Separation system and efficient capture of contaminants using magnetic nanoparticles

• US 20070114181A1
• Filed: 01/09/2006
• Published: 05/24/2007
• Est. Priority Date: 01/07/2005
• Status: Active Grant

• Current Assignee: The Board of Trustees of the University of Arkansas (University of Arkansas System)
• Original Assignee: The Board of Trustees of the University of Arkansas (University of Arkansas System)
• Inventors: Li, Yanbin, Ye, Zunzhang, Varshney, Madhukar
• Granted Patent: US 7,699,979 B2
• Time in Patent Office: Days
• US Class Current: 210/695
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C02F 2209/36 Biological material, e.g. enzymes or ATP
• CPC Class Codes: G01N 33/54326 Magnetic particles
• CPC Class Codes: G01N 35/0098 involving analyte bound to insoluble magnetic carrier, e.g. using magnetic separation magnetic particles used in immunoassays G01N33/54326; magnetic separation in general B03C
• CPC Class Codes: Y10T 436/13 Tracers or tags

Abstract

Methods are disclosed for the capture, detection, separation, isolation and quantification of contaminants in a starting material. Also disclosed are competitive assay methods for the detection and quantification of contaminants in a starting material. Kits for use with the method are disclosed as well. A system for capturing, separating and/or concentrating contaminants from a material is also presented. The system captures, separates and/or concentrates contaminants such as bacteria, viruses, other microorganisms, and/or larger items, such as insects, from a variety of materials, such as food, and environmental and clinical materials. In general, the system uses a rotating magnetic field to mix the material with magnetic particles to capture the target contaminants, and a fixed magnetic field to separate and concentrate the captured target contaminants.

Claims

1. A method of separating a contaminant from an untreated starting material, the method comprising:

a) immunolabeling a contaminant in the untreated starting material; and

b) nanomagnetically separating the contaminant from the untreated starting material.

2. The method of claim 1, wherein said starting material is selected from the group consisting of a food product, an environmental sample and a clinical sample.

3. The method of claim 2, wherein the food product is selected from the group consisting of a fruit, a vegetable, a raw food, a ready-to-eat food, a beef product, a pork product, a poultry product, a sea food product, or a diary product.

4. The method of claim 1, wherein the contaminant is selected from the group consisting of a prokaryote, a eukaryote, a virus, and a polypeptide.

5. The method of claim 4, wherein the prokaryote is selected from the group consisting of Escherichia coli, Escherichia coli O157:

H7, Salmonella spp., and Listeria monocytogenes.

6. A method of separating a contaminant from an untreated starting material, the method comprising:

a) contacting said starting material with an affinity moiety capable of binding the contaminant to form a target comprising the affinity moiety bound to the contaminant;

b) contacting the target of step (a) with a magnetic nanoparticle capable of binding the affinity moiety to form a magnetic target; and

c) separating the magnetic target from said starting material.

7. The method of claim 6, wherein the magnetic nanoparticle is bound to the affinity moiety prior to step (a).

8. The method of claim 6, wherein the affinity moiety comprises an antibody.

9. The method of claim 8, wherein the magnetic nanoparticle is coupled to a linker capable of binding the antibody.

10. The method of claim 9, wherein the linker is selected from the group consisting of Protein A, Protein G, an Fc receptor, and an anti-Fc antibody.

11. The method of claim 10, wherein the linker comprises a bridging complex selected from the group consisting of:

biotin-streptavidin, biotin-avidin, Protein A-IgG, Protein G-IgG, and IgG-anti-IgG.

12. The method of claim 6, wherein said starting material is selected from the group consisting of a food product, an environmental sample and a clinical sample.

13. The method of claim 12, wherein the food product is selected from the group consisting of a fruit, a vegetable, a raw food, a ready-to-eat food, a beef product, a pork product, a poultry product, a sea food product, and a diary product.

14. The method of claim 13, wherein the poultry product is selected from the group consisting of a chicken carcass, a chicken carcass wash water sample, a deboned chicken, a ground poultry meat sample and a poultry patty.

15. The method of claim 12, wherein the environmental sample is selected from the group consisting of a water sample, an air sample and a soil sample.

16. The method of claim 12, wherein the clinical sample is selected from the group consisting of a urine sample, a blood sample, a fecal sample, a swab from the surface of the skin, a swab from the surface of an organ, and a tissue sample.

17. The method of claim 6, wherein the contaminant is selected from the group consisting of a prokaryote, a eukaryote, a virus, and a polypeptide.

18. The method of claim 17, wherein the prokaryote is selected from the group consisting of Escherichia coli, Escherichia coli O157:

H7, Salmonella spp., and Listeria monocytogenes.

19. The method of claim 17, wherein the polypeptide is selected from the group consisting of a toxin and a prion.

20. The method of claim 6, further comprising:

e) isolating the contaminant from the magnetic target.

21. The method of claim 6, further comprising:

e) subjecting the magnetic target and the contaminant to antibiotic resistance testing.

22. The method of claim 6, further comprising:

e) subjecting the magnetic target to microbiologic, immunologic, or nucleic acid based assays.

23. A method of quantifying the amount of a contaminant in an untreated starting material, the method comprising:

a) contacting said starting material with an affinity moiety capable of binding the contaminant to form a target comprising the affinity moiety bound to the contaminant;

b) contacting the target of step (a) with a magnetic nanoparticle capable of binding the affinity moiety to form a magnetic target;

c) separating the magnetic target from said starting material; and

d) determining the quantity of the contaminant in said starting material.

