Strip electrode with conductive nano tube printing

Abstract

A sensor system that detects a current representative of a compound in a liquid mixture features a multi or three electrode strip adapted for releasable attachment to signal readout circuitry. The strip comprises an elongated support which is preferably flat adapted for releasable attachment to the readout circuitry; a first conductor and a second and a third conductor each extend along the support and comprise means for connection to the circuitry. The circuit is formed with single-walled or multi walled nanotubes conductive traces and may be formed from multiple layers or dispersions containing, carbon nanotubes, carbon nanotubes/antimony tin oxide, carbon nanotubes/platinum, or carbon nanotubes/silver or carbon nanotubes/silver-chloride. An active electrode formed from a separate conductive carbon nanotubes layer or suitable dispersion, positioned to contact the liquid mixture and the first conductor, comprises a deposit of an enzyme capable of catalyzing a reaction involving the compound and preferably an electron mediator, capable of transferring electrons between the enzyme-catalyzed reaction and the first conductor. A reference electrode also formed from a conductive carbon nanotube layer or suitable dispersion is positioned to contact the mixture and the second conductor. The system includes circuitry adapted to provide an electrical signal representative of the current which is formed from printing conductive inks made with nano size particles such as conductive carbon or carbon/platinum or carbon/silver, or carbon nanotubes/antimony tin oxide to form a conductive carbon nanotube layers. The multiple-electrode strip is manufactured, by then applying the enzyme and preferably the mediator onto the electrode. Alternatively the electrode can have a carbon nanotubes/antimony tin oxide, carbon nanotubes/platinum, or carbon nanotubes/silver or carbon nanotubes/silver-chloride surface and or a conductive carbon or silver ink surface connecting leg. The carbon nanotube solution is first coated and patterned into electro shapes and the conductive carbon nanotubes, carbon or silver ink can be attached by printing the ink to interface with the carbon nanotube electro surface. A platinum electrode test strip is also disclosed that is formed from either nano platinum distributed in the carbon nanotube layer or by application or incorporation of platinum to the carbon nanotube conductive ink.

1 . A method for making an electrochemical reaction surface from a conductive film, comprising: providing a plurality of nanotubes with an outer diameter of less than 10 nm; and forming a film of said nanotubes on a surface of a substrate. 
     
     
         2 . The method of  claim 1 , wherein the step of forming the film comprises a method selected from the group consisting of spray painting, dip coating, spin coating, knife coating, kiss coating, gravure coating, screen printing, ink jet printing, and pad printing. 
     
     
         3 . A multi-layered structure for making an electrochemical reaction surface comprising: an electrically conductive film comprising a plurality of nanotubes with an outer diameter of less than 10 nm; and a polymeric layer disposed on at least a portion of said electrically conductive film. 
     
     
         4 . The multi-layered structure of  claim 3 , wherein said nanotubes are selected from the group consisting of single-walled nanotubes (SWNTs), double-walled nanotubes (DWNTs), multi-walled nanotubes (MWNTs), and mixtures thereof. 
     
     
         5 . The multi-layered structure of  claim 3 , wherein said nanotubes are substantially single-walled nanotubes (SWNTs). 
     
     
         6 . The multi-layered structure of  claim 3 , wherein said nanotubes are present in said film at about 0.001 to about 10% based on weight. 
     
     
         7 . The multi-layered structure of  claim 3 , wherein the film has a volume resistance in the range of about 100 ohms/cm 2 to about 50,000 ohms/cm 2. 
     
     
         8 . The multi-layered structure of  claim 3 , wherein the film is in the form of a solid film, a foam, or a fluid. 
     
     
         9 . The multi-layered structure of  claim 3 , further comprising a polymeric material, wherein the polymeric material comprises a material selected from the group consisting of thermoplastics, thermosetting polymers, elastomers, conducting polymers and combinations thereof. 
     
     
         10 . The multi-layered structure of  claim 3 , further comprising a polymeric material, wherein the polymeric material comprises a material selected from the group consisting of ceramic hybrid polymers, phosphine oxides and chalcogenides. 
     
