Nanoscale self-assembly nanosensors for nerve gas analogs and explosives

COLL 499

Subra Muralidharan, subra.murali@wsu.edu, Narayanan Srividya, narayanan_srivid@wsu.edu, William Lizik, wlizik@hotmail.com, Shankar Varaganti, sushank_chem@yahoo.com, Yogesh Datar, ydatar@wsu.edu, and Deepak Thimmaraju. School of Molecular Biosciences, Washington State University, 515 Heald Hall, Pullman, WA 99164
We have been investigating the concept of self-assembled nanostructures for the selective and sensitive sensing of nerve gases and explosives through signal transduction. Our concept is centered on bottom up assembly of nanoparticle-monomer-nanomolecule-receptor (NMNR) sensors for nerve gas analogs such as diethylchloro phosphate (DCP) and explosive molecules such as dinitrotoluene (DNT) and trinitrotoluene (TNT). We have fabricated and studied sensors that change fluorescence of the receptor, nanomolecule, and monomer upon binding a target compound. The nanoparticles that we have investigated include silica, gold, and quantum dots, the monomer a new class of stilbenes and styrylpyridines, the nanomolecules the Zn and Ru complexes of bipyridyl, and the receptors a variety of nitrogen heterocycles and organofluorine compounds. Several variations of these sensors where one or more constituents such as nanomolecule are absent have also been investigated. Both “switch on” and “switch off” sensors, namely those in which there is an increase in fluorescence and decrease in fluorescence respectively upon binding a target compound have been identified and characterized in terms of their mode of binding and equilibrium constants for association. Important results of these studies will be presented.