24. The method of claim 23, wherein the quantity of the contaminant is determined by a method selected from the group consisting of plate counting, ELISA, PCR, quantum dot biolabeling and biosensors.

25. The method of claim 23, wherein said starting material is selected from the group consisting of a food product, an environmental sample and a clinical sample.

26. The method of claim 23, wherein the contaminant is selected from the group consisting of a prokaryote, a eukaryote, a virus, and a polypeptide.

27. The method of claim 23, wherein the magnetic nanoparticle is bound to the affinity moiety prior to step (a).

28. A kit for separating a contaminant from a untreated starting material, the kit comprising:

a) a magnetic nanoparticle capable of binding an affinity moiety; and

b) an affinity moiety capable of binding the contaminant.

29. The kit of claim 28, further comprising a stomacher.

30. The kit of claim 28, wherein the affinity moiety comprises an antibody.

31. The kit of claim 30, wherein the antibody is coupled to the magnetic nanoparticle.

32. The kit of claim 30, wherein the magnetic nanoparticle is coupled to a linker capable of binding the antibody.

33. The kit of claim 28, further comprising:

c) at least one solution comprising a known concentration of the contaminant.

34. A method of separating a contaminant from a starting material, the method consisting of:

a) homogenizing the starting material;

b) contacting the homogenized starting material of step (a) with an affinity moiety capable of binding the contaminant to form a target, the target comprising the affinity moiety bound to the contaminant;

c) contacting the target of step (b) with a magnetic nanoparticle capable of binding the affinity moiety to form a magnetic target; and

d) separating the magnetic target from the homogenized starting material.

35. The method of claim 34, wherein the affinity moiety comprises an antibody.

36. The method of claim 35, wherein the antibody is coupled to the magnetic nanoparticle.

37. The method of claim 34, wherein said starting material is selected from the group consisting of a food product, an environmental sample and a clinical sample.

38. The method of claim 37, wherein the food product is selected from the group consisting of a fruit, a vegetable, a raw food, a ready-to-eat food, a beef product, a pork product, a poultry product, a sea food product, and a diary product.

39. The method of claim 34, wherein the contaminant is selected from the group consisting of a prokaryote, a eukaryote, a virus, and a polypeptide.

40. A method of quantifying the amount of a contaminant in a starting material, the method consisting of:

a) homogenizing the starting material;

b) contacting the homogenized starting material of step (a) with an affinity moiety capable of binding the contaminant to form a target comprising the affinity moiety bound to the contaminant;

c) contacting the target of step (b) with a magnetic nanoparticle capable of binding the affinity moiety to form a magnetic target;

d) separating the magnetic target from the homogenized starting material; and

e) determining the quantity of the contaminant in the starting material.

41. A method of detecting a contaminant in a starting material, the method comprising:

a) contacting the starting material containing the contaminant and a control material not containing the contaminant with

     1) a marker coupled to an affinity moiety, the affinity moiety capable of binding the contaminant, the marker having a characteristic emission spectrum, and

     2) a competitor complex comprising a magnetic nanoparticle coupled to the contaminant;

b) separating the competitor complex from each of the starting material and the control material; and

c) detecting the characteristic emission spectrum of the marker associated with the competitor complex from each of the starting material and the control material, wherein a decrease in the intensity of the characteristic emission spectrum of the competitor complex from the starting material as compared to the intensity of the characteristic emission spectrum of the competitor complex from the control material is indicative of the presence of the contaminant in the starting material.

42. The method of claim 41, wherein the contaminant is selected from the group consisting of a prokaryote, a eukaryote, a virus, a polypeptide and a chemical.

43. The method of claim 42, wherein the chemical is selected from the group consisting of a herbicide and a pesticide.

44. The method of claim 43, wherein the herbicide is 2-chloro-4-(ethylamine)-6-(isopropylamine)-s-triazine.

45. A method for quantifying a contaminant in a starting material, the method comprising:

a) contacting the starting material containing the contaminant, a control material not containing the contaminant and at least one control material containing a known amount of the contaminant with

     1) a marker coupled to an affinity moiety capable of binding the contaminant, the marker having a characteristic emission spectrum, and

     2) a competitor complex comprising a magnetic nanoparticle coupled to the contaminant;

b) separating the competitor complex from each of the starting material, the control material not containing the contaminant and at least one control material containing a known amount of the contaminant;

c) detecting the characteristic emission spectrum of the marker associated with the competitor complex from each of the starting material, the control material not containing the contaminant and at least one control material containing a known amount of the contaminant; and

d) comparing the intensity of the characteristic emission spectrum associated with the competitor complex from the starting material to the intensity of the characteristic emission spectrum associated with the competitor complex from the control material containing a known amount of the contaminant, wherein the intensity of the characteristic emission spectrum is indicative of the quantity of the contaminant in the starting material.

46. A system for separating a contaminant from a material, the system comprising:

a housing;

a chamber supported by the housing and configured to receive the material and a plurality of magnetic particles;

a controller configured to produce a first signal to mix the magnetic particles with the material and a second signal to separate the contaminant from the material; and

a magnetic field subsystem in communication with the controller and configured to create within the chamber a rotational magnetic field in response to the first signal and a fixed magnetic field in response to the second signal.