Analyte specific chemical sensor with a ligand and an analogue bound on the sensing surface

• US 5,156,972 A
• Filed: 09/05/1990
• Issued: 10/20/1992
• Est. Priority Date: 09/05/1989
• Status: Expired due to Term

• Current Assignee: The State Of Israel
• Original Assignee: The State of Israel Atomic Energy Commission Soreq Nuclear Research/Center
• Inventors: Issachar, David
• Primary Examiner(s): Housel, James C.
• Assistant Examiner(s): CHAN, KWONG
• Application Number:
  US07/577,744
• Time in Patent Office: 776 Days
• Field of Search: 435/7.93, 435/288, 435/808, 435/817, 435/287, 435/291, 422/82.01-82.08, 204/403
• US Class Current: 422/68.1
• CPC Class Codes: C12M 41/46 of cellular or enzymatic activity or functionality, e.g. cell viability
• CPC Class Codes: G01N 33/54353 with ligand attached to the carrier via a chemical coupling agent coatings G01N33/54393
• 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 33/68 involving proteins, peptides or amino acids involving lipoproteins G01N33/92
• CPC Class Codes: G01N 33/9486 Analgesics, e.g. opiates, aspirine
• CPC Class Codes: Y10S 435/808 Optical sensing apparatus
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode

Abstract

An analyte specific chemical sensor for determining an analyte in a test medium. The sensor comprises a sensing surface which is coated with reversible competitive recognition units (RCRUs) each of which contains as constituent components at least one receptor and at least one ligand, one of which components is an analyte analogue. In these RCRUs the receptor and the ligand are a priori connected to each other, directly or indirectly, in such configuration that even when, for example, an analyte analogue ligand is displaced from the receptor by an analyte ligand, the analogue will still be retained in relatively close proximity to the receptor. In addition, the relative positions of the receptor and the ligand in the RCRU are such that when no analytes are present or when the analyte concentration is at a low level, they are affinity conjugated by a specific affinity interaction. The fluctuations of analyte concentrations in the test sample affect the chemical occurrences at the RCRUs, and consequently the physico-chemical characteristics of its components. The changes in the analyte concentration are monitored, according to the present invention, by continuously measuring the changes of the above physico-chemical characteristics induced by occurrences at the RCRUs, namely inner association and dissociation. Such physico-chemical characteristics may be, for example, photochemical, e.g. light absorption, light emission, light scattering and light polarization; electrochemical; and piezoelectrical.

Claims

1. An analyte-specific chemical sensor for determining an analyte in a test medium, comprising a carrier body with a sensing surface having attached thereto a plurality of reversible competitive recognition units, called, RCRUs each comprising as constituent components at least one bound receptor and one bound ligand arranged in such relationship that in the absence of analyte the receptor or receptors and the ligand or ligands of each RCRU associate to form a conjugate, which conjugate competitively disassociates in the presence of the analyte said receptor and ligand remaining bound to said surface and reassociate when the analyte concentration in the test medium is decreased;

wherein at least one detectable physico-chemical property of the RCRU is modulated by fluctuations of the analyte concentration as a correlate of the dissociation and reassociation of the components of the RCRU.

2. A sensor according to claim 1, wherein the constituent components of each RCRU are bound directly to the sensing surface.

3. A sensor according to claim 1 wherein the constituent components of each RCRU are bound to the sensing surface via at least one spacer molecule.

4. A sensor according to claim 3, wherein each of the constituent components of each RCRUs is linked to the sensing surface separately via its own spacer molecule.

5. A sensor according to claim 3, wherein said constituent components of each RCRUs are interconnected by a common spacer molecule to form a molecular construct with receptor and ligand moieties, which construct is linked to the sensing surface.

6. A sensor according to claim 5, wherein said construct is linked directly to the sensing surface.

7. A sensor according to claim 5, wherein said construct is linked to the sensing surface by means of a spacer molecule.

8. A sensor according to claim 1, wherein the constituent components of the RCRU are complementary participants in an immunogenic type reaction and are selected from the groups of antibodies and antigens.

9. An apparatus for continuously measuring the concentration of an analyte in liquid or gaseous phase, comprising a probing vessel fitted with a sensor according to claim 1, and at least one transducer which transduces receptor-ligand association and dissociation into at least one measurable physico-chemical phenomenon.

10. Apparatus according to claim 9 designed as a monitor for continuous operation, wherein said probing vessel is adapted for the continuous throughflow of a liquid or gaseous test fluid.

11. An apparatus according to claim 9, wherein the detected physico-chemical phenomenon is optical, electrochemical or piezoelectrical.

12. An analyte-specific chemical sensor for determining an analyte in a test medium, comprising a carrier body with a sensing surface having attached thereto a plurality of reversible competitive recognition units, called, RCRUs each comprising as constituent components at least one bound receptor and one bound ligand arranged in such relationship that in the absence of analyte the receptor or receptors and the ligand or ligands of each RCRU associate to form a conjugate, which conjugate competitively disassociates in the presence of the analyte, said receptor and ligand remaining bound to said surface, and reassociates when the analyte concentration in the test medium is decreased;

wherein each of either of the constituent receptor or receptors and ligand or ligands of the RCRU bears a labelling group at least one detectable physico-chemical property of which is modulated by fluctuations of the analyte concentration as a correlate of the dissociation and reassociation of the components of the RCRU.

13. A sensor according to claim 12 wherein said labelling group manifests an optical activity which is reversibly modulated by fluctuations of the analyte concentration in the test medium.

14. A sensor according to claim 12, wherein each of either of the said receptor or receptors and ligand or ligands of each RCRU is a recognizer and the other is an analyte analogue bearing a luminophore group producing upon excitation a luminescence which is modulated by fluctuations of the analyte concentration in the test medium.

15. A sensor according to claim 14, wherein the sensor body is a waveguide and the analyte analogue is excited by an evanescent light wave propagating at the interface between said waveguide and a liquid or gaseous test fluid.

16. A sensor according to claim 15, wherein said waveguide is designed to conduct the luminescence emitted by the labelled analyte analogue.

17. A sensor according to claim 15, wherein said waveguide is an optical fibre having an unclad sensing portion coated with RCRUs.

18. A sensor according to claim 15, wherein said waveguide is a flat body having at least one face coated with RCRUs.

19. A sensor according to claim 16, wherein the labelled analyte analogue emits a polarized luminescence is modulated by fluctuations of the analyte concentration in the test medium.

20. A sensor according to claim 14, wherein each recognizer bears a quencher group which upon formation of said inner conjugate suppresses the luminescence of the analyte analogue, which luminescence increases upon dissociation of said inner conjugate.

21. A sensor according to claim 14, wherein each recognizer bears an enhancer group which upon formation of said inner conjugate enhances the luminescence of the analyte analogue, which luminescence increases upon dissociation of said inner conjugate.

22. A sensor according to claim 12 wherein said labelling group manifests an electrochemical activity which is modulated by fluctuations of the analyte concentration in the test medium.

23. A sensor according to claim 22, wherein the carrier body is an electrode.

24. A sensor according to claim 22, wherein the carrier body is a field effect transistor.

25. A sensor according to claim 12, wherein the the carrier body is a piezoelectric transducer the frequency of which is modulated by the fluctuations of the analyte concentration.