SELF-ACTUATING SIGNAL PRODUCING DETECTION DEVICES AND METHODS

• US 20090117574A1
• Filed: 09/17/2008
• Published: 05/07/2009
• Est. Priority Date: 09/17/2007
• Status: Active Grant

• Current Assignee: Red Ivory LLC
• Original Assignee: Siometrix Corporation
• Inventors: JOKHADZE, GEORGE G., LABGOLD, MARC ROBERT
• Granted Patent: US 11,307,201 B2
• Time in Patent Office: Days
• US Class Current: 435/6
• CPC Class Codes: C12Q 1/6825 Nucleic acid detection involving sensors
• CPC Class Codes: C12Q 2563/113 the label being electroactive, e.g. redox labels
• CPC Class Codes: C12Q 2563/125 the label being enzymatic, i.e. proteins, and non proteins, such as nucleic acid with enzymatic activity
• CPC Class Codes: C12Q 2565/607 being a sensor, e.g. electrode
• CPC Class Codes: G01N 33/5438 Electrodes

Abstract

An assay system is provided of great sensitivity and portability where the presence of a specific target in a sample, as well as its concentration (qualification and quantification) is detected by reason of a potential or voltage in a closed circuit, built up a redox reaction. The reaction is produced by binding a capture moiety to an enzymatic redox reaction partner, allowing the capture moiety to bind to any target in the sample, and washing any such bound target. The bound target, if not immobilized, may be immobilized through use of a second capture moiety. Substrate for the enzyme is then added. The action of the enzyme upon the substrate frees electrons, creating a potential across an anode and cathode which may be separated by a membrane.

Claims

1. An assay system for the detection of a target in a liquid sample, wherein said assay system comprises:

a first capture moiety which binds to any target present in said sample, said first capture moiety complexed with an enzymatic redox reaction component;

a substrate recognized by said enzyme, which substrate, when acted upon by said enzyme, releases electrons; and

a circuit which detects the presence of electric potential or current developed by the release of electrons from said substrate when digested by said enzyme.

2. The assay system of claim 1, wherein said target comprises an amino acid sequence, and said first capture moiety comprises an antibody which binds to said target at a given epitope.

3. The assay system of claim 1, wherein said target comprises a nucleic acid sequence, and said first capture moiety binds to said target by hybridizing to a portion of said sequence.

4. The assay system of claim 1, wherein sad system comprises a second capture moiety which binds to any said target present in said sample simultaneously with said first capture moiety, said second capture moiety bearing a collection moiety for collecting all such second capture moieties bound to said target.

5. The assay system of claim 4, wherein said collection moiety comprises a magnetic bead.

6. The assay system of claim 4, wherein said collection moiety comprises a chemical tag bound by a column through which the sample is run after being admixed with said first and second capture moieties.

7. The assay system of claim 1, wherein said enzymatic redox reaction component is an oxidase or dehydrogenase of said substrate.

8. The assay system of claim 5, wherein said substrate is selected from the group consisting of glucose, lactose, fructose, mannose, cholin, methanol and ethanol.

9. The assay system of claim 6, wherein said substrate is glucose and said enzymatic redox reaction component is glucose oxidase.

10. The assay system of claim 1, further comprising a reaction chamber wherein said first capture moiety coupled with said enzymatic redox reaction component, said second capture moiety bound to a collection moiety, said sample and said substrate are combined, said assay system further comprising an anode and a cathode connected to said reaction chamber, wherein a potential or current developed across said cathode and anode due to generation of electrons by action on said substrate by said enzymatic redox reaction component is detected as evidence of the presence of target in said sample.

11. The assay system of claim 1, wherein said assay system comprises a display for presenting the detection of said potential.

12. The assay system of claim 11, wherein said display comprises at least one of a computer, a light emitting diode, a liquid crystal diode and a meter.

13. An assay method for detecting the presence of a target in a sample, said method comprising using the assay system of claim 1, wherein said first capture moiety complexed with an enzymatic redox reaction component is combined with said sample under conditions which permit binding of said first capture moiety to and said target in said sample, and subsequently adding said substrate to said bound target, wherein any potential or current generated by reaction between said enzymatic redox reaction component and said substrate is detected as a signal reflecting the presence of said target in said sample.

14. The method of claim 13, wherein said method further comprises adding a second capture moiety bound to a collection moiety which is combined with said sample under conditions which permit simultaneous binding of said first and second capture moieties to said sample, any said target in said sample bound by said first and second capture moieties is retained by said collection moiety while all remaining material is washed away, said retained target is resuspended in liquid and said substrate is added to said liquid.

15. The method of claim 14, wherein said target comprises a nucleic acid sequence, and said first and second capture moieties comprise different oligomers which hybridize with said target simultaneously.

16. The method of claim 14, wherein said target comprises an amino acid sequence, and said first and second capture moieties comprise different antibodies which bind to said target at different epitopes.

17. The method of claim 14, wherein said collection moiety comprises a magnetic bead and said collection moiety bound to said target through said second capture moiety is retained by application of a magnetic field thereto.

18. The method of claim 13, wherein said enzymatic redox reaction component is an oxidase or dehydrogenase of said substrate.

19. The method of claim 18, wherein said substrate is glucose and said enzymatic redox reaction component is glucose oxidase.

20. The method of claim 14, wherein said first capture moiety and second capture moiety are added to said sample sequentially.

21. The method of claim 14, wherein said first capture moiety and second capture moiety are added to said sample simultaneously.

22. The method of claim 13, wherein said signal is communicated to a computer which stores said signal.

23. The method of claim 22, wherein said computer communicates the signal to a third party.

24. The method of claim 13, wherein the strength of said signal is correlated with the amount of said target present in said sample.

25. The method of claim 13, wherein said signal is not measured for a period of time of at least one minute following addition of said substrate to said separated target.

26. A device for measuring the signal generated by the method of claim 13, comprising a disposable cartridge, the cartridge comprising a reaction chamber in which said sample is combined with said first capture moiety, an anode and a cathode in physical contact with said reaction chamber, said cartridge being insertable in a device body such that said cartridge is in contact with a display which measures the potential between said anode and said cathode following addition of said substrate to said reaction chamber, wherein the signal detected by said display is reflective of one of the presence or concentration of said target.

27. The device of claim 26, wherein said anode and said cathode are separated by a semipermeable membrane.

28. The device of claim 27, wherein said semipermeable membrane is an ion exchange membrane.

29. The device of claim 28, wherein said ion exchange membrane is a proton exchange membrane.

30. The device of claim 27, wherein said membrane is painted on said cathode.

31. The device of claim 26, wherein said anode and cathode are connected to a RFID device which emits a signal correlated with the potential generated by digestion of said substrate by said enzymatic redox reaction component.