Process and Device for Emulating a Counter-Electrode in a Monolithically Integrated Electrochemical Analysis System

• US 20080073225A1
• Filed: 06/29/2005
• Published: 03/27/2008
• Est. Priority Date: 06/29/2004
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Paulus, Christian
• Granted Patent: US 8,617,382 B2
• Time in Patent Office: Days
• US Class Current: 205/792
• CPC Class Codes: G01N 27/3277 being a redox reaction, e.g. detection by cyclic voltammetry voltammetry per se G01N27/42, G01N27/48
• CPC Class Codes: G01N 33/5438 Electrodes

Abstract

A sensor array with at least three electrodes and a switching unit is disclosed, as well as a process for operating such a sensor array for implementing an electrochemical analysis process. The at least three electrodes can be selectively switched as counter-electrodes or as a working electrode which can be electrically coupled to an electrolytic analyte. The at least three electrodes are set up in such a way that sensor events occur at an electrode switched as working electrode in the electrolyte solution, in the presence of the electrolytic analyte. The electrodes which are not required as working electrodes at a particular point in time for detecting the electrolytic analyte can thus be switched together to form the counter-electrode of the sensor array, thus dispensing with the need for a separate counter-electrode.

Claims

1. A sensor array which is monolithically integrated at least one of in and on a substrate, comprising:

at least three electrodes, designed as biosensor arrangements for detection of biomolecules; and

a switching unit, designed such that at least one of the at least three electrodes is selectively connected as a working electrode, which is coupled to an electrolytic analyte, the other electrodes of the at least three electrodes being connected as an opposing electrode, wherein the at least three electrodes are designed such that sensor events take place at the one electrode, connected as a working electrode, of the at least three electrodes in the electrolyte solution when in the presence of the electrolytic analyte.

2. The sensor array as claimed in claim 1, wherein the switching unit has at least one MOS transistor, which is provided within the sensor array.

3. The sensor array as claimed in claim 1, wherein the switching unit is provided outside the sensor array, and the operating circuit for the at least two electrodes which are connected as a common opposing electrode in the sensor array is driven such that the electrode potential follows the potential at the opposing electrode connection of a potentiostat.

4. The sensor array as claimed in claim 1, further comprising a control circuit to at least one of drive, select and read at least one of the at least three electrodes.

5. The sensor array as claimed in claim 1, wherein the sensor array includes 50 to 1 000 000 electrodes.

6. The sensor array as claimed in claim 1, wherein the plurality of at least three electrodes are designed for detection of substances which are at least one of oxidizable and reducible.

7. The sensor array as claimed in claim 1, wherein the sensor array is designed for detection of at least one of nucleic acid molecules, peptides and proteins.

8. The sensor array as claimed in claim 1, wherein capture molecules are immobilized on the surface of the electrodes.

9. The sensor array as claimed in claim 1, wherein the sensor array is designed such that a sensor signal is generatable via electrochemically active markings in the presence of an electrolytic analyte.

10. The sensor array as claimed in claim 9, wherein the electrochemically active markings have metal complex markings.

11. The sensor array as claimed in claim 9, wherein the electrochemically active markings have ferrocene markings.

20. The sensor array as claimed in claim 10, wherein the electrochemically active markings have ferrocene markings.

12. A method for operation of a sensor array which is monolithically integrated at least one of in and on a substrate in an electrochemical analysis method, wherein the sensor array includes at least three electrodes, the majority of the at least three electrodes being designed as biosensor arrangements for detection of biomolecules, and includes a switching unit designed such that at least one of the at least three electrodes is selectively connected as a working electrode and the other electrodes of the at least three electrodes are connected as an opposing electrodes, and wherein the at least three electrodes are designed such that sensor events take place at one electrode, connected as the working electrode, of the at least three electrodes in the electrolyte solution when in the presence of the electrolytic analyte, the method comprising:

(a) connecting at least two electrodes, of the at least three electrodes, to the opposing electrode connection of a potentiostat, thus providing the opposing electrode of the sensor array;

(b) connecting at least one electrode of the at least three electrodes, as a working electrode for detection of an electrolytic analyte;

(c) connecting, after detection of the electrolytic analyte at the working electrodes in (b), at least one electrode of the at least three electrodes electrode for detection of an electrolytic analyte;

(d) connecting at least one electrode of the at least three electrodes according to (a) as an opposing electrode; and

(e) repeating steps (a) to (d) as often as required.

13. A method for operation of a sensor array in an electrochemical analysis method as claimed in claim 12, wherein the total surface area of the electrodes which are connected as opposing electrodes is at least ten times as large as the total surface area of the electrodes which are connected as working electrodes.

14. A method for operation of a sensor array in an electrochemical analysis method as claimed in claim 12, wherein at least one substance in an electrolyte is determined at least one of qualitatively and quantitatively on the basis of at least one of its characteristic oxidation and its characteristic reduction voltage via at least one of voltammetry, amperometry and coulometry.

15. The method for operation of a sensor array in an electrochemical analysis method as claimed in claim 12, wherein ferrocene-marked capture molecules are immobilized on the electrodes in order to analyze biomolecules, and the concentration of the biomolecules is determined by measurement of the amount of charge flowing during oxidation of the ferrocene.

16. The method for operation of a sensor array in an electrochemical analysis method as claimed in claim 12, wherein an external opposing electrode is additionally used in order to improve the time response of the overall system.

17. The method for operation of a sensor array in an electrochemical analysis method as claimed in claim 12, wherein the operating circuit of a working electrode is deactivated by use of a switching unit, for connection as an opposing electrodes.

21. A method for operation of a sensor array in an electrochemical analysis method as claimed in claim 13, wherein at least one substance in an electrolyte is determined at least one of qualitatively and quantitatively on the basis of at least one of its characteristic oxidation and its characteristic reduction voltage via at least one of voltammetry, amperometry and coulometry.

18. (canceled)

19. (canceled)