Oxygenator Antithrombotic Coating via Colloidal Circulation

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Solution Overview

Problem

Existing methods for manufacturing hollow fiber membrane oxygenators face challenges in achieving a sufficient coating of antithrombotic polymeric compounds on the outer surfaces of hollow fiber membranes, leading to inadequate prevention of platelet adhesion and activation, and leakage of blood plasma components.

Innovation Solution

A method involving the use of a colloidal solution containing an antithrombotic polymeric compound is filled into the blood flow path and circulated between the blood inlet and outlet ports, ensuring a sufficient coating of the compound on the outer surfaces of the hollow fiber membranes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a coating solution containing antithrombotic polymeric compound is applied to hollow fiber membranes, then platelet adhesion and activation are suppressed, but the coating solution penetrates into fine holes causing blood plasma leakage

Engineering Contradiction:

Improveantithrombotic activityVSAvoidblood plasma leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state of the antithrombotic polymeric compound from dissolved solution state to colloidal particle state. This parameter change allows the compound to maintain its antithrombotic function while preventing penetration into fine holes, as the colloidal particles are too large to pass through the membrane pores.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes the porous structure of the hollow fiber membranes by controlling the size of colloidal particles relative to the pore size. The colloidal particles are designed to be larger than the fine holes in the membrane, allowing them to adhere to the surface without penetrating through, thus preventing plasma leakage while maintaining antithrombotic protection.

Inventive Principle:

Principle #31Porous materials

2Object-affected harmful factors

If a colloidal solution with large particle size is used to prevent penetration into fine holes, then blood plasma leakage is prevented, but coating efficiency and sufficient coating amount are reduced

Engineering Contradiction:

Improveblood plasma leakage preventionVSAvoidcoating efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent employs dynamic circulation of the colloidal solution through the blood flow path multiple times. This dynamic approach allows successive waves of colloidal particles to reach and coat the outer surfaces of the hollow fiber membranes, accumulating sufficient coating amount despite the low adhesion efficiency of individual pass.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent maintains continuous circulation of the colloidal solution through the blood flow path for extended periods, ensuring continuous supply of antithrombotic polymeric compound to the membrane surfaces. This continuous action compensates for the low coating efficiency per unit time and achieves sufficient overall coating.

Inventive Principle:

Principle #20Continuity of useful action

3Ease of manufacture

If conventional coating methods are used, then manufacturing process is simple, but sufficient coating of antithrombotic compound on outer surfaces is not achieved

Engineering Contradiction:

Improvecoating process simplicityVSAvoidcoating uniformity and sufficiency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses hydraulic circulation of the colloidal solution through the blood flow path to deliver the coating material to the outer surfaces of the hollow fiber membranes. This hydraulic approach maintains process simplicity while improving coating sufficiency, as the flowing solution naturally reaches all exposed surfaces without complex application equipment.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 enhances the coating efficiency of antithrombotic polymeric compounds on the oxygenator surfaces, reducing platelet adhesion and activation while preventing blood plasma leakage, thereby improving the antithrombotic activity and gas exchange capacity of the oxygenator.

Implementation Method 1

a method involving the use of a colloidal solution containing an antithrombotic polymeric compound is filled into the blood flow path and circulated between the blood inlet and outlet ports, ensuring a sufficient coating of the compound on the outer surfaces of the hollow fiber membranes

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS11779690B2Oxygenator antithrombotic coating and method of manufacture

Publication Date: 2023.10.10 TERUMO KK

AI summary

Hollow fiber membranes in an oxygenator for an extracorporeal blood circulator are coated with an antithrombotic polymeric material. The porous hollow fiber membranes for gas exchange have outer surfaces, inner surfaces forming lumens, opening portions through which the outer surfaces communicate with the inner surfaces in a housing. A blood flow path is outside of the hollow fiber membrane bundle in the housing, between a blood inlet port and a blood outlet port. The coating is obtained by filling the blood flow path with a colloidal solution containing an antithrombotic polymeric compound, and moving the colloid solution between the blood inlet port and the blood outlet port for a time that coats a predetermined amount of antithrombotic polymeric compound on the outer surfaces of the hollow fiber membranes. Other surfaces within the oxygenator contacting the blood flow likewise receive the coating.