TRI-ELECTRODE APPARATUS AND METHODS FOR MOLECULAR ANALYSIS

• US 20150276637A1
• Filed: 03/06/2015
• Published: 10/01/2015
• Est. Priority Date: 03/07/2014
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: PRASAD, Shalini, PANNEER SELVAM, Anjan
• Granted Patent: US 10,641,721 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01N 27/026 Dielectric impedance spectroscopy electrochemical impedance spectroscopy for measuring corrosion G01N17/02
• CPC Class Codes: G01N 27/028 Circuits therefor measuring impedance per se G01R27/02
• CPC Class Codes: G01N 33/48707 by electrical means G01N33/49, G01N33/493 take precedence
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base

Abstract

The claimed invention is an apparatus and method for performing impedance spectroscopy with a handheld measuring device. Conformal analyte sensor circuits comprising a porous nanotextured substrate and a conductive material situated on the top surface of the solid substrate in a circuit design may be used alone or in combination with a handheld potentiometer. Also disclosed are methods of detecting and/or quantifying target analytes in a sample using a handheld measuring device.

Claims

1. A method of detecting or quantifying multiple types of target analytes in a sample using a handheld measuring device and a conformal analyte sensor circuit comprising the steps of:

(a) placing a sample containing multiple target analytes on a conformal substrate having a sensor circuit comprising a first electrode, a second electrode, and a third electrode;

(b) applying a first alternating input electric voltage between the first electrode and the second electrode at a first phase angle;

(c) applying a second alternating input electric voltage between the third electrode and the second electrode at a second phase angle, wherein the first phase angle and the second phase angle are separated by a constant delta phase angle;

(d) measuring the output current at different frequencies and varying phase angles for different analytes;

(e) amplifying an output current flowing from the first electrode and from the third electrode through the second electrode using a programmable gain amplifier;

(f) sectioning an electrical double layer into a plurality of planes, wherein the electrical double layer is proximal to a surface of first electrode, a surface of the second electrode, and a surface of the third electrode;

(g) varying the first phase angle of the first input electric voltage and the second phase angle of the second input electric voltage;

(h) identifying the first phase angle and the second phase angle at which a maximum impedance change occurs;

(i) measuring the impedance identified at the first phase angle and the second phase angle; and

(j) using the measured impedance and associated phase angle and output current at different frequencies to detect multiple target analytes or calculate concentrations of target analytes by use of a standard calibration curve.

14. The method of claim 1, wherein the first alternating input electric voltage and the second alternating input electric voltage have a frequency between 50 Hz and 5,000 Hz.

18. The method of claim 1, wherein the first alternating input electric voltage and the second alternating input electric voltage are between 100 mV and 500 mV.

2. An analyte sensor circuit comprising:

a substrate having a surface comprising porous and non-porous regions which can be in plane or out of plane with a well delineated conformal hydrophobic barrier passivating conductive material situated on the surface in a circuit design, thereby creating a circuit comprising a first electrode, a second electrode and a third electrode;

a programmable gain amplifier operably coupled to the first electrode, the second electrode, and the third electrode; and

a programmable microcontroller operably coupled to the programmable gain amplifier, the first electrode, the second electrode, and the third electrode, wherein the programmable microcontroller is configured to;

(a) apply a first alternating input electric voltage between the first electrode and the second electrode of the conformal analyte sensor circuit;

(b) apply a second alternating input electric voltage between the third electrode and the second electrode at a second phase angle, wherein the first phase angle and the second phase angle are separated by a constant delta phase angle;

(c) amplify an output current flowing from the first electrode and from the third electrode through the second electrode using a programmable gain amplifier;

(d) section an electrical double layer into a plurality of planes in three dimensional space, wherein the electrical double layer is proximal to a surface of the first electrode, a surface of the second electrode and to a surface of the third electrode;

(e) vary the first phase angle of the first input electric voltage and the second phase angle of the second input electric voltage;

(f) identify the first phase angle and the second phase angle at which a maximum impedance change occurs;

(g) measure the impedance identified at the first phase angle and the second phase angle; and

(i) use the measured impedance to detect the target analyte or calculate a concentration of the target analyte by use of a standard calibration curve.

3. The device of claim 2 wherein:

the device comprises additional circuits and wherein each circuit comprises a first electrode, a second electrode and a third electrode each operably coupled to the programmable gain amplifier; and

the programmable microcontroller is configured to perform steps (a)-(i) for each of the additional circuits to capture changes to the impedance and phase in real time with millisecond precision.

