Nanoparticle polyanion conjugates and methods of use thereof in detecting analytes

1. A nanoparticle having a plurality of polyanionic polymer conjugates attached thereto, said polyanionic polymer conjugates having the formula

L—O—[PO 2 —O-Z-O] n —PO 2 —O—X

wherein n ranges from 1 to 200; L represents a moiety comprising a functional group for attaching the polyanion polymer to a nanoparticle surface; Z represents a bridging group, and X represents Q, X′ or -Q-X′, wherein Q represents a functional group comprising a carboxylic acid or an amino group for attaching a recognition probe to the polyanion polymer, and X′ represents a recognition probe.

2. The nanoparticle of claim 1 , wherein the polyanionic polymer conjugate further comprises a detection label bound thereto.

3. The nanoparticle of claim 2 , wherein the detection label comprises a chromophore, a fluorescent label, a UV label, a radioisotope, a Raman label or a SERS (surface enhanced raman spectroscopy) label, or an enzyme.

4. The nanoparticle of claim 1 , wherein the recognition probe comprises a protein, a peptide, a nucleic acid, a peptide nucleic acid, a linked nucleic acid, a nucleoside triphosphate, a carbohydrate, a lipid, a lipid bound protein, an aptamer, a virus, a cell fragment, or a whole cell.

5. The nanoparticle of claim 4 , wherein the lipid bound protein comprises a G-protein coupled receptor.

6. The nanoparticle of claim 1 , wherein the recognition probe comprises an antibody, an antigen, a receptor, or a ligand.

7. The nanoparticle of claim 1 wherein L comprises an alkanethiol containing group, a phosphorothioate containing group, a substituted alkylsiloxane containing, a polythiol containing group, or a cyclic disulfide containing group.

8. The nanoparticle of claim 1 wherein Z comprises a polymer, —C 1 -C 10 -alkyl-, —COO—, —CHR 2 (CH 2 ) v COO—, —OCO—R 1 N(CH 2 ) v—NR 1 —, —OC(CH 2 ) v —, —(CH 2 ) v —, —O—(CH 2 ) v —O—, —RN—(CH 2 ) v —,

v is 0-30 and R 1 is H or is G(CH 2 ) v , wherein G is —CH 3 , —CHCH 3 , —COOH, —CO 2 (CH 2 ) v CH 3 , —OH, or —CH 2 OH.

9. A kit for detecting the presence or absence of a target analyte in a sample comprising:

(a) nanoparticles having polyanionic polymer conjugates bound thereto, wherein the polyanion polymers have the formula:

L-O—[PO 2 —O-Z-O] n —PO 2 —O—X

wherein n ranges from 1 to 200; L represents a moiety comprising a functional group for attaching the polyanion polymer to a nanoparticle surface; Z represents a bridging group, and X represents Q, X′ or -Q-X′, wherein Q represents a functional group comprising a carboxylic acid or an amino group for attaching a recognition probe to the polyanion polymer, and X′ represents a recognition probe; and

(b) an optional substrate for observing a detectable change.

10. The kit of claim 9 , wherein the polyanionic polymer conjugate further comprises a detection label bound thereto.

11. The kit of claim 10 , wherein the detection label comprises a chromophore, a fluorescent label, a UV label, a radioisotope, a Raman label or a SERS (surface enhanced raman spectroscopy) label, or an enzyme.

12. The kit of claim 9 , wherein the probe comprises a protein, a peptide, a nucleic acid, a peptide nucleic acid, a linked nucleic acid, a nucleoside triphosphate, a carbohydrate, a lipid, a lipid bound protein, an aptamer, a virus, a cell fragment, or a whole cell.

13. The kit of claim 12 , wherein the lipid bound protein comprises a G-protein coupled receptor.

14. The kit of claim 9 , wherein the probe comprises an antibody, an antigen, a receptor, or a ligand.

15. The kit of claim 9 wherein the substrate is a transparent substrate or an opaque white substrate.