Nanopore device for reversible ion and molecule sensing or migration

Patent metadata

Field	Value
Publication number	US-11243188-B2
Application number	US-201916422735-A
Country	US
Kind code	B2
Filing date	May 24, 2019
Priority date	Mar 4, 2011
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

Disclosed are methods and devices for detection of ion migration and binding, utilizing a nanopipette adapted for use in an electrochemical sensing circuit. The nanopipette may be functionalized on its interior bore with metal chelators for binding and sensing metal ions or other specific binding molecules such as boronic acid for binding and sensing glucose. Such a functionalized nanopipette is comprised in an electrical sensor that detects when the nanopipette selectively and reversibly binds ions or small molecules. Also disclosed is a nanoreactor, comprising a nanopipette, for controlling precipitation in aqueous solutions by voltage-directed ion migration, wherein ions may be directed out of the interior bore by a repulsing charge in the bore.

First claim

What is claimed is:

1. A method for detecting an analyte in a sample, the method comprising:
providing an apparatus comprising a nanopipette, the nanopipette comprising:
a capillary portion defining an interior bore of the nanopipette leading to a nanopore, the interior bore comprises therein an electrode and an interior solution;
a coating on an interior surface of said nanopore, comprising:
(i) a polyelectrolyte layer bound directly to the interior surface; and
(ii) a binding molecule linked to the polyelectrolyte layer, wherein the binding molecule specifically binds to the analyte, wherein the analyte is an ion or a small molecule;

contacting the nanopipette with the sample such that the interior solution is in communication with the sample through the nanopore; and
generating a voltage between electrodes and measuring positive and negative ionic current through the sample, the nanopore, and the interior solution,
wherein a change in negative ionic current indicates presence of the analyte in the sample.

2. The method of claim 1 , wherein the binding molecule is a boronic acid or boronic ester.

3. The method of claim 1 , wherein the polyelectrolyte is a polycation.

4. The method of claim 3 , wherein the polycation is a polyalkyl pyridine or a polyamine.

5. The method of claim 2 , wherein the coating further comprises a portion that extends into and partially blocks the nanopore.

6. The method of claim 1 , wherein the binding molecule is a chelating agent.

7. The method of claim 6 , wherein the polyelectrolyte layer is selected from the group consisting of: (a) a polyacrylic layer, (b) a polyamine layer; and (c) alternating layers of polyacrylic and polyamine.

8. The method of claim 7 , wherein the polyamine is a polyalkyl pyridine.

9. The method of claim 1 , wherein the binding molecule is an ion binding polymer and comprises a polysaccharide or a polypeptide.

10. The method of claim 9 , wherein the polymer is calmodulin.

11. The method of claim 9 , wherein the polymer is chitosan.

12. A method for detecting a saccharide analyte in a sample, comprising:
providing a nanopipette having an interior bore and a nanopore opening into the sample, wherein the nanopipette comprises an electrode within the interior bore in contact with an interior solution, and a reference electrode in contact with the sample,
wherein the nanopipette comprises a coating on an inner surface of the nanopore,
wherein the coating comprises a binding molecule specific for binding the saccharide analyte;
generating a voltage between the electrodes; and
measuring positive and negative ionic current through the sample, the nanopore, and the interior solution,
wherein change in negative ionic current indicates binding of the saccharide analyte in the sample to the coating.

13. The method apparatus of claim 12 wherein the binding molecule is a protein.

14. The method apparatus of claim 12 wherein the binding molecule is a boronic acid.

15. The method apparatus of claim 12 wherein the nanopipette is a quartz nanopipette.

16. The method apparatus of claim 12 wherein the coating comprises a polycation.

17. An apparatus for creating an ionic compound from two different ions in solution, comprising:
a nanopipette comprising at least one first ion species having a charge in a first solution inside of the nanopipette, the nanopipette having a nanopore between an interior of the nanopipette and an exterior solution;
a second ion species in the exterior solution, wherein the first solution and the exterior solution have the same polarity; and
a voltage control circuit configured for applying, to the first ion species having a charge in the first solution inside of the nanopipette, a voltage across the nanopore of opposite charge from the charge on the first ion species, said voltage sufficient to cause migration of said first ion species to the nanopore to react with said second ion species to form an ionic compound,
wherein the nanopipette has a capillary portion defining an interior bore of the nanopipette, wherein the interior bore is elongated and tapers to a tip with the nanopore positioned at the tip of the nanopipette, wherein the nanopore has an inner diameter in the range of 37 nm-82 nm and the outer diameter of the nanopore is less than 1 μm,
wherein the first solution is different from the exterior solution and the first and second ion species are isolated from each other in the first and exterior solutions, respectively, prior to creating the ionic compound.

18. The apparatus of claim 17 , wherein the nanopore inner diameter is in the range of 40 nm-60 nm.

19. The apparatus of claim 17 , wherein the nanopipette has a capillary portion defining an interior bore of the nanopipette leading to the nanopore and a coating on an interior surface of the nanopore, the coating comprising:
(i) a polyelectrolyte layer bound directly to the interior surface; and
(ii) a binding molecule, linked to the polyelectrolyte layer, specific for binding an analyte which is selected from the group consisting of an ion or a small molecule having a molecular weight of less than 200 atomic mass units.

20. The apparatus of claim 19 , wherein the binding molecule is a boronic acid or boronic esters and the polyelectrolyte layer is a polycation layer.

Assignees

• Univ California

Inventors

• Pourmand Nader
• Vilozny Boaz
• Actis Paolo
• Seger R Adam

Classifications

• G01N35/00

  Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor · CPC title

• B82Y35/00

  Methods or apparatus for measurement or analysis of nanostructures · CPC title

• G01Q60/44

  SICM [Scanning Ion-Conductance Microscopy] or apparatus therefor, e.g. SICM probes · CPC title

• G01N27/3277

  being a redox reaction, e.g. detection by cyclic voltammetry (voltammetry per se G01N27/42, G01N27/48) · CPC title

• B01L3/50273

  characterised by the means or forces applied to move the fluids · CPC title