Apertured Cover Sheet for Wound Dressing Silver Release

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Solution Overview

Problem

Advanced wound dressings with antimicrobial properties face challenges in maintaining therapeutic effectiveness while preventing the shedding of silver-coated fibers into the wound and minimizing adherency issues.

Innovation Solution

A wound dressing comprising an antimicrobial absorbent layer with metallic silver and a liquid-impermeable apertured sheet, where the apertures have a mean effective diameter of 1mm to 2mm and a percentage open area of 17% to 25%, preventing fiber shedding and maintaining antimicrobial efficacy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a perforated top sheet is used to reduce adherency, then the wound contacting surface becomes less adhesive, but the therapeutic effectiveness of metallic silver delivery is reduced

Engineering Contradiction:
ImproveadherencyVSAvoidtherapeutic effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent optimizes specific parameters of the apertured sheet: aperture size (0.2mm to 0.8mm) and open area percentage (5% to 25%). These parameter changes create a balance where the apertures are small enough to prevent fiber shedding and maintain silver containment, yet large and numerous enough to provide adequate wound contact and therapeutic effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses an apertured sheet with controlled porosity (open area 5%-25%) to achieve both non-adherency and therapeutic effectiveness. The porous structure allows the sheet to maintain physical contact with the wound surface while the controlled aperture size prevents excessive fiber shedding and maintains metallic silver delivery.

Inventive Principle:
Principle #31Porous materials

2Loss of substance

If small aperture size is used to prevent fiber shedding, then fiber retention is improved, but silver release and antimicrobial effectiveness are reduced

Engineering Contradiction:
Improvefiber sheddingVSAvoidantimicrobial effectiveness
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The patent identifies and optimizes the aperture size parameter within a specific range (0.2mm to 0.8mm). This parameter change achieves the dual benefit of preventing fiber shedding (by keeping apertures small enough to retain fibers) while maintaining adequate silver release (by ensuring apertures are not so small as to block therapeutic agent delivery).

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The use of a porous apertured sheet with controlled pore size and distribution allows the system to simultaneously achieve fiber retention and antimicrobial effectiveness. The porous structure provides pathways for silver release while the controlled pore dimensions prevent fiber loss.

Inventive Principle:
Principle #31Porous materials

3Reliability

If high open area percentage is used to improve silver release, then antimicrobial effectiveness is enhanced, but adherency problems increase

Engineering Contradiction:
Improveantimicrobial effectivenessVSAvoidadherency
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the open area percentage parameter within the range of 5% to 25%. This parameter change balances two opposing requirements: sufficient open area to allow silver release and maintain antimicrobial effectiveness, while limited enough open area to prevent excessive adherency problems.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The apertured sheet functions as a porous material with controlled porosity (25% maximum open area). This controlled porosity allows the sheet to provide adequate pathways for silver release and wound contact while limiting the overall open area to maintain acceptable adherency characteristics.

Inventive Principle:
Principle #31Porous materials

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 described configuration optimizes silver release and bacterial reduction, preventing fiber shedding and maintaining antimicrobial effectiveness, as demonstrated by specific aperture size and density combinations.

Implementation Method 1

the apertures have a mean effective diameter of from 1mm to 2mm, and the percentage open area of the apertured sheet is from 17% to 25%

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2214728B1Wound dressing with apertured cover sheet
Publication Date: 2012.06.27 SYSTAGENIX WOUND MANAGEMENT IP CO BV
  • EP2214728B1 patent drawingFigure 1~3
  • EP2214728B1 patent drawingFigure 2(a)~2(e)
  • EP2214728B1 patent drawingFigure 4

AI summary

A wound dressing comprising an antimicrobial absorbent layer containing silver, and an apertured sheet covering the antimicrobial absorbent layer, wherein the apertured sheet is formed from a liquid-impermeable sheet material having an array of apertures therein, said apertures having a mean effective diameter of from about 0.5mm to about 2mm, and wherein the percentage open area of the apertured sheet is from about 7% to about 25%. The selection of apertures in this range provides enhanced antimicrobial efficacy.