Artificial Lung Hollow Fiber Membrane Coating Surface Tension

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Solution Overview

Problem

Hollow fiber membrane artificial lungs with thin walls face challenges in suppressing blood plasma leakage and maintaining gas exchange capacity, as the coating polymer penetrates into fine holes, leading to increased leakage and reduced antithrombotic activity.

Innovation Solution

Adjusting the surface tension of the coating solution containing alkoxyalkyl (meth)acrylate polymer to a specific range (40 to 55 dyn/cm) prevents polymer penetration into the hollow fiber membranes, reducing blood plasma leakage and enhancing antithrombotic activity by ensuring the polymer remains on the surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the hollow fiber membrane wall thickness is reduced to minimize the size of the artificial lung, then the device size is reduced, but blood plasma leakage increases

Engineering Contradiction:

Improvedevice sizeVSAvoidblood plasma leakage

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The invention changes the surface tension parameter of the coating solution from conventional values to a specific range of 30-40 dyn/cm. This parameter change prevents the coating polymer from penetrating into the fine holes of thin-walled hollow fiber membranes, thereby maintaining blood plasma leakage resistance while preserving the reduced device size enabled by thin walls.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite coating system consisting of a specifically formulated coating solution with controlled surface tension properties applied to the hollow fiber membrane surface. This composite approach combines the membrane structure with a surface modification layer that provides both antithrombotic activity and leakage prevention without requiring increased wall thickness.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If a coating solution with conventional surface tension is used, then the coating can be applied to the hollow fiber membrane, but the polymer penetrates into fine holes causing increased blood plasma leakage

Engineering Contradiction:

Improvecoating applicationVSAvoidblood plasma leakage

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention modifies the surface tension parameter of the coating solution to a specific range of 30-40 dyn/cm, which is lower than conventional coating solutions. This parameter adjustment allows the coating to be applied easily to the hollow fiber membrane while preventing polymer penetration into the fine holes, thereby simultaneously achieving ease of manufacture and reduced blood plasma leakage.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If thin-walled hollow fiber membranes are used, then gas exchange capacity is improved, but the ability to suppress blood plasma leakage deteriorates

Engineering Contradiction:

Improvegas exchange capacityVSAvoidblood plasma leakage suppression

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention changes the surface tension parameter of the coating solution to 30-40 dyn/cm, which prevents polymer penetration into the fine holes of thin-walled membranes. This allows thin-walled hollow fiber membranes to maintain both their high gas exchange capacity and their ability to suppress blood plasma leakage, resolving the trade-off between these two performance parameters.

Inventive Principle:

Principle #35Parameter changes

4Strength

If the coating polymer penetrates into fine holes of the hollow fiber membrane, then the coating adheres to the membrane, but antithrombotic activity is reduced

Engineering Contradiction:

Improvecoating adhesionVSAvoidantithrombotic activity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The invention adjusts the surface tension of the coating solution to a specific range of 30-40 dyn/cm, which is low enough to prevent polymer penetration into the fine holes of the hollow fiber membrane. This maintains the polymer on the surface where it can provide antithrombotic activity while still achieving adequate adhesion through surface coating.

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 effectively suppresses blood plasma leakage and maintains high gas exchange capacity even in thin-walled hollow fiber membranes, with a blood plasma leakage resistance performance of 15 mmHg or less and excellent antithrombotic activity.

Implementation Method 1

Adjusting the surface tension of the coating solution containing alkoxyalkyl (meth)acrylate polymer to a specific range (40 to 55 dyn/cm) prevents polymer penetration into the hollow fiber membranes

Methodology Applied

Scientific EffectSurface tension: Surface Tension

Data Source

PatentUS10758657B2Artificial lung and method for manufacturing artificial lung

Publication Date: 2020.09.01 TERUMO KK

AI summary

An artificial lung is provided that includes a plurality of porous hollow fiber membranes for gas exchange comprising a hydrophobic polymer material, wherein the hollow fiber membranes have inner surfaces forming lumens and outer surfaces, and wherein at least one of the inner surfaces or the outer surfaces is coated with a polymer-containing solution that has a surface tension of 40 to 55 dyn/cm and that contains a solvent and a polymer having a structural unit represented by Formula (I):wherein in Formula (I), R3 represents a hydrogen atom or a methyl group, R1 represents an alkylene group having 1 to 4 carbon atoms, and R2 represents an alkyl group having 1 to 4 carbon atoms.