pH-Triggered Wound Dressing with Sterilization-Stable Infection Detection

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Solution Overview

Problem

Existing wound dressings fail to maintain wound humidity while effectively absorbing exudate and provide easy visual inspection of wound conditions, particularly in the presence of infections, and are not stable under sterilization conditions.

Innovation Solution

A wound dressing comprising a hydrogel layer, a pH-sensitive polymer layer, and compartments containing a carrier with fluorescent dye, where the pH-sensitive polymer has different solubility at pH 4 and 8, allowing the dye to be triggered by wound conditions rather than the dressing itself, ensuring integrity under sterilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a wound dressing contains fluorescent dye to indicate infection, then visual detection of wound state is improved, but the dye may be released during sterilization causing false indications

Engineering Contradiction:
Improvedetection accuracyVSAvoidsterilization stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A pH-sensitive polymer layer is introduced as an intermediary barrier between the fluorescent dye and the external environment. This polymer remains intact during sterilization (protecting the dye) but dissolves at alkaline pH values (above 7.2) indicating infection, thereby controlling when the dye is released and preventing both premature release during sterilization and delayed release upon infection detection

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system utilizes changes in pH parameter to control dye release. The pH-sensitive polymer has different solubility characteristics at different pH values - stable at neutral/acidic pH during sterilization and storage, but dissolves at alkaline pH (above 7.2) that occurs in infected wounds. This parameter change triggers the controlled release of fluorescent dye only when infection is present

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the dressing uses a transparent material to allow visual inspection, then ease of operation is improved, but the fluorescence detection sensitivity may be reduced

Engineering Contradiction:
Improvevisual inspection easeVSAvoidfluorescence detection sensitivity
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The detection mechanism transitions from direct visual inspection through the dressing material to fluorescence detection in a different dimension (optical wavelength). The dressing remains transparent for general visual inspection, while the fluorescent dye provides enhanced detection sensitivity by emitting light at a different wavelength that can be observed even through the transparent material, adding a new dimensional approach to detection

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Object-affected harmful factors

If the dressing absorbs excessive exudate to keep the wound clean, then wound hygiene is improved, but wound moisture necessary for healing is reduced

Engineering Contradiction:
Improveexudate accumulationVSAvoidwound moisture
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The dressing structure creates different local zones with different absorption characteristics. The hydrogel layer provides high absorption capacity in specific areas to manage exudate, while other regions maintain moisture-balancing properties. This spatial differentiation of absorption quality allows simultaneous exudate removal and moisture retention in different locations of the wound bed

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 dressing effectively maintains wound moisture, absorbs exudate, and provides visual indication of infection through fluorescent dye release, while maintaining structural integrity during sterilization processes.

Implementation Method 1

the pH-sensitive polymer has different solubility at pH 4 and 8, allowing the dye to be triggered by wound conditions rather than the dressing itself

Methodology Applied
Scientific EffectpH-sensitive dissolution:

Implementation Method 2

contains a substance being able to absorb wound exudate from the wound and to provide moisture to the wound

Methodology Applied
Scientific EffectHydrogel absorption: Hydrogel

Implementation Method 3

one or more compartments comprising carrier containing fluorescent dye

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3643328B1Ph-triggered diagnostic wound dressing
Publication Date: 2025.10.22 PAUL HARTMANN AG
  • EP3643328B1 patent drawingFigure 1~2
  • EP3643328B1 patent drawingFigure 3A~4
  • EP3643328B1 patent drawing

AI summary

The invention relates to a functional wound dressing being able to detect and indicate the state of the wound, in particular with regard to an infection which is reported to be frequently associated with poorly healing wounds, such as chronic wounds. The present wound dressing can be used in moist wound healing and contains a substance being able to absorb wound exudate from the wound and to provide moisture to the wound.