Sensor Response and Computational Molecular Modelling

This paper concerns the application to the sensor field of the various modes of computational exploration, representation and prediction of the nature of intermolecular interactions that lie at the heart of the response selectivity of chemical and biosensors to analyte species. Such a strategy is expected to be helpful in the understanding of response associated with existing sensor-receptor combinations, and in the possible design of new surfaces for the detection of environmental molecules. A key issue in this area is the role of shape complementarity between the receptor site and the analyte molecule and its connection to the interaction energies of instigated hydrogen bonds. We have used three distinct methods for the study of such molecular interactive systems; these are molecular mechanics and semi-empirical and ab initio quantum mechanical models. These methods applied to the problem of intermolecular interactions must accurately reproduce the molecular geometry of the separate receptor and analyte entities, and the hydrogen-bonded complex. In addition, reasonable values for the relative energies of these moieties must be available.In present paper we will describe an explicit comparison of the results of computational methods applied to a receptor-analyte combination with experimental measurements of responses of SAW and TSM acoustic wave sensors to organonitrocontaining compounds. The system involved concerns the hydrogen-bonding of nitro functional group species to amino-silanes bound on the sensor surface. The correlation between theory and experiment clearly demonstrates the difficulties in facile interpretation of the results of calculation on the one hand, but great utility for the redesign of new surface receptors on the other.