NMR systems and methods for the rapid detection of analytes

1. A composition comprising:

(a) a liquid sample containing an analyte; and

(b) within the liquid sample from 1×10 6 to 1×10 13 magnetic particles per milliliter of the liquid sample, the magnetic particles having a mean diameter of from 700 nm to 950 nm, a T 2 relaxivity per particle of from 1×10 4 to 1×10 12 and binding moieties specific to the analyte are conjugated to their surface,

wherein the analyte from the sample is bound to at least one of the binding moieties on at least one magnetic particle.

2. A composition comprising:

(a) a liquid sample suspected of containing a Candida nucleic acid; and

(b) within the liquid sample from 1×10 6 to 1×10 13 magnetic particles per milliliter of the liquid sample, the magnetic particles having a mean diameter of from 700 nm to 950 nm, a T 2 relaxivity per particle of from 1×10 9 to 1×10 12 mM −1 s −1 , and having a first nucleic acid probe and a second nucleic acid probe conjugated to their surface selected so that the first nucleic acid probe is operative to bind to a first segment of the Candida nucleic acid and the second nucleic acid probe is operative to bind to a second segment of the Candida nucleic acid.

3. The composition of claim 2 , wherein the liquid sample is derived from a whole blood sample.

4. A composition, comprising:

(a) a liquid sample containing one or more nucleic acid amplicons generated from an amplification reaction; and

(b) within the liquid sample from 1×10 6 to 1×10 13 magnetic particles per milliliter of the liquid sample, the magnetic particles having a mean diameter of from 700 nm to 950 nm, a T 2 relaxivity per particle of from 1×10 4 to 1×10 12 mM −1 s −1 , and having a first nucleic acid probe and a second nucleic acid probe conjugated to their surface selected so that the first nucleic acid probe is operative to bind to a first segment of the nucleic acid amplicons and the second nucleic acid probe is operative to bind to a second segment of the nucleic acid amplicons.

5. A composition, comprising:

(a) a liquid sample containing Candida nucleic acid amplicons generated from an amplification reaction; and

(b) within the liquid sample from 1×10 6 to 1×10 13 magnetic particles per milliliter of the liquid sample, the magnetic particles having a mean diameter of from 700 nm to 950 nm, a T 2 relaxivity per particle of from 1×10 4 to 1×10 12 mM −1 s −1 , and having a first nucleic acid probe and a second nucleic acid probe conjugated to their surface selected so that the first nucleic acid probe is operative to bind to a first segment of the Candida nucleic acid amplicons and the second nucleic acid probe is operative to bind to a second segment of the Candida nucleic acid amplicons.

6. The composition of claim 5 , wherein said magnetic particles have a T 2 relaxivity per particle of from 1×10 9 to 1×10 12 mM −1 s −1 .

7. The composition of claim 5 , the binding of the first probe to a first segment of the Candida amplicon and the binding of the second probe to a second segment of the Candida amplicon form magnetic particle-amplicon aggregates.

8. The composition of claim 7 , wherein said magnetic particles have a T 2 relaxivity per particle of from 1×10 9 to 1×10 12 mM −1 s −1 .

9. The aggregate of claim 7 , wherein the Candida nucleic acid amplicons are amplified from Candida albicans, and wherein the first probe comprises the oligonucleotide sequence:

(SEQ ID NO: 3)

5′-ACC CAG CGG TTT GAG GGA GAA AC-3′,

and the second probe comprises the oligonucleotide sequence:

(SEQ ID NO: 4)

5′-AAA GTT TGA AGA TAT ACG TGG TGG ACG TTA-3′.

10. The aggregate of claim 7 , wherein the Candida nucleic acid amplicons are amplified from Candida krusei , and wherein the first probe comprises the oligonucleotide sequence:

(SEQ ID NO: 5)

5′-CGC ACG CGC AAG ATG GAA ACG-3′,

and the second probe comprises the oligonucleotide sequence:

(SEQ ID NO: 6)

5′-AAG TTC AGC GGG TAT TCC TAC CT-3′.

11. The aggregate of claim 7 , wherein the Candida nucleic acid amplicons are amplified from Candida glabrata , and wherein the first probe comprises the oligonucleotide sequence:

(SEQ ID NO: 7)

5′-CTA CCA AAC ACA ATG TGT TTG AGA AG-3′,

and the second probe comprises the oligonucleotide sequence:

(SEQ ID NO: 8)

5′-CCT GAT TTG AGG TCA AAC TTA AAG ACG TCT G-3′.

