Bioabsorbable Suture Fiber Composition for Secure Stretchable Knots

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing sutures, both non-absorbable and bioabsorbable, face challenges such as difficulty in knot formation and unraveling, tissue invasion, infection risk, knot loosening, and lack of stretchability, leading to tissue damage and foreign-body sensation.

Innovation Solution

A bioabsorbable fibrous medical material made from a polyhydroxyalkanoate copolymer with a high elongation at break and low elastic modulus, allowing easy knot formation and stretchability, reducing the need for multiple knots and minimizing tissue tension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional bioabsorbable sutures are made from stiff polymers like PGA, then tensile strength is maintained, but knot formation is difficult and knots are large and easy to unravel

Engineering Contradiction:
Improvetensile strengthVSAvoidknot formation
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The invention changes the physical parameters of the suture material by using copolymerization to reduce the elastic modulus from the high stiffness of PGA to a range of 50-500 MPa. This parameter change enables the material to form small, secure knots while maintaining adequate tensile strength through optimized copolymer composition and molecular weight

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite polymer system by copolymerizing glycolide with other monomers (such as L-lactide, ε-caprolactone, or trimethylene carbonate) to achieve a balance between tensile strength and knotability. The composite structure allows the suture to have both strength and flexibility needed for easy knot formation

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If monofilament sutures are used to reduce infection risk, then infection resistance is improved, but knot security is poor and multiple knots are required

Engineering Contradiction:
Improveinfection resistanceVSAvoidknot security
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention modifies the mechanical parameters of monofilament sutures by controlling the elastic modulus to 50-500 MPa through copolymer composition. This parameter change allows a single knot to achieve sufficient security without requiring multiple knots, while maintaining the infection resistance benefits of monofilament construction

Inventive Principle:
Principle #35Parameter changes

3Strength

If sutures with high elastic modulus are used to maintain tissue tension, then tensile strength is maintained, but tissue damage occurs due to lack of stretchability

Engineering Contradiction:
Improvetensile strengthVSAvoidtissue damage
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention optimizes the elastic modulus parameter to a specific range of 50-500 MPa through copolymerization, creating a balance where the suture maintains adequate tensile strength while having sufficient stretchability to accommodate tissue movement and swelling without causing damage

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 material enables small, hard-to-unravel knots with minimal force, reducing tissue damage and foreign-body sensation while accommodating tissue movement and swelling.

Implementation Method 1

bioabsorbable aliphatic polymer

Methodology Applied
Scientific EffectBioabsorption: Decomposition (biological)

Implementation Method 2

biodegradable polyester copolymer

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

stretchable and bioabsorbable aliphatic polymer fibers

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 4

elongation at break of 75% or more

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP4233922B1Bioabsorbable fibrous medical material
Publication Date: 2025.11.12 MITSUBISHI GAS CHEM CO INC
  • EP4233922B1 patent drawingFigure 1
  • EP4233922B1 patent drawingFigure 2
  • EP4233922B1 patent drawingFigure 3

AI summary

An object of the present invention is to provide a bioabsorbable and stretchable fibrous medical material that enables formation of ligation which provides a small and hard-to-unravel knot even with a weak force. The present invention provides a fibrous medical material which is a fibrous material composed of a molded article provided by spinning and drawing a bioabsorbable aliphatic polymer, wherein an elongation at break is 75% or greater, an intermediate elastic modulus in tension at a strain ranging from 0.25% and 10% is lower than an initial elastic modulus in tension at a strain ranging from 0.05% to 0.25%, the intermediate elastic modulus in tension is 400 MPa or less, and a residual strain rate after 100% deformation is 70% or less.