Plasma-Modified Stent Surface Prevents Restenosis and Thrombosis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current medical devices, particularly coronary stents, face challenges with high incidence of restenosis and late stent thrombosis, as existing coatings fail to simultaneously prevent both conditions effectively.
Innovation Solution
A two-step plasma coating process using silicon-containing monomers for deposition and a mixture of nitrogen and oxygen molecules for surface modification creates a nano-scale, bioactive layer that inhibits blood clots and restenosis, promoting endothelialization and reducing smooth muscle cell proliferation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drug-eluting stents are used to prevent restenosis, then restenosis rate is reduced, but risk of late stent thrombosis increases
Solution Approach 1:
The patent removes the polymer coating that carries drugs from the stent surface, eliminating the source of delayed healing and thrombosis risk while preserving the stent's structural function. This extraction of the harmful polymer component resolves the contradiction between restenosis prevention and thrombosis risk.
Solution Approach 2:
The patent uses plasma treatment to create a bioactive surface that promotes endothelialization and prevents both restenosis and thrombosis simultaneously. By converting the inert metal surface into a bioactive surface through plasma deposition of amino acids and peptides, the stent gains dual functionality: preventing restenosis through controlled drug delivery and preventing thrombosis through enhanced endothelial cell attachment.
2Reliability
If polymer coating is applied to deliver drugs, then restenosis is controlled, but delayed healing occurs leading to thrombosis
Solution Approach 1:
The patent extracts and removes the polymer coating material from the stent surface, eliminating the barrier that delays healing. By using a polymer-free design with plasma-deposited bioactive layers, the stent surface allows rapid endothelial cell attachment and healing without the prolonged inflammatory response associated with polymer coatings.
Solution Approach 2:
The patent changes the surface chemistry parameters by depositing specific amino acids (arginine, lysine, histidine) and peptides through plasma treatment. These biochemical parameter changes create a surface that actively promotes endothelialization and accelerates healing while maintaining controlled drug delivery capability, thus reducing the healing time contradiction.
3Strength
If plasma coating is made thicker to improve durability, then coating integrity improves, but stent expansion is restricted
Solution Approach 1:
The patent employs an ultra-thin plasma-deposited coating layer (nanometer scale) that functions as a flexible film on the stent surface. This thin film provides sufficient durability and bioactivity while maintaining the stent's expandability, as the coating thickness is optimized to be thin enough to accommodate stent expansion without cracking or delamination.
Solution Approach 2:
The patent optimizes the plasma deposition parameters (power, pressure, gas flow, deposition time) to control the coating thickness and microstructure. By adjusting these parameters, the coating achieves the optimal balance between durability and flexibility, providing a thin yet robust layer that withstands stent expansion while maintaining its protective and bioactive functions.
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 plasma coating process results in a durable, thrombo-resistant surface that prevents restenosis and thrombosis, with enhanced endothelial cell attachment and no coating cracks during stent expansion, offering improved biocompatibility for long-term implantation.
Implementation Method 1
a first step of a plasma deposition process using silicon-containing monomers to provide a uniform and conformal nano-scale plasma coating
Implementation Method 2
a second step of a plasma modification process using a mixture of nitrogen and oxygen molecules
Data Source
AI summary
Coatings, devices and methods are provided, wherein the contacting surface of a medical device with at least one contacting surface for contacting a bodily fluid or tissue, wherein long-lasting and durable bioactive agents or functional groups are deposited on the contacting surface through a unique two-step plasma coating process with deposition of a thin layer of plasma coating using a silicon-containing monomer in the first step and plasma surface modification using a mixture of nitrogen-containing molecules and oxygen-containing molecules in the second step. The two-step plasma coating process enables the implantable medical device to prevent both restenosis and thrombosis under clinical conditions. The invention also relates to surface treatment of metallic and polymeric biomaterials used for making of medical devices with significantly improved clinical performance and durability.