A DNA programable electrochemical sensor for the direct detection of proteins

There is a need for the sensitive and selective detection of proteins and antibodies for diagnosis of various disease. Currently multi-step procedures that are of high cost and with slow response times are employed. We overcome these limitations using the chemistry and programmability of DNA. To achieve a responding capability of DNA nanostructure its modification with two recognition elements that include two redox tag molecules and a thiol group is achieved. The designed Y-shaped DNA “scaffold” nanostructure mimics the shape and the conformational variability of IgG bivalent antibodies. We exploit the formation of a bulky target-receptor complex that reduces the collisional dynamics of the Y-shaped DNA nanostructure producing a decrease in the current which in turn is related to the concentration of the biomarker to be analysed. This sensing platform was used to detect in a quantitative way two bivalent antibody targets and one multivalent protein target. To perform the measurement, there is no need for washing or incubation and the developed device can be further integrated to mobile phones or standalone setups offering a more efficient tool for future diagnostics.