Biological identification system with integrated sensor chip

• US 20020123048A1
• Filed: 05/03/2001
• Published: 09/05/2002
• Est. Priority Date: 05/03/2000
• Status: Active Grant

• Current Assignee: Department of Health and Human Services (State of Victoria)
• Original Assignee: GeneFluidics, Inc.
• Inventors: Gau, Vincent Jen-Jr.
• Granted Patent: US 7,399,585 B2
• Time in Patent Office: Days
• US Class Current: 435/6
• CPC Class Codes: B01J 2219/00317 Microwell devices, i.e. having large numbers of wells
• CPC Class Codes: B01J 2219/00497 Features relating to the solid phase supports
• CPC Class Codes: B01J 2219/00585 Parallel processes
• CPC Class Codes: B01J 2219/00596 Solid-phase processes
• CPC Class Codes: B01J 2219/00605 the compounds being directly bound or immobilised to solid supports
• CPC Class Codes: B01J 2219/0061 The surface being organic
• CPC Class Codes: B01J 2219/00612 the surface being inorganic
• CPC Class Codes: B01J 2219/00617 by chemical means
• CPC Class Codes: B01J 2219/00619 using hydrophilic or hydrophobic regions
• CPC Class Codes: B01J 2219/00621 by physical means, e.g. trenches, raised areas
• CPC Class Codes: B01J 2219/0063 Other, e.g. van der Waals forces, hydrogen bonding
• CPC Class Codes: B01J 2219/00637 by coating it with another layer
• CPC Class Codes: B01J 2219/00653 the compounds being bound to electrodes embedded in or on the solid supports
• CPC Class Codes: B01J 2219/00659 Two-dimensional arrays
• CPC Class Codes: B01J 2219/00702 Processes involving means for analysing and characterising the products
• CPC Class Codes: B01J 2219/00722 Nucleotides
• CPC Class Codes: B01J 2219/00725 Peptides
• CPC Class Codes: B01L 3/5088 confining liquids at a location by surface tension, e.g. virtual wells on plates, wires B01L3/50857 takes precedence
• CPC Class Codes: B81C 2201/0133 Wet etching
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C12Q 1/68 : involving nucleic acids
• CPC Class Codes: C12Q 1/6876 : Nucleic acid products used in the analysis of nucleic acids, e.g. primers or probes
• CPC Class Codes: C12Q 2600/156 : Polymorphic or mutational markers
• CPC Class Codes: C40B 40/06 : Libraries containing nucleotides or polynucleotides, or derivatives thereof
• CPC Class Codes: C40B 40/10 : Libraries containing peptides or polypeptides, or derivatives thereof
• CPC Class Codes: C40B 60/14 : for creating libraries
• CPC Class Codes: G01N 27/3277 : being a redox reaction, e.g. detection by cyclic voltammetry voltammetry per se G01N27/42, G01N27/48

Abstract

A microelectromechanical systems (MEMS) and integrated circuit (IC) based biosensor capable of sensing or detecting various ionic molecules and macromelecules (DNA, RNA or protein). The MEMS based biosensor may utilize a hybridization and enzyme amplification scheme and an electrochemical detection scheme for sensitivity improvement and system miniaturization. The biosensor or biosensors are incorporated on a single substrate. Preferably, the biosensor system comprises at least two electrodes. The electrodes may comprise a working electrode, a reference electrode and a counter (auxiliary) electrode. The biosensor or biosensors also provide an apparatus and method for confinement of reagent and/or solution in the biosensor or biosensors using surface tension at small scale. The confinement system provides controlled contacts between the reagent(s) and/or solution(s) with the components (i.e., electrodes) of the biosensor or biosensors using controllable surface properties and surface tension forces. The confinement system allows for incorporation of the biosensor or biosensors into a portable or handheld device and is immune to shaking and/or flipping. The invention also provide for a biosensor and/or sensors that are integrated with integrated circuit (IC) technologies. Preferably, the entire sensor system or systems are fabricated on a single IC substrate or chip and no external component and/or instrument is required for a complete detection system or systems. Preferably, the sensor system or systems are fabricated using the IC process and on a silicon substrate.

