WATER RELAXATION-BASED SENSORS

• US 20100120174A1
• Filed: 11/04/2009
• Published: 05/13/2010
• Est. Priority Date: 05/09/2005
• Status: Active Grant

• Current Assignee: The General Hospital Corporation (Mass General Brigham, Inc.)
• Original Assignee: The General Hospital Corporation (Mass General Brigham, Inc.)
• Inventors: Sun, Yi, Weissleder, Ralph, Josephson, Lee
• Granted Patent: US 8,535,949 B2
• Time in Patent Office: Days
• US Class Current: 436/526
• CPC Class Codes: A61B 5/14503 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors A61B5/1459, A61B5/1464, A61B5/1473, A61B5/1482, A61B5/14865 take precedence
• CPC Class Codes: G01N 27/745 for detecting magnetic beads used in biochemical assays concerning the assays G01N33/54326; sensors therefor G01R33/1269; automatic analysers therefor G01N35/0098
• CPC Class Codes: G01N 33/54326 Magnetic particles
• CPC Class Codes: G01N 33/54366 Apparatus specially adapted for solid-phase testing
• CPC Class Codes: G01R 33/465 applied to biological material, e.g. in vitro testing
• CPC Class Codes: G01R 33/50 based on the determination of relaxation times , e.g. T1 measurement by IR sequences; T2 measurement by multiple-echo sequences

Abstract

This invention relates to magnetic resonance-based sensors and related methods.

Claims

1. A method of detecting an analyte in an aqueous sample, the method comprising:

(i) providing a water relaxation sensor comprising;

(a) a walled enclosure enveloping a chamber, wherein the wall comprises an opening for passage of the analyte into and out of the chamber;

(b) a plurality of magnetic nanoparticles located within the chamber, each nanoparticle having at least one moiety that is covalently or noncovalently linked to the nanoparticle; and

optionally,

(c) at least one binding agent located within the chamber;

wherein the opening is smaller in size than the nanoparticles, and is larger in size than the analyte; and

wherein the moiety and the analyte each bind reversibly to the binding agent, when present, or the analyte binds reversibly to the moiety, to cause a reversible aggregation or disaggregation of the nanoparticles within the chamber in an equilibrium controlled process, wherein the equilibrium is dependent upon, and changes with, analyte concentration;

(ii) measuring relaxation times of the water inside of the chamber of the sensor in the absence of the analyte or under conditions that mimic the absence of the analyte;

(iii) contacting the sensor with the sample;

(iv) measuring relaxation times of the water inside of the chamber of the sensor; and

(v) comparing the T2 relaxation times measured in step (ii) and step (iv);

wherein a change in T2 relaxation times measured in step (iv) relative to the T2 relaxation times measured in step (ii) indicates the presence of the analyte.

2. The method of claim 1, wherein the analyte is a monovalent analyte.

3. The method of claim 1, wherein the analyte is a multivalent analyte.

4. The method of claim 1, wherein the change in the T2 relaxation times is measured using a magnetic resonance imaging method.

5. The method of claim 1, wherein the change in the T2 relaxation times is measured using a magnetic resonance non-imaging method.

6. The method of claim 1, wherein the analyte is a carbohydrate.

7. The method of claim 1, wherein the analyte is chiral.

8. The method of claim 7, wherein the chiral analyte is present together with one or more optically active moieties in the sample.

9. The method of claim 8, wherein the chiral analyte is present together with a stereoisomer of the chiral analyte in the sample.

10. The method of claim 9, wherein the chiral analyte is present together with an enantiomer of the chiral analyte in the sample.

11. The method of claim 7, wherein the chiral analyte is an amino acid.

12. The method of claim 1, wherein the analyte is a nucleic acid or an oligonucleotide.

13. The method of claim 1, wherein the analyte is a therapeutic agent or a metabolite of a therapeutic agent.

14. The method of claim 1, wherein the analyte is peptide or a protein.

15. The method of claim 1, wherein the opening is smaller in size than the binding agent.

16. The method of claim 1, wherein the moiety comprises a carbohydrate, an antibody, an amino acid, a nucleic acid, an oligonucleotide, a therapeutic agent or a metabolite thereof, a peptide, or a protein.

17. The method of claim 1, wherein the moiety comprises a molecular fragment of the analyte being detected or a molecular fragment of a derivative, isostere, or mimic of the analyte being detected.

18. The method of claim 1, wherein the moiety is linked to the nanoparticle by a functional group comprising —

NH—

, —

NHC(O)—

, —

(O)CNH—

, —

NHC(O)(CH₂)_nC(O), —

(O)C(CH₂)_nC(O)NH—

, —

NHC(O)(CH₂)_nC(O)NH—

, —

C(O)O—

, —

OC(O)—

, or —

SS—

, and wherein n is 0 to 20.

19. The method of claim 18, wherein the functional group is —

NHC(O)(CH₂)—

C(O)NH—

.

20. The method of claim 19, wherein n is 2.

21. The method of claim 1, wherein the binding agent is absent.

22. The method of claim 21, wherein the moiety comprises a protein.

23. The method of claim 21, wherein:

(a) when the analyte is absent, the chamber comprises substantially disaggregated nanoparticles; and

(b) when the analyte is present, the chamber comprises a nanoparticle aggregate, wherein the nanoparticle aggregate comprises nanoparticles bound to the exogenous analyte through the moiety.

24. The method of claim 1, wherein the binding agent is present.

25. The method of claim 24, wherein the binding agent comprises a protein or a monoclonal antibody.

26. The method of claim 24, wherein the moiety comprises a molecular fragment of the analyte being detected or a molecular fragment of a derivative, isostere, or mimic of the analyte being detected.

27. The method of claim 24, wherein:

(a) when the analyte is absent, the chamber comprises a nanoparticle aggregate, wherein the nanoparticle aggregate comprises nanoparticles bound to the binding agent through the moiety; and

(b) when the analyte is present, the nanoparticles are displaced from the binding agent by the analyte, and the chamber comprises substantially disaggregated nanoparticles.

28. The method of claim 1, wherein the opening has a size of from about 1 kDa to about 3 kDa.

29. The method of claim 1, wherein each of the nanoparticles has an overall size of from about 30 nm to about 60 nm.

30. The method of claim 23, wherein the nanoparticle aggregate has an overall size of at least about 100 nm.

31. The method of claim 1, wherein the moiety comprises a chiral compound.

32. The method of claim 1, wherein the moiety comprises a carbohydrate.

33. The method of claim 1, wherein the moiety comprises the structure:

34. The method of claim 1, wherein the binding agent is a protein that comprises at least two binding sites.

35. The method of claim 1, wherein the binding agent is a protein that comprises at least four binding sites.

36. The method of claim 1, wherein the binding agent is a protein that binds to a carbohydrate.

37. The method of claim 36, wherein the carbohydrate is glucose.

38. The method of claim 37, wherein the protein is concanavalin A.

39. The method of claim 1, wherein the binding agent comprises a monoclonal antibody, a polyclonal antibody, or a oligonucleotide.

40. The method of claim 1, wherein the magnetic nanoparticles each comprise a magnetic metal oxide.

41. The method of claim 40, wherein the magnetic metal oxide comprises a superparamagnetic metal oxide.

42. The method of claim 40, wherein the metal oxide comprises iron oxide.

43. The method of claim 42, wherein each of the magnetic nanoparticles is an amino-derivatized cross-linked iron oxide nanoparticle.