Methods for the electrochemical treatment of self-assembled monolayers

Abstract

The present invention provides compositions and methods directed to an electrode initialization step for the electrochemical treatment of monolayers used in electrochemical detection of target analytes on the surface of a monolayer. Electrode initialization creates a more stable monolayer, and resolves variability within the electrochemical signal detected on the monolayer.

1 - 18 . (canceled) 
     
     
         19 . An apparatus for detection of target nucleic acid, comprising:
 a biochip comprising detection electrodes;   un-hybridized capture probes;   label probes hybridized with target nucleic acid;   an electric signal; and   a detector for detecting the target nucleic acid.   
     
     
         20 . The apparatus of  claim 19 , wherein the label probes are labeled with an electrochemically active marker. 
     
     
         21 . The apparatus of  claim 19 , wherein the electrochemically active marker is an electron transfer moiety. 
     
     
         22 . The apparatus of  claim 19 , wherein the electron transfer moiety is a metallocene. 
     
     
         23 . The apparatus of  claim 22 , wherein the metallocene is a ferrocene or a ferrocene derivative. 
     
     
         24 . The apparatus of  claim 23 , wherein the metallocene is the ferrocene derivative. 
     
     
         25 . The apparatus of  claim 19 , wherein the electric signal increases a non-linear harmonic response. 
     
     
         26 . The apparatus of  claim 19 , wherein said electric signal reduces a fifth bump in a fourth harmonic signal. 
     
     
         27 . The apparatus of  claim 19 , wherein said electric signal reduces background nonspecific signal by about 15%. 
     
     
         28 . The apparatus of  claim 19 , wherein the detection electrodes are gold. 
     
     
         29 . The apparatus of  claim 19 , wherein the electric signal is applied for 0.5 to 5 seconds. 
     
     
         30 . The apparatus of  claim 19 , wherein the detection electrodes comprise a monolayer. 
     
     
         31 . The apparatus of  claim 30 , wherein the monolayer is a self-assembled monolayer. 
     
     
         32 . The apparatus of  claim 19 , wherein the capture probes further comprise an attachment linker. 
     
     
         33 . The apparatus of  claim 19 , wherein the electric signal is a voltage sweep from 150 mV to 750 mV. 
     
     
         34 . The apparatus of  claim 19 , wherein the label probes are free-floating, and wherein non-specific binding of the free-floating label probes is reduced following the electric signal. 
     
     
         35 . The apparatus of  claim 19 , wherein the label probes hybridized with target nucleic acid hybridize to the previously un-hybridized capture probe following the electric signal. 
     
     
         36 . The apparatus of  claim 19 , wherein the electric signal drives label probes hybridized with target nucleic acid away from the un-hybridized capture probes to prevent non-specific detectable signals. 
     
     
         37 . A method for preparing a monolayer, comprising
 a) providing an electrode comprising a monolayer; and   b) applying an electronic signal completed in 0.5 to 5 seconds to initialize the electrode, thereby preparing the monolayer in step a.   
     
     
         38 . An apparatus for electrochemical detection of target nucleic acid, comprising:
 a biochip comprising detection electrodes;   un-hybridized capture probes;   un-hybridized label probes;   label probes hybridized with target nucleic acid;   an electric signal; and   a detector for detecting the target nucleic acid