Label-free DNA detection using the narrow side of funnel-type etchednanopores

A sensitive; simple and label-free method for DNA detection is presented. Irradiated polyethylene terephthalate foils were etched to present conical tracks at a density of approximately 5×107 tracks per cm2. Probe DNA was immobilized at the narrow opening of the tracks (2–4 nm diameter). The presence of target DNA resulted in changes in both conductance and rectification ratios in a concentration-dependent manner. DNA concentrations as low as 2 nM could be detected using this simple two-step detection scheme.

► Label-free DNA sensing using etched irradiated PET membrane.
► Conductance increases as DNA concentration increases.
► Rectification ratio increases as DNA concentration increases.
► DNA sensing is performed on the tip of thepore.