Device and method for detecting redox reactions in solution

1. A device comprising:

a plurality of first reaction electrodes arranged in an array, the plurality of first reaction electrodes configured to be exposed to a solution and having a capacitance;

first circuitry configured to set a DC voltage on the plurality of first reaction electrodes, and configured to charge or discharge the capacitance through a redox reaction occurring at the plurality of first reaction electrodes; and

second circuitry configured to measure a rate of charging or discharging of the capacitance of the plurality of first reaction electrodes.

2. The device of claim 1 , wherein the second circuitry is configured to measure the rate of charging or discharging of the capacitance by measuring a voltage of the plurality of first reaction electrodes as a function of time.

3. The device of claim 1 , wherein the second circuitry is configured to measure the rate of charging or discharging of the capacitance by measuring an amount of voltage change from a voltage of the bias source at a time point.

4. The device of claim 1 , wherein the second circuitry is configured to measure the rate of charging or discharging of the capacitance by measuring an amount of time for a voltage of the plurality of first reaction electrodes to change from a voltage of the bias source by a predetermined amount.

5. A device comprising:

a plurality of first reaction electrodes arranged in an array, the plurality of first reaction electrodes configured to be exposed to a solution and having a capacitance;

first circuitry configured to controllably connect the plurality of first reaction electrodes to a bias source and controllably disconnect the plurality of first reaction electrodes from the bias source; and

second circuitry configured to measure a rate of charging or discharging of the capacitance of the plurality of first reaction electrodes.

6. The device of claim 5 , wherein the capacitance includes self-capacitance of the plurality of first reaction electrodes and capacitance of interfaces between the plurality of first reaction electrodes and the solution.

7. The device of claim 5 , wherein the charging or discharging of the capacitance is caused by redox reactions in the solution.

8. The device of claim 5 , further comprising a reference electrode with a fixed reduction potential to the solution.

9. The device of claim 8 , wherein the reference electrode is selected from the group consisting of standard hydrogen electrode (SHE), normal hydrogen electrode (NHE), reversible hydrogen electrode (RHE), saturated calomel electrode (SCE), copper-copper(II) sulfate electrode (CSE), silver-silver chloride (Ag/AgCI) electrode, silver pseudoreference electrode, and quasi-reference (QRE).

10. The device of claim 8 , further comprising a second reaction electrode configured to be electrically biased relative to the solution.

11. The device of claim 10 , wherein the second reaction electrode is not consumed.

12. The device of claim 10 , wherein the first reaction electrodes and/or the second reaction electrodes are coated with an organic or inorganic coating.

13. The device of claim 10 , wherein the first reaction electrodes are selected from the group consisting of platinum, gold, indium tin oxide, diamond-like carbon doped with impurities, glassy carbon, silver, carbon nanotube, graphene, and conducting polymers; and/or

wherein the second reaction electrodes are selected from the group consisting of platinum, gold, indium tin oxide, diamond-like carbon doped with impurities, glassy carbon, silver, carbon nanotube, graphene, and conducting polymers.

14. The device of claim 5 , wherein the plurality of first reaction electrodes are a material that is not consumed by the solution.

15. The device of claim 5 , wherein the first circuitry comprises a switch.

16. The device of claim 5 , wherein the second circuitry is configured to measure the rate of charging or discharging of the capacitance by measuring a voltage of the plurality of first reaction electrodes as a function of time.

17. The device of claim 16 , wherein the second circuitry is configured to measure the voltage of the plurality of first reaction electrodes without discharging the capacitance.

18. The device of claim 5 , wherein the second circuitry is configured to measure the rate of charging or discharging of the capacitance by measuring an amount of voltage change from a voltage of the bias source at a time point.

19. The device of claim 5 , wherein the second circuitry is configured to measure the rate of charging or discharging of the capacitance by measuring an amount of time for a voltage of the plurality of first reaction electrodes to change from a voltage of the bias source by a predetermined amount.

20. The device of claim 5 , wherein the device is a microchip.

21. The device of claim 5 , wherein the second circuitry comprises a memory.

22. The device of claim 5 , further comprising a multiplexer and a controller.

23. The device of claim 5 , further comprising at least one second reaction electrode in vicinity of at least one of the plurality of first reaction electrodes.

24. The device of claim 5 , wherein a geometric area of each of the first reaction electrodes is between 0.01 μm2 and 100 μm2.

25. The device of claim 5 , where the plurality of first reaction electrodes comprises between 100 and 10,000,000,000 first reaction electrodes; and the first circuitry comprises a plurality of measurement circuits, each of which corresponding to one of the plurality of first reaction electrodes.

26. The device of claim 5 , wherein the second circuitry is shared among more than one first electrodes in the plurality of first electrodes.