Bridged element for detection of a target substance

• US 20050074871A1
• Filed: 08/06/2004
• Published: 04/07/2005
• Est. Priority Date: 08/06/2003
• Status: Active Grant

• Current Assignee: Bio-Rad Laboratories Incorporated
• Original Assignee: The Procter & Gamble Company
• Inventors: Wright, Brad, Albert, Fred
• Granted Patent: US 8,078,408 B2
• Time in Patent Office: Days
• US Class Current: 435/287.200
• CPC Class Codes: C12Q 1/6825 Nucleic acid detection involving sensors
• CPC Class Codes: C12Q 2523/307 Denaturation or renaturation by electric current/voltage
• CPC Class Codes: G01N 33/54373 involving physiochemical end-point determination, e.g. wave-guides, FETS, gratings

Abstract

Physical changes resulting from an association between a template molecule and a target molecule are detected by monitoring changes in the template molecule. Exemplary changes include a change in a physical dimension or stiffness of the template molecule, a change in electrical conductivity of the template molecule and a change in the energy required to dissociate the target molecule and the template molecule. The magnitude of the change is indicative of the specific identity of the target molecule.

Claims

1. A device comprising:

a template molecule linked between at least two contact points including a first contact point disposed on a first surface and a second contact point disposed on a second surface, wherein the first surface is independent of the second surface, further wherein the template molecule includes at least one binding site for a target molecule; and

a detector coupled to the first contact point, the first contact point having a first physical parameter, the detector configured to generate an output signal based on a change in the first physical parameter, wherein the change in the first physical parameter corresponds to an association of the target molecule and the template molecule.

2. The device of claim 1 wherein the template molecule is a nucleic acid.

3. The device of claim 2 wherein the template molecule is ssDNA or ssRNA.

4. The device of claim 2 wherein the target molecule is a nucleic acid comprising a sequence sufficiently complementary to a sequence in the template molecule so that the target molecule will hybridize to said template molecule.

5. The device of claim 2 wherein the template molecule is a nucleic acid that is bonded to the first contact point at its 3′

-end and to the second contact point at its 5′

-end.

6. The device of claim 1 wherein the template molecule comprises a polypeptide.

7. The device of claim 6 wherein the polypeptide is bonded at its carboxy terminus to the first contact point and at its amino terminus to the second contact point.

8. The device of claim 6 wherein the polypeptide comprises a binding region for a target molecule wherein the target molecule is an antibody.

9. The device of claim 6 wherein the polypeptide comprises a binding site derived from an antibody that binds to a target molecule that comprises an antigenic site for said antibody.

10. The device of claim 6 wherein the polypeptide comprises a receptor site for a target molecule.

11. The device of claim 10 wherein the target molecule is an antagonist or agonist for a polypeptide comprising the receptor site.

12. The device of claim 1 wherein the target molecule is a polypeptide that comprises a receptor site for at least a portion of the template molecule.

13. The device of claim 1 wherein the target molecule is or comprises metal ions.

14. The device of claim 1 wherein the template molecule is a polysaccharide.

15. The device of claim 1 wherein the template molecule is a synthetic analog of a nucleic acid sequence.

16. The device of claim 1 wherein the template molecule is a synthetic analog of a polypeptide.

17. The device of claim 1 wherein the template molecule is a synthetic analog of a polysaccharide.

18. The device of claim 1 wherein the first physical parameter includes at least one of:

a resonant frequency of the first contact point relative to a reference point;

a resonant amplitude of the first contact point relative to the reference point;

a distance between the first contact point and the reference point; and

an alignment between the first contact point and the reference point.

19. The device of claim 18 wherein the reference point includes the second contact point.

20. The device of claim 1 wherein the first surface includes a suspended structure and the output signal is a function of a displacement of the suspended structure.

21. The device of claim 19 wherein the suspended structure includes a cantilever.

22. The device of claim 1 wherein the first surface includes a piezoelectric element and the output signal is a function of a force on the piezoelectric element.

23. The device of claim 1 wherein the first surface includes a movable surface.

24. The device of claim 1 wherein the detector includes at least one of an optical sensor, a magnetic field sensor, an electric field sensor, a capacitance sensor, a resistance sensor and a strain sensor.

