Highly selective chemical and biological sensors

Abstract

Methods and sensors for selective fluid sensing are provided. A sensor includes a resonant inductor-capacitor-resistor (LCR) circuit and a sensing material disposed over the LCR circuit. The sensing material includes a coordination compound of a ligand and a metal nanoparticle. The coordination compound has the formula: (X) n -M, where X includes an alkylamine group having the formula (R—NH 2 ), an alkylphosphine having the formula (R 3 —P), an alkylphosphine oxide having the formula (R 3 P═O), an alkyldithiocarbamate having the formula (R 2 NCS 2 ), an alkylxanthate having the formula (ROCS 2 ), or any combination thereof, R includes an alkyl group, n is 1, 2, or 3, and M includes the metal nanoparticle of gold, silver, platinum, palladium, alloys thereof, highly conductive metal nanoparticles, or any combination thereof. The sensing material is configured to allow selective detection of at least six different analyte fluids from an analyzed fluid mixture.

1 . A method for sensing an analyte of a plurality of analytes, comprising:
 exposing a sensing material disposed on a single resonant sensor antenna to an environment comprising the plurality of analytes;   varying a frequency of the single resonant sensor antenna over a frequency range using a network analyzer;   measuring at least six spectral parameters of the single resonant sensor antenna with the network analyzer;   analyzing the at least six spectral parameters over the frequency range using multivariate analysis to produce a multivariate signature;   comparing the multivariate signature to predetermined multivariate signatures formed from test results; and   detecting an analyte of the plurality of analytes based on the multivariate signature and the predetermined multivariate signatures.   
     
     
         2 . The method, as set forth in  claim 1 , wherein the at least six spectral parameters comprise at least six of a frequency of a maximum of a real part of an impedance spectrum, a magnitude of the real part of the impedance spectrum, a resonant frequency of an imaginary part of the impedance spectrum, an anti-resonant frequency of the imaginary part of the impedance spectrum, a signal magnitude at the resonant frequency of the imaginary of the impedance spectrum, a signal magnitude at the anti-resonant frequency of the imaginary part of the impedance spectrum, and a zero-reactance frequency of the imaginary part of the impedance spectrum. 
     
     
         3 . The method, as set forth in  claim 1 , wherein measuring at least six spectral parameters comprises measuring a frequency position of a real part of an impedance spectrum, and a magnitude of the real part of the impedance spectrum. 
     
     
         4 . The method, as set forth in  claim 1 , wherein measuring at least six spectral parameters comprises measuring a resonant frequency of the imaginary part of the impedance spectrum, and an anti-resonant frequency of the imaginary part of the impedance spectrum. 
     
     
         5 . The method, as set forth in  claim 1 , wherein producing the multivariate signature comprises using principal components analysis. 
     
     
         6 . The method, as set forth in  claim 1 , wherein measuring at least six spectral parameters of the single resonant sensor antenna with the network analyzer comprises supplying power to an integrated circuit (IC) chip of the resonant sensor at a first predetermined power level. 
     
     
         7 . A method for sensing an analyte of a plurality of analytes, comprising:
 measuring a real part and an imaginary part of an impedance spectrum of a resonant sensor antenna coated with a coordination compound of a ligand and a metal nanoparticle, wherein the ligand comprises a primary alkyl amine, trialkylphosphine, trialkylphosphine oxide, alkyldithiocarbamate, alkylxanthate or any combination thereof;   calculating at least six spectral parameters of the resonant sensor antenna coated with the coordination compound, wherein the at least six spectral parameters comprise at least six of a frequency of a maximum of the real part of the impedance spectrum, a magnitude of the real part of the impedance spectrum, a resonant frequency of the imaginary part of the impedance spectrum, an anti-resonant frequency of the imaginary part of the impedance spectrum, a signal magnitude at the resonant frequency of the imaginary part of the impedance spectrum, a signal magnitude at the anti-resonant frequency of the imaginary part of the impedance spectrum, and a zero-reactance frequency of the imaginary part of the impedance spectrum; and   reducing the impedance spectrum to a single data point using multivariate analysis to selectively identify the analyte of the plurality of analytes.   
     
