Diamond-containing electrodes for neurochemical detection

Abstract

This document provides methods and materials involved in assessing concentrations of analytes in an environment using a diamond-containing carbon electrode. For example, methods and materials for using FSCV or paired pulse voltammetry to discriminate analytes based on their adsorption characteristics to a diamond-containing carbon electrode are described herein.

What is claimed is: 
     
         1 . An apparatus for sensing an analyte present within an environment, the apparatus comprising:
 an electrical power source; and   a probe that is configured (i) to apply, using energy delivered from the electrical power source, an electrical stimulus to tissue of a mammal within the environment and (ii) to detect, within the environment, a response to the electrical stimulus that indicates a level of the analyte present within the environment;   wherein the probe includes an electrode for at least one of applying the electrical stimulus or detecting the response to the electrical stimulus, wherein the probe is made at least in part from a diamond-containing carbon material that includes a composition of both sp3-hybridized carbon and sp 2 -hybridized carbon.   
     
     
         2 . The apparatus of  claim 1 , wherein the composition of the diamond-containing carbon material includes about 2-percent to about 8-percent sp 2 -hybridized carbon, wherein the composition of the diamond-containing carbon material includes about 92-percent to about 98-percent sp 3  hybridized carbon. 
     
     
         3 . The apparatus of  claim 1 , wherein the composition of the diamond-containing carbon material includes about 2-percent to about 30-percent sp 2 -hybridized carbon. 
     
     
         4 . The apparatus of  claim 1 , wherein the composition of the diamond-containing carbon material includes about 50-percent to about 98-percent sp 3 -hybridized carbon. 
     
     
         5 . The apparatus of  claim 1 , wherein the diamond-containing carbon material is further doped with one or more material elements to increase electrical conductivity of the diamond-containing carbon material. 
     
     
         6 . The apparatus of  claim 5 , wherein the one or more material elements includes boron. 
     
     
         7 . The apparatus of  claim 1 , wherein the electrode has an elongated geometry and includes a first end having a conically-shaped tip, wherein the conically-shaped tip includes a conductive outer layer made of the diamond-containing carbon material. 
     
     
         8 . The apparatus of  claim 1 , wherein the electrode comprises an insulated portion and a conductive portion, wherein the conductive portion includes a conductive outer layer made of the diamond-containing carbon material. 
     
     
         9 . The apparatus of  claim 8 , wherein the insulated portion comprises an elongated cylindrical rod. 
     
     
         10 . The apparatus of  claim 9 , wherein the elongated cylindrical rod is made of at least one of tungsten, a platinum group metal, a platinum alloy, or a silicon containing material. 
     
     
         11 . The apparatus of  claim 1 , wherein:
 the probe is configured to apply the electrical stimulus to brain tissue in a region of a brain of the mammal,   the probe is configured to detect a response that indicates a level of a neurochemical or ion that is present in the region of the brain, and   the apparatus further comprises a processing unit in wireless communication with the probe, wherein the processing unit is configured (i) to receive information from the probe about the response that indicates the level of the neurochemical or the ion that is present in the region of the brain and (ii) to send information to the probe about at least one of a level or timing of electrical stimulus to apply to the brain tissue.   
     
     
         12 . The apparatus of  claim 1 , wherein the probe is configured to detect the response that indicates the level of the neurochemical or the ion that is present in the region of the brain using a fast-scan cyclic voltammetry technique. 
     
     
         13 . The apparatus of  claim 1 , wherein the probe is configured to detect the response that indicates the level of the neurochemical or the ion that is present in the region of the brain using an amperometry technique.