A Comparison of DNA–DNA Hybridization Kinetics in Complex Media on Planar and Nanostructured Electrodes

A comprehensive investigation into how nanostructures alter real-time DNA hybridization kinetics in both buffer and complex media and under a wide range of probe and target concentrations is currently lacking. In response, we use a real-time, wash-free, and <i>in situ</i> assay to study DNA hybridization kinetics by performing continuous electrochemical measurements in different media. We investigated the differences in hybridization kinetics under three regimes of probe density (low, medium, and high) and over three orders of magnitude of target concentrations (0.01-1 μM). Additionally, we compared the performance of planar and nanostructured electrodes in buffer, blood, urine, and saliva. Our experiments indicate that adding nanostructures to the transducer surface is only effective under a specific probe/target concentration regime. Additionally, we found that direct electrochemical readout is possible in the examined physiological media, with measurements in blood showing the highest and saliva showing the lowest signal magnitudes compared to buffer.