VERSATILE AND SENSITIVE BIOSENSOR

• US 20140342359A1
• Filed: 11/21/2012
• Published: 11/20/2014
• Est. Priority Date: 11/23/2011
• Status: Abandoned Application

• Current Assignee: The Governing Council of the University of Toronto (University of Toronto)
• Original Assignee: The Governing Council of the University of Toronto (University of Toronto)
• Inventors: Kelley, Shana O., Sargent, Edward Hartley, Das, Jagotamoy, Zaragoza, Alexandre, Cederquist, Kristin
• Application Number:
  US14/360,528
• Publication Number:
  US 20140342359A1
• Time in Patent Office: Days
• US Class Current: 435/6.11
• CPC Class Codes: C12Q 1/6818 involving interaction of two or more labels, e.g. resonant energy transfer
• CPC Class Codes: C12Q 1/6825 Nucleic acid detection involving sensors
• CPC Class Codes: C12Q 2525/107 incorporating a peptide nucleic acid
• CPC Class Codes: C12Q 2527/146 Concentration of target or template
• CPC Class Codes: G01N 27/327 Biochemical electrodes , e.g. electrical or mechanical details for in vitro measurements
• CPC Class Codes: G01N 27/3275 Sensing specific biomolecules, e.g. nucleic acid strands, based on an electrode surface reaction
• 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 27/4145 specially adapted for biomolecules, e.g. gate electrode with immobilised receptors
• CPC Class Codes: G01N 33/54373 involving physiochemical end-point determination, e.g. wave-guides, FETS, gratings
• CPC Class Codes: G01N 33/5438 Electrodes
• CPC Class Codes: G01N 33/94 involving narcotics or drugs or pharmaceuticals, neurotransmitters or associated receptors

Abstract

Contemplated methods and devices comprise use of a charged probe and a neutralizer in the electrochemical detection of a wide range of analytes, including nucleic acids, proteins, and small molecules. In certain embodiments the neutralizer forms a complex with the probe that has a reduced charge magnitude compared to the probe itself, and is displaced from the probe when the complex is exposed to the analyte.

Claims

1. A method of detecting an analyte, comprising;

contacting a sample with a reversible first complex comprising a probe affixed to a sensor surface and a pseudoligand having a charge opposed to that of the probe; and

detecting the presence of a second complex formed by displacement of the pseudoligand from the probe by the analyte, if present in the sample, wherein the presence of the second complex indicates the presence of the analyte.

2. The method of claim 1, wherein the first complex has a first charge state and the second complex has a second charge state, and wherein detecting the presence of the second complex comprises determining a difference between the first charge state and the second charge state.

3. The method of claims 1 or 2, wherein the second charge state has a greater overall magnitude than the first charge state.

4. The method of any of claims 1-3, wherein detecting the presence of the second complex comprises measuring a change in current amplitude caused by for the formation of the second complex.

5. The method of claim 4, wherein an increase in the current amplitude above a predetermined threshold is indicative of the presence of the analyte.

6. The method of claims 4 or 5, wherein the magnitude of the change in the current amplitude is indicative of the concentration of the analyte in the sample.

7. The method of any of claims 1-3, wherein detecting comprises measuring a change in voltage caused by the formation of the second complex.

8. The method of any of claims 1-7, wherein an affinity of the probe for the pseudoligand is less than an affinity of the probe for the analyte.

9. The method of any of claims 1-7, wherein an affinity of the probe for the pseudoligand is greater than an affinity of the probe for the analyte.

10. The method of any of claims 1-9, wherein the relative stabilities of the first complex and the second complex are modified by manipulating temperature.

11. The method of any of claims 1-10, wherein the relative stabilities of the first complex and the second complex are modified by the composition of the buffer.

12. The method of any of claims 1-11, wherein the analyte is a nucleic acid.

13. The method of any of claims 1-11, wherein the analyte is a protein or protein fragment.

14. The method of claims 1-11, wherein the analyte is selected from the group consisting of nucleotides, nucleotide analogs, drugs of abuse, therapeutic drugs, and environmental contaminants.

