Degradable Polyester Stent with Metal Particles

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Solution Overview

Problem

Current biodegradable stents face issues such as poor mechanical properties, rapid degradation, vascular lumen loss, inflammation, intimal hyperplasia, and lack of radiopacity, with existing solutions failing to effectively address these challenges.

Innovation Solution

A degradable polyester stent is developed by blending a biodegradable polyester matrix with metal-based powders, which improves mechanical properties and crystallization, and includes metal ions that inhibit vascular restenosis and enhance radiopacity through the use of materials like polylactic acid and magnesium-based alloys.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If biodegradable polymer stents are used, then the stent can degrade in the body into absorbable or metabolizable organic substances, but the mechanical properties are poorer and the size is larger compared with metal stents

Engineering Contradiction:

ImprovebiocompatibilityVSAvoidmechanical properties

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent uses composite materials by combining biodegradable polymer (PLA) with metal particles (magnesium, iron, or their alloys) to create a stent that exhibits both biocompatibility and improved mechanical properties. The metal particles serve as reinforcing agents within the polymer matrix, resolving the contradiction between biodegradability and mechanical strength.

Inventive Principle:

Principle #40Composite materials

2Reliability

If magnesium alloys stents are used, then the stent has good biocompatibility and mechanical properties, but the degradation is too fast resulting in too fast decay of mechanical strength

Engineering Contradiction:

ImprovebiocompatibilityVSAvoiddegradation time

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies local quality by incorporating metal particles specifically within the polymer matrix rather than using pure magnesium alloy. This localized distribution of metal particles provides controlled degradation behavior, maintaining mechanical strength longer while preserving biocompatibility.

Inventive Principle:

Principle #3Local quality

3Strength

If iron-based alloy stents are used, then the mechanical property meets the requirement, but the corrosion rate is difficult to control and the corrosion degradation mechanisms are unknown

Engineering Contradiction:

Improvemechanical propertyVSAvoidcorrosion control complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

4Duration of action of stationary object

If polymer coating is applied on magnesium stent to prevent fast degradation, then the degradation can be controlled, but the coating must be dense enough to prevent body fluid permeation

Engineering Contradiction:

Improvedegradation controlVSAvoidcoating density requirement

Core Design Contradiction:

Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

5Difficulty of detecting and measuring

If radiopaque particles are coated on stent surface to achieve radiopacity, then the stent becomes radiopaque, but the mechanical strength of the radiopaque layer is relatively low

Engineering Contradiction:

ImproveradiopacityVSAvoidmechanical strength

Core Design Contradiction:

Difficulty of detecting and measuringVSStrength

Solution Approach 1:

The patent merges the radiopaque function with the structural function by incorporating metal particles (magnesium, iron, or their alloys) directly into the polymer matrix. These metal particles serve dual purposes: providing radiopacity for detection and acting as reinforcing agents to maintain mechanical strength, eliminating the need for separate radiopaque coating layers.

Inventive Principle:

Principle #5Merging (Combining)

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 stent exhibits improved mechanical strength, prolonged degradation time, reduced inflammation, and enhanced radiopacity, with metal ions preventing vascular restenosis and improving fatigue life, while maintaining biocompatibility and ease of production.

Implementation Method 1

the metal-based material has a nucleating effect on the polyester material, improving the crystallization rate and degree of crystallinity of the polyester material

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Implementation Method 2

Metal ions released from the degradable metal material can prevent or inhibit the occurrence of vascular restenosis

Methodology Applied

Scientific EffectIon release and biological activity:

Data Source

PatentUS9642731B2Degradable polyester stent and preparation method thereof

Publication Date: 2017.05.09 SHANGHAI MICROPORT MEDICAL (GROUP) CO LTD

AI summary

A degradable polyester stent is disclosed, which includes a polyester composite, wherein the polyester composite is produced from a biodegradable polyester and a metal-based material. A method of preparing the degradable polyester stent is also disclosed. The method can improve the mechanical properties of the biodegradable copolymer stent and can achieve the radiopacity of the main body and the overall of the stent.