Impact of immobilization support on colorimetric microarrays performances.

We report here a comparison of support materials for colorimetric hybridization assays on microarrays. Four surfaces with various chemistries and architectures (roughness and porosity) were evaluated: (i) bare and (ii) activated polystyrene surfaces classically used for ELISA; (iii) a double-sided adhesive support; and (iv) a porous nitrocellulose/cellulose acetate membrane. Each substrate was functionalized with a microarray of probes and subjected to an enzymatic colorimetric DNA hybridization test. Tests were carried out in a 96-well assembly suitable for automated high-throughput analysis. Colorimetry results, microscopy observations and a chemiluminescence study showed that the test efficiency not only depends on the surface probe density but that the capacity of the material to retain the colored enzymatic product is also a critical parameter. All parameters being considered, the adhesive coated surface proposes the best surface properties for efficient colorimetric microarrays.