Special Issue "Supramolecular Sensors"

Guest Editor
Dr. Peter J. Cragg
School of Pharmacy and Biomolecular Sciences, Cockcroft Building, University of Brighton, Lewes Road, Brighton BN2 4GJ, UK
Website: http://www.brighton.ac.uk/pharmacy/contact/details.php?uid=pjc10
E-Mail:
Interests: molecular recognition; supramolecular chemistry; chemical sensors; biosensors; molecular modelling

Supramolecular chemistry is a comparatively young branch of the science that began to emerge as a distinct discipline in the late 1960s. Although work on complex molecular systems can be traced back to the early 19th Century, the term 'supramolecular chemistry' was only introduced in 1987 by the Nobel Prize winning chemist Jean-Marie Lehn. He defined it as the "chemistry of molecular assemblies and of the intermolecular bond" or, more simply, "chemistry beyond the molecule". Given this definition, almost all of chemistry and biology could be thought of as 'supramolecular' - from the crystallisation of sodium chloride to viral infection - but, crucially, supramolecular researchers use their knowledge of intermolecular interactions to manipulate molecular recognition events.
Sensing applications of supramolecular chemistry, in which molecules are chosen for their size, shape and charge complementarity with the desired analyte, rely on exploiting the forces involved in the formation of non-covalent 'host-guest' complexes. The 'host' molecules, containing a binding site that is highly specific for an analyte 'guest', are used as sensors to register analyte binding through a variety of mechanisms such as colorimetric, fluorescent or electrochemical signals. The most significant non-covalent factors are electrostatics, cation-? interactions, hydrogen bonding, ?-? stacking and van der Waals forces. Although often individually weak, these intermolecular interactions exert a great influence on the stability of supramolecular complexes through a synergistic effect.
The application of a 'supramolecular philosophy' to problems in analytical science has led to a range of molecules capable of recognising analytes with high specificity. In all cases the requirements of the sensor are the same: the host must bind to the guest in preference to all competing species and it must register the binding event in a measureable form. This has led to the 'receptor-spacer-reporter' design of many supramolecular sensors.
This issue of Sensors illustrates the range of compounds that can be incorporated into sensors to help detect and monitor analytes of environmental and medical importance. Supramolecular chemistry is central to such research as it stands at a point where the spheres of chemistry, biology and diagnostic techniques intersect.

supramolecular, sensor, host-guest, macrocycle, crown ether, calixarene, luminescent, fluorescent, colorimetric, electrochemical, redox active.