Braided Stent Coating Uniformity via Dynamic Twist and Diameter Control
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Solution Overview
Problem
Current medical devices, particularly braided stents, face challenges in maintaining patency due to restenosis and complex loading conditions in peripheral vessels, which are not adequately addressed by existing coatings and coating methods.
Innovation Solution
A method for applying a coating composition onto braided medical devices involving multiple passes with axial translation and rotation, or a combination thereof, while varying the device's diameter and twist, using solvents with specific viscosities and surface tensions to ensure uniform coverage and resistance to abrasion and fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating is applied to braided medical devices, then restenosis is reduced and drug delivery is improved, but the coating is susceptible to abrasion and fatigue under complex loading conditions
Solution Approach 1:
The patent applies a multi-layer coating system comprising an inner layer and an outer layer with different material compositions and properties. The inner layer provides adhesion and initial drug delivery, while the outer layer provides enhanced mechanical durability and abrasion resistance. This composite structure allows each layer to specialize in specific functions, resolving the contradiction between restenosis reduction and coating strength.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the coating materials, including viscosity, surface tension, and molecular weight, to optimize both biological performance (restenosis reduction) and mechanical performance (abrasion and fatigue resistance). By carefully selecting and adjusting these parameters, the coating achieves dual functionality without compromise.
2Manufacturing precision
If multiple passes with varying diameter and twist are used during coating application, then uniform coverage is improved, but the application process complexity increases
Solution Approach 1:
The patent employs dynamic adjustment of the medical device parameters (diameter and twist) during the coating application process. The device is progressively deformed through controlled expansion and twisting motions, allowing the coating to be applied uniformly across varying surface geometries. This dynamic approach ensures complete coverage while managing process complexity through systematic parameter variation.
Solution Approach 2:
The coating application is divided into multiple discrete passes, with each pass targeting specific regions or aspects of the device surface. By segmenting the complex application process into manageable stages with controlled parameter variations, the patent achieves uniform coverage without overwhelming complexity in any single operation.
3Duration of action of stationary object
If solvents with high viscosity and surface tension are used, then coating durability is improved, but coating application uniformity deteriorates
Solution Approach 1:
The patent carefully selects and adjusts the viscosity and surface tension parameters of the coating solvents to achieve an optimal balance. By controlling these physical parameters within specific ranges and using multiple passes with parameter variation, the coating achieves both uniform application and long-term durability, resolving the contradiction between these two properties.
Data Source
AI summary
Embodiments of the present invention encompass methods of forming coatings, particularly coatings for medical devices, and more particularly, for braided or woven medical devices. Embodiments of the present invention encompass the coatings and the coated devices. The coatings may include a polymer and optionally a therapeutic agent.