Magnesium Vascular Scaffold Coating for Radiopaque Marker Stability
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Solution Overview
Problem
Existing biodegradable vascular scaffolds made of magnesium alloys face issues with uncontrolled degradation, galvanic corrosion, and inadequate X-ray visibility, which can lead to premature detachment and restenosis, complicating their manufacturing and deployment.
Innovation Solution
A vascular scaffold made of a biodegradable magnesium alloy with a form-fitting or force-fitting rare-earth metal radiopaque marker, such as dysprosium, is covered with an inorganic magnesium fluoride coating, minimizing galvanic corrosion and ensuring stable radiopacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a biodegradable magnesium alloy scaffold is used, then the scaffold can be degraded by the body after temporary support, but the degradation is uncontrolled and leads to premature detachment
Solution Approach 1:
The scaffold is pre-coated with magnesium fluoride and equipped with rare-earth metal radiopaque markers before implantation. This preliminary protective action controls the degradation rate by forming a stable surface layer that prevents premature breakdown, while the radiopaque markers enable real-time monitoring of scaffold position and integrity throughout the degradation process.
Solution Approach 2:
The invention changes the chemical composition parameters of the magnesium alloy by adding specific rare-earth metals (Y, Gd, Dy, Er, Tb) at controlled concentrations (0.1-5.0 wt%). This compositional modification alters the electrochemical properties and degradation kinetics of the scaffold, enabling controlled degradation over the desired time period while maintaining mechanical stability.
2Difficulty of detecting and measuring
If radiopaque markers are added to enhance X-ray visibility, then detection is improved, but galvanic corrosion occurs between the marker and scaffold
Solution Approach 1:
The rare-earth metal radiopaque markers are integrated into the magnesium alloy matrix with homogeneous distribution at the atomic level. This homogeneity eliminates galvanic corrosion by ensuring uniform electrochemical properties throughout the material, while the rare-earth metals provide sufficient X-ray contrast for imaging.
Solution Approach 2:
The invention creates a composite magnesium alloy material combining magnesium base metal with rare-earth metal elements (Y, Gd, Dy, Er, Tb). This composite structure provides both the radiopacity needed for X-ray detection and the mechanical properties required for scaffold function, while the controlled composition prevents galvanic corrosion.
3Ease of manufacture
If the scaffold structure is simplified for easy manufacturing, then production is easier, but the scaffold cannot provide sufficient support to prevent restenosis
Solution Approach 1:
The invention optimizes the compositional parameters of the magnesium alloy by incorporating rare-earth metals at specific concentrations (0.1-5.0 wt% each). This parameter change enhances the mechanical strength and radial support capability of the scaffold, enabling it to prevent restenosis while maintaining manufacturability through conventional processes.
Solution Approach 2:
The scaffold provides localized enhanced strength at the strut structures through the rare-earth metal reinforcement, while maintaining overall structural simplicity. The radiopaque markers are strategically positioned at specific locations to provide monitoring capability without adding manufacturing complexity to the entire scaffold structure.
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 provides a scaffold with controlled degradation and enhanced X-ray visibility, reducing the risk of restenosis and ensuring the scaffold remains intact during endothelialization, facilitating easy manufacturing and safe deployment.
Implementation Method 1
minimizing galvanic corrosion and ensuring stable radiopacity
Implementation Method 2
enhanced X-ray visibility
Data Source
Figure 1
Figure 2~3
Figure 4A
AI summary
The present invention relates to vascular scaffolds made of a biodegradable magnesium alloy comprising a cylindrical scaffold body formed of interconnected struts, wherein the interconnected struts comprise at least one structure designed to hold at least one radiopaque marker, wherein the at least one structure holds at least one radiopaque marker in a form-fitting or force-fitting manner, wherein the at least one radiopaque marker is dysprosium, and wherein the vascular scaffold is completely covered with an inorganic coating comprising magnesium fluoride. The vascular scaffolds according the invention can additionally be coated with an organic coating and/or with at least one antiinflammatory, antiproliferative, antiangiogenic, antirestenotic, and/or antithrombogenic active agent.