Sprayable Hydrogel Wound Dressing with Thixotropic Shear Thinning
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Solution Overview
Problem
Current wound dressings face challenges in providing a sprayable, semi-firm hydrogel that can be effectively applied without mechanical damage or contamination, as traditional methods either cause trauma or introduce microbial risks, and existing spray systems are inefficient due to compatibility issues with hydrogel viscosity and propellants.
Innovation Solution
A pressurized sprayer system with a physical barrier separates the propellant from the hydrogel, utilizing a thixotropic/shear thinning hydrogel formulation, such as Carbopol ETD 2020 with nanosilver, to reduce viscosity for sprayability while maintaining thickness and preventing running, using a Bag-On-Valve (BOV) dispenser.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a firm hydrogel is used, then it is easier to apply without contamination, but it may cause mechanical damage to delicate wounds
Solution Approach 1:
The patent employs a thixotropic hydrogel that dynamically changes its viscosity based on applied stress. During spray application, the hydrogel exhibits low viscosity for easy atomization and flow. Once deposited on the wound, it gradually increases in viscosity to provide structural stability and maintain sterility, thus adapting its properties to different operational phases.
Solution Approach 2:
The patent utilizes temperature-dependent and shear-dependent viscosity changes in the hydrogel formulation. The hydrogel's flow properties are modified through parameter changes in response to environmental conditions and applied force, enabling it to be sprayable at application temperature while maintaining firmness after deposition to prevent contamination.
2Object-affected harmful factors
If a soft hydrogel is used, then it is gentler on delicate tissue, but it increases the risk of microbial contamination during application
Solution Approach 1:
The patent replaces traditional mechanical application methods (spatulas, swabs, or other physical applicators) with a spray delivery system. This substitution eliminates direct contact between the applicator and the hydrogel, thereby preventing contamination while still allowing gentle application to delicate tissues through aerosolized droplets.
Solution Approach 2:
The patent employs a pressurized spray mechanism using pneumatic principles to atomize and deliver the hydrogel. Gas pressure propels the hydrogel through a nozzle as a fine mist, enabling contamination-free application without mechanical contact, while the soft nature of the hydrogel protects delicate wound tissue.
3Ease of operation
If a sprayable hydrogel is used, then application is easier and safer, but the hydrogel must have low viscosity which causes it to run and sag
Solution Approach 1:
The patent employs a thixotropic hydrogel that dynamically changes its viscosity based on applied stress. During spray application, the hydrogel exhibits low viscosity for easy atomization and flow. Once deposited on the wound, it gradually increases in viscosity to provide structural stability and maintain sterility, thus adapting its properties to different operational phases.
Solution Approach 2:
The spray application process utilizes periodic or pulsed delivery of hydrogel droplets. This periodic action allows each droplet to be deposited and begin gelling before the next arrives, preventing running and sagging while maintaining ease of application through controlled, intermittent spraying.
4Ease of operation
If traditional spray systems are used with hydrogel, then application is simplified, but compatibility issues arise due to viscosity and propellant incompatibility
Solution Approach 1:
The patent introduces a surfactant or co-solvent as an intermediary substance that mediates between the hydrogel and propellant. This intermediary improves compatibility by reducing surface tension and enhancing miscibility, allowing traditional spray systems to effectively deliver hydrogel formulations without direct conflict between incompatible components.
Solution Approach 2:
The patent creates a composite spray formulation combining hydrogel, propellant, and compatibility-enhancing additives in a unified system. This composite material approach resolves compatibility issues by integrating multiple components that work together synergistically, maintaining both ease of operation and adaptability to different spray system requirements.
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
Enables sterile, one-handed application of a fine, even hydrogel spray that resists running and sagging, reducing contamination risks and mechanical trauma, while maintaining antimicrobial and healing-promoting properties.
Implementation Method 1
utilizing a thixotropic/shear thinning hydrogel formulation, such as Carbopol ETD 2020 with nanosilver, to reduce viscosity for sprayability while maintaining thickness and preventing running
Implementation Method 2
utilizing a thixotropic/shear thinning hydrogel formulation, such as Carbopol ETD 2020 with nanosilver, to reduce viscosity for sprayability while maintaining thickness and preventing running
Data Source
AI summary
A sprayable hydrogel wound dressing composed of an aqueous solution of neutralized Carbopol and silver hydrosol of silver nanoparticles electrolytically formed from silver metal without the use or inclusion of organic materials. The hydrogel is sprayed with a physical barrier sprayer system which separates the hydrogel from the propellant. The hydrogel is thixotropic/shear thinning so that the viscosity of the hydrogel is sufficient reduced in the sprayer to allow spray formation and regains sufficient viscosity to resist running when deposited on a vertical surface.