Patent ID: 7939734
Filing Date: 2011-05-10
Classification: G01N,Y10S

Abstract:
1. A method for sensing presence of a target biomolecule in a liquid solution, the method comprising: providing an array of at least first and second carbon nanotubes (CNTs), where a first end of each of the at least first and second CNTs is electrically connected by at least one signal carrying line to, and is oriented substantially perpendicular to a surface of, an electronics device that transduces or otherwise provides an identifiable change in an electrochemical signal when a target biomolecule becomes attached to or interacts with at least one CNT in the array, where the electrochemical signal is at least one of a differential pulse voltammetry signal, an AC voltammetry signal, a square wave voltammetry signal, and an electrochemical impedance spectroscopy signal, a fast scan cyclic voltammetry signal, a conventional cyclic voltammetry signal, a conventional potentiometry signal, and a conventional amperometry signal; providing an electrically insulating material that substantially fills an interstitial space between, and substantially covers surfaces of, the first and second CNTs and the at least one signal carrying line, and removing a sufficient amount of the insulating material to expose a second end of the first CNT and a second end of the second CNT, by at least one of mechanical polishing, chemical mechanical polishing, plasma etching and chemical etching, to prevent attachment of a probe biomolecule to a side surface of the first and second CNTs; providing a surface passivation layer on exposed surfaces of the interstitial insulating material, to suppress attachment of a biomolecule in an adjacent liquid solution to the surface of the interstitial insulating material; electrochemically etching the surface passivation layer at selected locations to expose the second end of the first and second CNTs; functionalizing the second end of the first and second CNTs with a probe biomolecule that can interact with or become attached to the second end of the first and second CNTs, where the probe biomolecule is at least one of an oligonucleotide, a peptide, a ligand, a protein and an enzyme; immersing the second end of the first and second CNTs in the liquid solution that may contain at least one target biomolecule; when the target biomolecule is present in the solution, allowing the target biomolecule to interact with or become attached to the probe biomolecules at the functionalized second end of the first and second CNTs and to generate a change in an electrochemical signal of at least one of the functionalized first and second CNTs; interpreting lack of receipt of the change in the electrochemical signal as indicating that at least one of the following conditions is present: (i) no target biomolecule is present in the solution and (ii) the target biomolecule is present in the solution in an amount that is less than a threshold amount; and interpreting receipt of the change in the electrochemical signal as indicating that at least one target biomolecule is present in the solution in an amount at least equal to the threshold amount.