X-Ray Marker Break-Off Structure for Corrosion-Safe Scaffold Bonding

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Solution Overview

Problem

Existing methods for producing x-ray markers face challenges in achieving high radiopacity while maintaining minimal preparative effort and preventing corrosion-accelerating local elements, especially when integrated with degradable scaffolds like stents, due to limitations in material composition and processing viscosity.

Innovation Solution

A method involving pre-cutting x-ray markers with inwardly offset breaking points connected via webs, allowing for efficient production, handling, and integration with scaffolds without premature detachment, using laser cutting and acid treatment for passivation to prevent corrosion and enhance radiopacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the fraction of x-ray-absorbing particles is increased to improve radiopacity, then the radiopacity is improved, but the mixture viscosity increases making processing impossible

Engineering Contradiction:

ImproveradiopacityVSAvoidprocessing viscosity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the physical state of the x-ray-absorbing particles from solid particles in a polymer matrix to a metal layer deposited on the scaffold. This fundamental parameter change allows achieving high radiopacity (metal layers are highly x-ray absorbing) without the viscosity problems of particle-polymer composites, since the metal is applied as a coating rather than mixed into a viscous matrix.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If solid markers are adhesively bonded to the scaffold to simplify production, then production effort is reduced, but corrosion-accelerating local elements form due to direct contact between dissimilar metals

Engineering Contradiction:

Improveproduction effortVSAvoidcorrosion risk

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a polymer adhesive layer as an intermediary between the metal marker and the metallic scaffold. This adhesive layer electrically isolates the two metals, preventing galvanic corrosion while still providing mechanical bonding. The adhesive serves as a mediator that enables both low production effort (simple adhesive bonding) and corrosion protection simultaneously.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the x-ray marker is firmly bonded to the scaffold to ensure stability, then marker stability is improved, but mechanical stress during scaffold degradation increases causing marker detachment

Engineering Contradiction:

Improvemarker stabilityVSAvoidbond strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies a polymer adhesive layer beforehand that acts as a cushioning interface between the rigid metal marker and the degradable metallic scaffold. This adhesive layer has mechanical properties that accommodate the scaffold's degradation and dimensional changes, absorbing mechanical stress and preventing marker detachment while maintaining marker stability during the implant's service life.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Reliability

If high concentration of x-ray absorbing particles is used to achieve radiopacity, then radiopacity is improved, but the mixture becomes too viscous for injection processing

Engineering Contradiction:

ImproveradiopacityVSAvoidinjection processing capability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the mechanical mixing and injection processing of particle-polymer composites with a deposition process. Instead of mechanically mixing particles into a viscous polymer and injecting, the metal marker is deposited as a layer on the scaffold surface. This substitution of the processing mechanism eliminates viscosity limitations entirely, allowing high radiopacity without compromising productivity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables the production of a large number of x-ray markers with consistent properties, reducing mechanical stress and corrosion risks, while ensuring strong adhesion and improved radiopacity, thus enhancing the efficiency and reliability of marker placement on scaffolds.

Implementation Method 1

at least one region (1) of the material layer (2) forming the x-ray marker to be produced is pre-cut

Methodology Applied

Scientific EffectLaser cutting: Laser Ablation

Implementation Method 2

acid treatment for passivation to prevent corrosion

Methodology Applied

Scientific EffectPassivation: Oxidation

Implementation Method 3

x-ray-absorbing particles... the mass fraction of x-ray-absorbing particles in the composite decisively determines the radiopacity

Methodology Applied

Scientific EffectX-ray absorption: Absorption (EM radiation)

Data Source

PatentEP3568111B1X-ray markers for scaffolds

Publication Date: 2021.03.03 BIOTRONIK AG

Figure 1A~1B
Figure 2A~2B
Figure 3

AI summary

The invention relates to a method for producing x-ray markers (1), during which method a predetermined breaking point (21) is severed in order to detach x-ray markers (1) from part (22) of a material layer (2). The invention also relates to an x-ray marker, a medical implant, and a semifinished product.