Evaporation-enhanced impedance sensing for highly-sensitive differentiation of dsDNA from ssDNA

In this paper, we adopt a radically different approach to beat the diffusion limit through time-dependent evaporation of microliter-sized droplets (containing DNA molecules) pinned onto an array of electroplated nickel electrodes, and thereby achieve highly sensitive, statistically-robust, label-free, non-faradaic impedance-based differentiation of ssDNA vs. dsDNA at femtomolar (~fM) concentration. The proposed approach is ideally suited for integration in a portable, array format, and could be used in real-time point-of-care applications for which highly sensitive, yet selective detection of DNA hybridization is desired.