Allosteric Signal-Amplification Sensing of Peptides with Cyclodextrin-Polymer Conjugates in Aqueous Media

Signal-amplification techniques such as polymerase chain reactions (PCR) can detect trace amounts of target analytes. The development of signal amplification techniques presents a major challenge to researchers from multidisciplinary sciences such as analytical supramolecular chemistry. In this study, permethylated cyclodextrin-polymer conjugates achieved the highly sensitive signal amplification detection of angiotensins I-IV and xenopsin-related peptide 2 in aqueous media through positive cooperativity or homotropic allosterism. Indeed, the binding constants of these permethylated cyclodextrin-polymer-based chemosensors were found to be higher than those obtained using unmodified cyclodextrin recognition units by a factor of 104-105. Our spectroscopic results and theoretical calculations reveal that microenvironmental solvation and synchronous cooperative complexation play critical roles during the amplification events. The functional chemosensors developed in this study are an attractive alternative to conventional host/receptor molecules.