12. The aggregate of claim 7 , wherein the Candida nucleic acid amplicons are amplified from Candida parapsilosis or Candida tropicalis , and wherein the first probe comprises the oligonucleotide sequence:

(SEQ ID NO: 9)

5′-AGT CCT ACC TGA TTT GAG GTCNitIndAA-3′,

and the second probe comprises the oligonucleotide sequence:

(SEQ ID NO: 10)

5′-CCG NitIndGG GTT TGA GGG AGA AAT-3′.

13. The composition of claim 5 , wherein the Candida nucleic acid amplicons are amplified from Candida albicans, and wherein the first probe comprises the oligonucleotide sequence:

(SEQ ID NO: 3)

5′-ACC CAG CGG TTT GAG GGA GAA AC-3′,

and the second probe comprises the oligonucleotide sequence:

(SEQ ID NO: 4)

5′-AAA GTT TGA AGA TAT ACG TGG TGG ACG TTA-3′.

14. The composition of claim 5 , wherein the Candida nucleic acid amplicons are amplified from Candida krusei , and wherein the first probe comprises the oligonucleotide sequence:

(SEQ ID NO: 5)

5′-CGC ACG CGC AAG ATG GAA ACG-3′,

and the second probe comprises the oligonucleotide sequence:

(SEQ ID NO: 6)

5′-AAG TTC AGC GGG TAT TCC TAC CT-3′.

15. The composition of claim 5 , wherein the Candida nucleic acid amplicons are amplified from Candida glabrata , and wherein the first probe comprises the oligonucleotide sequence:

(SEQ ID NO: 7)

5′-CTA CCA AAC ACA ATG TGT TTG AGA AG-3′,

and the second probe comprises the oligonucleotide sequence:

(SEQ ID NO: 8)

5′-CCT GAT TTG AGG TCA AAC TTA AAG ACG TCT G-3′.

16. The composition of claim 5 , wherein the Candida nucleic acid amplicons are amplified from Candida parapsilosis or Candida tropicalis , and wherein the first probe comprises the oligonucleotide sequence:

(SEQ ID NO: 9)

5′-AGT CCT ACC TGA TTT GAG GTCNitIndAA-3′,

and the second probe comprises the oligonucleotide sequence:

(SEQ ID NO: 10)

5′-CCG NitIndGG GTT TGA GGG AGA AAT-3′.

17. A composition comprising:

(a) a liquid sample containing nucleic acid amplicons generated from an amplification reaction;

(b) within the liquid sample from 1×10 6 to 1×10 13 magnetic particles per milliliter of the liquid sample, the magnetic particles having a mean diameter of from 700 nm to 950 nm, a T 2 relaxivity per particle of from 1×10 4 to 1×10 12 mM −1 s −1 , and having a first nucleic acid probe and a second nucleic acid probe conjugated to their surface and selected to hybridize to a first segment and a second segment of the nucleic acid amplicons to form aggregates, the aggregates comprising the magnetic particles and the nucleic acid amplicons.

18. The composition of claim 17 , wherein said magnetic particles have T 2 relaxivity per particle of from 1×10 9 to 1×10 12 mM −1 s −1 .

19. A method of detecting the presence of an analyte, comprising:

(a) combining a liquid sample containing an analyte with a population of 1×10 6 to 1×10 13 magnetic particles per milliliter of the liquid sample, the magnetic particles having a mean diameter of from 700 nm to 950 nm, a T 2 relaxivity per particle of from 1×10 4 to 1×10 12 mM −1 s −1 , and binding moieties specific to a first binding site on the analyte are conjugated to their surface;

(b) exposing the sample to a magnetic field to capture or concentrate the magnetic particles and the analyte;

(c) exposing the concentrated magnetic particles to a surface derivatized with ligands complementary to a second binding site on the analyte thereby forming magnetic particle-analyte-ligand complexes;

(d) placing the analyte-bound magnetic particles in a well having an radiofrequency (RF) coil disposed about the well, the RF coil configured to detect a signal produced by exposing the liquid sample to a bias magnetic field created using one or more magnets and an RF pulse sequence;

(e) exposing the sample to a bias magnetic field and an RF pulse sequence;

(f) following step (e), measuring the T2 relaxation signal; and

(g) wherein an increase in T2 relaxation measured in step (f) indicates the presence of said analyte in the liquid sample.