A mechanism is provided for fabricating nanochannels for a nanodevice. Insulating film is deposited on a substrate. A nanowire is patterned on the film. Insulating material is deposited on the nanowire and film. A first circular hole is formed in the insulating material as an inlet, over a first tip of the nanowire to expose the first tip. A second circular hole is formed as an outlet, over a second tip of the nanowire opposite the first tip to expose the second tip. A nanochannel connects the first and second holes by etching away the nanowire via an etchant in the first and the second holes. A first reservoir is attached over the first hole in connection with the nanochannel at a previous location of the first tip. A second reservoir is attached over the second hole in connection with the nanochannel at a previous location of the second tip.