15. The method of any of claims 1-11, wherein the analyte has a molecular weight of less than about 500 daltons.

16. The method of any of claims 1-15, wherein the probe comprises a nucleic acid.

17. The method of any of claims 1-16, wherein the pseudoligand comprises a PNA.

18. The method of claim 17, wherein the PNA comprises one or more appended cationic functional groups.

19. The method of claims 17 or 18, wherein the PNA comprises one or more base pair mismatches with a probe nucleic acid sequence.

20. The method of claim 1, further comprising forming the second complex between the pseudoligand and the analyte.

21. The method of claim 1, further comprising forming the second complex between the probe and the analyte.

22. A device for detecting an analyte, comprising:

a sensor having a sensor surface, the sensor surface having a probe affixed thereto;

an inlet for contacting a sample with a reversible first complex comprising the probe and a pseudoligand having a charge opposed to that of the probe; and

a detection unit for detecting the presence of a second complex formed by displacement of the pseudoligand from the probe by the analyte, if present in the sample, wherein the presence of the second complex indicates the presence of the analyte.

23. The device of claim 22, wherein detecting the presence of a second complex comprises detecting an increase in charge at or near the sensor surface.

24. The device of claims 22 or 23, further comprising a plurality of sensor surfaces wherein at least two of the sensor surfaces comprise different probes.

25. The device of claims 22-24, wherein the first complex is formed prior to contacting the sample with the first complex.

26. The device of any of claims 22-25, wherein the sensor is configured to provide a response that is dependent on the charge at said sensor surface.

27. The device of any of claims 22-26, wherein the sensor is selected from the group consisting of a nanostructured electrochemical detection electrode, a field-effect transistor, a microcantilever, and an electrochemical sensor.

28. The device of any of claims 22-27, wherein the analyte is a nucleic acid.

29. The device of any of claims 22-27, wherein the analyte is a protein or protein fragment.

30. The device of any of claims 22-27, wherein the analyte has a molecular weight of less than about 500 daltons.

31. The device of any of claims 22-30, wherein the probe comprises a nucleic acid.

32. The device of any of claims 22-31, wherein the pseudoligand comprises a PNA.

33. The device of claim 32, wherein the PNA comprises appended cationic functional groups.

34. The device of claims 32 or 33, wherein the PNA comprises one or more base pair mismatches with a probe nucleic acid sequence.

35. A system for detecting an analyte, comprising:

a sensor having a sensor surface, the sensor surface having a probe affixed thereto;

an inlet for contacting a sample with a reversible first complex comprising the probe and a pseudoligand having a charge opposed to that of the probe;

a detection unit for detecting the presence of a second complex formed by the analyte, if present in the sample, and at least one of the pseudoligand or the probe, wherein the presence of the second complex indicates the presence of the analyte; and

a communication unit in communication with the detection unit for communicating a result of the detection to a user.

36. The system of claim 35, wherein the detection unit is configured to detect the presence of a second complex by measuring a difference in charge at the sensor surface.

37. The system of claims 35 or 36, further comprising a plurality of sensor surfaces wherein at least two of the sensor surfaces comprise different probes.

38. The system of claims 35-37, wherein the first complex is formed prior to contacting the sample with the first complex.

39. The system of any of claims 35-38, wherein the sensor is configured to provide a response that is dependent on the charge at said sensor surface.

40. The system of any of claims 35-39, wherein the sensor is selected from the group consisting of a nanostructured electrochemical detection electrode, a field-effect transistor, a microcantilever, and an electrochemical sensor.

41. The system of any of claims 35-40, wherein the analyte is a nucleic acid.

42. The system of any of claims 35-40, wherein the analyte is a protein or protein fragment.

43. The system of any of claims 35-40, wherein the analyte has a molecular weight of less than about 500 daltons.

44. The system of any of claims 35-43, wherein the probe comprises a nucleic acid.

45. The system of any of claims 35-44, wherein the pseudoligand comprises a PNA.

46. The system of claim 45, wherein the PNA comprises appended cationic functional groups.

47. The system of claims 45 or 46, wherein the PNA comprises one or more base pair mismatches with a probe nucleic acid sequence.

