Braided Stent Coating Uniformity via Heat Treatment
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Solution Overview
Problem
Current methods for manufacturing braided stents with coatings face challenges in achieving an even distribution of coating materials, often resulting in imperfections such as webbing, delamination, and uneven layering, which can lead to risks like blockages in blood vessels.
Innovation Solution
A heat-treated stent with a braided structure is coated using a process that maintains the stent in a longitudinally stretched configuration during coating, employing air knifing and specific coating fixtures to ensure a uniform, imperfection-free coating, particularly using anti-thrombogenic materials like 2-Methacryloyloxyethyl phosphorylcholine, to prevent webbing and delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating is applied to a braided stent, then the anti-thrombogenic effect is improved, but coating imperfections such as webbing, delamination, and uneven layering occur
Solution Approach 1:
The stent is heat-treated before coating to stabilize its structure and reduce thermal shrinkage during the coating process. This preliminary heat treatment ensures the stent maintains dimensional stability, preventing coating imperfections like webbing and delamination while allowing uniform coating application for optimal anti-thrombogenic performance
Solution Approach 2:
The coating process parameters are optimized by controlling the stent temperature within a specific range (200-400°C) during coating application. This temperature control allows the coating to be applied evenly without causing excessive thermal shrinkage or structural changes to the braided stent, thereby achieving both uniform coating and effective anti-thrombogenic properties
2Manufacturing precision
If the stent is heat-treated to reduce shrinkage, then coating uniformity is improved, but the heat treatment process complexity increases
Solution Approach 1:
The heat treatment step is integrated into the existing stent manufacturing process, combining it with the coating process rather than being a separate, standalone operation. This integration allows the stent to be heat-treated in-situ before coating without requiring additional equipment or complex process sequences, thereby achieving coating uniformity while minimizing process complexity
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 results in a stent with a substantially complete and uniform coating that is free of webbing and delamination, reducing thrombogenicity and enhancing the safety and effectiveness of the stent in treating aneurysms by minimizing the risk of blood vessel blockages.
Implementation Method 1
a heat-treated device (e.g., stent) is provided that comprises an even coating that is substantially free of imperfections
Implementation Method 2
a heat-treated device (e.g., stent) is provided that comprises an even coating
Data Source
Figure 1~2
Figure 3A~3C
Figure 4~5A
AI summary
Coating methods and related devices are provided. Such devices can include stents. For example, the device can comprise a sidewall and a plurality of pores in the sidewall that are sized to inhibit flow of blood through the sidewall into an aneurysm to a degree sufficient to lead to thrombosis and healing of the aneurysm when the tubular member is positioned in a blood vessel and adjacent to the aneurysm. The device can also comprise an anti-thrombogenic coating distributed over at least a portion of the device such that the pores are substantially free of webs formed by the coating.