Claims

1. A method of detecting the presence or measuring the quantity of a target analyte in a sample reagent comprising the steps of:

contacting a microfabricated electrochemical biosensor with the sample reagent, the microfabricated electrochemical biosensor comprising;

(a) a substrate; and

(b) at least two electrically conductive electrodes fabricated on the substrate by integrated circuit technology, each of the electrical conductive electrodes consisting of a single layer of an electrically conductive material;

containing the sample reagent in contact with the conducting electrodes;

measuring a electrical signal output from the microfabricated electrochemical biosensor; and

determining from the signal output the presence and/or quantity of the target analyte in the sample reagent.

2. The method of claim 1 wherein the electrochemical biosensor further comprises an adhesive underneath each of the electrodes, the adhesive allowing for better adhesion of each of the electrodes to the substrate.

3. The method of claim 2 wherein the sample reagent is a biological fluid containing macromolecules.

4. The method of claim 2 wherein the sample reagent is a biological fluid containing ionic molecules or atoms.

5. The method of claim 2 wherein the substrate is selected from the group consisting of silicon, gallium arsenide, plastic and glass.

6. The method of claim 2 wherein the substrate comprises a material made out of silicon.

7. The method of claim 2 wherein the electrically conductive material is selected from the group consisting of gold, aluminum, chromium, copper, platinum, titanium, nickel and titanium.

8. The method of claim 2 wherein the electrically conductive material is gold.

9. The method of claim 2 wherein the adhesive is selected from the group of consisting of chromium, titanium, and glue.

10. The method of claim 2 wherein the adhesive comprises chromium.

11. The method of claim 2 wherein the substrate further comprises a well structure containing at least one of the electrodes.

12. The method of claim 2 wherein the electrochemical biosensor comprises at least three electrically conductive electrodes.

13. The method of claim 12 wherein each of the electrically conductive electrodes consists of a single layer of gold.

14. The method of claim 2 wherein the step of determining from the signal output the presence and/or quantity of the target analyte in the reagent further comprises the steps of:

calibrating the electrochemical biosensor with a first calibrating solution that contains a known amount of the target analyte to be detected and a second calibrating solution that contains an undetectable amount of the target analyte to be detected;

obtaining a reference signal output; and

comparing the reference signal with the measured signal to determine the presence and/or quantity of the molecules in the sample reagent.

15. The method of claim 14 wherein the substrate is selected from the group consisting of silicon, gallium arsenide, plastic and glass.

16. The method of claim 14 wherein the electrically conductive material is selected from the group consisting of gold, aluminum, chromium, copper, platinum, nickel and titanium.

17. The method of claim 14 wherein the electrically conductive material is gold.

18. The method of claim 14 wherein the adhesive is selected from the group of material consisting of chromium, titanium, and glue.

19. The method of claim 14 wherein the substrate further comprises a well structure underneath at least one of the electrodes.

20. The method of claim 14 wherein a surface on at least one of the electrodes is surface modified for anchoring macromolecules on the surface.

21. A method of detecting the presence or measuring the quantity of at least one molecule in a sample reagent comprising the steps of:

contacting a microfabricated electrochemical biosensor with the sample reagent, the microfabricated electrochemical biosensor comprising;

(a) a silicon substrate; and

(b) three electrically conductive electrodes fabricated on the substrate by integrated circuit technology, each of the electrically conductive electrodes consisting of a single layer of gold;

containing the sample reagent in contact with the conducting electrodes;

measuring a signal output from the microfabricated electrochemical biosensor; and

determining from the signal output the presence and/or quantity of the molecules in the sample reagent.

22. A microfabricated electrochemical biosensor comprising:

a silicon substrate; and

three electrical conductive electrodes for redox sensing fabricated on the substrate by integrated circuit technology, each of the electrical conductive electrodes consisting of a single layer of gold.

24. The method of claim 23 wherein the components comprise at least one electrode selected from the group consisting of a counter electrode and a reference electrode.

25. The method of claim 23 wherein at least one reagent comprises a first reagent and a second reagent.

26. The method of claim 25 wherein the step of applying reagent to the biosensor comprises the steps of:

covering the first reagent over the first area; and

covering the second reagent over the second area.

27. The method of claim 26 wherein the first area is shaped in a first geometry that is designed to confine the first reagent within the first area.

