Iron Implant with Halogen Coating for Controlled Degradation

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Solution Overview

Problem

Current metallic implants, such as stents, face issues with prolonged dwell time and variability in degradation due to coatings that are prone to mechanical stress and micro-crack formation, leading to uncontrolled degradation and potential vascular occlusion.

Innovation Solution

A metallic implant with a surface layer containing an ionic compound with halogen ions, such as chloride or bromide, and a diffusion barrier layer to control degradation and prevent coating damage during deformation, ensuring controlled degradation within a target timeframe.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If protective layers are applied to extend degradation time, then the implant maintains mechanical integrity longer, but the degradation becomes delayed beyond the required time window

Engineering Contradiction:

Improvedwell timeVSAvoiddegradation timing control

Core Design Contradiction:

Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition of the protective layer to include halogen-containing compounds (chloride, bromide, or iodide ions) at controlled concentrations (0.1-10 wt%). This chemical parameter change accelerates the degradation rate through enhanced corrosion mechanisms while maintaining the protective layer's barrier function, thereby achieving degradation within the required time window rather than extending it

Inventive Principle:

Principle #35Parameter changes

2Duration of action of stationary object

If the implant degrades faster to reduce dwell time, then the mechanical integrity is lost prematurely, but if it degrades slower, the dwell time becomes too long

Engineering Contradiction:

Improvedwell timeVSAvoidmechanical integrity

Core Design Contradiction:

Duration of action of stationary objectVSStrength

Solution Approach 1:

The patent applies local quality by creating non-uniform distribution of halogen-containing compounds within the protective layer through controlled application methods. This results in localized variations in degradation rate, with some regions degrading faster than others, allowing the implant to maintain overall structural integrity while achieving the target degradation timeline through progressive localized breakdown

Inventive Principle:

Principle #3Local quality

3Reliability

If coatings are applied to protect the implant surface, then corrosion resistance is improved, but the coatings are prone to micro-crack formation during deformation

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidcoating integrity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies composite materials by combining the protective layer with halogen-containing compounds (creating a composite structure). This composite approach provides both corrosion protection through the barrier layer and controlled degradation acceleration through the halogen compounds, while the composite structure itself is more resistant to micro-crack formation compared to conventional homogeneous coatings

Inventive Principle:

Principle #40Composite materials

4Duration of action of stationary object

If conventional protective layers are used, then degradation is delayed, but variability in degradation remains high

Engineering Contradiction:

Improvedwell timeVSAvoiddegradation consistency

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent applies feedback mechanisms through the halogen-containing compounds that create autocatalytic corrosion effects. As degradation begins, the released metal ions interact with the halogen compounds to accelerate further degradation in a controlled feedback loop, ensuring consistent degradation timing across different implants rather than high variability

Inventive Principle:

Principle #23Feedback

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 solution enables controlled degradation of the implant within a specific timeframe, reducing the risk of vascular occlusion and improving biocompatibility while maintaining mechanical integrity, thus addressing the challenges of prolonged dwell time and variability in existing technologies.

Implementation Method 1

the dissolution that occurs as the result of the degradation process... in the case of iron-based implants, it is generally not possible, using the solutions mentioned above, to place the dissolution that occurs as the result of the degradation process and the crosspiece breaks that result from this into the required time window

Methodology Applied

Scientific EffectElectrochemical corrosion: Crevice Corrosion

Implementation Method 2

a second layer which covers at least part of the first layer and forms a diffusion barrier for the ions of the at least one halogen of the ionic compound

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS8709073B2Implant and method for production of the same

Publication Date: 2014.04.29 BIOTRONIK AG

AI summary

One example embodiment of the present invention relates to an implant, particularly an intraluminal endoprosthesis, having a body that contains metallic material, preferably iron. The implant body has a first layer with at least one ionic compound that contains ions of at least one halogen, particularly chloride ions and/or bromide ions, on at least part of its surface. Furthermore, a method for the production of such an implant is described.