Sulfonated Polymer Coating for Stent Biocompatibility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Interventional medical devices, particularly stents, face biocompatibility issues due to poor compatibility with the human body, leading to thrombosis and post-operative complications, and existing polymer coatings do not adequately address these issues.
Innovation Solution
A multilayer coating system for medical devices featuring a sulfonate group-containing polymer as the outermost layer, with a sulfonated styrene-olefin copolymer, specifically a sulfonated styrene-isobutylene diblock or triblock copolymer, providing a surface similar to heparin for improved biocompatibility and controlled drug release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional polymer materials (polymethacrylates, fluoropolymers, polyethylene-based polymers, or polystyrene-based polymers) are used for coating interventional medical devices, then industrial application experience is available, but biocompatibility is poor leading to thrombosis and post-operative complications
Solution Approach 1:
The patent uses a composite coating system comprising multiple layers with different polymer materials. The inner layer uses conventional polymers for ease of manufacture, while the outer layer uses sulfonated styrene-olefin copolymer for improved biocompatibility. This composite structure combines the advantages of both material types to resolve the contradiction between manufacturing ease and biocompatibility.
Solution Approach 2:
The patent applies different material properties to different parts of the coating system. The inner layer is optimized for manufacturing and structural support, while the outer layer is specifically designed with sulfonated styrene-olefin copolymer to provide enhanced biocompatibility and thrombosis resistance where it contacts blood. This local differentiation resolves the contradiction by assigning appropriate materials to appropriate functions.
2Reliability
If the degree of sulfonation is increased to improve biocompatibility, then cell compatibility improves, but the lipid-soluble nature of the polymer may be reduced affecting drug delivery
Solution Approach 1:
The patent optimizes the degree of sulfonation parameter to a specific range (5-30 mol%) to achieve the desired balance between biocompatibility and drug delivery. By carefully controlling this chemical parameter, the coating maintains sufficient lipid solubility for drug incorporation while providing adequate hydrophilic character for cell compatibility and thrombosis resistance.
Solution Approach 2:
The multilayer composite structure allows the inner layer to provide drug reservoir functionality while the outer sulfonated layer provides biocompatibility. This composite approach resolves the contradiction by separating the drug delivery function from the biocompatibility function into different layers.
3Device complexity
If a single-layer coating is used, then the device structure is simple, but it cannot provide both drug release and adequate biocompatibility protection
Solution Approach 1:
The patent divides the coating into multiple functional layers: an inner layer for drug incorporation and release, and an outer layer for biocompatibility and thrombosis resistance. This segmentation allows each layer to specialize in its function, resolving the contradiction between structural simplicity and therapeutic effectiveness.
Solution Approach 2:
The multilayer composite coating structure combines materials with different properties to simultaneously achieve drug delivery and biocompatibility protection. The inner layer provides drug reservoir and controlled release, while the outer sulfonated layer provides cell compatibility and thrombosis resistance, together resolving the limitations of single-layer coatings.
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 coating enhances cell compatibility, reduces thrombosis, and allows for controlled drug delivery, promoting endothelialization and minimizing complications post-implantation.
Implementation Method 1
the material of the outmost layer of the coating layer is a sulfonate group-containing polymer... providing a surface similar to heparin for improved biocompatibility
Implementation Method 2
allows for controlled drug delivery, promoting endothelialization and minimizing complications post-implantation
Data Source
Figure 1~3
Figure 4~6
AI summary
The present invention discloses an interventional medical device and methods of making the same. At least one coating layer is disposed on the outer surface of the interventional medical device and the material of the outmost layer of the coating layer is a sulfonate group-containing polymer. In the present invention, the material of the outmost layer of the interventional medical device is a sulfonate group-containing polymer. The polymer is endowed with a same surface property as that of heparin in addition to appropriate hydrophilicity due to the presence of the sulfonate group. After the interventional medical device is implanted into the human body, a hydrophilic surface is formed on the outer surface of the interventional medical device which is also negatively charged in the body fluid. Therefore, cells can easily adhere and grow on the outer surface thereof as a result of the enhanced cell compatibility. Furthermore, due to a surface property that is the same as that of heparin, the material is provided with excellent anticoagulant properties which inhibit the thrombosis and lower down the incidence rate of post-operational complications.