System and method for Raman spectroscopy assay using paramagnetic particles

• US 20060240572A1
• Filed: 08/24/2005
• Published: 10/26/2006
• Est. Priority Date: 08/24/2004
• Status: Active Grant

• Current Assignee: University of Wyoming
• Original Assignee: University of Wyoming
• Inventors: Ray, Bryan H., Carron, Keith T.
• Granted Patent: US 9,494,581 B2
• Time in Patent Office: Days
• US Class Current: 436/524
• CPC Class Codes: G01N 2021/651 Cuvettes therefore
• CPC Class Codes: G01N 21/658 enhancement Raman, e.g. surface plasmons
• CPC Class Codes: G01N 33/54326 Magnetic particles
• CPC Class Codes: G01N 33/54353 with ligand attached to the carrier via a chemical coupling agent coatings G01N33/54393

Abstract

A Raman spectroscopy technique allows an analyte, a paramagnetic particle, and a spectral enhancement particle to combine in solution and for the combination product to be localized by a magnetic field for analysis. The spectral enhancement particle may be comprised of an active SERS metal particle with or without a material coating. The spectral enhancement particle may function as a reporter for the presence of the analyte or merely increase the magnitude of the Raman spectrum of the analyte. The technique is applicable to both immunoassays and chemical assays. Multiple spectral enhancement particle reporters may be measured in a single assay that can detect multiple analytes using the SERS effect.

Claims

1. A method for performing an assay to determine the presence of at least one analyte, the method comprising

binding at least one of a plurality of spectral enhancement particles, at least one of a plurality of paramagnetic particles, and at least one analyte in a solution, should the at least one analyte be present in the solution;

applying a magnetic field to the solution; and

concentrating at least a portion of the plurality of paramagnetic particles in a discrete location using the influence of the magnetic field.

2. The method of claim 1 further comprising

interrogating the discrete location with a laser light beam;

and

acquiring a Raman spectrum from Raman scattered light from the discrete location.

3. The method of claim 2, wherein

the assay is an immunoassay;

the at least one analyte is at least one antigen;

at least a first portion of the spectral enhancement particles are connected with a first antibody specific to the at least one antigen and a spectral flag compound; and

at least a first portion of the paramagnetic particles are connected with a second antibody specific to the at least one antigen; and

wherein the step of binding further comprises

binding the first portion of the paramagnetic particles to the first portion of the spectral enhancement particles via the at least one antigen when the spectral enhancement particles with the first antibody and the paramagnetic particles with the second antibody are in the presence of the at least one antigen.

4. The method of claim 3 further comprising determining whether the spectral flag compound is present in the discrete location as a result of the binding of the first portion of the paramagnetic particles to the first portion of the spectral enhancement particles via the at least one antigen by analyzing the Raman spectrum for a signature spectrum of the spectral flag compound.

5. The method of claim 4 further comprising indicating the presence or absence of the antigen in the solution based upon the presence or absence, respectively, of the signature spectrum of the spectral flag compound.

6. The method of claim 3, wherein the first antibody is the same as the second antibody.

7. The method of claim 2 further comprising magnifying the amplitude of the Raman scattered light through the presence and influence of the spectral enhancement particles.

8. The method of claim 2 further comprising translating the Raman spectrum into a barcode.

9. The method of claim 1 further comprising varying the magnetic field to pull the plurality of paramagnetic particles in multiple directions within the solution, thereby creating a mechanical convection within the solution.

10. The method of claim 2 further comprising at least semi-continuously introducing the solution into a sampling chamber.

11. The method of claim 4, wherein

the at least one antigen comprises a plurality of antigens;

the plurality of spectral enhancement particles includes a plurality of subsets of the spectral enhancement particles, wherein each of the subsets is connected with a respective antibody specific to a respective one of the plurality of antigens and a respective spectral flag compound unique to the respective subset; and

the plurality of paramagnetic particles includes a plurality of subsets of the paramagnetic particles, wherein each of the subsets is connected with a respective antibody specific to a respective one of the plurality of antigens; and

wherein

the step of binding further comprises binding respective subsets of the paramagnetic particles to respective subsets of the spectral enhancement particles via respective ones of the plurality of antigens; and

the step of determining further comprises determining whether one or more of the unique spectral flag compounds is present in the discrete location.

12. The method of claim 2, wherein

the assay is a chemical assay;

the solution comprises a plurality of first tethers, each of the first tethers having a first binding end with an affinity for the spectral enhancement particles and a second binding end with an affinity for the paramagnetic particles;

the solution further comprises a plurality of second tethers, each of the second tethers having a first binding end with an affinity for the spectral enhancement particles and a second binding end with an affinity for the analyte; and

wherein the step of binding further comprises

binding the paramagnetic particles to the spectral enhancement particles via the first tethers; and

binding the spectral enhancement particles to the analyte via the second tethers in the circumstance the analyte is in the solution.

13. The method of claim 12 further comprising determining whether the analyte is present in the solution by analyzing a resulting Raman spectrum for a signature spectrum of the analyte.

14. The method of claim 12 further comprising indicating the presence or absence of the analyte in the solution based upon the presence or absence, respectively, of the signature spectrum of the analyte.

15. The method of claim 13, wherein

the at least one analyte comprises a plurality of analytes;

and

the plurality of second tethers comprises a plurality of subsets of the second tethers, wherein each the of the subsets has a unique second binding end that is specific to a respective one of the plurality of analytes; and

wherein

the step of determining further comprises determining whether one or more of the plurality of analytes is present in the discrete location.

16. A method for coupling a paramagnetic particle and a spectral enhancement particle, the method comprising

introducing a plurality of spectral enhancement particles into a solution;

introducing a plurality of paramagnetic particles into the solution;

introducing a tether into the solution having a first binding end with an affinity for the spectral enhancement particles and a second binding end with an affinity for the paramagnetic particles; and

attaching the paramagnetic particles to the spectral enhancement particles via the first tether.

17. The method of claim 16 further comprising

applying a magnetic field to the solution;

and

concentrating the paramagnetic particles and attached spectral enhancement particles into a discrete location using the influence of the magnetic field.

18. The method of claim 17 further comprising removing the paramagnetic particles and attached spectral enhancement particles from the solution.

19. A Raman spectroscopy assay system comprising

a sample chamber;

a magnet positioned adjacent the sample chamber;

a plurality of spectral enhancement particles adapted to bind with an analyte positioned within the sample chamber;

a plurality of paramagnetic particles positioned within the sample chamber, wherein the plurality of paramagnetic particles are adapted to bind with either the spectral enhancement particles or the analyte and attracted by a magnetic field generated by the magnet;

a laser aligned with the magnet such that a light beam generated by the laser is directed into the sample chamber to a position where the paramagnetic particles concentrate under the influence of the magnetic field generated by the magnet; and

a Raman analyzer positioned to acquire Raman scattered light reflected from the analyte when bound with the plurality of spectral enhancement particles.

20. The system of claim 19 further comprising a plurality of magnets positioned adjacent and about the sample chamber.

21. The system of claim 19, wherein the magnet is an electromagnet.