Modulation of a response signal to distinguish between analyte and background signals

1. A method, comprising:

detecting an analyte response signal transmitted from within a lumen of subsurface vasculature inside a body, wherein the analyte response signal is indicative of interaction of functionalized particles with one or more target analytes present in blood circulating in the subsurface vasculature;

detecting an unbound particle signal transmitted from within the lumen of subsurface vasculature, wherein the unbound particle signal is indicative of functionalized particles that are not interacting with the one or more target analytes;

detecting a background signal;

applying a modulation to a portion of the subsurface vasculature, wherein the modulation alters the analyte response signal and the unbound particle signal, such that the analyte response signal is affected differently than the unbound particle signal and the background signal; and

differentiating the analyte response signal from the unbound particle signal and the background signal based, at least in part, on the modulation.

2. The method of claim 1 , further comprising introducing the functionalized particles into the lumen of subsurface vasculature by injection, ingestion, inhalation, or transdermally.

3. The method of claim 1 , further comprising:

directing an interrogating signal into the subsurface vasculature; and

detecting the analyte response signal transmitted from the subsurface vasculature in response to the interrogating signal.

4. The method of claim 1 , wherein the modulation alters the analyte response signal by spatially modulating the functionalized particles that are interacting with the one or more target analytes.

5. The method of claim 1 , wherein the modulation alters one or more properties of the functionalized particles that are interacting with the one or more target analytes.

6. The method of claim 5 , wherein the one or more properties of the functionalized particles comprises one or more of: optical properties, magnetic properties, electric properties, thermal properties, acoustic properties, and physical properties.

7. The method of claim 1 , wherein the functionalized particles each comprise at least one of an antibody, a peptide, a nucleic acid, a protein, a low molecular weight ligand, a polysaccharide, a polyunsaturated fatty acid, a plasmid, or an aptamer.

8. A method, comprising:

detecting an analyte response signal transmitted from an environment, wherein the analyte response signal is indicative of interaction of functionalized particles with one or more target analytes;

detecting an unbound particle signal transmitted from the environment, wherein the unbound particle signal is indicative of functionalized particles that are not interacting with the one or more target analytes;

detecting a background signal;

applying a modulation to a portion of the environment, wherein the modulation alters the analyte response signal and unbound particle signal, such that the analyte response signal is affected differently than the unbound particle signal and background signal; and

differentiating the analyte response signal from the unbound particle signal and the background signal based, at least in part, on the modulation.

9. The method of claim 8 , further comprising:

directing an interrogating signal into the environment; and

detecting the analyte response signal transmitted from the environment in response to the interrogating signal.

10. The method of claim 8 , wherein the environment comprises a living body.

11. The method of claim 10 , wherein the functionalized particles interact with one or more target analytes present in the living body.

12. The method of claim 10 , wherein the functionalized particles are introduced into a body fluid comprising blood, tear fluid, urine, lymph, cerebrospinal fluid, or mucus.

13. The method of claim 10 , further comprising:

introducing the functionalized particles into the living body by injection, ingestion, inhalation, or transdermally.

14. The method of claim 8 , wherein the functionalized particles each comprise at least one of an antibody, a peptide, a nucleic acid, a protein, a low molecular weight ligand, a polysaccharide, a polyunsaturated fatty acid, a plasmid, or an aptamer.

15. A device, comprising:

a detector that detects:

an analyte response signal transmitted from an environment, wherein the analyte response signal is indicative of interaction of one or more target analytes with functionalized particles present in the environment;

an unbound particle signal transmitted from the environment, wherein the unbound particle signal is indicative of functionalized particles that are not interacting with the one or more target analytes; and

a background signal;

a modulation source that alters the analyte response signal and the unbound particle signal, such that the analyte response signal is affected differently than the unbound particle signal and background signal; and

a processor that non-invasively detects the one or more target analytes by differentiating the analyte response signal from the unbound particle signal and the background signal based, at least in part, on the modulation.

16. The device of claim 15 , wherein the environment comprises a living body.

17. The device of claim 16 , further comprising a wearable device mountable to an external surface of the living body, wherein the detector is mounted on the wearable device.

18. The device of claim 15 , wherein at least a portion of the modulation source is mounted on the wearable device.

19. The device of claim 15 , wherein the modulation source alters the analyte response signal differently than the background signal.

20. The device of claim 15 , further comprising an interrogating signal source that directs an interrogation signal source into the environment, the analyte response signal being transmitted in response to the interrogating signal.