Diagnostic method employing a mixture of normally separable protein-coated particles

• US 4,115,535 A
• Filed: 06/22/1977
• Issued: 09/19/1978
• Est. Priority Date: 06/22/1977
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Giaever, Ivar
• Primary Examiner(s): Padgett, Benjamin R.
• Assistant Examiner(s): Nucker, Christine M.
• Application Number:
  US05/809,005
• Time in Patent Office: 454 Days
• Field of Search: 424/1, 424/1.5, 424/12, 23/230 B
• US Class Current: 436/526
• CPC Class Codes: G01N 33/54333 Modification of conditions of immunological binding reaction, e.g. use of more than one type of particle, use of chemical agents to improve binding, choice of incubation time or application of magnetic field during binding reaction
• CPC Class Codes: G01N 33/585 with a particulate label, e.g. coloured latex
• CPC Class Codes: G01N 33/76 Human chorionic gonadotropin including luteinising hormone, follicle stimulating hormone, thyroid stimulating hormone or their receptors
• CPC Class Codes: Y10S 436/804 Radioisotope, e.g. radioimmunoassay
• CPC Class Codes: Y10S 436/805 Optical property
• CPC Class Codes: Y10S 436/806 Electrical property or magnetic property
• CPC Class Codes: Y10S 436/814 Pregnancy
• CPC Class Codes: Y10S 436/818 Human chorionic gonadotropin

Abstract

A mixture of two different kinds of particles having distinctive, different properties is employed for determining the presence of a select protein in, or the absence of a select protein from, a solution. The first kind of particle provides a property facilitating separation, while the second kind of particle provides a property facilitating detection. The particles are coated with the same protein, a protein able to interact specifically with the select protein.

Claims

1. A diagnostic method for determining the presence or absence of select protein in a liquid sample comprising the steps of:

dispersing a plurality of finely divided inert first particles and a plurality of finely divided inert second particles in the sample liquid, said first particles possessing a property facilitating separation thereof from said sample liquid, said second particles possessing a property facilitating detection thereof, said first and second particles both being coated with protein material specific to said select protein;

separating said first particles from said sample liquid utilizing the separation-facilitating property thereof, and

determining whether a substantial portion of said plurality of second particles have accompanied said separated first particles.

2. The diagnostic method of claim 1 wherein said first particles are metallic and said second particles are plastic beads.

3. The diagnostic method recited in claim 2 wherein the metal particles are magnetically responsive and the plastic beads are fluorescent.

4. The diagnostic method recited in claim 3 wherein the metal particles are nickel and the fluorescent plastic beads comprise polystyrene containing anthracene.

5. The diagnostic method recited in claim 3 wherein the metal particles are nickel and the fluorescent plastic beads comprise polystyrene containing fluorescein.

6. The diagnostic method recited in claim 2 wherein the plastic beads are distinctly colored.

7. The diagnostic method recited in claim 2 wherein the plastic beads are radioactively tagged.

8. The diagnostic method recited in claim 7 wherein the metal is magnetically responsive.

9. The diagnostic method recited in claim 1 wherein the first and second particles have a size of less than about one micron.

10. The diagnostic method recited in claim 1 wherein the concentration by volume of first particles is approximately equal to the concentration by volume of the second particles.

11. The diagnostic method recited in claim 1 wherein the total concentration of said particles per milliliter of final liquid volume is in the range of from about 10⁷ to about 10¹⁰ particles/ml.

12. The diagnostic method recited in claim 11 wherein the concentration of particles per milliliter is about 10⁹ particles/ml.

13. The diagnostic method recited in claim 1 wherein the bonding of the protein material to the second particles is by means of a coupling agent.

14. The diagnostic method recited in claim 1 wherein the bonding of the protein material to the first particles is by means of a coupling agent.

15. The diagnostic method of claim 1 wherein the protein material with which the particles are coated is antigenic in nature.

16. The diagnostic method of claim 1 wherein the protein material with which the particles are coated is made up of antibodies.

17. The diagnostic method recited in claim 16 wherein the select protein is the antibody to human chorionic gonadotropin and the protein layer bonded to the particles is human chorionic gonadotropin.

18. The diagnostic method of claim 1 wherein determining whether a substantial portion of the plurality of second particles has accompanied the separated first particles is accomplished by examining said separated first particles.

19. The diagnostic method of claim 1 wherein determining whether a substantial portion of the plurality of second particles has accompanied the separated first particles is accomplished by examining the sample liquid.