Methods and Devices for Detecting Structural Changes in a Molecule Measuring Electrochemical Impedance

Abstract

The invention relates to a method of detecting a structural change in a molecule, said molecule being attached to a surface, said surface being electrically conductive, wherein the phase of the electrochemical impedance at said surface is monitored, and wherein a change in the phase in the electrochemical impedance at said surface indicates a change in the structure of said molecule. The invention further relates to methods for making arrays having molecules such as, polypeptides attached to electrically conductive surfaces such as electrodes, and to arrays.

1 . A method of detecting a structural change in a molecule, said molecule being attached to a surface, said surface being electrically conductive, wherein the phase of the electrochemical impedance at said surface is monitored, and wherein a change in the phase in the electrochemical impedance at said surface indicates a change in the structure of said molecule. 
   
   
       2 . A method according to  claim 1 , wherein the surface comprises an electrode, and wherein the molecule comprises a polypeptide. 
   
   
       3 - 19 . (canceled) 
   
   
       20 . A method of detecting a structural change in a polypeptide, said method comprising
 (a) providing an array comprising at least two electrodes   wherein said electrodes have one or more of:
 (i) a diameter of 100 μm or less, and 
 (ii) a spacing of 100 μm or less; and 
   (b) attaching said polypeptide to at least one electrode of said array   (c) monitoring the electrical properties of the at least one electrode of (b),   wherein the phase of the electrochemical impedance at said electrode of step (c) is monitored, and wherein a change in the phase in the electrochemical impedance at said electrode indicates a structural change in said polypeptide.   
   
   
       21 . A method according to  claim 20 , wherein said array comprises at least 10 individually addressable electrodes. 
   
   
       22 . A method according to  claim 20 , wherein said electrodes have one or more of:
 (i) a diameter of 20 μm or less, and   (ii) a spacing of 15 μm or less.   
   
   
       23 . A method according to  claim 20 , wherein said electrodes have both (i) and (ii). 
   
   
       24 . A method according to  claim 1 , wherein said structural change is selected from the group consisting of:
 (i) the binding of an entity to said molecule,   (ii) a conformational change in said molecule, and   (iii) chemical modification of said molecule.   
   
   
       25 . A method according to  claim 1 , wherein said structural change is selected from the group consisting of:
 (i) the binding of an entity to said molecule,   (ii) a conformational change in said molecule, and   (iii) chemical modification of said molecule.   
   
   
       26 . A method according to  claim 2 , wherein the polypeptide comprises a scaffold protein. 
   
   
       27 . A method according to  claim 26 , wherein the polypeptide comprises a peptide aptamer. 
   
   
       28 . A method according to  claim 1 , wherein said electrode comprises metal. 
   
   
       29 . A method according to  claim 28 , wherein said metal comprises gold. 
   
   
       30 . A method according to  claim 2 , wherein said polypeptide is attached to said electrode by a thiol linkage. 
   
   
       31 . An array comprising at least two electrically conductive electrodes, at least one of said electrodes having attached thereto a molecule of biological interest, said molecule comprising a polypeptide,
 wherein said array comprises at least 10 individually addressable electrodes,   wherein said electrodes have one or more of:
 (i) a diameter of 100 μm or less, and 
 (ii) a spacing of 100 μm or less, and 
   wherein the polypeptide comprises a scaffold protein.   
   
   
       32 . An array according to  claim 31 , wherein the molecule comprises a peptide aptamer. 
   
   
       33 . A method of making an apparatus for studying a molecule of biological interest, said method comprising
 (i) providing a substrate comprising at least two or more electrodes wherein at least one of said electrodes further comprises a masking agent;   (ii) removing said masking agent from at least one electrode by application of an electrochemical potential to said electrode, wherein an electrochemical potential of between −0.9 V and −1.5 V vs Ag/AgCl is applied to said electrode; and   (iii) attaching to said electrode a molecule of biological interest,   wherein during removal of said masking agent from said at least one electrode, the electrochemical potential of at least one further electrode is controlled to prevent removal of the masking agent therefrom.   
   
   
       34 . A method according to  claim 33 , wherein the electrochemical potential of said at least one further electrode is controlled to −0.2 V vs Ag/AgCl during the desorption process 
   
   
       35 . A method according to  claim 33 , wherein an electrochemical potential of −1.4 V vs Ag/AgCl is applied for 120 seconds to said electrode of step (ii).