A nanopore is a small pore in an electrically insulating membrane, that can be used as a molecular probe. It can be a biological protein channel in a lipid bilayer or a pore in a solid-state membrane. Possible applications include rapid DNA sequencing, separation of single stranded and double stranded DNA in solution, determination of length of polymers and separation of polymers by length. The size of the nanopore must be made to be just a little larger than the molecule which is to be detected, a molecule entering the nanopore will change its electrical properties in ways which can be measured. To make measurements with a nanopore, polymers and electrolytes in solution are applied a voltage, i.e. there are electrodes on each side of the membrane with the nanopore.

Solid-state nanopores are generally made in silicon compound membranes, one of the most common being Si3N4. Solid-state nanopores can be manufactured with several techniques including ion-beam sculpting and electron beams.