     
         11 . The multi-layered structure of  claim 3 , further comprising a polymeric material wherein the nanotubes are dispersed substantially homogenously throughout the polymeric material. 
     
     
         12 . The multi-layered structure of  claim 3 , further comprising a polymeric material wherein the nanotubes are present in a gradient fashion. 
     
     
         13 . The multi-layered structure of  claim 3 , further comprising a polymeric material wherein the nanotubes are present on a surface of said polymeric material. 
     
     
         14 . The multi-layered structure of  claim 3 , further comprising a polymeric material wherein the nanotubes are formed in an internal layer of said polymeric material. 
     
     
         15 . The multi-layered structure of  claim 3 , further comprising an opaque substrate, wherein the nanotubes are present on a surface of said opaque substrate. 
     
     
         16 . The multi-layered structure of  claim 3 , further comprising an additive selected from the group consisting of a dispersing agent, a binder, a cross-linking agent, a stabilizer agent, a coloring agent, a UV absorbent agent, and a charge adjusting agent. 
     
     
         17 . The multi-layered structure of  claim 3 , wherein the film has a total transmittance of at least about 60%. 
     
     
         18 . The multi-layered structure of  claim 3 , wherein said film has a thickness between about 0.005 to about 1,000 microns. 
     
     
         19 . The multi-layered structure of  claim 3 , wherein the nanotubes are oriented. 
     
     
         20 . The multi-layered structure of  claim 3 , wherein the nanotubes are oriented in the plane of the film. 
     
     
         21 . An electrochemical reactive surface formed from a dispersion of nanotubes comprising a plurality of nanotubes with an outer diameter of less than 10 nm and having a surface morphology of less than 33 microns RMS. 
     
     
         22 . The dispersion of  claim 21 , wherein said nanotubes have an outer diameter of about 0.5 to 10 nm. 
     
     
         23 . The dispersion of  claim 21 , wherein said nanotubes are selected from the group consisting of single-walled nanotubes (SWNTs), double-walled nanotubes (DWNTs), multi-walled nanotubes (MWNTs), and mixtures thereof. 
     
     
         24 . The dispersion of  claim 21 , wherein said nanotubes are substantially single-walled nanotubes (SWNTs). 
     
     
         25 . The dispersion of  claim 21 , further comprising a polymeric material, wherein the polymeric material comprises a material selected from the group consisting of thermoplastics, thermosetting polymers, elastomers, conducting polymers and combinations thereof. 
     
     
         26 . The dispersion of  claim 21 , further comprising a polymeric material, wherein the polymeric material comprises a material selected from the group consisting of ceramic hybrid polymers, and phosphine oxides chalcogenides. 
     
     
         27 . The dispersion of  claim 21 , further comprising a plasticizer, softening agent, filler, reinforcing agent, processing aid, stabilizer, antioxidant, dispersing agent, binder, a cross-linking agent, a coloring agent, a UV absorbent agent, or a charge adjusting agent. 
     
     
         28 . The dispersion of  claim 21 , further comprising conductive organic materials, inorganic materials, or combinations or mixtures thereof. 
     
     
         29 . The dispersion of  claim 21 , wherein the conductive organic materials are selected from the group consisting of buckeyballs, carbon black, fullerenes, nanotubes with an outer diameter of greater than about 0.5 nm, and combinations and mixtures thereof. 
     
     
         30 . The dispersion of  claim 21 , wherein the conductive inorganic materials are selected from the group consisting of aluminum, antimony, beryllium, cadmium, chromium, cobalt, copper, doped metal oxides, iron, gold, lead, manganese, magnesium, mercury, metal oxides, nickel, platinum, silver, steel, titanium, zinc, and combinations and mixtures thereof. 
     
     
         31 . The dispersion of  claim 21 , further comprising a conductive material selected from the group consisting of tin-indium mixed oxide, antimony-tin mixed oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide and combinations and mixtures thereof. 
     
     
         32 . The dispersion of  claim 21 , further comprising conductors, fluids, gelatins, ionic compounds, semiconductors, solids, surfactants, or combinations or mixtures thereof.