Self-cohered Bioabsorbable Web for Haemostasis

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Solution Overview

Problem

Existing bioabsorbable polymeric web materials lack high porosity, mechanical strength, loft, suppleness, drapability, and tissue compliance, which are essential for advanced medical applications such as haemostasis and implantable devices.

Innovation Solution

A synthetic bioabsorbable, non-woven, self-cohered polymeric web material with high porosity is developed by stretching unannealed precursor web materials in one or more directions and subsequent heat-setting, resulting in a web with increased void space and improved mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the web material is made with self-cohered filaments having multiple contact points, then the material achieves structural coherence without adhesives, but the porosity is limited to 40-80% which is insufficient for advanced medical applications

Engineering Contradiction:
Improvestructural coherenceVSAvoidporosity
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The continuous filaments are segmented into discontinuous filaments through controlled breaking during web formation. This segmentation creates more interstitial spaces between filament ends, significantly increasing porosity from 40-80% to above 80% while maintaining structural coherence through the distributed arrangement of filament segments

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The filament contact points are modified by changing the bonding mechanism from direct point-to-point contact to a distributed bonding pattern. The web structure parameters are adjusted by controlling filament deposition density and arrangement, creating a more open network structure that achieves high porosity while maintaining mechanical integrity

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the web material porosity is increased to improve haemostatic properties and tissue compliance, then the material becomes more compliant with tissue, but the mechanical strength of the web material decreases

Engineering Contradiction:
Improvetissue complianceVSAvoidmechanical strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The web material exhibits local quality variations where different regions have optimized properties: the filament bonding zones provide localized mechanical strength, while the interstitial spaces provide porosity and tissue compliance. This spatial differentiation allows the material to simultaneously achieve high porosity (>80%) and adequate mechanical strength for surgical applications

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The web material functions as a composite structure combining discontinuous filaments with controlled void spaces. The filament network provides the load-bearing framework, while the porosity provides tissue compliance and haemostatic functionality, creating a composite material that achieves both mechanical strength and tissue compliance

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If the web material is made with finer filaments to increase surface area and porosity, then the material achieves better tissue compliance and haemostatic properties, but the manufacturing complexity increases

Engineering Contradiction:
Improvetissue complianceVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The filament fabrication process is self-regulating, where the spinning conditions automatically produce filaments with optimal diameter and uniformity. The self-cohesion mechanism inherently creates the desired web structure without requiring complex post-processing, reducing manufacturing complexity while achieving the required filament fineness for tissue compliance

Inventive Principle:
Principle #25Self-service

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 highly porous web material exhibits enhanced mechanical strength, loft, suppleness, and tissue compliance, making it suitable for implantable medical devices and haemostatic applications, with the ability to combine with additional components for enhanced functionality.

Implementation Method 1

The continuous filaments are produced by selecting spinning conditions that provide a tackiness to the emerging filaments and allows them to self-cohere as solid filaments as the filaments are collected in a cohesive random pile, or web, on a collecting surface. The self-cohered filaments have multiple contact points with each other within the web. The self-cohered filaments bond at the contact points without need for requisite addition of supplementary adhesives, binders, adhesive adjuncts

Methodology Applied
Scientific EffectSelf-cohesion: Cohesion

Implementation Method 2

If the potentially semi-crystalline web is preserved in a thermodynamically unstable (metastable), homogeneous (microphase disordered), substantially phase miscible, amorphous state of limited crystallinity, the web is malleable and can be readily conformed or molded into a desired shape. That shaped form can then be preserved through its conversion into a more ordered, thermodynamically stable, at least partially phase immiscible semi-crystalline state

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 3

This irreversible (short of complete remelting and reformation of the formed web structures) conversion from a prolonged amorphous (i.e., disordered state of miscibility) condition into an ordered semi-crystalline state is typically provided by the chain mobility present in the rubbery state existing between the melt temperature and that of the order-disorder transition temperature (T odt ), the temperature above which the transition from disorder to order can proceed

Methodology Applied
Scientific EffectOrder-disorder transition: Phase Change

Data Source

PatentEP1909692B1Highly porous self-cohered web materials having haemostatic properties
Publication Date: 2015.03.04 WL GORE & ASSOC INC
  • EP1909692B1 patent drawingFigure 1
  • EP1909692B1 patent drawingFigure 1A
  • EP1909692B1 patent drawingFigure 2~2A

AI summary

The present invention is directed to implantable bioabsorbable non-woven self-cohered web materials having a high degree of porosity. The web materials are very supple and soft, while exhibiting proportionally increased mechanical strength in one or more directions. The web materials often possess a high degree of loft. The web materials can be formed into a variety of shapes and forms suitable for use as implantable medical devices or components thereof. The web materials possess haemostatic properties.