4. A device configured to detect and quantify analytes, the device comprising:

a conformal sensor circuit; and

a handheld reader coupled to the conformal sensor circuit, wherein the device is configured simultaneously detect and quantify multiple target analytes from a single sample.

5. The device of claim 4 wherein the conformal sensor circuit comprises:

a substrate having a surface comprising a conductive material situated on the surface in a circuit design, thereby creating a circuit comprising a first electrode, a second electrode and a third electrode;

a programmable gain amplifier operably coupled to the first electrode, the second electrode, and the third electrode; and

a programmable microcontroller operably coupled to the programmable gain amplifier, the first electrode, the second electrode, and the third electrode, wherein the programmable microcontroller is configured to;

(a) apply a first alternating input electric voltage between the first electrode and the second electrode of the conformal analyte sensor circuit;

(b) apply a second alternating input electric voltage between the third electrode and the second electrode at a second phase angle, wherein the first phase angle and the second phase angle are separated by a constant delta phase angle;

(c) amplify an output current flowing from the first electrode and from the third electrode through the second electrode using a programmable gain amplifier;

(d) section an electrical double layer into a plurality of planes in three dimensional space, wherein the electrical double layer is proximal to a surface of the first electrode, a surface of the second electrode and to a surface of the third electrode;

(e) vary the first phase angle of the first input electric voltage and the second phase angle of the second input electric voltage;

(f) identify the first phase angle and the second phase angle at which a maximum impedance change occurs;

(g) measure the impedance identified at the first phase angle and the second phase angle; and

(i) use the measured impedance to detect the target analyte or calculate a concentration of the target analyte by use of a standard calibration curve.

6. A method of detecting or quantifying a target analyte in a sample using a handheld measuring device and a conformal analyte sensor circuit comprising the steps of:

(a) placing a sample containing multiple target analytes on a conformal substrate having a sensor circuit comprising a first electrode, a second electrode, a third electrode, a fourth electrode, a fifth electrode and a sixth electrode;

(b) applying a first alternating input electric voltage between the first electrode and the second electrode at a first phase angle;

(c) applying a second alternating input electric voltage between the third electrode and the second electrode at a second phase angle, wherein the first phase angle and the second phase angle are separated by a first constant delta phase angle;

(d) measuring a first output current at different frequencies over a first range of frequencies and varying phase angles over a first range of phase angles;

(e) amplifying the first output current flowing from the first electrode and from the third electrode through the second electrode using a programmable gain amplifier;

(f) sectioning a first electrical double layer into a plurality of planes in three dimensional space, wherein the first electrical double layer is proximal to a surface of first electrode, a surface of the second electrode, and a surface of the third electrode;

(g) varying the first phase angle of the first input electric voltage and the second phase angle of the second input electric voltage over the first range of phase angles;

(h) identifying the first phase angle and the second phase angle at which a first maximum impedance change occurs;

(i) measuring the impedance identified at the first phase angle and the second phase angle;

(j) using the measured impedance at different frequencies to detect a first target analyte or calculate a concentration of the first target analyte by use of a standard calibration curve;

(k) applying a third alternating input electric voltage between the fourth electrode and the fifth electrode at a third phase angle;

(l) applying a fourth alternating input electric voltage between the sixth electrode and the fifth electrode at a fourth phase angle, wherein the third phase angle and the fourth phase angle are separated by a second constant delta phase angle;

(m) measuring a second output current at different frequencies over a second range of frequencies and varying phase angles over a second range of phase angles;

(n) amplifying the second output current flowing from the fourth electrode and from the sixth electrode through the fifth electrode using the programmable gain amplifier;

(o) sectioning a second electrical double layer into a plurality of planes, wherein the second electrical double layer is proximal to a surface of fourth electrode, a surface of the fifth electrode, and a surface of the sixth electrode;

(p) varying the third phase angle of the third input electric voltage and the fourth phase angle of the fourth input electric voltage over the second range of phase angles;

(q) identifying the third phase angle and the fourth phase angle at which a second maximum impedance change occurs;

(r) measuring the impedance identified at the third phase angle and the fourth phase angle; and

(s) using the measured impedance and phase change at different frequencies to detect a second target analyte or calculate a concentration of the second target analyte by use of a standard calibration curve.

