Biosensor device and method

• US 6,107,080 A
• Filed: 04/24/1997
• Issued: 08/22/2000
• Est. Priority Date: 04/25/1996
• Status: Expired due to Fees

• Current Assignee: McGill University
• Original Assignee: McGill University
• Inventors: Lennox, R. Bruce
• Primary Examiner(s): Chin, Christopher L.
• Application Number:
  US08/845,658
• Time in Patent Office: 1,216 Days
• Field of Search: 204/400, 204/403, 204/416, 204/418, 204/290 R, 422/82.01, 422/82.03, 435/6, 435/287.1, 435/287.2, 435/817, 435/283.1, 436/149, 436/150, 436/518, 436/528, 436/806
• US Class Current: 204/403.01
• 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 2219/00704 integrated with the reactor apparatus
• CPC Class Codes: B01J 2219/00725 Peptides
• CPC Class Codes: C12Q 1/003 Functionalisation
• CPC Class Codes: C40B 40/10 Libraries containing peptides or polypeptides, or derivatives thereof
• 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: Y10S 435/817 Enzyme or microbe electrode
• CPC Class Codes: Y10S 436/806 Electrical property or magnetic property

Abstract

A biosensor apparatus for detecting a binding event between a ligand and receptor. The apparatus includes an electrode substrate coated with a high-dielectric hydrocarbon-chain monolayer, and having ligands attached to the exposed monolayer surface. Binding of a receptor to the monolayer-bound ligand, and the resultant perturbation of the monolayer structure, causes ion-mediated electron flow across the monolayer. In one embodiment, the monolayers have a coil-coil heterodimer embedded therein, one subunit of which is attached to the substrate, and the second of which carries the ligand at the monolayer surface.

Claims

1. A biosensor apparatus for detecting a binding event between a ligand and ligand-binding receptor, comprising

a working electrode having (i) a conductive detection surface, (ii) formed on said conductive detection surface, a monolayer composed of hydrocarbon chains anchored at their proximal ends to said conductive detection surface, said chains being sufficiently close-packed and ordered to form an effective barrier to electron flow across the monolayer mediated by a redox ion species in an aqueous solution, when such a solution is placed in contact with the monolayer, and (iii) such ligand attached to the distal ends of a portion of said chains, such that binding of a ligand-binding receptor to ligand perturbs the monolayer sufficiently to measurably increase electron flow across the monolayer mediated by such redox ion species,

a chamber for containing such an aqueous solution of redox species in contact with said monolayer,

means for introducing receptor into said chamber, and circuit means for measuring ion-mediated electron flow across said monolayer, in response to binding events occurring between said receptor and ligand, said circuit means including a counter electrode positioned in said chamber to contact such aqueous solution, when the latter is placed in said chamber,

wherein binding of receptor to the ligand on the working electrode is effective to perturb said monolayer, and thereby increase the flow of redox carriers in the solution across said monolayer, producing a detectable change in current flow between said working electrode n said counter electrode.

2. The apparatus of claim 1, wherein the working electrode has a gold detection surface and said monolayer is composed of 8-22 carbon atom chains attached at their proximal ends to the detection surface by a thiol linkage.

3. The apparatus of claim 1, wherein said chains have a molecular density of about 3 to 5 chains/nm².

4. The apparatus of claim 3, wherein the dielectric constant of said monolayer, in the presence of such solution but in the absence of such binding receptor, is less than about 2.

5. The apparatus of claim 4, wherein the change in dielectric constant of said monolayer, in the presence of such solution and a detectable of such binding receptor, is at least about 10%.

6. The apparatus of claim 1, for use in detecting the presence, in a body-fluid sample, of

a receptor which forms with said ligand, a ligand-receptor binding pair selected from the group consisting of antigen-antibody, hormone-receptor, drug-receptor, cell-surface antigen-lectin, biotin-avidin, and complementary nucleic acid strands.

7. The apparatus of claim 6, for use in detecting an antibody analyte, where the antigen forms an immunospecific binding pair with the antibody analyte.

8. The apparatus of claim 6, for use in detecting a single-stranded polynucleotide, wherein said ligand is an oligonucleotide whose sequence is complementary to a portion of the sequence of the single-stranded polynucleotide.

9. The apparatus of claim 1, for use in detecting the presence, in a body-fluid sample, of a ligand analyte which forms with a receptor, a ligand-receptor binding pair selected from the group consisting of antigen-antibody, effector-receptor, drug-receptor, cell-surface antigen-lectin, biotin-avidin, oligonucleotide sequence-DNA binding protein, and first and second complementary nucleic acid strands, and the apparatus further includes, for inclusion in such solution, a receptor whose binding to the analyte prevents its binding to the monolayer-bound ligand.

10. The apparatus of claim 9, for use in detecting an antigen analyte, wherein the ligand is an analyte or analyte analog, and the apparatus further includes, for inclusion in such solution, an antibody whose binding to the analyte prevents its binding to the monolayer-bound ligand.