Functionalized nanopipette biosensor

A device for specific detection of one or more analytes in a sample containing electrolyte, comprising:

• (a) a quartz or glass capillary nanopipette having a tip with a nanoscale opening between an interior of the nanopipette and an external area for contacting the sample, said nanopipette having a hollow structure defining an internal volume communicating with the sample and said nanoscale opening of between 10 and 100 nm in diameter and constructed so that ionic current may be detectibly reduced when the tip is blocked by specific binding of analyte in the sample to a peptide analyte binding molecule;
• (b) a peptide analyte binding molecule specifically binding to the analyte in the sample and chemically attached to said tip through a polymeric coating on the surface of the hollow structure;
• (c) a first electrode, arranged to be in contact with electrolyte in the interior of the nanopipette, and further arranged to be connected to an amplifier input in a current detecting circuit configured to provide a predetermined alternating signal and to detect both positive and negative ionic currents;
• and
• (d) a second electrode, arranged to be in contact with the electrolyte, exterior of the nanopipette, and further arranged for connection to the current detecting circuit, whereby electrolyte in the interior of the nanopipette and electrolyte in a bath permits ionic current to flow between the electrodes and through the nanoscale opening in the tip;
• (e) a second quartz or glass capillary nanopipette having a tip with a nanoscale opening between an interior of the nanopipette and an external area for contacting the sample, said nanopipette having a hollow structure defining an internal volume communicating with the sample and said tip having chemically attached thereto a second peptide analyte binding molecule chemically attached to said tip through a polymeric coating on the surface of the hollow structure,
• wherein said nanoscale opening is constructed so that ionic current may be detectibly reduced when the tip is blocked by specific binding of a second analyte in the sample to the peptide analyte binding molecule;
• and
• (f) a third electrode, arranged to be in contact with electrolyte in the interior of the second capillary nanopipette, and further arranged to be connected to an amplifier input in a current and said current detecting circuit.