7. The method of claim 6 wherein the first range of frequencies and the second range of frequencies are different.

8. The method of claim 6 wherein the first range of phase angles and the second range of phase angles are different.

9. The method of claim 6 wherein the first range of frequencies and the second range of frequencies are equal.

10. The method of claim 6 wherein the first range of phase angles and the second range of phase angles are equal.

11. The method of claim 6 wherein steps (a)-(j) are performed concurrently with steps (k)-(s).

12. A method of detecting or quantifying a target analyte in a sample using a handheld measuring device and a conformal analyte sensor circuit comprising the steps of:

(a) applying a first input electric voltage between a first electrode and a second electrode of a conformal analyte sensor circuit;

(b) applying a second input electric voltage between a third electrode and the second electrode of the conformal analyte sensor circuit;

(c) amplifying an output current flowing from the first electrode and from the third electrode through the second electrode using a programmable gain amplifier;

(d) calculating an impedance by comparing the first input electric voltage and the second input electric voltage to the output current using a programmable microcontroller; and

(e) detecting a target analyte or calculating a target analyte concentration from the calculated impedance using a programmable microcontroller.

13. A method of detecting or quantifying multiple target analytes in a sample using a handheld measuring device and a conformal analyte sensor circuit comprising the steps of:

(a) applying a first input electric voltage between a first electrode and a second electrode of a conformal analyte sensor circuit;

(b) applying a second input electric voltage between a third electrode and the second electrode of the conformal analyte sensor circuit;

(c) shifting an angular orientation of an electric field of the second input electric voltage;

(d) amplifying an output current flowing through the first electrode using a programmable gain amplifier;

(e) detecting a presence of one or more target analytes by comparing the angular orientation of the electric field to the output current.

15-17. -17. (canceled)

19-53. -53. (canceled)

54. A method of assembling an analyte sensor circuit, the method comprising:

(a) providing a solid porous nanotextured substrate; and

(b) transferring the analyte sensor circuit design onto a top surface of the porous nanotextured substrate using conductive material.

55-62. -62. (canceled)

63. A handheld device for measuring a target analyte comprising:

(a) a programmable gain amplifier configured to be operably coupled to a first electrode, a second electrode, and a third electrode; and

(b) a programmable microcontroller operably coupled to the programmable gain amplifier, the first electrode, the second electrode, and the third electrode;

wherein the programmable microcontroller is operable to apply a first alternating input electric voltage between the first electrode and the second electrode;

the programmable microcontroller is operable to apply a second alternating input electric voltage between the third electrode and the second electrode;

the programmable gain amplifier is operable to amplify an alternating output current flowing from the first electrode and from the third electrode through the second electrode;

the programmable microcontroller is operable to calculate an impedance by comparing the first input electric voltage and the second input electric voltage to the measured output current; and

the programmable microcontroller is operable to calculate a target analyte concentration from the calculated impedance.

83. A kit comprising:

(a) a conformal circuit comprising;

a solid substrate having a top surface, wherein the substrate comprises a porous or nanotextured substrate; and

a conductive material situated on the top surface of the solid substrate in a circuit design, thereby creating a circuit comprising the first electrode, the second electrode, and the third electrode; and

(b) a handheld measuring device of claim 63.

64. A handheld device for measuring a target analyte comprising:

(a) a programmable gain amplifier configured to be operably coupled to a first electrode, a second electrode, and a third electrode;

(b) a programmable microcontroller operably coupled to the programmable gain amplifier, the first electrode, the second electrode, and the third electrode;

wherein the programmable microcontroller is operable to apply a first alternating input electric voltage between the first electrode and the second electrode;

the programmable microcontroller is operable to apply a second alternating input electric voltage between the third electrode and the second electrode;

the programmable gain amplifier is operable to shift the angular orientation of an electric field of the second alternating input electric voltage;

the programmable gain amplifier is operable to amplify an alternating output current flowing through the third electrode;

the programmable microcontroller is operable to calculate an amplitude of the alternating output current; and

the programmable microcontroller is operable to detect a presence of one or more target analytes by comparing the angular orientation to the amplitude of the alternating output current.

65-81. -81. (canceled)

82. A method of calibrating a handheld measuring device by testing a plurality of solutions having known target analyte concentrations comprising:

(a) applying a first input electric voltage between a first electrode and a second electrode for each of the plurality of solutions;

(b) applying a second input electric voltage between a third electrode and a second electrode for each of the plurality of solutions;

(c) amplifying an output current flowing from the first electrode and from the third electrode through the second electrode using a programmable gain amplifier;

(d) calculating an impedance for each of the plurality of solutions by comparing the first input electric voltage and the second input electric voltage to the output current using a programmable microcontroller; and

(e) calculating coefficients of the standard quadratic equation z_i=b₁x²+b₂x+c, wherein z_i is the impedance, x is the known target analyte concentrations, and b₁, b₂, and c are the coefficients.