48. An assay composition for use in drug screening, comprising a reversible first complex comprising a probe molecule affixed to a sensor surface and a pseudoligand having complementarity with said probe molecule, said first complex having a first charge state, wherein an affinity of the probe for the pseudoligand is less than an affinity of the probe for the drug to thereby allow said drug to displace the pseudoligand from the first complex to form a second complex and wherein the second complex has a second charge state.

49. The assay composition of claim 48, wherein the second charge state has a greater overall magnitude than the first charge state.

50. The assay composition of claims 48 or 49, wherein the probe comprises a nucleic acid.

51. The assay composition of any of claims 48-50, wherein the pseudoligand comprises a PNA.

52. The assay composition of claim 51, wherein the PNA comprises one or more appended cationic functional groups.

53. The assay composition of claims 51 or 52, wherein the PNA comprises one or more base pair mismatches with a probe nucleic acid sequence.

54. An assay composition of any of claims 48-53, wherein the drug is a therapeutic drug.

55. An assay composition of any of claims 48-53, wherein the drug is a drug of abuse.

56. A kit comprising a device having a sensor surface with a probe affixed thereto, wherein the kit further comprises a pseudoligand capable of forming a reversible complex with the probe and having a charge opposed to that of the probe.

57. The kit of claim 56, further comprising a detection unit for detecting a difference in charge at the sensor surface.

58. The kit of claims 56 or 57, wherein the first complex is formed prior to contacting the sample with the first complex.

59. The kit of any of claims 56-58, wherein the sensor is configured to provide a response that is dependent on the charge at said sensor surface.

60. The kit of any of claims 56-59, wherein the sensor is selected from the group consisting of a nanostructured electrochemical detection electrode, a field-effect transistor, a microcantilever, and an electrochemical sensor.

61. The kit of any of claims 56-60, wherein the analyte is a nucleic acid.

62. The kit of any of claims 56-60, wherein the analyte is a protein or protein fragment.

63. The kit of any of claims 56-60, wherein the analyte has a molecular weight of less than about 500 daltons.

64. The kit of any of claims 56-63, wherein the probe comprises a nucleic acid.

65. The kit of any of claims 56-64, wherein the pseudoligand comprises a PNA.

66. The kit of claim 65, wherein the PNA comprises appended cationic functional groups.

67. The kit of claims 65 or 66, wherein the PNA comprises one or more base pair mismatches with a probe nucleic acid sequence.

68. A sensor for detecting an analyte comprising:

a sensor surface comprising a plurality of electrodes;

a probe affixed to at least one of the plurality of electrodes; and

a pseudoligand capable of forming a reversible first complex with the probe such that the pseudoligand is displaced by an analyte when contacted with the first complex.

69. The sensor of claim 68, wherein a second complex is formed when the pseudoligand is displaced.

70. The sensor of claim 69, further comprising a detection unit that is configured to detect the presence of a second complex by measuring a difference in charge at the sensor surface.

71. The sensor of claims 68-70, wherein different probes are affixed to each of the plurality of electrodes.

72. The sensor of claims 68-71, wherein the first complex is formed prior to contact with a sample containing the analyte.

73. The sensor of any of claims 68-72, wherein the sensor is configured to provide a response that is dependent on the charge at said sensor surface.

74. The sensor of any of claims 68-73, wherein the sensor is selected from the group consisting of a nanostructured electrochemical detection electrode, a field-effect transistor, a microcantilever, and an electrochemical sensor.

75. The sensor of any of claims 68-74, wherein the analyte is a nucleic acid.

76. The sensor of any of claims 68-74, wherein the analyte is a protein or protein fragment.

77. The sensor of any of claims 68-74, wherein the analyte has a molecular weight of less than about 500 daltons.

78. The sensor of any of claims 68-77, wherein the probe comprises a nucleic acid.

79. The sensor of any of claims 68-77, wherein the pseudoligand comprises a PNA.

80. The sensor of claim 79, wherein the PNA comprises appended cationic functional groups.

81. The sensor of claims 79 or 80, wherein the PNA comprises one or more base pair mismatches with a probe nucleic acid sequence.