Negative Pressure Wound Dressing With Ionic Silver Contact Layer

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Solution Overview

Problem

Conventional wound dressings with incorporated antimicrobial agents face inefficiencies in maintaining effective antimicrobial presence at the wound site due to absorption of the agent into the absorbent layer, leading to reduced efficacy and potential adverse side effects from increased agent concentrations.

Innovation Solution

A negative pressure wound dressing with a wound contact layer comprising multiple layers of carboxyalkylcellulose or sodium carboxymethylcellulose fibers, impregnated with ionic silver, which maintains antimicrobial efficacy at the wound site by preventing absorption of the agent into the absorbent layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the antimicrobial agent is associated with an absorbent layer that is separated from the wound by a wound contact layer, then the absorbent layer can prevent pooling of exudate, but the efficacy of the antimicrobial at the wound site is minimal

Engineering Contradiction:

Improveantimicrobial efficacy at wound siteVSAvoidlayer separation structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The wound contact layer acts as an intermediary between the absorbent layer containing the antimicrobial agent and the wound site. It allows controlled transfer of the antimicrobial agent from the absorbent layer to the wound site while maintaining the structural separation needed for exudate management. This resolves the contradiction by enabling both layer separation for pooling prevention and antimicrobial efficacy through the mediating wound contact layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the antimicrobial agent is associated with a conventional wound contact layer, then the agent can be delivered to the wound site, but the agent is absorbed into the exudate and lost from the wound site

Engineering Contradiction:

Improveantimicrobial efficacy at wound siteVSAvoidantimicrobial agent loss

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The absorbent layer serves as an intermediary reservoir that continuously supplies the antimicrobial agent to the wound contact layer, which then delivers it to the wound site. This intermediate storage mechanism prevents direct depletion of the agent from the wound site into the exudate, as the absorbent layer replenishes it continuously.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The antimicrobial agent is pre-loaded into the absorbent layer before the dressing is applied to the wound. This preliminary positioning allows the agent to be gradually released through the wound contact layer to the wound site over time, preventing immediate absorption and loss into the exudate while maintaining sustained efficacy.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the quantity of antimicrobial agent is increased to mitigate absorption loss, then the antimicrobial efficacy may be maintained, but undesirable side effects such as cytotoxicity and skin staining occur

Engineering Contradiction:

Improveantimicrobial efficacyVSAvoidcytotoxicity and skin staining

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The wound contact layer and absorbent layer structure creates an intermediary delivery system that controls the release rate of the antimicrobial agent. This controlled release through the layered structure maintains effective concentrations at the wound site while preventing excessive accumulation that would cause cytotoxicity and skin staining, thus resolving the contradiction between efficacy and safety.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 dressing achieves a 4-log reduction of microorganisms at the wound site within 48 hours, maintaining antimicrobial activity without the need for frequent replacement and minimizing adverse effects.

Implementation Method 1

the wound contact layer comprises multiple layers each formed of carboxyalkylcellulose, or a salt thereof, fibres

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

the wound contact layer comprises an antimicrobial agent comprising ionic silver... ionic silver eliminates, or at least significantly reduces the number of, microorganisms at a wound site

Methodology Applied

Scientific EffectAntimicrobial action of ionic silver:

Implementation Method 3

negative pressure facilitates wound healing through a number of mechanisms, including removal of excess exudate

Methodology Applied

Scientific EffectNegative pressure suction: Suction

Data Source

PatentEP4577254B1Wound dressing

Publication Date: 2025.11.26 CONVATEC LTD

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AI summary

A negative pressure wound dressing comprising a backing layer, an adhesive skin contact layer and an absorbent structure wherein the adhesive skin contact layer is configured to detachably adhere the dressing to a dermal surface, wherein the backing layer comprises an aperture for connection to a negative pressure source, wherein the absorbent structure comprises a wound contact layer arranged to contact the wound when the adhesive skin contact layer is adhered to the skin adjacent the wound, further wherein the wound contact layer comprises an antimicrobial agent comprising ionic silver.