Treatment of substrates

Abstract

A method of treating a substrate, which method comprises providing an electrolyte in contact with the substrate and an array of electrodes adjacent the surface and in contact with the electrolyte, and altering the potential of at least one electrode so as to generate an active redox product which modifies the substrate adjacent the at least one electrode, characterized in that the electrolyte is chosen such that the active redox product is quenchable by a second redox product. The method is particularly suitable for the step-wise chemical synthesis of oligomers such as oligonucleotides bound to a surface.

1 - 29 . (cancelled)  
     
     
         30 . A method of treating a substrate, which method comprises providing an electrolyte in contact with the substrate and electrodes adjacent the substrate and in contact with the electrolyte, altering the potential of at least one first electrode so as to generate an active redox product which modifies the substrate adjacent the first electrode, generating a second redox product by a second electrode in proximity to the first electrode, characterised in that the electrolyte is such that the active redox product is quenchable by the second redox product and in that the substrate to be modified does not form either a first electrode or a second electrode, and is separate from the first and second electrodes.  
     
     
         31 . The method of  claim 30 , wherein the electrolyte comprises a solvent and wherein neither the active redox product nor the second redox product are formed from the solvent.  
     
     
         32 . The method of  claim 30 , wherein the electrolyte comprises an organic solvent.  
     
     
         33 . The method of  claim 32 , wherein the solvent is selected from tetrahydrofuran (THF), methanol, ethanol, dimethylformamide (DMF), dichloromethane, diethyl ether, dimethylsulfoxide (DMSO) or acetonitrile.  
     
     
         34 . The method of  claim 30 , wherein the quenching reaction regenerates the electrolyte.  
     
     
         35 . The method of  claim 30 , wherein the active redox product is a proton.  
     
     
         36 . The method of  claim 30 , wherein the second redox product is an organic radical anion.  
     
     
         37 . The method of  claim 31 , wherein the electrolyte is a solution of hydroquinone and benzoquinone, or derivatives thereof.  
     
     
         38 . The method of  claim 30 , wherein the electrolyte is a solution of:  
       
         
           
           
               
               
           
         
       
       wherein R 3 , R 4 , R 5  and R 6  are independently selected from: 
 hydrogen, halo, hydroxyl, thio, nitro, amino, optionally substituted C 1  to C 15  hydrocarbyl wherein up to three C atoms may optionally be replaced by N, O and/or S atoms; or  
 R 3  and R 4  and/or R 5  and R 6  together form an optionally substituted C 1  and C 15  cyclohydrocarbylene wherein up to three C atoms may optionally be replaced by N, O and/or S atoms.  
 
     
     
         39 . The method of  claim 30 , wherein the electrolyte is a solution of hydroquinone and benzoquinone in acetonitrile.  
     
     
         40 . The method of  claim 30 , wherein the electrolyte further comprises a conductivity enhancer.  
     
     
         41 . The method of  claim 40 , wherein the conductivity enhancer is a tetra(C 1-8  alkyl) ammonium salt.  
     
     
         42 . The method of  claim 41 , wherein the conductivity enhancer is tetrabutylammonium hexafluorophosphate.  
     
     
         43 . The method of  claim 30 , wherein, for the purposes of performing several treatments in sequence, an array of electrodes are connected up so that each treatment is performed by altering the potential of a chosen set of one or more of the electrodes of the array.  
     
     
         44 . The method of  claim 30 , wherein the substrate comprises an array of substances bound to a surface.  
     
     
         45 . The method of  claim 44 , wherein the surface is a surface of an oxidized silicon wafer.  
     
     
         46 . The method of  claim 44 , wherein the substances to be treated comprise an acid labile protecting group.  
     
     
         47 . The method of  claim 46 , wherein each treatment is performed by connecting at least one electrode of the array as an anode at a potential to remove an acid labile protecting group from a substance on the surface.  
     
     
         48 . The method of  claim 43 , wherein the or each treatment is performed in the course of a stepwise chemical synthesis of an oligomer.  
     
     
         49 . A method of synthesising a set of oligomers comprising the steps of: 
 (a) providing a substrate having attached thereto an array of substances having a protecting group, an electrolyte in contact with the substrate and an array of electrodes adjacent the substrate and in contact with the electrolyte;    (b) selectively altering the potential of one or more of the electrodes so as to generate    (i) an active redox product which removes the protecting group from selected substances and a second redox product;    (c) coupling a protected monomer with the deprotected substances formed in step (b); and    (d) repeating steps (b) and (c), while varying the one or more electrodes selected in step (b), so as to synthesise a set of oligomers;    characterized in that the electrolyte is chosen such that the active redox product is quenchable by the second redox product, wherein the substrate to be modified does not form an electrode, and is separate from the array of electrodes.    
     
     
         50 . The method of  claim 49 , wherein the electrolyte comprises a solvent and wherein neither the active redox product nor the second redox product are formed from the solvent.  
     
     
         51 . The method of  claim 49 , wherein the electrolyte comprises an organic solvent.  
     
     
         52 . The method of  claim 51 , wherein the solvent is selected from tetrahydrofuran (THF), methanol, ethanol, dimethylformamide (DMF), dichloromethane, diethyl ether, dimethylsulfoxide (DMSO) or acetonitrile.  
     
     
         53 . The method of  claim 49 , wherein the quenching reaction regenerates the electrolyte.  
     
     
         54 . The method of  claim 49 , wherein the array of substances are attached to a surface and the oligomer is synthesized on said surface.  
     
     
         55 . The method of  claim 49 , wherein the oligomers are oligonucleotides.  
     
     
         56 . The method of  claim 49 , wherein the active redox product is a proton and the protecting groups are acid labile protecting groups.  
     
     
         57 . The method of  claim 49 , wherein the electrolyte is a solution of hydroquinone and benzoquinone, or derivatives thereof.  
     
     
         58 . An array of electrodes, comprising a block of insulating material having a surface, and deposits of iridium spaced apart in an array on the surface, each deposit being provided with electrical connecting means for altering its potential.  
     
     
         59 . The array of  claim 58 , wherein the block of insulating material is an oxidized silicon wafer.  
     
     
         60 . The array of  claim 58 , wherein the deposits of iridium are in the form of spaced apart parallel lines.  
     
     
         61 . The array of  claim 58 , wherein said array is made by a process comprising the steps of: 
 (i) providing a silicon wafer having a layer of silicon dioxide on the surface thereof;    (ii) depositing iridium in a spaced apart array on the silicon dioxide surface; and    (iii) annealing the iridium in air at a temperature in the range of 200-500° C.