Controlled translocation of a polymer in an electrolytic sensing system

A method of sequencing a polymer in an electrolytic sensing system comprising a first fluid chamber containing a first electrolyte;

• a second fluid chamber containing a second electrolyte;
• a barrier having a channel therein and defining a narrow measurement region, said barrier separating the first and second fluid chambers;
• a DC source adapted to apply a substantially constant electric field across the measurement region via electrodes in electrical contact with respective first and second fluid chambers;
• an AC source adapted to apply an oscillating electrical parameter across the measurement region via an electrode in electrical contact with one of the respective first and second fluid chambers;
• and a sensor, the method comprising:
• introducing a polymer to the first fluid chamber;
• applying a substantially constant electric field across the channel utilizing said DC source to provide a translocation force to the polymer;
• applying an oscillating electrical parameter across the channel utilizing said AC source;
• measuring the oscillating electrical parameter to detect a blocking signal when the polymer is within the channel;
• and
• filtering and demodulating the blocking signal to generate a measured signal indicative of a particular monomer or set of monomers of the polymer.