Biodegradable Alloy Stent Polymer Coating for Thrombosis Reduction
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Solution Overview
Problem
Current coronary stents face issues with late-stent thrombosis and in-stent restenosis due to thrombogenicity, leading to complications such as blood clots and inflammation, and existing biodegradable stents lack the mechanical properties of metallic counterparts, causing increased inflammatory responses.
Innovation Solution
Treatment of biodegradable alloys, such as magnesium-based and iron-based alloys, with mechanical polishing, anodization, and polymer coating to enhance anti-thrombogenicity and biocompatibility, reducing platelet adherence and improving corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If biodegradable polymeric stents are used, then late stent thrombosis and secondary surgeries are reduced, but mechanical properties deteriorate and inflammatory response increases
Solution Approach 1:
The invention uses composite materials by coating biodegradable alloy stents with biodegradable polymer layers. The alloy substrate (e.g., magnesium-based) provides mechanical strength and structural integrity, while the polymer coating (e.g., polyglycolic acid, polylactic acid) provides anti-thrombogenic properties and controlled drug delivery. This composite structure resolves the contradiction by combining the advantages of both materials.
Solution Approach 2:
The invention changes the surface parameters of the stent by applying polymer coatings with specific thicknesses (e.g., 1-10 micrometers) and compositions. The coating parameters can be adjusted to optimize both mechanical properties (through thickness control) and anti-thrombogenicity (through material selection and surface morphology control), resolving the contradiction between these properties.
2Strength
If metallic stents are used, then mechanical strength is maintained, but thrombogenicity increases leading to blood clots and inflammation
Solution Approach 1:
The biodegradable polymer coating acts as an intermediary layer between the metallic/biodegradable alloy stent and the blood environment. This intermediate layer prevents direct contact between the alloy surface and blood components, thereby reducing thrombogenicity while maintaining the mechanical integrity of the underlying alloy structure.
Solution Approach 2:
The invention changes the surface parameters of the alloy stent through polymer coating, modifying surface energy, wettability, and roughness to reduce platelet adhesion and thrombus formation. The coating transforms the inherently thrombogenic metal surface into a biocompatible interface, resolving the contradiction between mechanical strength and thrombogenicity.
3Strength
If alloy surface is exposed to vascular blood flow, then mechanical properties are retained, but thrombus formation occurs due to electron transfer with fibrinogen
Solution Approach 1:
The polymer coating serves as an intermediary barrier between the alloy surface and blood fibrinogen. It prevents the electron transfer process that initiates thrombosis by blocking direct interaction between the alloy surface and blood proteins, while the alloy substrate maintains its structural properties intact.
Solution Approach 2:
The invention converts the inherently thrombogenic alloy surface into a beneficial anti-thrombogenic interface by applying polymer coatings. The harmful electron transfer property of the alloy surface is transformed into a benefit through the coating, which provides a non-thrombogenic surface while the alloy's mechanical properties remain intact underneath.
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 significantly reduces thrombosis and restenosis, lowers the need for secondary surgeries, and enhances the mechanical properties of biodegradable stents, making them safer and more effective for cardiovascular applications.
Implementation Method 1
anodization (A)
Implementation Method 2
anodization (A)
Implementation Method 3
polymer coating (P)
Data Source
AI summary
The invention pertains to methods of treating alloys, particularly, biodegradable alloys containing Mg, Zn or Fe. The alloys can be treated with at least one of the following procedures: mechanical polishing, anodization, and polymer coating. Advantageously, methods provided herein enhance the anti-thrombogenicity of the alloy surface. Such materials can be used for preparing biomedical devices, such as endovascular implants, vascular implants, drug-eluting stents, orthopedic prostheses, or implantable chips. Methods of treating a subject by implanting the biomedical devices into the subject are also provided.