Hydrogel Wound Dressing With pH-Triggered Buffer Release

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Solution Overview

Problem

Existing wound dressings fail to effectively manage moisture levels and exudate while providing targeted wound healing substances based on the wound's condition, particularly in cases of infection or poor healing.

Innovation Solution

A wound dressing comprising a hydrogel layer, a pH-sensitive polymer layer, and compartments containing buffer substances, where the pH-sensitive polymer's solubility changes based on pH, allowing controlled release of buffer substances only when needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a wound dressing continuously provides buffer substances to the wound, then the wound healing is promoted through pH stabilization, but unnecessary provision of substances occurs when the wound is healing properly, leading to resource waste and potential disruption of natural healing processes

Engineering Contradiction:
Improvewound healing promotionVSAvoidunnecessary buffer substance provision
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent employs pH-sensitive polymers that change their solubility and release properties based on the wound's pH level. When the wound pH becomes alkaline (indicating infection or poor healing), the pH-sensitive polymer dissolves and releases buffer substances. When the wound pH is normal, the polymer remains intact and does not release substances, thus avoiding unnecessary provision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The wound dressing incorporates a feedback mechanism where the pH-sensitive polymer continuously monitors the wound's pH condition and automatically adjusts the release of buffer substances accordingly. This closed-loop system ensures substances are provided only when the wound condition warrants intervention.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If a wound dressing absorbs all exudate from the wound, then bacterial growth is reduced by removing nutrient medium, but the wound becomes too dry which impairs the healing process that requires moisture

Engineering Contradiction:
Improvebacterial growth reductionVSAvoidwound moisture level
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent uses hydrogels with specific swelling and deswelling properties that respond to the wound environment. The hydrogel absorbs excess exudate when present, maintaining a balanced moisture level. The material's capacity to absorb and retain moisture dynamically adjusts based on the wound's exudate production, preventing both excessive wetness and dryness.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If a wound dressing releases healing substances immediately upon application, then the treatment effect is achieved quickly, but the substances are released regardless of whether the wound condition requires them, reducing treatment precision

Engineering Contradiction:
Improvehealing substance delivery speedVSAvoidwound condition assessment accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent utilizes pH-sensitive polymers that remain stable at normal wound pH levels but dissolve and release their contents when exposed to alkaline conditions. This parameter-based triggering ensures that healing substances are released only when the wound pH indicates infection or poor healing, achieving both rapid release when needed and conditional precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces mechanical or time-based release mechanisms with a chemical sensing and response system. Instead of releasing substances based on time elapsed or physical activation, the system uses pH-sensitive chemical polymers that automatically respond to the wound's chemical environment, enabling intelligent, condition-based release.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If a wound dressing uses complex pH-sensitive release mechanisms, then targeted provision of healing substances is achieved, but the device complexity increases making manufacturing and sterilization more difficult

Engineering Contradiction:
Improvetargeted substance provisionVSAvoidpH-sensitive polymer layer structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates pH-sensitive polymers directly into the wound dressing matrix, creating a composite material where the pH-sensitive functionality is inherent to the dressing structure itself. This approach combines multiple functions (moisture management, pH sensing, and controlled release) into a single integrated system, reducing overall device complexity while maintaining targeted provision capabilities.

Inventive Principle:
Principle #40Composite 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 dressing maintains optimal moisture levels, absorbs excess exudate, and provides healing substances only when necessary, enhancing wound healing by stabilizing pH and inhibiting bacterial growth.

Implementation Method 1

the solubility of the pH-sensitive polymer at a pH value of 4 is less than at a pH value of 8

Methodology Applied
Scientific EffectpH-sensitive solubility change:

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

Data Source

PatentEP3643330B1Ph-triggered buffered wound dressing
Publication Date: 2025.10.22 PAUL HARTMANN AG
  • EP3643330B1 patent drawingFigure 1~2
  • EP3643330B1 patent drawingFigure 3A~4
  • EP3643330B1 patent drawing

AI summary

The invention relates to a functional wound dressing being able to provide substances supporting the healing of a wound to the wound depending on the condition of the wound. In particular, in case of an infection which is reported to be frequently associated with poorly healing wounds, such as chronic wounds, buffer substances are provided to the wound whereas in other cases no buffer substances are provided. 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.