Nanotube electrochemistry

Abstract

The invention relates to electrodes for electrochemical analysis comprising: —an insulating surface; —carbon nanotubes situated on the insulating surface at a density of at least 0.1 μm CNT Um −2 ; and —an electrically conducting material in electrical contact with the carbon nanotubes; wherein the carbon nanotubes cover an area of no more than about 5.0% of the insulating surface. Methods of making such electrodes and assay devices or kits with such electrodes, are also provided.

1 .- 42 . (canceled) 
     
     
         43 . An electrode for electrochemical analysis, comprising:
 an insulating surface;   carbon nanotubes situated on the insulating surface at a density of at least 0.1 μm CNT  μm −2 ; and   an electrically conducting material in electrical contact with the carbon nanotubes;   wherein the carbon nanotubes cover an area of no more than about 1.0% of the insulating surface.   
     
     
         44 . The electrode of  claim 43 , wherein the carbon nanotubes further comprise multi-walled carbon nanotubes (MWNTs). 
     
     
         45 . The electrode of  claim 44 , wherein the carbon nanotubes further comprise single-walled carbon nanotubes (SWNTs). 
     
     
         46 . The electrode of  claim 43 , wherein the insulating surface comprises silicon with a silicon oxide coating. 
     
     
         47 . The electrode of  claim 43 , wherein the electrically conducting material comprises gold. 
     
     
         48 . The electrode of  claim 43 , wherein the carbon nanotubes are partially coated by deposition of a material. 
     
     
         49 . The electrode of  claim 48 , wherein the material is selected from the group consisting of metals, semiconducting materials, and organic polymers. 
     
     
         50 . The electrode of  claim 49 , wherein the material is selected from the group consisting of platinum, silver, palladium, gold, copper, mercury, titanium, CdSe, CdTe, CdS, P3HT, pentacene, and doped polyaniline. 
     
     
         51 . The electrode of  claim 43 , wherein said electrode is a microelectrode or an ultramicroelectrode. 
     
     
         52 . The electrode of  claim 51 , wherein said electrode is an ultramicroelectrode. 
     
     
         53 . A method of manufacturing an electrode according to claim  1 , comprising:
 depositing a quantity of catalytic nanoparticles onto an insulating surface;   exposing the insulating surface to heat, a source of hydrogen gas, and a source of a carbon-containing gas to grow the nanotubes; and   depositing an electrically conducting material on the insulating surface so that it is in electrical contact with the carbon nanotubes;   wherein no annealing step is carried out prior to the deposition of the catalytic nanoparticles.   
     
     
         54 . The method of  claim 53 , wherein the carbon nanotubes are grown on the insulating surface using catalyzed chemical vapor deposition. 
     
     
         55 . A method of electrochemically analyzing a solution, comprising:
 providing the electrode of  claim 43 ;   contacting said electrode with a sample of said solution to be analyzed; and   applying a potential across said electrode to electrochemically analyze said sample;   wherein said solution has a concentration of no more than about 100 μM.   
     
     
         56 . The method of  claim 55 , wherein said solution has a concentration of no more than about 10 μM. 
     
     
         57 . An assay device or kit comprising the electrode of claim  1 . 
     
     
         58 . The assay device or kit of  claim 57 , further comprising a counter electrode and a reference electrode. 
     
     
         59 . The assay device or kit of  claim 57 , further comprising a flow cell. 
     
     
         60 . The assay device or kit of  claim 57 , further comprising a recordal means.