Electrospun Tendon Sheath with Dual-Surface Texture

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Solution Overview

Problem

Current methods for repairing ruptured tendons face challenges such as adhesion formation and insufficient mechanical strength, leading to reduced range of motion and risk of re-rupture.

Innovation Solution

A tubular sheath made of a biocompatible and biodegradable polymer with a double-layered electrospun mesh, featuring a rough inner surface and a smooth outer surface, is used. The inner layer is made of DegraPol, while the outer layer is a blend of high molecular weight hyaluronic acid and polyethylene oxide, enhancing lubrication and reducing adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single-layer electrospun polymer tube is used for tendon repair, then the device provides basic structural support and biodegradability, but adhesion formation occurs and mechanical strength is insufficient

Engineering Contradiction:
Improvetendon healing effectivenessVSAvoidadhesion formation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The tubular sheath is divided into two distinct layers: an inner layer made of neat DegraPol and an outer layer made of DegraPol blended with hyaluronic acid. This segmentation allows each layer to perform its specific function - the inner layer provides structural support while the outer layer prevents adhesion, thereby resolving the contradiction between providing structural support and preventing adhesion formation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the tubular sheath are assigned different material compositions tailored to local requirements. The inner layer uses pure DegraPol for structural integrity at the tendon interface, while the outer layer incorporates hyaluronic acid for adhesion prevention at the surrounding tissue interface. This local differentiation resolves the contradiction by optimizing each region for its specific function

Inventive Principle:
Principle #3Local quality

2Strength

If a single-layer electrospun polymer tube is used for tendon repair, then the device provides basic structural support, but mechanical strength at the rupture site is insufficient leading to re-rupture risk

Engineering Contradiction:
Improvemechanical strength at rupture siteVSAvoidrisk of re-rupture
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The outer layer is constructed as a composite material combining DegraPol polymer with hyaluronic acid biomolecules. This composite structure provides enhanced mechanical strength through the polymer matrix while the hyaluronic acid contributes to tissue regeneration and strength development, thereby resolving the contradiction between providing immediate structural support and ensuring long-term reliability

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If the outer surface of the tubular sheath is rough, then adhesion formation increases, but if the outer surface is smooth, then lubrication is reduced

Engineering Contradiction:
Improvelubrication for tendon movementVSAvoidadhesion to surrounding tissue
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The inner surface is designed with a specific roughness to promote tendon integration while the outer surface is designed with a smooth texture to provide lubrication and prevent adhesion to surrounding tissues. This local differentiation of surface properties resolves the contradiction by optimizing each surface for its specific interaction - the inner surface with tendon tissue and the outer surface with surrounding tissues

Inventive Principle:
Principle #3Local quality

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 device significantly reduces adhesion formation and enhances the mechanical strength of the repaired tendon, leading to improved healing and reduced risk of re-rupture.

Implementation Method 1

The tubular sheath (T) comprises an elastic fiber mesh formed by electrospinning of said polymer

Methodology Applied
Scientific EffectElectrospinning: Electrohydrodynamics

Implementation Method 2

The first, inner wall surface is comparatively rough (W R )... significantly reduces adhesion formation

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

The second, outer wall surface is comparatively smooth (W s )... enhancing lubrication and reducing adhesion

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 4

The polymer is a biodegradable polyester urethane block copolymer... made of a biocompatible and biodegradable polymer

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentEP4559486A1A device for repair surgery of cylindrical organs, particularly ruptured tendons, and method of producing such device
Publication Date: 2025.05.28 UNIVERSITY OF ZURICH
  • EP4559486A1 patent drawingFigure 1~3
  • EP4559486A1 patent drawingFigure 4A~4D
  • EP4559486A1 patent drawingFigure 5A~5C

AI summary

A device for repair surgery of cylindrical organs, particularly of ruptured tendons, is configured as a tubular sheath (T) made of a mesh of elastic fibers formed by electrospinning biocompatible and biodegradable polymers. The tubular sheath has a first, inner wall surface and a second,outer wall surface substantially parallel thereto, with said first wall surface being comparatively rough (WR) and said second wall surface being comparatively smooth (Ws).