Medical Stent Surface Topography via Photochemical Etching
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Solution Overview
Problem
Current intravascular stents face challenges with slow endothelial cell migration onto their surface, leading to potential reocclusion and restenosis due to the lack of topographical features that could enhance cell migration and integration, which is crucial for preventing thrombosis and maintaining patency.
Innovation Solution
A method of manufacturing medical devices with topographical features by chemically etching the surface using a photosensitive material, irradiation, and subsequent chemical machining to create patterns that promote cell migration and integration, applicable to stents and other implants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stent surface is kept smooth through electropolishing, then the biocompatibility and endothelial cell migration are improved, but the ability to promote rapid cell integration and reduce restenosis is worsened
Solution Approach 1:
The patent applies local quality by creating specific topographical features (grooves, pits, or raised patterns) at localized regions on the stent surface rather than maintaining uniform smoothness. These localized topographical modifications provide enhanced cell attachment sites while preserving overall surface smoothness, thereby resolving the contradiction between biocompatibility and rapid cell integration.
Solution Approach 2:
The patent employs preliminary action by pre-forming topographical features on the stent surface during manufacturing before implantation. This preliminary structuring of the surface prepares the stent to actively guide and accelerate endothelial cell migration and integration immediately upon implantation, rather than relying solely on passive smooth surface properties.
2Productivity
If topographical features are added to the stent surface to enhance cell migration, then the cell integration rate is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent replaces complex mechanical machining processes with photochemical etching technology. By using photomasks and chemical etchants, the desired topographical features are created through selective chemical removal of material based on light exposure patterns, significantly simplifying the manufacturing process compared to traditional mechanical methods while achieving the required surface complexity.
Solution Approach 2:
The patent utilizes parameter changes by controlling the etching depth, pattern geometry, and distribution through adjustment of photomask design and etching conditions. This allows optimization of topographical features to achieve maximum cell integration rate while maintaining manufacturability and controlling the complexity of the surface structure.
3Productivity
If chemical etching is used to create topographical features, then the cell migration promotion is improved, but the manufacturing precision control becomes more difficult
Solution Approach 1:
The patent employs copying by using photomasks as precise templates that replicate desired topographical patterns onto the stent surface. The photomask serves as a master copy that defines the exact geometry, size, and distribution of features, ensuring consistent and precise reproduction of surface patterns across multiple stents while facilitating cell migration.
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 method increases the rate of endothelial cell migration onto the stent surface, enhancing biocompatibility and reducing the risk of reocclusion by creating a conducive environment for cell growth and integration.
Implementation Method 1
coating the surface of the device with a photosensitive material; irradiating the surface of the device by a source of exposing radiation
Implementation Method 2
etching light exposed areas to produce at least one topographical feature in the surface of the device
Data Source
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AI summary
The invention relates to methods and apparatus for manufacturing medical devices wherein the medical device has a surface treated to promote the migration of cells onto the surface of the medical device. In particular, the surface of the medical device has at least one topographical feature formed therein.