CALIBRATION AND PROFILING OF A NANOPORE ARRAY DEVICE

Abstract

A method of calibrating a nanopore array device. The nanopore array device comprising: a common electrode, an array of sensing elements each comprising a sensing electrode and a nanopore channel, and an ionic solution in contact with the common electrode and the array of sensing electrodes, the ionic solution providing electrical communication between the common electrode and each of the array of sensing electrodes via the corresponding array of nanopore channels. The method comprises the steps of: applying a two or more test signals across the nanopore channels between the common electrode and array of sensing electrode measuring a corresponding current or voltage value associated with each sensing electrode for each test signal, determining an offset value for each sensing electrode from the measured current or voltage signals, and calculating a general offset value from the determined offset values, and applying a calibrated signal between the common electrode and sensing electrodes; wherein the calibrated signal is adjusted by the general offset value.

Description

Claims

1. A method of calibrating a nanopore array device, the nanopore array device comprising: a common electrode, an array of sensing elements each comprising a sensing electrode and a nanopore channel, and an ionic solution in contact with the common electrode and the array of sensing electrodes, the ionic solution providing electrical communication between the common electrode and each of the array of sensing electrodes via the corresponding array of nanopore channels;the method comprising: applying a two or more test signals across the nanopore channels between the common electrode and array of sensing electrodes;measuring a corresponding current or voltage value associated with each sensing electrode for each test signal,determining an offset value for each sensing electrode from the measured current or voltage signals, and calculating a general offset value from the determined offset values, andapplying a calibrated signal between the common electrode and sensing electrodes; wherein the calibrated signal is adjusted by the general offset value.

2. The method according to claim 1, wherein the calibrated signal is a voltage, the test signals are voltages, and the offset value is a voltage such that the corresponding measurements associated with each test signal is a measurement of current.

3. The method according to claim 1 or claim 2; wherein the sensing electrodes are divided into groups, and a general offset value is determined for each of the groups of sensing electrodes.

4. The method according to any one of claims 1 to 3, wherein a global offset value is determined across the entire array of sensing electrode.

5. The method according to any one of the previous claims, wherein the method includes an additional step of carrying out a linear regression to determine the offset value.

6. The method according to claim 5, wherein the method includes estimating a gradient value from the linear regression.

7. The method according to any one of the previous claims, wherein at least three test signals are applied across the common electrode to give three or more corresponding current or voltage measurements associated with each test signal.

8. A method according to any one of the previous claims, wherein the nanopore array device further comprises a redox mediator, and the sensing electrodes and common electrode are selected from an inert metal.

9. The method according to any one of the previous claims, wherein each sensing element in the array comprises a well which houses a corresponding sensing electrode, and each nanopore channel comprises a protein pore inserted in an amphiphilic membrane, the amphiphilic membrane extending across an opening of each of the wells.

10. The method according to any one of the previous claims, wherein the nanopore channel comprises a nanopore provided in a solid-state substrate.

11. The method according to any one of claims 2 to 10, further comprising the step of measuring ion current through a nanopore under the application of the calibrated voltage.

12. The method according to claim 11, wherein the ion current is measured to determine the interaction of an analyte of interest with a nanopore.

13. The method according to claim 12 where the analyte of interest is a polynucleotide and the measured ion current is due to translocation of the polynucleotide through a nanopore.

14. The method according to any one of claims 11 to 13, wherein the method is performed after the calibrated signal has been used for one or more successive periods of time, such that new offset values, a new general offset value and a new calibrated signal are calculated for each period of time.

15. The method according to claim 14 wherein a sensing electrode having an offset value falling outside of a threshold value is disconnected from the nanopore array device.

16. The method according to claim 14 or claim 15, wherein a sensing electrode is reconnected after a further period of time where it is determined that the new offset value for said sensing electrode falls within a new threshold value.

17. The method according to claim 15, wherein the offset value for a sensing electrode whose offset value is determined as being greater than the new threshold value is not used to calculate the general offset value.

18. The method according to any one of claims 1 to 13, wherein the offset value for a sensing electrode whose offset value is determined as being greater than a threshold value is not used to calculate the general offset value.

19. The method according to any one of the previous claims, wherein the test signals are applied below a limit value relative to the calibrated signal.

20. A method of profiling a nanopore array device, the nanopore array device comprising: a common electrode, an array of sensing elements each comprising a sensing electrode and a nanopore channel, and an ionic solution in contact with the common electrode and the array of sensing electrodes, the ionic solution providing electrical communication between the common electrode and each of the array of sensing electrodes via the corresponding array of nanopore channels;the method comprising: applying a two or more test signals across the nanopore channels between the common electrode and array of sensing electrodes;measuring a corresponding current or voltage value associated with each sensing electrode for each test signal,determining an offset value for each sensing electrode from the measured current or voltage signals, andreviewing the offset values to generate a profile for each sensing element.

21. The method according to claim 20, wherein the method further comprises the step of selecting sensing elements to receive a working signal based on their profile.

22. The method according to claim 21, wherein a working signal is applied to the selected sensing elements to generate a measurement.

23. The method according to any one of claims 20 to 22, wherein the nanopore array device further comprises a redox mediator in the ionic solution, and the working signal is applied to adjust the redox chemistry of the mediator.

24. The method according to any one of claims 20 to 23, wherein the method is performed after the nanopore array device has been in use for one or more successive periods of time, such that new offset values are determined, and a new profile for each sensing element is provided for each period of time.