Biodegradable Metal Scaffold With Polymer Coating

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Solution Overview

Problem

Biodegradable in vivo supporting devices often disintegrate uncontrolled, breaking into large pieces that can interfere with body fluid circulation, necessitating a controlled degradation mechanism.

Innovation Solution

A biodegradable metal scaffold coated with a biodegradable polymer, where the polymer coating degrades at a controlled rate to encapsulate the metal scaffold, preventing fragmentation and ensuring absorption within the body tissue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a biodegradable supporting device is used, then there is no need to remove the device after correction of the underlying defect, but the device may disintegrate in an uncontrolled manner and break into large pieces that interfere with normal circulation

Engineering Contradiction:

ImproveNo need for device removalVSAvoidControlled degradation

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent employs a composite structure consisting of a biodegradable metal scaffold (magnesium alloy with rare earth metals) combined with a biodegradable polymer coating. This composite material system allows the polymer to control the degradation process while the metal scaffold provides structural support, preventing uncontrolled disintegration and large fragment formation that would interfere with circulation.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the metal scaffold by incorporating specific rare earth metals (at least 0.5 wt.%) along with magnesium (at least 96 wt.%) and manganese (at least 1 wt.%). These compositional changes alter the degradation characteristics of the metal, enabling controlled degradation rates that prevent harmful fragmentation while maintaining structural integrity during the functional period.

Inventive Principle:

Principle #35Parameter changes

2Duration of action of moving object

If the metal scaffold degrades too quickly, then absorption occurs faster, but fragmentation and interference with body fluid circulation increase

Engineering Contradiction:

ImproveDegradation timeVSAvoidFragmentation and circulation interference

Core Design Contradiction:

Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The biodegradable polymer coating acts as an intermediary layer between the metal scaffold and the body environment. It controls the degradation process by regulating the interaction between the metal scaffold and body fluids, preventing direct rapid degradation that would cause fragmentation and circulation interference, while allowing controlled absorption over time.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The composite structure of polymer-coated metal scaffold provides differentiated degradation behavior where the polymer degrades at a controlled rate, protecting the metal scaffold from rapid degradation and preventing harmful fragmentation, thus resolving the contradiction between degradation speed and fragmentation risk.

Inventive Principle:

Principle #40Composite materials

3Speed

If the polymer coating degrades faster than the metal scaffold, then the metal scaffold is exposed earlier, but the metal scaffold may disintegrate before complete absorption

Engineering Contradiction:

ImprovePolymer degradation rateVSAvoidMetal scaffold integrity

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent carefully controls the compositional parameters of the metal scaffold, specifically incorporating rare earth metals at controlled concentrations (at least 0.5 wt.%) to modify the metal's degradation kinetics. This ensures that even when the polymer coating degrades faster and exposes the metal scaffold, the metal degrades at a controlled rate that maintains structural integrity and prevents disintegration before complete absorption.

Inventive Principle:

Principle #35Parameter changes

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 solution enables controlled degradation of the metal scaffold, preventing fragmentation and ensuring safe absorption, thus maintaining normal body fluid circulation and reducing the risk of device-related complications.

Implementation Method 1

The biodegradable polymer coating has a degradation rate that controls the exposure of the metal scaffold, preventing fragmentation

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

The biodegradable polymer coating covering at least a portion of the biodegradable metal scaffold degrades to encapsulate the metal scaffold

Methodology Applied

Scientific EffectBiodegradation: Decomposition (biological)

Implementation Method 3

The biodegradable metal scaffold comprises a magnesium alloy... absorbed within the body tissue

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 4

The biodegradable metal scaffold... degradation of the metal scaffold, preventing fragmentation and ensuring absorption within the body tissue

Methodology Applied

Scientific EffectCorrosion: Crevice Corrosion

Data Source

PatentEP2822611B1Biodegradable supporting device

Publication Date: 2020.12.16 Q3 MEDICAL DEVICES LTD

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Figure 3A~4A
Figure 4B~5A

AI summary

A biodegradable in vivo supporting device is disclosed. The in vivo supporting device comprises a biodegradable metal scaffold and a biodegradable polymer coating covering at least a portion of the biodegradable metal scaffold, wherein the biodegradable polymer coating has a degradation rate that is faster than the degradation rate of the biodegradable metal scaffold.