METHOD AND APPARATUS FOR IMMUNOLOGICAL DETECTION OF BIOLOGICAL PARTICLES

• US 3,853,467 A
• Filed: 08/15/1973
• Issued: 12/10/1974
• Est. Priority Date: 08/15/1973
• Status: Expired due to Term

• Current Assignee: Ivar Giaever
• Original Assignee: Ivar Giaever
• Inventors: Giaever, Ivar
• Primary Examiner(s): Wolk, Morris O.
• Assistant Examiner(s): Marantz, Sidney
• Application Number:
  US05/388,406
• Time in Patent Office: 482 Days
• Field of Search: 23/23B,253R,253TP 195/13.5R 424/12 117/71R
• US Class Current: 435/5
• CPC Class Codes: C12Q 1/70 involving virus or bacteriophage immunoassay for viruses G01N33/56983
• CPC Class Codes: G01N 33/553 Metal or metal coated
• CPC Class Codes: Y10S 436/805 Optical property
• CPC Class Codes: Y10S 436/806 Electrical property or magnetic property

Abstract

Method and apparatus for the detection of biological particles such as viruses, bacteria, and other cells by detection of the occurrence of an immunological reaction between the particle to be detected and its antibody. In one embodiment a substrate having an etchable metal surface is coated with a layer of antibodies to the biological particle to be detected. The antibody coated substrate is exposed to a fluid suspected of containing the biological particles to be detected. After such exposure, the structure is coated with a layer of a non-etachable metal of sufficient thickness to cover the antibody layer but of insufficient thickness to completely coat the biological particles and form a continuous film. The structure is then exposed to an etchant. After etching, positions at which biological particles had been immunologically bonded to their antibodies are observable as voids in the structure.

Claims

1. Apparatus for detecting biological particles of a particular species in a fluid comprising:

a substrate;

a metal film on a surface of said substrate;

a layer of antibodies to said species of biological particle, said antibodies being adsorbed on said metal film;

means for applying a second metal layer over said layer of antibodies and any of said biological particles bonded thereto; and

means for selectively etching said biological particles, said metal film, and said antibodies.

2. The apparatus of claim 1 wherein:

said means for selectively etching comprises an acid;

said metal film comprises a metal which is etchable by said acid; and

said second metal layer comprises a metal which is resistant to etching by said acid.

3. The apparatus of claim 2 wherein said second metal layer has voids therein, said voids being disposed about the peripheries of said biological particles.

4. The apparatus of claim 3 wherein said substrate comprises a light-transmissive material which is resistant to etching by said acid.

5. The apparatus of claim 4 including additionally means for directing light onto a surface of said substrate.

6. The apparatus of claim 5 wherein said means for directing light onto a surface of said substrate comprises:

an enclosure having first and second end members, said second end member having an aperture therein;

a lamp within said enclosure adjacent said first end member; and

means attached to a surface of said second end member external to said enclosure for receiving said substrate and for positioning said substrate adjacent said aperture.

7. The apparatus of claim 6 further including means external to said enclosure for receiving light transmitted through said substrate and for indicating the quantity of light energy received.

8. A METHOD FOR DETECTING BIOLOGICAL PARTICLES OF A PARTICULAR SPECIES IN A FLUID COMPRISING THE STEPS OF:

IMMERSING A SUBSTRATE HAVING A METAL SURFACE INTO A SOLUTION OF ANTIBODIES TO WHICH SPECIES OF BIOLOGICAL PARTICLE TO ADHERE A LAYER OF SAID ANTIBODIES THEREON;

IMMERSING SAID SUBSTRATE HAVING SAID ANTIBODIES THEREON INTO SAID FLUID WHEREBY A PLURALITY OF SAID BIOLOGICAL PARTICLES, IF PRESENT IN SAID FLUID, IMMUNOLOGICALLY BOND TO SAID ANTIBODIES;

APPLYING A SECOND METAL LAYER OVER SAID LAYER OF ANTIBODIES AND ANY OF SAID BIOLOGICAL PATICLES;

IMMERSING SAID SUBSTRATE IN AN ETCHANT SOLUTION;

AND

9. The method of claim 8 further including the step of:

bonding a metal film to a wafer of light-transmissive material to form said substrate.

10. The method of claim 8 wherein said applying step more particularly comprises the steps of:

immersing said substrate in a solution of a salt of said second metal;

immersing a block of said second metal in said solution of salt; and

applying an electrical potential difference between said block and said metal surface to electroplate said second metal onto said substrate.

11. The method of claim 8 wherein said applying step comprises evaporating said second metal onto said substrate.

12. The method of claim 8 wherein said applying step further includes the step of monitoring the deposition of said second metal to insure that said second metal layer is discontinuous about the peripheries of said biological particles.

13. The method of claim 8 wherein said examining step comprises microscopic examination of said substrate.

14. The method of claim 8 wherein said examining step more particularly comprises:

backlighting said substrate; and

visually observing as points of transmitted light locations on said substrate at which said biological particles had been bonded.

15. The method of claim 8 wherein said examining step more particularly comprises:

backlighting said substrate;

receiving and integrating light transmitted through said substrate; and

indicating the integrated quantity of said light to provide a measure of the concentration of said biological particles in said fluid.

16. Apparatus for detecting biological particles of a particular species in a fluid comprising:

a substrate;

an etchable film on a surface of said substrate;

a layer of antibodies to said species of biological particle, said antibodies being adsorbed on said etchable film;

means for applying a layer of non-etchable material over said layer of antibodies and any of said biological particles bonded thereto; and

means for selectively etching said biological particles, said etchable film, and said antibodies.

17. The apparatus of claim 16 wherein:

said means for selectively etching comprises an acid;

said etchable film comprises a metal which is etchable by said acid; and

said layer of non-etchable material comprises a metal which is resistant to etching by said acid.

18. The apparatus of claim 16 wherein said etchable film is opaque and said non-etchable material is light transmissive.