Flat Stent Drug Coating Uniformity via Preliminary Action
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Solution Overview
Problem
Current stent coating methods struggle with achieving uniformity and differential treatment of the luminal and vessel wall sides, leading to inefficiencies in coating distribution and increased costs due to the difficulty in controlling the coating ratio and the slow pace of existing processes.
Innovation Solution
A method involving the coating of stents in a flat sheet form before assembly, allowing for precise application of polymer and drug coatings on both sides, enabling differential treatment and improved uniformity through techniques like physical vapor deposition or spraying, which can be applied before or after electropolishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If coating is applied to cylindrical finished stents using spraying or dipping methods, then the stent surface can be coated with polymer and drug, but uniformity of coating is difficult to achieve and the coating ratio between luminal and vessel wall sides cannot be controlled
Solution Approach 1:
The patent applies coating to the flat stent panel before rolling it into a cylindrical shape. This preliminary coating action allows the coating to be applied uniformly across the flat surface where gravity and spray distribution are more controllable, before the complex cylindrical geometry is formed that would make subsequent coating difficult and non-uniform
2Adaptability or versatility
If conventional coating methods are used on finished cylindrical stents, then coating can be applied to both luminal and vessel wall sides, but differential treatment of the two sides is not possible and the coating ratio is hard to control
Solution Approach 1:
The patent applies different coatings or different coating conditions to different regions of the flat stent panel before rolling. This allows the luminal side and vessel wall side to receive different polymer compositions, drug concentrations, or coating thicknesses, enabling differential treatment tailored to the specific requirements of each surface while maintaining precise control over the coating ratio
3Productivity
If spraying or dipping methods are used on rotating cylindrical stents, then coating can be applied to the stent surface, but the process is slow and capacity is limited
Solution Approach 1:
The patent performs coating on flat stent panels before they are rolled into cylindrical shapes. This preliminary action allows for faster, more controlled coating processes on flat surfaces that can be coated in batches or using automated spray systems, significantly increasing productivity while maintaining uniformity that would be difficult to achieve on rotating cylindrical stents
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
This approach enhances the uniformity and cost efficiency of stent coating, allowing for precise control over the luminal and vessel wall side treatments, improving the delivery of therapeutic agents and reducing the occurrence of restenosis.
Implementation Method 1
allowing for precise application of polymer and drug coatings on both sides, enabling differential treatment and improved uniformity through techniques like physical vapor deposition or spraying
Data Source
Figure 1A~5A
Figure 1B
Figure 2A~2B
AI summary
A drug-coated stent and a method for fabricating the stent are disclosed. The stent has an originally flat pattern and connection points where the sides of the flat pattern are joined. The method includes the steps of a) cutting a stent pattern into a flat piece of metal thereby to produce a metal pattern, b) spraying the flat metal stent pattern with a polymer and a drug, c) deforming the metal pattern so as to cause two opposing sides to meet, and d) joining the two opposing sides at least at one point. Substantially no portion of the stent projects into the lumen of the stent when the stent is expanded against the internal wall of a blood vessel.