Nanopore based ion-selective electrodes

• US 8,123,922 B2
• Filed: 09/07/2007
• Issued: 02/28/2012
• Est. Priority Date: 09/07/2006
• Status: Active Grant

• Current Assignee: University of Utah Research Foundation (State of Utah)
• Original Assignee: University of Utah Research Foundation (State of Utah)
• Inventors: White, Henry S., White, Ryan J., Brown, Richard B., Nam, Hakhyun, Shim, Jun Ho
• Primary Examiner(s): Noguerola, Alex
• Application Number:
  US11/852,061
• Publication Number:
  US 20100038243A1
• Time in Patent Office: 1,635 Days
• Field of Search: 204416-420, 205/789, 205/789.5
• US Class Current: 204/416
• CPC Class Codes: G01N 27/333 Ion-selective electrodes or membranes glass electrodes G01N27/36
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor

Abstract

Nanopore based ion-selective electrodes and methods of their manufacture as well as methods for their use are disclosed and described. The nanopore based ion-selective electrode can include a pore being present in a solid material and having a nanosize opening in the solid material, a metal conductor disposed inside the pore opposite the opening in the solid material, a reference electrode material contacting said metal conductor and disposed inside the pore, a conductive composition in contact with the reference electrode and disposed in the pore, and an ion-selective membrane. The ion-selective membrane can be configured to isolate the metal conductor, reference electrode material, and conductive composition together within the pore.

Claims

1. A nanopore based ion-selective electrode, comprising:

a pore present in a solid material and having a nanosize opening in the solid material;

an electrical conductor disposed inside the pore opposite the opening in the solid material, wherein said electrical conductor is a microdisk;

a reference electrode material contacting said electrical conductor and disposed inside said pore;

a conductive composition in contact with said reference electrode and disposed in said pore; and

an ion-selective membrane configured to isolate the electrical conductor, reference electrode material, and conductive composition together within said pore.

2. The nanopore based ion-selective electrode of claim 1, wherein the electrical conductor is a Pt micro disk.

3. The nanopore based ion-selective electrode of claim 1, wherein the solid material is selected from the group consisting of glass, polymer, quartz, metal oxide, and combinations thereof.

4. The nanopore based ion-selective electrode of claim 1, wherein the nanosize opening in the solid material is from about 5 nm to about 200 nm in diameter.

5. The nanopore based ion-selective electrode of claim 1, wherein the reference electrode material comprises Ag/AgCl or IrO_x.

6. The nanopore based ion-selective electrode of claim 1, wherein the reference electrode material is electrolytically deposited onto the electrical conductor.

7. The nanopore based ion-selective electrode of claim 1, wherein the conductive composition is a conductive solution or hydrogel.

8. The nanopore based ion-selective electrode of claim 1, wherein the ion-selective membrane is deposited at or across the pore opening.

9. The nanopore based ion-selective electrode of claim 1, wherein the pore has a conical shape.

10. The nanopore based ion-selective electrode of claim 1, wherein the nanopore based ion-selective electrode has a diameter of the nanosize opening to pore volume ratio from about 1:

10 (nm;

μ

l) to about 1;

1000 (nm;

μ

l).

11. An ion-selective electrochemical sensor, comprising:

the nanopore ion-selective electrode of claim 1, and a processing unit for processing information from the ion-selective electrode operatively connected to the nanopore ion-selective electrode.

12. The ion-selective electrochemical sensor of claim 11, wherein the ion-selective electrochemical sensor includes an array of two or more nanopore electrodes.

13. The nanopore based ion-selective electrode of claim 1, wherein the ion-selective membrane is located in the pore.

14. A process for producing a nanopore-based all-solid-state ion-selective electrode (ISE), said process comprising:

a) forming a nanopore within a solid material and having a pore opening and an enclosed volume, wherein a conductive material is oriented opposite the pore opening within the nanopore wherein the conductive material is a microdisk;

b) forming a reference electrode layer adjacent the conductive material;

c) forming a conductive composition adjacent the reference electrode layer; and

d) orienting an ion selective membrane so as to isolate the enclosed volume from fluids external to the nanopore.

15. The process of claim 14, wherein:

a) the step of forming the nanopore includes sealing a conductive metal wire in the solid material, said solid material being glass or quartz;

exposing a disk of said conductive metal wire by gentle grinding; and

etching away at least a portion of the conductive metal wire to form the nanopore;

b) the step of forming the reference electrode layer includes electroplating the exposed disk of the conductive metal within the pore with Ag to form a layer of silver on the exposed disk, and chloridating at least a portion of the Ag layer in order to obtain a AgCl/Ag layer within the pore.

16. The process of claim 15, further comprising adjusting an ion concentration in the conductive composition sufficient to sufficient to prevent the chemical dissolution of the reference electrode.

17. The process of claim 15, wherein the steps of forming are each additive processes.

18. The nanopore based ion-selective electrode of claim 17, wherein the electrical conductor is selected from the group consisting of platinum, copper, silver, gold, tin, lead, conductive polymer, and alloys thereof.

19. The process of claim 15, wherein the conductive metal wire is selected from the group consisting of platinum, copper, silver, gold, tin, lead, and alloys thereof.

20. The process of claim 14, wherein the conductive material is a platinum wire.

21. The process of claim 14, wherein the nanopore has an external opening, said external opening having a diameter of from 5 nm to 200 nm.

22. The process of claim 14, wherein the conductive composition is a hydrogel.

23. The process of claim 14, wherein the nanopore-based all-solid-state ISE exhibits a potentiometric response behavior of about 30 mV/decade to super-Nernstian.

24. The process of claim 23, wherein the ion selective membrane has a plasticizer ratio which is sufficiently low that the potentiometric response behavior is about 40 mV/decade to super-Nernstian.

25. The process of claim 14, wherein the ion-selective membrane is located in the nanopore.