Nanoscale SECM Electrode Fabrication via Segmented Nanowire Growth

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Solution Overview

Problem

Current methods for preparing nanoscale electrodes are laborious and not cost-effective, limiting their use in high-resolution detection and mapping of target molecules from single cell surfaces, particularly in aptamer-based biosensing applications.

Innovation Solution

A novel method for fabricating nanoscale SECM electrodes using electrochemically grown noble metal nanowires, such as gold and platinum, with tapered-tip electrodes and aptamers for selective detection and mapping of target molecules, enabling high-resolution biosensing and reducing noble metal consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional ultramicroelectrodes with diameters of several microns are used, then the electrode structure is simple and fabrication is straightforward, but the spatial resolution is insufficient for site-specific target molecule detection from single cell surfaces

Engineering Contradiction:

Improvespatial resolutionVSAvoidelectrode fabrication complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The electrode is segmented into a shaft portion and a protruded probe portion, with the probe having a smaller diameter than the shaft. This segmentation enables the tip to achieve nanoscale dimensions for high spatial resolution while the shaft maintains larger dimensions for mechanical stability and easier handling.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A nanoscale electrode tip is nested within a micropipette shaft structure. The protruded probe is positioned at the tip of the micropipette, creating a nested configuration that combines the stability of the micropipette with the high resolution of the nanoscale probe.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Manufacturing precision

If nanoscale electrodes are used to achieve high spatial resolution, then site-specific detection capability is improved, but current preparation methods are laborious and not cost-effective

Engineering Contradiction:

Improvespatial resolutionVSAvoidfabrication ease

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The micropipette shaft is prepared in advance with a tapered tip through conventional techniques before the nanoscale electrode is formed. This preliminary preparation simplifies the subsequent nanofabrication process by providing a pre-formed structural foundation that requires minimal additional processing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The micropipette shaft serves as an intermediary structure that facilitates the formation and handling of the nanoscale electrode tip. The shaft provides mechanical support and a convenient handle for manipulating the fragile nanoscale probe during fabrication and operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If several micron diameter electrodes are used, then fabrication is simpler, but they are too large to effectively enable site-specific target molecule detection from a single cell surface

Engineering Contradiction:

Improvefabrication simplicityVSAvoiddetection precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the electrode have different diameters optimized for different functions: the shaft has a larger diameter for mechanical stability and easy handling, while the protruded probe has a nanoscale diameter for high-resolution local detection. This local quality variation allows the single electrode to satisfy multiple contradictory requirements.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method provides cost-effective, high-resolution detection and mapping of target molecules from single cell surfaces, enhancing spatial resolution and enabling efficient localization of molecules, critical for applications like cancer detection and neurological data recording.

Implementation Method 1

applying an electrical potential between the tips to grow a nanowire formed of the noble metal in the saturated solution

Methodology Applied

Scientific EffectElectrochemical deposition: Electrodeposition

Data Source

PatentUS11543429B2Nanoscale scanning electrochemical microscopy electrode method

Publication Date: 2023.01.03 MORGAN STATE UNIVERSITY

AI summary

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.