System and method for single molecule detection

Abstract

A single molecule sensing or detecting device includes a first electrode and a second electrode separated from the first electrode by a gap. The first electrode and the second electrode have an opening formed therethrough. At least one of the first electrode and the second electrode is functionalized with a recognition molecule. The recognition molecule has an effective length L1 and is configured to selectively bind to a target molecule having an effective length L2. The size of the gap is configured to be greater than L2, but less than or equal to the sum of L1 and L2.

What is claimed is: 
     
         1 . A sensing device for sensing protein fluctuations comprising:
 a first electrode;   a second electrode separated from the first electrode by a gap,   a first recognition molecule having a first end and a second end, the first end being connected to the first electrode and the second end being connected to a protein at a first point;   a second recognition molecule having a first end and a second end, the first end being connected to the second electrode and the second end being connected to the protein at a second point;   a means for applying a voltage bias; and   a detector configured to detect fluctuations in current.   
     
     
         2 . The sensing device of  claim 1 , wherein the first and the second recognition molecules are identical. 
     
     
         3 . The device of  claim 1 , wherein the size of the gap is between about 2 nm to about 15 nm. 
     
     
         4 . The device of  claim 1 , wherein the size of the gap is between about 2 nm to about 10 nm. 
     
     
         5 . The device of  claim 1 , wherein the size of the gap is between about 5 nm to about 15 nm. 
     
     
         6 . The device of  claim 1 , wherein the first and second recognition molecules comprise a peptide. 
     
     
         7 . A method for detecting protein fluctuations, the method comprising:
 applying a voltage bias across a first electrode to a second electrode of a sensing device, the sensing device comprising:
 the first electrode; 
 the second electrode separated from the first electrode by a gap, 
 a first recognition molecule having a first end and a second end, the first end being connected to the first electrode and the second end being connected to a protein at a first point; 
 a second recognition molecule having a first end and a second end, the first end being connected to the second electrode and the second end being connected to the protein at a second point; 
   monitoring current generated between the first and second electrode over time;   wherein protein fluctuation is detected if the current generated fluctuates.   
     
     
         8 . The method of  claim 7 , wherein the first and the second recognition molecules are identical. 
     
     
         9 . The method of  claim 7 , wherein the first and the second recognition molecules are identical. 
     
     
         10 . The method of  claim 7 , wherein the size of the gap is between about 2 nm to about 15 nm. 
     
     
         11 . The method of  claim 7 , wherein the size of the gap is between about 2 nm to about 10 nm. 
     
     
         12 . The method of  claim 7 , wherein the size of the gap is between about 5 nm to about 15 nm. 
     
     
         13 . The method of  claim 7 , wherein the first and second recognition molecules comprise a peptide.