High-throughput multiplexed competitive immunoassay for pollutants sensing in water.

The present study described the development and evaluation of a new fully automated multiplex competitive immunoassay enabling the simultaneous detection of five water pollutants (okadaic acid (OA), 2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine (atrazine), 2.4-dichlorophenoxyacetic acid (2,4-D), 2,4,6-trinitrotoluene (TNT), and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX)). The technology is taking advantage of an optical-clear pressure-sensitive adhesive on which biomolecules can be immobilized and that can be integrated within a classical 96-well format. The optimization of the microarray composition and cross-reaction was performed using an original approach where probe molecules (haptens) were conjugated to different carriers such as protein (bovine serum albumin or ovalbumin), amino-functionalized latex beads, or dextran polymer and arrayed at the surface of the adhesive. A total of 17 different probes were then arrayed together with controls on the adhesive surface and screened toward their specific reactivity and cross-reactivity. Once optimized, the complete setup was used for the detection of the five target molecules (less than 3 h for 96 samples). Limits of detection of 0.02, 0.01, 0.01, 100, and 0.02 μg L(-1) were found for OA, atrazine, 2,4-D, TNT, and RDX, respectively. The proof of concept of the multiplex competitive detection (semiquantitative or qualitative) of the five pollutants was also demonstrated on 16 spiked samples.