Biosensor device and method

• US 5,955,379 A
• Filed: 04/24/1997
• Issued: 09/21/1999
• Est. Priority Date: 04/25/1996
• Status: Expired due to Fees

• Current Assignee: McGill University, Pence Incorporated
• Original Assignee: McGill University, Pence Incorporated
• Inventors: Railton, Craig, Hodges, Robert S., Irvin, Randall T., Bundle, David R., Kitov, Pavel, Armstrong, Glen, Lennox, R. Bruce
• Primary Examiner(s): Housel, James C.
• Assistant Examiner(s): Nguyen, Bao-Thuy L.
• Application Number:
  US08/845,659
• Time in Patent Office: 880 Days
• Field of Search: 436/518, 436/525, 436/528, 436/807, 436/806, 436/904, 435/7.1, 435/7.5, 427/2.11, 422/82.02
• US Class Current: 436/528
• CPC Class Codes: B01J 2219/00653 the compounds being bound to electrodes embedded in or on the solid supports
• CPC Class Codes: C12Q 1/003 Functionalisation
• CPC Class Codes: G01N 33/5438 Electrodes
• CPC Class Codes: Y10S 436/806 Electrical property or magnetic property
• CPC Class Codes: Y10S 436/807 Apparatus included in process claim, e.g. physical support structures
• CPC Class Codes: Y10S 436/904 Oxidation - reduction indicators

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 binding between an oligosaccharide ligand and ligand-specific binding receptor, comprising

an electrode including

(i) a detection surface,

(ii) formed on said detection surface, a close-packed and ordered monolayer comprising hydrocarbon chains anchored at their proximal ends to the detection surface, said chains being sufficiently close-packed and ordered to form an effective barrier to inhibit contact of a redox species, in an aqueous solution in contact with the monolayer, with said detection surface and thereby reduce measurably electron flow across the monolayer mediated by said redox species, and

(iii) said oligosaccharide ligand attached to the distal ends of a portion of said chains, such that binding of said ligand-specific binding receptor to said oligosaccharide ligand perturbs the monolayer sufficiently to allow said redox species to contact said detection surface to donate or accept electrons from said surface and thereby increase measurably electron flow across the monolayer mediated by said redox species,

a chamber for holding said aqueous solution of redox species in contact with said monolayer,

means for introducing said receptor into said chamber, and

circuit means, comprising voltage generating means, for measuring electron flow mediated by said redox species across said monolayer, in response to binding occurring between said receptor and said oligosaccharide ligand.

2. The apparatus of claim 1, wherein the detection surface is a gold detection surface and wherein the hydrocarbon chains are 8-22 carbon atom chains anchored at their proximal ends to the detection surface by a thiol linkage.

3. The apparatus of claim 1, wherein said close-packed and ordered monolayer has a molecular density of about 3 to 5 chains/nm².

4. The apparatus of claim 3, wherein said oligosaccharide ligand is a disaccharide.

5. The apparatus of claim 3, wherein said oligosaccharide ligand is a trisaccharide.

6. The apparatus of claim 5, wherein said ligand-specific binding receptor is a Verotoxin receptor.

7. A biosensor apparatus for detecting binding between an oligosaccharide ligand and ligand-specific binding receptor, comprising

an electrode substrate comprising a detection surface,

formed on said detection surface, a close-packed and ordered monolayer comprising hydrocarbon chains anchored at their proximal ends to the detection surface, said chains being sufficiently close-packed and ordered to inhibit contact of a redox species, in an aqueous solution in contact with the monolayer, with said detection surface and thereby reduce measurably electron flow across the monolayer mediated by said redox species;

also anchored to the detection surface, a heterodimer-subunit complex composed of first and second peptides that together form α

-helical coiled-coil heterodimer, and said oligosaccharide ligand, where

(i) said first peptide is covalently bound to the detection surface,

(ii) the oligosaccharide ligand is covalently attached to said second peptide;

(iii) binding of said second peptide to said first peptide, to form said heterodimer-subunit complex, is effective to inhibit contact of said redox species with said detection surface and thereby reduce measurably electron flow across the monolayer mediated by said redox species, relative to electron flow observed in the presence of said first peptide alone, and

(iv) binding of said ligand-binding receptor to said ligand is effective to allow said redox species to contact said detection surface to donate or accept electrons from said surface and thereby increase measurably the electron flow across the monolayer mediated by said redox species,

a chamber for holding said aqueous solution of redox species in contact with said monolayer,

means for introducing said receptor into said chamber, and

circuit means, comprising voltage generating means, for measuring electron flow mediated by said redox species across said monolayer, in response to binding events occurring between said receptor and said oligosaccharide ligand.

8. The apparatus of claim 7, wherein said oligosaccharide ligand is a disaccharide.

9. The apparatus of claim 7, wherein said oligosaccharide ligand is a trisaccharide.

10. The apparatus of claim 9, wherein said ligand-specific binding receptor is a Verotoxin receptor.