     
         8 . The method, as set forth in  claim 7 , wherein the coordination compound has the formula:
   (X) n -M, wherein:   X comprises an alkylamine group having the formula (R—NH 2 ), an alkylphosphine having the formula (R 3 —P), an alkylphosphine oxide having the formula (R 3 P═O), an alkyldithiocarbamate having the formula (R 2 NCS 2 ), an alkylxanthate having the formula (ROCS 2 ), or any combination thereof;   R comprises an alkyl group, wherein the alkyl group has the formula C y H 2y+1 , wherein y=1 to 18;   n is 1, 2, or 3; and   M comprises the metal nanoparticle of gold, silver, platinum, palladium, alloys thereof, highly conductive metal nanoparticles, or any combination thereof.   
     
     
         9 . The method, as set forth in  claim 7 , wherein measuring the impedance spectrum and calculating the at least six spectral parameters comprises measuring over a resonant frequency range of the resonant sensor. 
     
     
         10 . The method, as set forth in  claim 7 , wherein calculating at least six spectral parameters comprises calculating the frequency of the maximum of the real part of the impedance spectrum and the magnitude of the real part of the impedance spectrum. 
     
     
         11 . The method, as set forth in  claim 7 , wherein calculating at least six spectral parameters comprises calculating the resonant frequency of the imaginary part of the impedance spectrum and the anti-resonant frequency of the imaginary part of the impedance spectrum. 
     
     
         12 . The method, as set forth in  claim 7 , wherein reducing the impedance spectrum to a single data point comprises calculating a multivariate signature. 
     
     
         13 . The method, as set forth in  claim 12 , wherein calculating the multivariate signature comprises using principal components analysis. 
     
     
         14 . The method, as set forth in  claim 7 , wherein measuring the impedance spectrum and calculating the at least six spectral parameters comprises supplying power to an integrated circuit (IC) chip of the resonant sensor at a first predetermined power level. 
     
     
         15 . The method, as set forth in  claim 14 , wherein measuring the impedance spectrum and calculating at least six spectral parameters comprises alternating the power supplied to the IC chip of the resonant sensor between the first predetermined power level and a second predetermined power level. 
     
     
         16 . The method, as set forth in  claim 15 , wherein the first predetermined power level and the second predetermined power level are between −50 dBm and +40 dBm. 
     
     
         17 . A method for sensing an analyte of a plurality of analytes, comprising:
 exposing a radio-frequency identification (RFID) sensor coated with a coordination compound of a ligand and a metal nanoparticle to an environment comprising the plurality of analytes, wherein the ligand comprises a primary alkyl amine, trialkylphosphine, trialkylphosphine oxide, alkyldithiocarbamate, alkylxanthate or any combination thereof;   varying a frequency of the RFID sensor over a frequency range using a network analyzer;   measuring a real part and an imaginary part of an impedance spectrum of the RFID sensor;   calculating at least six spectral parameters of the RFID sensor;   analyzing the at least six spectral parameters over the frequency range using   
       multivariate analysis to produce a multivariate signature; and
 identifying the analyte of the plurality of analytes based on the multivariate signature. 
 
     
     
         18 . The method, as set forth in  claim 17 , wherein the at least six spectral parameters comprise at least six of a frequency of a maximum of the real part of the impedance spectrum, a magnitude of the real part of the impedance spectrum, a resonant frequency of the imaginary part of the impedance spectrum, an anti-resonant frequency of the imaginary part of the impedance spectrum, a signal magnitude at the resonant frequency of the imaginary part of the impedance spectrum, a signal magnitude at the anti-resonant frequency of the imaginary part of the impedance spectrum, and a zero-reactance frequency of the imaginary part of the impedance spectrum. 
     
     
         19 . The method, as set forth in  claim 17 , wherein measuring a real part and an imaginary part of an impedance spectrum of the RFID sensor comprises supplying power to an integrated circuit (IC) chip of the RFID sensor at a first predetermined power level and alternating the power supplied to the IC chip of the RFID sensor between the first predetermined power level and a second predetermined power level. 
     
     
         20 . The method, as set forth in  claim 17 , wherein the frequency range is a frequency range of the RFID sensor.