Method for detecting an analyte molecule
The invention relates to a method for detecting the presence or amount of an analyte, said method comprising (a) coupling the analyte to a carrier molecule, wherein the carrier molecule is larger in size, electrically charged and/or polar, to form an analyte:carrier molecule complex; (b) contacting the analyte:carrier molecule complex of (a) with an analyte-binding molecule coupled to a semiconducting nanostructure; and (c) determining the change in conductance upon binding of the analyte:carrier molecule complex to the analyte-binding molecule and correlating the determined change in conductance to the presence or amount of the analyte. Alternatively, the analyte:carrier molecule complex of (a) is immobilized on the nanostructure and the immobilized analyte:carrier molecule complex is contacted with the analyte-binding molecule.
1 . A method for detecting the presence or amount of an analyte, said method comprising:
(a) coupling the analyte to a carrier molecule, wherein the carrier molecule is larger in size, electrically charged and/or polar, to form an analyte:carrier molecule complex;
(b) contacting the analyte:carrier molecule complex of (a) with an analyte-binding molecule coupled to a semiconducting nanostructure; and
(c) determining the change in conductance upon binding of the analyte:carrier molecule complex to the analyte-binding molecule and correlating the determined change in conductance to the presence or amount of the analyte.
2 . The method of claim 1 , wherein the carrier molecule is conjugated to a signal enhancer.
3 . The method of claim 2 , wherein the signal enhancer is selected from the group consisting of a metal nanoparticle, a quantum dot, a carbon-based nanomaterial, a silicon particle, a silica particle, an organic molecule, and a mixture thereof.
4 . A method for detecting the presence or amount of an analyte, said method comprising:
(a) coupling the analyte to a carrier molecule, wherein the carrier molecule is larger in size, electrically charged and/or polar, to form an analyte:carrier molecule complex;
(b) immobilizing the analyte:carrier molecule complex of (a) on a semiconducting nanostructure;
(c) contacting the immobilized analyte:carrier molecule complex with an analyte-binding molecule; and
(d) determining the change in conductance upon binding of the analyte-binding molecule to the immobilized analyte:carrier molecule complex and correlating the determined change in conductance to the presence or amount of the analyte.
5 . The method of claim 4 , wherein in (a) a defined amount of analyte is used and prior to (c) a defined amount of analyte-binding molecules is contacted with an unknown amount of the analyte to form a mixture of free analyte-binding molecules and analyte-bound analyte-binding molecules, wherein in (d) the change of conductance upon binding of the free analyte-binding molecules to the immobilized analyte:carrier molecule complex is determined and correlated to the presence or amount of the analyte contacted with the analyte-binding molecule prior to (c).
6 . The method of claim 5 , wherein the change in conductance is inversely proportional to the amount of the analyte.
7 . The method of claim 4 , wherein the analyte-binding molecule is conjugated to a signal enhancer.
8 . The method of claim 7 , wherein the signal enhancer is selected from the group consisting of a metal nanoparticle, a quantum dot, a carbon-based nanomaterial, a silicon particle, a silica particle, an organic molecule, and a mixture thereof.
9 . The method of claim 8 , wherein the metal nanoparticle consists of a metal selected from the group consisting of copper, gold, silver and platinum.
10 . The method of claim 1 , wherein the semiconducting nanostructure comprises a nanostructure selected from the group consisting of a nanotube, a nanowire, a nanopillar, a nanorod, a nanosphere, and a mixture thereof.
11 . The method of claim 10 , wherein the semiconducting nanostructure comprises a carbon semiconductor nanotube or nanowire.
12 . The method of claim 11 , wherein the carbon semiconductor nanotube or nanowire is selected from the group consisting of a single nanotube or nanowire, multiple nanotubes or nanowires, or a network of nanotubes or nanowires.
13 . The method of claim 1 , wherein the semiconducting nanostructure is deposited across metal electrodes.
14 . The method of claim 12 , wherein the carbon semiconductor nanotube or nanowire is a network of nanotubes or nanowires in the form of a flexible, laminated network.
15 . The method of claim 1 , wherein the nanostructure is placed in a microfluidic channel.
16 . The method of claim 15 , wherein the nanostructure in the microfluidic channel forms part of a transistor or a resistor.
17 . The method of claim 16 , wherein the transistor is a field effect transistor (FET).
18 . The method of claim 17 , wherein the transistor is a liquid-gated field effect transistor (LGFET).
19 . The method of claim 1 , wherein each carrier molecule is coupled to 2 or more analyte molecules.
20 . The method of claim 1 , wherein the coupling of the analyte to the carrier molecule is covalent coupling.
21 . The method of claim 1 , wherein the coupling of the analyte-binding molecule to the nanostructure, or the immobilization of the analyte:carrier molecule complex on the nanostructure, is covalent.
22 . The method of claim 1 , wherein the analyte has a size of below 1 kD or below 500 D.
23 . The method of claim 1 , wherein the analyte is a small organic molecule or immunological hapten.
24 . The method of claim 23 , wherein the analyte is selected from the group consisting of a drug, toxin, pesticide and metabolites thereof.
25 . The method of claim 24 , wherein the drug is morphine, or a derivative, or metabolite thereof.
26 . The method of claim 24 , wherein the pesticide is atrazine or 2,4-dichlorophenoxyacetic acid.
27 . The method of claim 1 , wherein the carrier molecule has a size of above 1 kDa or above 5 kDa.
28 . The method of claim 27 , wherein the carrier molecule is an albumin.
29 . The method of claim 28 , wherein the carrier molecule is bovine serum albumin.
30 . The method of claim 1 , wherein the analyte-binding molecule specifically binds the analyte.
31 . The method of claim 1 , wherein the analyte-binding molecule is selected from the group consisting of an antibody, antibody fragment, antibody variant, antibody-like molecule, or receptor protein.
32 . A fluidic sensor device for determining the presence of an analyte in a fluid sample, the sensor device comprising:
a substrate comprising a microchannel, wherein the microchannel comprises a detection area, and wherein the detection area is arranged to be contactable by the fluid sample flowing through the microchannel, wherein the detection area comprises a network of semiconducting nanostructures, wherein an analyte:carrier molecule complex or an analyte-binding molecule is coupled to the network of nanostructures; and
a first electrode and a second electrode, wherein the first electrode and the second electrode are electrically connected to the detection area.
33 . The fluidic sensor device of claim 32 , wherein the sensor device is a transistor or resistor.
34 . The fluidic sensor device of claim 33 , wherein the sensor device is a field effect transistor (FET).
35 . The fluidic sensor device of claim 34 , wherein the sensor device is a liquid-gated field effect transistor (LGFET).