Nanoscale scanning electrochemical microscopy electrode method

Patent metadata

Field	Value
Publication number	US-11543429-B2
Application number	US-202016857821-A
Country	US
Kind code	B2
Filing date	Apr 24, 2020
Priority date	Apr 25, 2019
Publication date	Jan 3, 2023
Grant date	Jan 3, 2023

Abstract

Disclosed is a method for preparing nanoscale electrodes comprised of electrochemically grown noble metal nanowires, and use of the same for the detection of extremely small concentrations of molecules. Such nanoscale electrodes provide target molecule release information from submicron areas on the cell surface, significantly increasing the spatial resolution of the target molecule mapping of a cell surface to enable localization of target molecules on the cell surface, which can be critical for the detection of certain cells with different properties in a given group of cells, such as circulating tumor cells.

First claim

What is claimed is:

1. A method for detecting the presence of a target molecule on a surface of a cell, comprising:
providing a pair of tapered-tip electrodes;
placing a tip of each of said tapered-tip electrodes in a saturated solution of a noble metal salt;
applying an electrical potential between said tips to grow a nanowire formed of the noble metal in the saturated solution, said nanowire having a first end affixed to one of said tapered-tip electrodes and a second, free end opposite said first end;
attaching an aptamer to said second, free end of the nanowire;
applying said second, free end of said nanowire to a single cell; and
recording an electronic signal from the nanowire indicative of the presence of a target molecule on the single cell having a binding affinity with the aptamer on the second, free end of the nanowire.

2. The method of claim 1 , wherein said nanowire has a diameter of not greater than 100 nm.

3. The method of claim 1 , further comprising repeating said applying and recording steps on said single cell to determine the locations of multiple target molecules on a surface of said single cell.

4. The method of claim 1 , further comprising the step of forming said tapered-tip electrodes by electrochemically etching a pair of metal wires.

5. The method of claim 4 , wherein said metal wires comprise tungsten.

6. The method of claim 4 , wherein said tapered-tip electrodes are electrochemically etched to produce said tapered tips having a minimum diameter of no greater than 2 μm.

7. The method of claim 1 , wherein said step of applying an electrical potential further comprises applying an alternating current potential having a frequency of at least 5 MHz.

8. The method of claim 7 , wherein said alternating current potential further comprises a square wave alternating current potential.

9. The method of claim 1 , further comprising the step of placing said one of said tapered-tip electrodes and said nanowire inside of a glass insulator.

10. The method of claim 9 , wherein said glass insulator further comprises borosilicate capillary glass.

11. The method of claim 9 , further comprising the step of exposing said second, free end of said nanowire by sanding and polishing and end of said glass insulator to form a glass insulated nanowire electrode.

12. The method of claim 1 , further comprising the step of terminating the aptamer with a redox indicator.

13. The method of claim 1 , wherein the noble metal salt further comprises gold chloride.

14. A method of forming a nanowire electrode configured for the detection of the presence and location of a single molecule on a surface of a cell, comprising the steps of:
providing a pair of tapered-tip electrodes;
placing a tip of each of said tapered-tip electrodes in a saturated solution of a noble metal salt;
applying an electrical potential between said tips to grow a nanowire formed of the noble metal in the saturated solution, said nanowire having a first end affixed to one of said tapered-tip electrodes and a second, free end opposite said first end, and wherein said nanowire has a diameter of not greater than 100 nm; and
attaching an aptamer to said second, free end of the nanowire.

15. The method of claim 14 , further comprising the step of forming said tapered-tip electrodes by electrochemically etching a pair of tungsten wires to produce said tapered tips having a minimum diameter of no greater than 2 μm.

16. The method of claim 14 , wherein said step of applying an electrical potential further comprises applying a square wave alternating current potential having a frequency of at least 5 MHz.

17. The method of claim 14 , further comprising the steps of placing said one of said tapered-tip electrodes and said nanowire inside of a glass insulator, and exposing said second, free end of said nanowire by sanding and polishing and end of said glass insulator to form a glass insulated nanowire electrode.

18. The method of claim 14 , further comprising the step of terminating the aptamer with a redox indicator.

19. The method of claim 14 , wherein the noble metal salt further comprises gold chloride.

20. A nanowire configured for detecting the presence of a target molecule on a surface of a cell, comprising:
a tapered-tip electrode;
a nanowire formed of a noble metal affixed to said tapered-tip electrode, wherein said nanowire has a diameter of not greater than 100 nm;
a glass insulator surrounding said tapered-tip electrode and said nanowire, wherein an end of said nanowire extends outside of said glass insulator; and
an aptamer attached to said end of said nanowire, wherein said aptamer is selected for having a binding affinity to a target molecule on the surface of a cell.

Assignees

• Morgan State Univ

Inventors

• Ozturk Birol
• Guver Alperen
• Milas Peker

Classifications

• G01N33/5438

  Electrodes · CPC title

• G01N33/554

  the carrier being a biological cell or cell fragment, e.g. bacteria, yeast cells · CPC title

• G01Q70/12

  Nanotube tips · CPC title

• G01Q60/60 Primary

  SECM [Scanning Electro-Chemical Microscopy] or apparatus therefor, e.g. SECM probes · CPC title

• C12Q1/005

  involving specific analytes or enzymes (including groups of enzymes, e.g. oxydases; C12Q1/004 takes precedence) · CPC title