Carbon Fiber Electrodes for Brain Molecule Detection

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Solution Overview

Problem

Implantable electrochemical detection electrodes, particularly biosensors, face challenges due to their invasive nature, leading to tissue damage and instability, as existing methods struggle to achieve small diameters and long-term catalytic stability for accurate brain molecule monitoring.

Innovation Solution

A method involving vacuum deposition to create thin, high-purity metal layers on support filaments, with an insulating underlayer and adhesion sub-layer, to produce electrochemical detection electrodes with diameters less than 15 μm, enhancing stability and sensitivity for hydrogen peroxide detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the diameter of implantable biosensors is reduced to less than 15 μm to minimize tissue damage, then tissue damage and inflammation are reduced, but no platinum wire is rigid enough to achieve such small sizes

Engineering Contradiction:
Improvetissue damageVSAvoidelectrode diameter
Core Design Contradiction:
Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The patent employs flexible carbon fiber as the core structure instead of rigid platinum wire, enabling the electrode to achieve a diameter of less than 15 μm while maintaining structural integrity. The carbon fiber's flexibility allows it to conform to tissue without causing damage, directly resolving the contradiction between small size and structural rigidity

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite structure by coating carbon fiber with vacuum-deposited metal layers (platinum, ruthenium, or rhodium). This composite approach combines the flexibility and small-diameter capability of carbon fiber with the catalytic properties of metals, enabling both minimal tissue damage and effective electrochemical detection

Inventive Principle:
Principle #40Composite materials

2Length of moving object

If carbon fiber is used to achieve small diameter electrodes, then small size is achieved, but carbon is poorly suited to hydrogen peroxide oxidation and enzyme immobilization is unstable

Engineering Contradiction:
Improveelectrode diameterVSAvoidenzyme immobilization stability
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent introduces vacuum-deposited metal layers (platinum, ruthenium, or rhodium) as an intermediary coating on the carbon fiber surface. This metal layer serves as a mediator that provides both catalytic activity for hydrogen peroxide oxidation and stable binding sites for enzyme immobilization, resolving the contradiction between small size and reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the surface chemical parameters of carbon fiber through vacuum deposition of metal layers, transforming it from a material poorly suited for enzyme immobilization to one with excellent catalytic and binding properties. This parameter change enables stable enzyme retention while maintaining the small diameter advantage

Inventive Principle:
Principle #35Parameter changes

3Reliability

If electrodeposition is used to deposit metal layers on carbon fiber, then catalytic properties are achieved, but the metallic deposits are unstable and quickly lose catalytic properties

Engineering Contradiction:
Improvecatalytic stabilityVSAvoiddeposition process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the electrochemical deposition process with vacuum deposition (physical vapor deposition). This substitution eliminates the instability issues associated with electrodeposition while maintaining ease of manufacture through a simplified single-step process that produces stable, adherent metal coatings with excellent catalytic properties

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If vacuum deposition is used to create thin metal layers, then high purity and stability are achieved, but the process complexity increases

Engineering Contradiction:
Improvemetallic layer stabilityVSAvoiddeposition process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the metal coating process from complex multi-step electrochemical procedures and implements it as a single vacuum deposition step. This extraction simplifies the overall manufacturing process while producing high-purity, stable metal layers, resolving the contradiction between reliability and process complexity

Inventive Principle:
Principle #2Taking out (Extraction)

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

This approach reduces tissue damage and inflammation, enabling long-term, stable detection of brain molecules, suitable for both animal experimentation and human clinical neuro-monitoring, with improved sensitivity and reduced methodological biases.

Implementation Method 1

The inventors propose using a vacuum deposition metallization process. The inventors discovered that vacuum deposition yields a thin, high-purity metallic layer with excellent catalytic properties and high stability.

Methodology Applied
Scientific EffectVacuum deposition: Physical Vapour Deposition

Implementation Method 2

The deposition is preferably carried out by a vacuum deposition process such as chemical vapor deposition or physical vapor deposition.

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 3

The electrode catalyzes a redox reaction on its surface, generating a redox current indicating the presence and/or quantity of an oxidizable or reducible compound in its vicinity.

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 4

The hydrogen peroxide is then oxidized at the electrode surface, and the resulting oxidation current is detected to provide a quantitative estimate of the concentration of the molecule of interest

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 5

In particular, the filament is a carbon fiber coated with an insulating underlayer and a metallic layer capable of catalyzing the oxidation of an oxidizable compound

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentEP3283874B1Implantable electrodes for electrochemical detection
Publication Date: 2022.02.23 UNIV CLAUDE BERNARD LYON 1
  • EP3283874B1 patent drawingFigure 1A~1B
  • EP3283874B1 patent drawingFigure 2~3

AI summary

The present application relates to a process for manufacturing an electrode for electrochemical detection for detecting an analyte, said process comprising depositing, on a carrier filament, a metal layer able to catalyse the oxidation of an oxidisable compound, said deposition being carried out by a vacuum deposition process. The process may also comprise depositing, on the metallised filament, an enzymic layer able to catalyse the degradation of said analyte while generating said oxidisable compound. The invention also relates to an electrode manufactured using this process, to an associated device, and to a method for electrochemically detecting an analyte, in particular O2.