Multiplex microarray ELISA versus classical ELISA, a comparison study of pollutant sensing for environmental analysis.

The present study describes the development, optimization and performance comparison of three ELISAs and one multiplex immunoassay in a microarray format. The developed systems were dedicated to the detection of three different classes of pollutants (pesticide, explosive and toxin) in water. The characteristics and performances of these two types of assays were evaluated and compared, in order to verify that multiplex immunoassays can replace ELISA for multiple analyte sensing. 2,4-Dichlorophenoxyacetic acid, 2,4,6-trinitrotoluene and okadaic acid were chosen as model targets and were immobilized in classical microtiter plate wells or arrayed at the surface of a microarray integrated within a classical 96-well plate. Once optimized, the classical ELISAs and microarray-based ELISA performances were evaluated and compared in terms of limit of detection, IC50, linearity range and reproducibility. Classical ELISAs provided quite good sensitivity (limit of detection down to 10 μg L(-1)), but the multiplex immunoassay was proven to be more sensitive (limit of detection down to 0.01 μg L(-1)), more reproducible and an advantageous tool in terms of cost and time expenses. This multiplex tool was then used for the successful detection of the three target molecules in spiked water samples and achieved very promising recovery rates.