between receptors and indicators via a spacer, the
indicator displacement assay (IDA) offers an innovative and powerful sensing
approach for various target analytes in the realm of host-guest chemistry. In this
chapter, we have assembled the background and conceptual details in order to give
essence to the readers about this innovative sensing approach. The photophysical
phenomenon and diverse non-covalent interactions involved in the sensing mechanism
have been detailed. We have elucidated the need and urgency to replace the ISR
approach with IDA, one having numerous advantages. The evolutionary extension of
IDA for enzymatic conversion known as supramolecular tandem assays has also been
described in this chapter. We believe that the present introductory chapter will give a
better understanding to readers who are new to this field.
Keywords: Analyte, Competitive binding, Dynamic, Detection, Enantiomeric excess, Enzyme, Fluorescence quenching, Guest, Host, Indicator displacement assay, Indicators, Macrocycle, Non-covalent interaction, Receptors, Reversible, Recognition, Sensors, Signal, Substrate, Tandem assays.
