Galvanic Implant Using Cobalt-Titanium Couple for Ion Elution

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Solution Overview

Problem

Current orthopedic implant devices face challenges in achieving antimicrobial properties without requiring external operations or treatments, leading to increased patient burden due to microbial growth and infection risks.

Innovation Solution

An antimicrobial implant device is created using a combination of a cobalt-based alloy and a titanium-based alloy, where the contact between these materials in vivo forms an electric circuit, allowing antimicrobial metal ions to be eluted and providing antimicrobial properties to the implant surface and surrounding area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a silver coating is applied to the implant device, then antimicrobial property is improved, but device complexity and external operation requirements worsen

Engineering Contradiction:
Improveantimicrobial propertyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines two different materials (first material with antimicrobial metal, second material with nobler surface) into a single implant device structure. This merging eliminates the need for separate external power sources and control systems required by prior art, while maintaining antimicrobial effectiveness through the electric circuit formed between the two materials.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The implant device serves multiple functions simultaneously: it provides structural support as an orthopedic implant, generates electric current through the contact between two materials to enable ion elution, and delivers antimicrobial protection. This multi-functionality eliminates the need for separate external antimicrobial delivery systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If external power source and terminals are added to achieve antimicrobial property, then antimicrobial effectiveness is improved, but ease of operation worsens

Engineering Contradiction:
Improveantimicrobial effectivenessVSAvoidease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The implant device generates its own electric current through the contact between the first material (with antimicrobial metal) and the second material (with nobler surface) in the presence of electrolyte. This self-generated current drives the elution of antimicrobial metal ions without requiring external power sources, terminals, or external operations to activate or maintain the antimicrobial function.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts and eliminates the external power source and terminal components from the system. Instead of requiring external equipment, the essential function of generating electric current for ion elution is achieved through the intrinsic contact between the two materials within the implant device itself.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If treatment or external operation is needed to impart antimicrobial property, then antimicrobial property is achieved, but loss of time worsens

Engineering Contradiction:
Improveantimicrobial propertyVSAvoidloss of time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The antimicrobial metal ions are eluted and become active immediately upon implantation, as the electric circuit is automatically formed by the contact between the two materials in the physiological environment. No preliminary treatment, activation step, or external operation is required - the antimicrobial function begins working from the moment the device is implanted.

Inventive Principle:
Principle #10Preliminary action

4Ease of manufacture

If silver coating is used without galvanic couple, then manufacturing is simpler, but antimicrobial effectiveness worsens

Engineering Contradiction:
Improveease of manufactureVSAvoidantimicrobial effectiveness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The implant device uses a composite structure combining two materials with different electrochemical properties: the first material containing antimicrobial metal (such as silver, copper, or cadmium) and the second material with a nobler surface. This composite structure creates a galvanic couple that enhances the elution of antimicrobial metal ions compared to simple silver coating, improving antimicrobial effectiveness while maintaining manufacturability.

Inventive Principle:
Principle #40Composite materials

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 solution enables the implant device to achieve antimicrobial properties without external operations, significantly reducing patient burden by effectively inhibiting microbial growth and infection through ion elution from the cobalt-based alloy when in contact with the titanium-based alloy in a biological environment.

Implementation Method 1

at least a surface of the first material comprises an antimicrobial metal; at least a surface of the second material is nobler than the first material; an electric circuit is formed between the first material and the second material when the device is implanted in vivo for use; and ions of the antimicrobial metal are eluted from the first material under a presence of an electrolyte

Methodology Applied
Scientific EffectGalvanic corrosion:

Implementation Method 2

ions of the antimicrobial metal are eluted from the first material under a presence of an electrolyte to impart an antimicrobial property

Methodology Applied
Scientific EffectIon elution:

Data Source

PatentEP3424451B1Antibacterial device to be implanted in vivo
Publication Date: 2022.07.20 MEDTRONIC SOFAMOR DANEK
  • EP3424451B1 patent drawingFigure 1~2
  • EP3424451B1 patent drawingFigure 3~4
  • EP3424451B1 patent drawing

AI summary

Provided is an implant device that can achieve an antimicrobial property, simply by being implanted in vivo, to reduce the burden on patients. An antimicrobial implant device made of a first material and a second material, wherein at least a surface of the first material comprises an antimicrobial metal; at least a surface of the second material is nobler than the first material; an electric circuit is formed between the first material and the second material when the device is implanted in vivo for use; and ions of the antimicrobial metal are eluted from the first material under a presence of an electrolyte to impart an antimicrobial property to a surface and/or a surrounding area of the first material.