Abstract

Multiplexed Assays for Diagnostics and Environment

Loic Blum, Director, Universite Lyon 1

A multiplexed blood group genotyping system based on a classical 96-well plate with up to 200 spots per well was first developed associated with a colorimetric detection. An innovative immobilization process of biological elements on standard polymeric adhesive supports applicable to 96-, 384- and 1536-well micro-plates has been developed. This technology was successfully transferred to protein immobilization for multiplex allergy diagnosis. For that purpose, crude allergen extracts and recombinant proteins (birch tree pollen, hazelnut, cherry, apple) were arrayed for the detection of allergen-specific IgE in crude human sera. Another application concerns the simultaneous detection of five water pollutants (okadaic acid; atrazine; 2.4-dichlorophenoxyacetic acid; 2,4,6-trinitrotoluene and 1,3,5-trinitroperhydro-1,3,5-triazine). Using a double role membrane for both bioprobe immobilization and reaction media filtering, tumor-associated antigens microarrays were also designed to detect auto-antibodies directly in patient sera. For that application, 12 different probes were selected according to their occurrence in cancer pathologies. Finally, using also a 96-well format but with a different support incorporating 96 screen-printed carbon electrodes, an electrochemical method for the multiplexed monitoring of redox enzymatic reactions was developed allowing the screening of oxidoreductase activities as well as the screening of grafted or soluble redox mediators. The method is usable for both direct and indirect electron transfer reactions in bioelectronic interfaces.