Medical Separation Membrane Copolymer Against Platelet-Protein Adhesion

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Solution Overview

Problem

Conventional medical devices suffer from adhesion of platelets and proteins, leading to deterioration of fractionation performance and water permeability, particularly in blood purifiers like artificial kidney modules, due to inadequate consideration of polymer mobility and hydrophilicity/hydrophobicity balance.

Innovation Solution

A medical separation membrane using a copolymer with a balanced hydrophobic and hydrophilic structure, characterized by a static contact angle of 30-70 degrees and a glass transition temperature of 45-90 degrees, effectively suppressing platelet and protein adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If only hydrophilization of material surface is performed, then hydrophilicity is improved, but suppression of platelet and protein adhesion deteriorates

Engineering Contradiction:
ImprovehydrophilicityVSAvoidplatelet and protein adhesion
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The invention changes the parameter of glass transition temperature to a specific range (45-90°C) to optimize polymer mobility and adhesion suppression. This parameter optimization resolves the contradiction by finding the optimal balance point where hydrophilicity is sufficient but platelet and protein adhesion is minimized

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a copolymer comprising a hydrophobic unit and a hydrophilic unit, creating a composite material structure. This composite approach resolves the contradiction by combining both hydrophobic and hydrophilic characteristics in a single material system, achieving balanced performance

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If a vinylpyrrolidone/vinyl acetate copolymer is used, then commercial availability is improved, but long-term suppression of protein adhesion deteriorates

Engineering Contradiction:
Improvecommercial availabilityVSAvoidprotein adhesion over time
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention optimizes the glass transition temperature parameter to 45-90°C, which is higher than conventional copolymers. This parameter change improves long-term stability and protein adhesion suppression while maintaining manufacturing feasibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces a terminal alkyl group with 2-20 carbon atoms in the side chain of the hydrophobic unit, creating local hydrophobic regions. This local quality modification enhances long-term protein adhesion suppression while maintaining overall copolymer processability

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If glass transition temperature is lowered to improve polymer mobility, then adhesion suppression is improved, but handling property and stability deteriorate

Engineering Contradiction:
Improveadhesion suppressionVSAvoidhandling property
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The invention optimizes the glass transition temperature to a specific range (45-90°C) that balances polymer mobility and handling properties. This parameter optimization ensures sufficient mobility for adhesion suppression while maintaining adequate stability for practical handling

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 membrane significantly reduces platelet and protein adhesion even when in contact with biological components for extended periods, maintaining performance and stability.

Implementation Method 1

a hydrophilic unit and having only one glass transition temperature in a range of from 45°C or higher and lower than 90°C

Methodology Applied
Scientific EffectHydrophilic interaction: Hydrophile

Data Source

PatentEP3508232B1Medical separation membrane, and blood purifier
Publication Date: 2025.08.06 TORAY INDUSTRIES INC
  • EP3508232B1 patent drawingFigure 1
  • EP3508232B1 patent drawingFigure 2
  • EP3508232B1 patent drawingFigure 3

AI summary

The purpose of the present invention is to provide a medical material capable of suppressing adhesion of platelets and proteins even when in contact with biological components such as blood for an extended period of time. The present invention provides a medical material that is a copolymer comprising hydrophobic units and hydrophilic units in which the hydrophobic units have a C2-20 terminal alkyl group in a side chain, the static contact angle of water in the copolymer is at least 30° and less than 70°, and the glass transition temperature of the copolymer exists at only one point in the range from 45°C to less than 90°C.