Competition Experiments

Abstract

Abstract Competition assays, particularly indicator displacement assays (IDAs), are now a popular approach for supramolecular detection and sensing. Contrary to the traditional indicator–spacer–receptor approach, an IDA is based on guest competition between an analyte and an indicator for binding of the receptor (host). As a result, synthesis to incorporate the indicator is avoided in the creation of an IDA, and the selection of indicators can be used to impact the assay. IDAs have been utilized to detect and sense various kinds of analytes, including anions, cations, and neutral molecules. Moreover, both synthetic and biological hosts have been explored in IDAs, thereby expanding the scope of IDAs. Besides utilization in individual analyte sensing, IDAs are amenable to pattern‐recognition‐based differential sensing. Recently, IDAs have been explored to discriminate structurally similar analytes, generating diagnostic fingerprints for complex mixtures. Enantioselective indicator displacement assays (eIDAs) have also been explored and have great potential for application in asymmetric catalyst discovery. IDAs with different detection methods, different kinds of guests, and different kinds of hosts are discussed in this chapter.