Magnesium Biodegradable Stent Lithographic Foil Manufacturing

Solution Overview

Problem

Current biodegradable stents, particularly those made of magnesium, face challenges in manufacturing efficiency and mechanical properties, with existing methods like laser cutting being expensive and low-productivity, and magnesium wire braiding requiring high-cost and limited-diameter wires, while also needing to overcome issues of low tensile strength and elasticity.

Innovation Solution

The use of lithographic techniques such as optical photolithography, electron beam lithography, x-ray lithography, or nanoimprint lithography to configure and etch magnesium foil into balloon-expandable stents with specific designs that prevent overstressing and breaking, such as having a spiral configuration and discontinuous rings, allowing for stress-free expansion and self-expansion capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If laser cutting is used to configure stent features, then manufacturing precision is improved, but productivity deteriorates and manufacturing cost increases

Engineering Contradiction:

Improvestent feature configuration precisionVSAvoidstent manufacturing productivity

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical laser cutting system with a mold-based stamping system. Pre-configured magnesium foil with stent features is stamped using molds, eliminating the need for sequential laser cutting operations. This substitution of mechanical stamping for laser processing dramatically increases productivity while maintaining manufacturing precision through well-designed mold tools.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent applies preliminary action by pre-configuring the stent features into the magnesium foil before the main forming process. The foil is supplied with pre-defined patterns, holes, and configurations already present, so that during stent manufacturing, these features are simply transferred or stamped rather than created from scratch through time-consuming laser operations.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If magnesium wire braiding is used to manufacture stents, then ease of manufacture is improved, but manufacturing cost increases and device complexity increases

Engineering Contradiction:

Improvestent manufacturing easeVSAvoidbraiding machine complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent extracts the complex braiding operation and replaces it with a simpler stamping process. Instead of feeding magnesium wire through complex braiding machines that require precise synchronization and handling of multiple wires, the invention uses pre-configured magnesium foil that is simply stamped and formed into the stent shape, dramatically simplifying the manufacturing equipment and process.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the fundamental manufacturing parameter from wire-based braiding to foil-based stamping. This parameter change transforms the manufacturing approach from a complex assembly process involving multiple wires and sophisticated braiding machinery to a simpler sheet metal forming process using standard stamping equipment.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If magnesium wire braiding is used, then ease of manufacture is improved, but manufacturing precision deteriorates

Engineering Contradiction:

Improvestent manufacturing easeVSAvoidstent feature configuration precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses copying by creating precise mold stamps that replicate the exact stent feature geometry. The mold tools are designed with high precision to copy the desired stent configuration, including intricate patterns, holes, and geometries, directly onto the magnesium foil through stamping, ensuring manufacturing precision comparable to or exceeding laser cutting while maintaining ease of manufacture.

Inventive Principle:

Principle #26Copying

4Reliability

If biodegradable magnesium stents are used, then reliability is improved by avoiding removal surgery, but strength deteriorates due to low tensile strength of magnesium

Engineering Contradiction:

Improvestent reliabilityVSAvoidmagnesium tensile strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent employs composite materials by combining magnesium with other metals or compounds to create alloys with enhanced mechanical properties. This allows the stent to maintain the biodegradability advantage of pure magnesium while gaining the tensile strength and structural integrity needed to support blood vessels during the critical healing period before complete degradation.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies parameter changes by modifying the magnesium material properties through alloying elements or surface treatments. By changing the compositional parameters of the magnesium material, the tensile strength and mechanical performance are improved while preserving the biodegradable characteristic that eliminates the need for removal surgery.

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

This approach enables the production of high-quality, reliable biodegradable magnesium stents that are cost-effective, scalable for mass production, and provide improved mechanical properties, reducing the need for invasive removal procedures and minimizing immune responses.

Implementation Method 1

performing a lithographic technique to configure the features and dimensions of the magnesium foil wherein the lithographic technique is used to transfer the stent features to both sides of the magnesium foil, wherein the lithographic technique is selected from at least one of optical photolithography, electron beam lithography, x-ray lithography, and nanoimprint lithography

Methodology Applied

Scientific EffectOptical photolithography: Photography

Implementation Method 2

performing a lithographic technique to configure the features and dimensions of the magnesium foil wherein the lithographic technique is used to transfer the stent features to both sides of the magnesium foil, wherein the lithographic technique is selected from at least one of optical photolithography, electron beam lithography, x-ray lithography, and nanoimprint lithography

Methodology Applied

Scientific EffectElectron beam lithography: Electron Beam

Implementation Method 3

performing a lithographic technique to configure the features and dimensions of the magnesium foil wherein the lithographic technique is used to transfer the stent features to both sides of the magnesium foil, wherein the lithographic technique is selected from at least one of optical photolithography, electron beam lithography, x-ray lithography, and nanoimprint lithography

Methodology Applied

Scientific EffectX-ray lithography: X-Ray

Implementation Method 4

etching the magnesium foil

Methodology Applied

Scientific EffectChemical etching: Erosion

Data Source

PatentUS10265205B2Methods for making magnesium biodegradable stents for medical implant applications

Publication Date: 2019.04.23 UNIVERSITY OF CINCINNATI

AI summary

Methods for making a magnesium biodegradable stent for medical implant applications, using magnesium foil or pure magnesium or magnesium alloys that are biodegradable and performing a lithographic technique to configure the features and dimensions of the magnesium foil, and rolling the magnesium foil to form a cylinder.