Apparatuses and methods for determining analyte charge

A system for detecting a charged analyte, comprising:

• a fluidic chamber comprising first and second portions and a membrane separate from and between the first and second portions, wherein the membrane comprises a pore suitable for (i) flow of an electrolyte between the first and second portions of the fluidic chamber and (ii) flow of at least one charged analyte tethered in proximity to the pore into the pore;
• first and second bias electrodes disposed in the first and second portions of the fluidic chamber, respectively;
• a first circuit connected to the first and second bias electrodes and configured to apply an electric field capable of causing the electrolyte to pass through the pore and further causing the at least one charged analyte that is tethered in proximity to the pore to be pulled into the pore, wherein the electric field has a strength of at least 105 Volts per meter;
• and
• a second circuit configured to measure a signal indicative of a charge or change in charge of the at least one charged analyte upon the at least one charged analyte being pulled into the pore while remaining tethered in proximity to the pore;
• wherein measuring the signal indicative of the change in charge includes:
• (i) measurement of a reference charge while the at least one charged analyte is pulled into the pore while remaining tethered in proximity to the pore, (ii) incorporation of a nucleotide that is complimentary to a nucleic acid molecule to be sequenced, (iii) sensing a changed charge after incorporation of the complimentary nucleotide while the at least one charged analyte is pulled into the pore while remaining tethered in proximity to the pore, and (iv) comparing the changed charge to the reference charge,
• wherein the at least one charged analyte is tethered in proximity to the pore via a covalent bond,
• wherein the membrane is a solid state membrane, and the at least one charged analyte is tethered via the covalent bond to an exterior surface of the solid state membrane, and
• wherein the membrane and a wall of the pore are surrounded by an electrical double layer (EDL), and wherein the electric field having the strength of at least 105 Volts per meter de-screens the EDL.