Device for Measurement of Exhaled Nitric Oxide Concentration

Abstract

Described is a personal device and methods for measuring the concentration of an analyte in a sample of gas. The device and method may utilize a chemically selective sensor element with low power consumption integrated with circuitry that enables wireless communication between the sensor and any suitable electronic readout such as a smartphone, tablet, or computer. In preferred form, the sensor circuitry relies upon the quantum capacitance effect of graphene as a transduction mechanism. Also in preferred form, the device and method employ the functionalization of the graphene-based sensor to determine the concentration of nitric oxide in exhaled breath.

1 . A device for detecting an analyte in a sample, comprising:
 a graphene-based variable capacitor comprising:
 a dielectric layer; 
 a graphene layer in contact with the dielectric layer; and 
 a modifying layer in contact with the graphene layer, wherein the modifying layer has an affinity for the analyte; and 
   a capacitance signal processor, programmed to receive data from the graphene-based variable capacitor and to determine the concentration of the analyte in the sample.   
     
     
         2 . The device of  claim 1 , wherein the graphene layer is in direct contact with the dielectric layer. 
     
     
         3 . The device of  claim 2 , wherein the direct contact with the dielectric layer is at least partially continuous. 
     
     
         4 . The device of  claim 2 , wherein the graphene layer is in physical and electrical contact with the dielectric layer. 
     
     
         5 . The device of  claim 1 , wherein the modifying layer is non-covalently bound to the graphene layer. 
     
     
         6 . The device of  claim 1 , wherein the modifying layer comprises molecules having a porphyrin ring system. 
     
     
         7 . The device of  claim 1 , wherein the modifying layer comprises nickel octaethylporphyrin non-covalently bound to the graphene layer. 
     
     
         8 . The device of  claim 1 , wherein the modifying layer is in physical and electrical contact with the graphene layer. 
     
     
         9 . The device of  claim 1 , wherein the graphene-based variable capacitor further comprises a gate electrode and a top electrode arranged in a multi-finger, planarized geometry. 
     
     
         10 . The device of  claim 9 , wherein the gate electrode is embedded in a supporting substrate. 
     
     
         11 . The device of  claim 9 , wherein the gate electrode is in contact with the dielectric layer, wherein the dielectric layer comprises a material having a high dielectric constant. 
     
     
         12 . The device of  claim 1 , wherein the capacitance signal processor processes data directly from the graphene-based variable capacitor to determine the concentration of the analyte in the sample. 
     
     
         13 . The device of  claim 1 , wherein the capacitance signal processor processes raw data from the graphene-based variable capacitor to determine the concentration of the analyte in the sample. 
     
     
         14 . The device of  claim 1 , wherein the data from the graphene-based variable capacitor is an analog signal. 
     
     
         15 . The device of  claim 1 , wherein the sample is a gas. 
     
     
         16 . The device of  claim 15 , wherein the sample is a gas and the device further comprises an inlet port that channels the gaseous sample to the graphene-based variable capacitor. 
     
     
         17 . The device of  claim 15 , further comprising a flow rate sensor configured to measure the rate at which the gaseous sample is channeled to the graphene-based variable capacitor. 
     
     
         18 . The device of  claim 15 , further comprising a flow rate sensor configured to regulate the rate at which the gaseous sample is channeled to the graphene-based variable capacitor. 
     
     
         19 . The device of  claim 1 , wherein the analyte is nitric oxide.