Braided Stent Coating Uniformity via Pre-Stretch
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Solution Overview
Problem
Existing medical devices, such as stents, face challenges in achieving an even coating distribution over their surface, particularly for braided structures, leading to issues like webbing, delamination, and uneven layering, which can result in improper blood flow and potential blockages.
Innovation Solution
A method involving a heat-treated stent with a braided design, where the device is maintained in a longitudinally stretched configuration during coating to prevent imperfections, using techniques like dipping and air knifing to ensure a uniform, web-free coating, particularly utilizing anti-thrombogenic materials like 2-Methacryloyloxyethyl phosphorylcholine, to create a substantially complete and uniform coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating is applied to a braided stent, then the thrombogenicity is reduced and blood flow is enhanced, but the coating becomes uneven with webs and delamination occurring
Solution Approach 1:
The stent is pre-stretched longitudinally before coating application to open up the braided structure and create uniform spacing between filaments. This preliminary action prevents coating material from accumulating in inter-filament spaces and eliminates web formation, enabling even coating distribution while maintaining the therapeutic benefit of reduced thrombogenicity
2Ease of operation
If the stent is coated to reduce thrombogenicity, then blood flow is enhanced, but webbing and delamination occur causing improper blood flow
Solution Approach 1:
The stent is pre-stretched longitudinally before coating application to open up the braided structure and create uniform spacing between filaments. This preliminary action prevents coating material from accumulating in inter-filament spaces and eliminates web formation, enabling even coating distribution while maintaining the therapeutic benefit of reduced thrombogenicity
Solution Approach 2:
The mechanical stretching process replaces the need for complex coating control mechanisms. By applying mechanical tension to the stent structure before coating, the method substitutes a simple mechanical preparation step for what would otherwise require sophisticated coating application systems to achieve uniform coverage without defects
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 uniform coating that is free of webs and delamination, reducing thrombogenicity and enhancing blood flow, allowing for effective treatment of aneurysms with reduced risk of complications.
Implementation Method 1
dipping the stent into a coating material to coat a first section of the stent
Implementation Method 2
removing excess coating material from the stent using techniques like dipping and air knifing
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.