25. The device of claim 1 wherein the detector includes at least one of a comparator and a bridge circuit.

26. The device of claim 1 wherein the detector includes a resonance driver in communication with the first surface.

27. The device of claim 1 wherein the first contact point has a second physical parameter, and wherein the detector is configured to generate the output signal based on a change in the second physical parameter, wherein the change in the second physical parameter corresponds to the association of the target molecule and the template molecule.

28. The device of claim 1 wherein the detector is coupled to the second contact point and wherein the first contact point having a first physical parameter includes the first contact point and the second contact point having a first electrical parameter.

29. The device of claim 28 wherein the detector includes a voltage source coupled to the first contact point and the second contact point and wherein the first electrical parameter includes a measure of a current.

30. The device of claim 29 wherein the voltage source is configured to supply an increasing potential.

31. The device of claim 28 wherein the detector includes a current source coupled to the first contact point and the second contact point and wherein the first electrical parameter includes a measure of a voltage.

32. The device of claim 31 wherein the current source is configured to supply an increasing current.

33. The device of claim 28 wherein the detector includes a driver circuit configured to deliver an electrical signal and wherein the change in the first physical parameter corresponds to a disbonding of the target molecule and the template molecule.

34. The device of claim 1 wherein at least one of the first surface and the second surface includes at least one of glass, quartz, silicon and a polymer.

35. The device of claim 1 wherein the template molecule includes at least one of thiol, gold, biotin and streptavidin.

36. A method comprising:

exposing a target molecule to a template molecule, the template molecule linked between at least two contact points including a first contact point disposed on a first surface and a second contact point disposed on a second surface, wherein the template molecule includes at least one binding site for a target molecule; and

generating an output signal as a function of a change in a first physical parameter measured using the first contact point relative to a reference point, wherein the change in the first physical parameter corresponds to an association of the target molecule and the template molecule.

37. The method of claim 36 further including:

monitoring a resonant frequency of the first contact point relative to a reference point;

monitoring a resonant amplitude of the first contact point relative to the reference point;

monitoring a distance between the first contact point and the reference point; and

monitoring an alignment between the first contact point and the reference point.

38. The method of claim 37 wherein the reference point includes the second contact point.

39. The method of claim 36 further including driving the first surface to resonance.

40. The method of claim 36 further including conducting a current using the template molecule before exposing.

41. The method of claim 36 further including:

conducting an increasing current using the template molecule;

monitoring for a voltage peak corresponding to disbanding of the target molecule and the template molecule; and

generating the output as a function of the current at the voltage peak.

42. The method of claim 36 further including:

applying an increasing voltage to the template molecule;

monitoring for a current peak corresponding to disbonding of the target molecule and the template molecule; and

generating the output as a function of the voltage at the current peak.

43. The method of claim 36 further including applying an electrical signal to the template molecule to disbond the target molecule.

44. A system comprising:

a target molecule introduction port for receiving a sample;

a sensor having a template molecule in communication with the target molecule introduction port, the template molecule disposed between a first point on a first surface and a second point on a second surface, the first surface independent of the second surface and wherein the template molecule has at least one binding site specific to a target molecule;

a detector coupled to the first point and configured to generate an output signal based on a change in a measured parameter of the first point and corresponding to an association of the template molecule with the target molecule; and

an output circuit to provide a result based on the output signal.

45. The system of claim 44 further including a plurality of sensors, each sensor coupled to the detector by a multiplexer.

46. The system of claim 44 a processor coupled to the detector and having access to a memory, wherein the memory provides data storage for identifying a target molecule based on the change in the measured parameter.

47. The system of claim 44 wherein the output circuit includes at least one of an interface, a display and a wireless transceiver.

48. The system of claim 44 further including a test circuit coupled to the template molecule to determine conductivity of the template molecule.

49. The system of claim 44 further including a reset circuit coupled to the template molecule to disbond a target molecule from the template molecule.

50. The system of claim 44 further including a housing for containment of at least one of the target molecule introduction port, the sensor, the detector and the output circuit.