A very simple sensing device based on biomimetic nanochannels has been developed for label-free,ultrasensitive and highly sequence-specific detection of DNA.Probe DNA was modified on the inner wall of the nanochannel surface by layer-by-layer(LBL)assembly.After probe DNA immobilization,DNA detection was realized by monitoring the rectified ion current when hybridization occurred.Due to three dimensional(3D)nanoscale environment of the nanochannel,this special geometry dramatically increased the surface area of the nanochannel for immobilization of probe molecules on the inner-surface and enlarged contact area between probes and target-molecules.