Polymeric Stent Manufacturing via Radial Deformation and Laser Machining
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Solution Overview
Problem
Polymeric stents face challenges such as low radial strength, brittleness, creep, stress relaxation, and physical aging, which affect their mechanical stability and longevity in the body, limiting their effectiveness in maintaining vascular patency and drug delivery.
Innovation Solution
A method involving extrusion and radial deformation of polymeric tubes to increase strength and toughness, combined with laser machining and crimping at elevated temperatures to distribute strain and reduce recoil, while controlling crystallinity to minimize physical aging and creep.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If polymeric stents are used to provide biological therapy and drug delivery, then local medication delivery is achieved with fewer side effects, but the stents exhibit low radial strength, brittleness, creep, stress relaxation, and physical aging
Solution Approach 1:
The patent applies parameter changes by controlling the glass transition temperature (Tg) of the polymeric material to be between -50°C and 50°C, and by controlling crystallinity between 0% and 80%. These parameter adjustments optimize both the mechanical properties (radial strength, resistance to creep and stress relaxation) and the drug delivery functionality of the stent, resolving the contradiction between side effect reduction and strength maintenance
2Quantity of substance
If polymeric stents are used for drug delivery, then local medication concentration is achieved, but the stents suffer from brittleness and mechanical failure
Solution Approach 1:
The patent changes material parameters by selecting polymers with specific glass transition temperatures (-50°C to 50°C) and controlling crystallinity (0% to 80%), which simultaneously enables effective drug delivery and improves mechanical reliability by reducing brittleness and resistance to mechanical failure
Solution Approach 2:
The patent employs composite polymeric materials that combine different polymer components to achieve both drug delivery capability and enhanced mechanical properties, resolving the contradiction between medication concentration and resistance to mechanical failure
3Duration of action of stationary object
If polymeric stents are implanted for long-term service, then vascular support is provided, but the stents experience creep, stress relaxation, and physical aging
Solution Approach 1:
The patent extends service life by controlling the glass transition temperature between -50°C and 50°C and crystallinity between 0% and 80%, which stabilizes the polymeric material against creep, stress relaxation, and physical aging, thereby maintaining mechanical stability throughout the intended service life
Solution Approach 2:
The patent performs preliminary stabilization of the polymeric material during manufacturing by controlling crystallinity and Tg, which pre-empts degradation mechanisms (creep, stress relaxation, physical aging) and ensures mechanical stability throughout the service life
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 enhances the radial strength and toughness of polymeric stents, reducing recoil and mechanical failure, and extends their service life by improving their mechanical stability and biodegradability, allowing for effective vascular support and drug delivery.
Implementation Method 1
forming the stent includes laser machining a stent pattern in the deformed tube with an ultra-short pulse laser
Implementation Method 2
crimping the stent on a support element, wherein a temperature of the stent during crimping is above an ambient temperature
Implementation Method 3
radially deforming the formed tube so that the deformed tube comprises the target diameter
Data Source
AI summary
Methods and systems of fabricating a polymeric stent are disclosed herein. Methods are disclosed that include forming a polymeric tube using extrusion, radially deforming the formed tube so that the deformed tube comprises a target diameter, forming a stent from the deformed tube, and forming a stent from the deformed tube. The stent is formed by laser machining a stent pattern in the deformed tube with an ultra-short pulse laser. Disclosed methods further include crimping the stent on a support element, wherein a temperature of the stent during crimping is above an ambient temperature.