Photo-Stable Silver Ion Wound Dressings via Polymer Complexes

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Solution Overview

Problem

Existing wound dressings with silver ions face issues of light sensitivity, leading to discoloration and instability, which affects their aesthetic appeal and effectiveness as antimicrobial agents.

Innovation Solution

A composition comprising a hydrophilic polymer, a hydrophobic polymer, and silver ions, where the silver ions associate with either hydrophilic or hydrophobic polymers through ionic, covalent, or coordinate bonds, forming a stable complex that is photo-stable and thermally stable, without the presence of chlorite ions, allowing for controlled release of silver ions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If silver ions are used in wound dressings, then antimicrobial efficacy is improved, but light sensitivity causes discoloration and instability

Engineering Contradiction:
Improveantimicrobial efficacyVSAvoidphoto-stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces hydrophilic and hydrophobic polymers as intermediary substances that complex with silver ions. These polymers act as mediators between the silver ions and the wound environment, providing photo-stability while maintaining antimicrobial efficacy. The polymer-silver ion complexes prevent direct exposure of silver ions to light, thereby preventing discoloration and instability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates composite materials by combining silver ions with hydrophilic and hydrophobic polymers in specific ratios. This composite approach allows the material to exhibit both the antimicrobial properties of silver ions and the photo-stability of the polymer matrix, resolving the contradiction between efficacy and stability.

Inventive Principle:
Principle #40Composite materials

2Reliability

If silver ions are released rapidly, then antimicrobial action is enhanced, but stability and controlled release are compromised

Engineering Contradiction:
Improveantimicrobial actionVSAvoidcontrolled release duration
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent employs dynamic release mechanisms where the polymer-silver ion complexes can adjust their release rate based on environmental conditions. The hydrophilic/hydrophobic balance allows the material to respond dynamically to the wound environment, providing rapid release when needed while maintaining long-term stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent controls the release parameters by adjusting the polymer composition ratios and cross-linking density. By changing these parameters, the release rate of silver ions can be tuned to achieve both rapid initial antimicrobial action and sustained long-term protection, resolving the contradiction between enhanced action and controlled duration.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If hydrophilic polymer content is increased, then silver ion association is improved, but release control and stability may be affected

Engineering Contradiction:
Improvesilver ion associationVSAvoidcomposition stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by creating distinct hydrophilic and hydrophobic phases within the polymer matrix. The hydrophilic regions provide sites for silver ion association while the hydrophobic regions maintain structural stability and control release. This spatial differentiation allows both high silver ion association and composition stability to coexist.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent optimizes the hydrophilic/hydrophobic polymer ratio as a key parameter to balance silver ion association and composition stability. By carefully adjusting this parameter, the material achieves maximum silver ion binding capacity while maintaining overall structural integrity and controlled release properties.

Inventive Principle:
Principle #35Parameter changes

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 solution provides a stable and controlled release of silver ions, preventing discoloration and maintaining antimicrobial efficacy while reducing the risk of infection in wounds, with adjustable release rates based on polymer ratios.

Implementation Method 1

the silver ion associates with at least one hydrophilic or hydrophobic polymer, wherein the association between the silver ion and the hydrophilic or hydrophobic polymers can be characterized as an ionic bond, a covalent bond, or a co-ordinate bond

Methodology Applied
Scientific EffectIonic bonding: Chemical Bonding

Implementation Method 2

the silver ion associates with at least one hydrophilic or hydrophobic polymer, wherein the association between the silver ion and the hydrophilic or hydrophobic polymers can be characterized as an ionic bond, a covalent bond, or a co-ordinate bond

Methodology Applied
Scientific EffectCoordination bonding: Chemical Bonding

Implementation Method 3

hydrophilic/hydrophobic polymer blends that can be used to control the rate of release of silver ions to a target site such as a wound

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentUS9364579B2Biocidal fibrous and film materials utilizing silver ion
Publication Date: 2016.06.14 SOUTHWEST RES INST

AI summary

Disclosed are compositions comprising a hydrophilic polymer, a hydrophobic polymer, and a silver ion, wherein the silver ion associates with at least one hydrophilic or hydrophobic polymer, and wherein the composition does not comprise an effective amount of a chlorite ion. Also disclosed are methods of making a photo-stable silver ion containing wound dressing and methods of reducing or preventing infection of a wound by using the compositions and wound dressings of the present invention.