Electrochemiluminescence DNA sensor array for multiplex detection of biowarfare agents

Development of a fully automated electrochemiluminescence (ECL) DNA assay for multiplex detection of six biowarfare agents is described. Aminated-DNA capture probes were covalently immobilised on activated-carbon electrodes and subsequently hybridised to target strands. Detection was achieved via a sandwich-type assay after Ru(bpy)<inf>3</inf>2+-labelled reporter probes were hybridised to the formed probetarget complexes. The assay was performed in an automated microsystem in a custom-designed ECL detection box with integrated fluidics, electronics, and movable photomultiplier detector. The obtained limits of detection were 0.61.2 nmol L1 for six targets ranging from 50 to 122 base pairs in size, with linear range 115 nmol L1. Non-specific adsorption and cross-reactivity were very low. Detection of six targets on a single chip was achieved with subnanomolar detection limits.