Sensors for analyte detection and methods of manufacture thereof
Disclosed herein is a sensor comprising a conduit; the conduit comprising an organic polymer; a working electrode; the working electrode being etched and decorated with a nanostructured material; a reference electrode; and a counter electrode; the working electrode, the reference electrode and the counter electrode being disposed in the conduit; the working electrode, the reference electrode and the counter electrode being separated from each other by an electrically insulating material; and wherein a cross-sectional area of the conduit that comprises a section of the working electrode, a section of the reference electrode and a section of the counter electrode is exposed to detect analytes.
1. A method comprising:
disposing a plurality of wires within a conduit; the wires being electrically separated by an insulating layer;
cutting the conduit into a cut conduit having a first side and an opposite second side;
polishing the first and second sides of the cut conduit to expose a first cross-sectional area and a second cross-sectional area of the plurality of the wires at the first side and the second side of the cut conduit respectively;
electrodepositing a sacrificial layer on the exposed first cross-sectional area of the plurality of the wires;
as step #1, selecting wires and electrochemically etching the sacrificial layer on the selected wire to expose a cross-sectional surface of the selected wire;
as step #2, electrochemically etching the exposed cross-sectional surface of the selected wire to produce nanostructure porosity;
as step #3, coating the exposed cross-sectional surface of the selected wire having the nanostructure porosity with an electro-catalytic moiety suitable for catalyzing a redox reaction of a given redox species to form a working electrode;
as step #4, performing an electrochemical cleaning process to clean the working electrode;
as step #5, electrodepositing a film of a permselective membrane to an exposed cross-sectional surface area of the working electrode;
as step #6, depositing first enzymes, which reacts with a first analyte to produce an electroactive species, onto the permselective membrane to render the working electrode, together with a reference electrode and a counter electrodes operative to detect the first analytes via an electrochemical oxidation or reduction reaction;
selecting a second wire from the plurality of the wires and performing steps #1 to #6 to form a second working electrode having a second enzyme deposited on a second permselective membrane of the second working electrode;
selecting a third wire from the plurality of the wires and performing steps #1 to #4 or steps #1 to #5 to form a reference electrode;
connecting the second cross-sectional area of the plurality of the wires to an active matrix, wherein the active matrix is electrically connected to microelectronic device for signal detection; and wherein the active matrix is operative to control which wire or wires among the plurality of the wires are used in detecting signals.
2. The method of claim 1 , wherein each of the plurality of the wires is coated with an electro-catalytic moiety composed of platinum nanoparticles.
3. The method of claim 1 , wherein the electrodeposited sacrificial layer is deposited via an electrochemical process.
4. The method of claim 3 , wherein the electrodeposited sacrificial layer comprises copper.
5. The method of claim 1 , wherein the electrodeposited sacrificial layer is removed via an electrochemical process.
6. The method of claim 1 , wherein the electro-catalytic moiety suitable for catalyzing the redox reaction of the given redox species is deposited via an electrochemical process.
7. The method of claim 1 , wherein the permselective membrane is deposited via an electrochemical process.
8. The method of claim 7 , wherein the said-permselective membrane comprises an electropolymerized flavin mononucleotide.
9. The method of claim 7 , wherein the said-permselective membrane comprises an electropolymerized mixture of flavin mononucleotide and nanotubes.
10. The method of claim 7 , wherein the permselective membrane comprises an electropolymerized mixture of flavin mononucleotide, nanotubes and conductive polymers formed from at least one monomer of ortho-phenylene diamine (OPD), para-phenylene-diamine, meta-phenylene diamine, phenol, pyrrole, flavins, naphthalene, polyaniline, aniline, thiophenes, sulfonated aniline, or sulfonated pyrrole.
11. The method of claim 1 , wherein the electro-catalytic moiety is specific to a metabolite.
12. The method of claim 10 , wherein the electro-catalytic moiety comprises glucose oxidase.
13. The method of claim 1 , wherein each of the plurality of the wires has a diameter of about 5 nanometers to about 1000 micrometers.