Understanding the Factors Affecting the Analytical Performance of Sandwich-hybridization Genosensors on Gold Electrodes

Hybridization-based electrochemical DNA sensors have become a methodological mainstay in a wide variety of fields. Among the possible assay formats, sandwich hybridization is the most powerful one. It is so called because the target sequence to be measured is hybridized between two complementary sequences. The analytical performance of this class of sensors is influenced by many construction and operational parameters, which need to be optimized. In this work, we comparatively analyze the analytical performance of different sandwich hybridization sensors, constructed on gold surfaces modified by chemisorption. We find that the structures of the designed probes as well as the topography of the gold support and the nature of the monolayer are key parameters affecting the sensitivity and reproducibility of the genosensors. Other important operational parameters are also described. The results of this study could serve as a guide in the design of genosensors for future applications.