Nanopore detection of single‐molecule binding within a metallosupramolecular cage

Borsley, S., Cooper, J. A. ORCID: https://orcid.org/0000-0002-3981-9246, Lusby, P. J. and Cockroft, S. L. (2018) Nanopore detection of single‐molecule binding within a metallosupramolecular cage. Chemistry – A European Journal, 24 (18). pp. 4542-4546. ISSN 1521-3765 doi: 10.1002/chem.201800760

Abstract/Summary

Guest encapsulation is a fundamental property of coordination cages. However, there is a paucity of methods capable of quantifying the dynamics of guest binding processes. Here, we demonstrate nanopore detection of single-molecule binding within metallosupramolecular cages. Real-time monitoring of the ion current flowing through a transmembrane α-hemolysin nanopore resolved the binding of different guests to both cage enantiomers. This enabled the single-molecule kinetics of guest binding to be quantified, whereas the ordering and durations of events were consistent with a guest-exchange mechanism that does not involve ligand dissociation. In addition to providing a new approach for single-molecule interrogation of dynamic supramolecular processes, this work also establishes that cage complexes which are too large to enter the nanopore can be exploited for detecting small molecules, thus constituting a new class of molecular adapter.