Multilayer Chitosan Wound Dressing with Reinforcing Layer

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Solution Overview

Problem

Current wound dressings face challenges in maintaining structural integrity while effectively absorbing blood and other bodily fluids and stemming fluid flow, particularly during application and removal, which can lead to tearing and foreign body responses.

Innovation Solution

A multilayer material comprising chitosan and/or its derivatives with a reinforcing material and a physiologically acceptable acid, allowing for in-situ formation of a chitosan salt upon contact with bodily fluids, providing enhanced absorbency and structural integrity without pre-treatment, and enabling easy application and removal without orientation concerns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If chitosan salt is used to provide fluid absorption and hemostasis, then the wound dressing can effectively absorb blood and bodily fluids, but the structural integrity of the dressing deteriorates causing tearing during application and removal

Engineering Contradiction:
Improvefluid absorption capacityVSAvoidstructural integrity
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The wound dressing is divided into multiple functional layers: a chitosan-containing layer for fluid absorption and hemostasis, a reinforcing layer (such as gauze or non-woven fabric) for structural support, and optionally a barrier layer. This segmentation allows each layer to perform its specific function without compromising the overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention combines chitosan (or chitosan derivatives) with other materials to create a composite wound dressing. The chitosan provides fluid absorption and hemostatic properties, while the composite structure with reinforcing materials maintains structural integrity and prevents tearing during application and removal.

Inventive Principle:
Principle #40Composite materials

2Reliability

If chitosan is pretreated with acid to form salt before incorporation into the dressing, then the hemostatic and absorption properties are enhanced, but the manufacturing process complexity increases

Engineering Contradiction:
Improvehemostatic effectivenessVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The chitosan is pretreated with acid to form the salt form before being incorporated into the wound dressing. This preliminary action ensures that the chitosan is in the optimal chemical form for hemostasis and fluid absorption, enhancing reliability without requiring complex in-situ treatment processes during manufacturing.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If a single-layer chitosan dressing is used to simplify the structure, then the manufacturing process is simplified, but the structural integrity and resistance to tearing deteriorates

Engineering Contradiction:
Improvestructure simplicityVSAvoidtear resistance
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The wound dressing is divided into multiple functional layers: a chitosan-containing layer for fluid absorption and hemostasis, a reinforcing layer (such as gauze or non-woven fabric) for structural support, and optionally a barrier layer. This segmentation allows each layer to perform its specific function without compromising the overall structure.

Inventive Principle:
Principle #1Segmentation

4Manufacturing precision

If the wound dressing is designed with asymmetric structure to indicate correct orientation, then the application accuracy is improved, but the ease of operation during emergency situations deteriorates

Engineering Contradiction:
Improveapplication orientation accuracyVSAvoidquick application speed
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The wound dressing is designed with homogeneous or symmetric properties from all sides, allowing it to be applied correctly regardless of orientation. This is achieved by ensuring that the active chitosan-containing layers are distributed uniformly or that both sides have equivalent functional characteristics, eliminating the need for orientation-specific application.

Inventive Principle:
Principle #33Homogeneity

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 multilayer material effectively absorbs and retains fluids, maintains structural integrity to prevent tearing, and facilitates easy removal, reducing the risk of foreign body responses and promoting wound healing by providing a moist environment.

Implementation Method 1

the chitosan derivative is selected from the group consisting of partially deacetylated chitin, carboxymethyl chitosan, hydroxyl butyl chitin, N-acyl chitosan, O-acyl chitosan, N-alkyl chitosan, O-alkyl chitosan, N-alkylidene chitosan, O-sulfonyl chitosan, sulfated chitosan, phosphorylated chitosan, nitrated chitosan, alkalichitin, alkalichitosan, or metal chelates with chitosan

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

The materials used to make the wound dressings act to absorb the blood and/or other bodily fluids

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

Chitosan materials can exhibit gelling properties when in the form of a salt. To obtain a chitosan salt, chitosan is typically mixed with an appropriate acid. The gelling properties of chitosan salts make them desirable for use as materials in wound dressings.

Methodology Applied
Scientific EffectGel formation: Gel

Implementation Method 4

a third layer located between the first and second layers comprising a reinforcing material

Methodology Applied
Scientific EffectMechanical support: Mechanical Force

Data Source

PatentEP3119443B1Wound dressing
Publication Date: 2021.05.12 MEDTRADE PROD
  • EP3119443B1 patent drawingFigure 1

AI summary

The present invention relates to materials for use as or in wound dressings. In particular, the present invention relates to a multilayer material for use as or in a wound dressing and to methods of making the multilayer material. The multilayer material comprises first and second layers comprising a chitosan and/or a chitosan derivative and a third layer located between the first and second layers comprising a reinforcing material, wherein one or more of the layers further comprises a physiologically acceptable acid.