NANOSTRUCTURES FOR IMPROVED MOLECULAR DETECTION
Nanostructures for improved molecular detection are disclosed. The nanostructures may be used to increase the ligand immobilization shift to increase the shift in signal of the analyte. In one embodiment, nanostructures are provided that may have small decay lengths and high sensitivity. In another embodiment, nanostructures are provided that may have large decay lengths and 3D surface matrix chemistries.
1 . A surface plasmon resonance (SPR) sensor medium, comprising:
a nanostructure portion comprising a ligand layer having a ligand that is sensitive to binding with a target analyte, the ligand layer comprising a ligand layer thickness;
wherein the nanostructure comprises a decay length and a sensitivity value; and
wherein the decay length corresponds to the ligand layer thickness and the sensitivity value is not less than about 175 nm per reflective index unit (nm/RIU).
2 . The sensor medium of claim 1 , wherein the decay length is not less than about 0.5 times the ligand layer thickness and not greater than about 1.5 times the ligand layer thickness.
3 . The sensor medium of claim 1 , wherein the decay length is not less than about 5 nm and not greater than about 18 nm.
4 . The sensor medium of claim 1 , wherein the decay length is about 11 nm and the sensitivity value is about 300 nm/RIU.
5 . The sensor medium of claim 1 , wherein the sensitivity value is maximized for the given ligand layer thickens that corresponds to the decay length.
6 . The sensor medium of claim 1 , wherein the decay length is matched to a size of the ligand.
7 . The sensor medium of claim 1 , wherein the ligand is operative to bind with a target analyte within the decay length relative to the sensor media to produce a shift in an optical signal of the sensor media corresponding to the sensitivity value.
8 . The sensor medium of claim 1 , wherein the ligand is much larger than the target analyte.
9 . The sensor medium of claim 8 , wherein the ligand is at least one order of magnitude larger than the target analyte.
10 . The sensor medium of claim 1 , wherein the ligand comprises a first protein.
11 . The sensor medium of claim 1 , wherein the target analyte comprises a second protein.
12 . The sensor medium of claim 1 , wherein the ligand is of a size not less than about 10 kDa and the analyte is of a size not greater than about 1 kDa.
13 . A surface plasmon resonance (SPR) sensor medium, comprising:
a nanostructure comprising a ligand layer having a ligand that is sensitive to binding with a target analyte;
wherein the nanostructure comprises a decay length that corresponds to the thickness of a three dimensional surface matrix chemistry containing the ligand layer.
14 . The sensor medium of claim 13 , wherein the three dimensional surface chemistry comprises at least one of dextran, chitosan, polyelectrolyte, or a sugar.
15 . The sensor medium of claim 13 , wherein the three dimensional surface chemistry comprises dextran chains, wherein the dextran chains comprise a plurality of bindings sites to which ligand may be bound in the sensor media.
16 . The sensor medium of claim 13 , wherein the ligand is much larger than the target analyte.
17 . The sensor medium of claim 16 , wherein the ligand is at least one order of magnitude larger than the target analyte.
18 . The sensor medium of claim 13 , wherein the ligand is of a size not less than about 10 kDa and the analyte is of a size not greater than about 1 Da.
19 . The sensor medium of claim 13 , wherein the three dimensional surface chemistries increase the density of analyte binding sites relative to a native or a substantially planar nanostructure surface.
20 . A method for detection of an analyte in a fluid using a surface plasmon resonance (SPR) sensor, comprising:
providing a SPR sensor medium comprising a nanostructure portion comprising a ligand layer having a ligand that is sensitive to binding with a target analyte, the ligand layer comprising a ligand layer thickness, wherein the nanostructure comprises a decay length and a sensitivity value, and wherein the decay length corresponds to the ligand layer thickness and the sensitivity value is not less than about 175 nm per reflective index unit (nm/RIU);
contacting a fluid comprising an analyte with the SPR sensor medium; and
measuring an optical signal to detect a change in the optical signal in response to the contacting to measure the analyte in the fluid.
21 . The method of claim 20 , wherein the SPR sensor medium is according to claim 2 .
22 . A method for detection of an analyte in a fluid using a surface plasmon resonance (SPR) sensor, comprising:
providing a SPR sensor medium comprising a nanostructure comprising a ligand layer having a ligand that is sensitive to binding with a target analyte, wherein the nanostructure comprises a decay length that corresponds to the thickness of a three dimensional surface matrix chemistry containing the ligand layer;
contacting a fluid comprising an analyte with the SPR sensor medium; and
measuring an optical signal to detect a change in the optical signal in response to the contacting to measure the analyte in the fluid.
23 . The method of claim 22 , wherein the SPR sensor medium is according to claim 13 .