28. The method of claim 27 wherein the second area is shaped in a second geometry that is designed to confine the second reagent with the second area.

29. The method of claim 25 wherein the first reagent is a biological fluid containing the target analyte and the second reagent is a chemical solution suitable for biological detection of the target analyte.

30. The method of claim 23 wherein the target analyte is selected from the group consisting of ionic molecule and macromolecule.

31. The method of claim 23 wherein the step of detecting the presence and/or quantity of the target analyte further comprises:

calibrating the biosensor with a first calibrating solution that contains a known amount of the analyte to be detected and a second calibrating solution that contains an undetectable amount of the analyte to be detected; and

utilizing the calibration results to detect the presence a quantity of target analyte in the reagent.

32. The method of claim 23 wherein the surface properties of the first and second areas are surface modified before application of reagent to the biosensor.

33. The method of claim 23 wherein the surface properties of the first and second areas are controlled by an external force field.

35. The device of claim 34 wherein the electrically conductive electrodes are selected from the group of materials consisting of gold, aluminum, chromium, copper, platinum, nickel and titanium.

36. The device of claim 34 wherein the electrically conductive electrodes are made out of gold.

37. The device of claim 34 wherein the semiconductor is selected from the group consisting of silicon and gallium arsenide.

38. The device of claim 34 wherein the semiconductor is silicon.

39. The device of claim 34 wherein the detection circuit comprises a current measurement device to detect a current signal from the redox event through a corresponding electrically connected electrode.

40. The device of claim 39 wherein the bias potential is a potential difference between at least two different electrodes to enable electron transfer for current detection.

23. A method of detection of a target analyte comprising the steps of:

providing a biosensor and at least one reagent, the biosensor comprising;

(a) a first area having a first surface property for immobilizing the target analyte contained in the reagent; and

(b) a second area having a second surface property different from the first surface property so that a sample of the reagent can be confined due to surface tension forces between the first area and the second area, the second area comprising components for detection of the target analyte;

applying a volume of reagent to the biosensor, wherein the coverage of the reagent over the biosensor is controlled by the volume of the reagent and the surface tension forces; and

detecting a presence and/or measuring a quantity of the target analyte by the biosensor.

34. A device for detecting a redox event of at least one analyte in a liquid reagent comprising:

a redox sensor fabricated on a semiconductor by using at least one of integrated circuit (IC) and micro electromechanical systems (MEMS) technology, the redox sensor includes at least two electrically conductive electrodes for signal output and bias control;

an isolation layer between the electrodes and the semiconductor;

an integrated circuit (IC) on the semiconductor and underneath the isolation layer, the integrated circuit comprising a detection circuit and a bias potential circuit for providing a bias potential to the detection circuit; and

wherein the isolation layer has a electrically conductive contact portion for electrically connecting the electrodes with the integrated circuit (IC).

41. A device for detecting a redox event of at least one analyte in a liquid reagent comprising:

a redox sensor on a semiconductor, the redox sensor comprising a reference electrode, a working electrode and a counter electrode;

an isolation layer between the redox sensor and the semiconductor;

an integrated circuit (IC) on the semiconductor and underneath the isolation layer, the integrated circuit comprising a detection circuit and a bias potential circuit for providing a bias potential to the detection circuit; and

wherein the isolation layer has a electrically conductive contact portion for electrically connecting the electrodes with the integrated circuit (IC).

42. The device of claim 41 wherein each of the electrodes consists of a single layer of electrically conductive material.

43. The device of claim 42 wherein the electrically conductive material is gold.

44. The device of claim 43 wherein the semiconductor is silicon.

45. The device of claim 44 wherein the detection circuit comprises a current measurement device to detect a current signal from the redox event through a corresponding electrically conductive electrode.

46. The device of claim 45 wherein the bias potential is a potential difference between at least two different electrodes to enable electron transfer for current detection.

47. The device of claim 41 wherein the semiconductor is selected from the group consisting of silicon and gallium arsenide.

48. The device of claim 41 wherein the semiconductor is silicon.

49. The device of claim 41 wherein the detection circuit comprises a current measurement device to detect a current signal from the redox event through a corresponding electrically conductive electrode.

50. The device of claim 49 wherein the bias potential is a potential difference between at least two different electrodes to enable electron transfer for current detection.