Multi-layer wound dressing single freeze-drying adhesion
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Solution Overview
Problem
Existing methods for producing multi-layer wound dressings require multiple freeze-drying processes, leading to weak adhesion between layers, increased handling complexity, and inefficient absorption of wound exudate due to the need for a separate carrier layer and cumbersome freezing procedures.
Innovation Solution
A method involving a single freeze-drying process for a multi-layer wound dressing using biocompatible materials like collagen and polysaccharides, such as alginate or cellulose, without a separate carrier layer, utilizing a polysaccharide dispersion with up to 40% concentration and a collagen suspension, and incorporating crosslinking agents and plasticizers to enhance adhesion and absorption capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple freeze-drying processes are used to produce multi-layer wound dressing, then the layers can be formed, but the adhesion between layers becomes weak and the handling complexity increases
Solution Approach 1:
The patent combines multiple freeze-drying operations into a single continuous process where multiple layers are assembled and freeze-dried simultaneously in one chamber. This eliminates the need to remove and re-assemble layers between freezing cycles, thereby maintaining strong inter-layer adhesion and significantly reducing handling complexity while ensuring stable composition throughout the multi-layer structure.
Solution Approach 2:
The patent prepares all layers with their respective materials (collagen, polysaccharides, crosslinking agents, plasticizers) in advance and assembles them in the correct sequence before initiating the single freeze-drying process. This preliminary assembly ensures that layers are properly positioned and bonded together from the start, preventing adhesion issues that would arise from multiple separate freeze-drying cycles.
2Stability of the object's composition
If a separate carrier layer is used in multi-layer wound dressing, then structural stability is provided, but the absorption capacity of wound exudate decreases
Solution Approach 1:
The patent creates a composite multi-layer structure where different functional materials (collagen layers, polysaccharide layers, crosslinking agents, and plasticizers) are combined in specific sequences. This composite approach provides structural stability through the collagen and crosslinking components while maintaining high exudate absorption capacity through the polysaccharide layers, eliminating the need for a separate carrier layer that would reduce absorption.
Solution Approach 2:
The patent assigns different functional properties to different layers: collagen layers provide structural stability and strength, while polysaccharide layers provide high absorption capacity. This local differentiation of material properties throughout the multi-layer structure allows each layer to optimize its specific function without requiring a separate carrier, thereby maintaining both structural integrity and maximum absorption capacity.
3Shape
If multiple freezing and thawing cycles are used, then layer formation is achieved, but the adhesion between layers weakens and handling becomes cumbersome
Solution Approach 1:
The patent merges the freezing and drying operations into a single freeze-drying cycle that processes all layers simultaneously in one continuous operation within a single chamber. This eliminates repeated removal, re-positioning, and re-freezing of intermediate layers, thereby maintaining strong adhesion and significantly improving handling ease while achieving proper layer formation.
Solution Approach 2:
The patent maintains continuous operation throughout the freeze-drying process, with all layers being frozen and dried in an unbroken sequence within the same chamber. This continuous action prevents interruption and re-handling of the multi-layer structure, ensuring strong inter-layer adhesion and making the process much easier to handle compared to multiple separate freezing and thawing cycles.
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 method produces a stable, cost-effective, and easily handled multi-layer wound dressing with improved adhesion and secretion absorption capacity, allowing for controlled exudate uptake and adjustable thickness and pore structure, eliminating the need for a separate carrier layer and simplifying the production process.
Implementation Method 1
A method involving a single freeze-drying process for a multi-layer wound dressing using biocompatible materials like collagen and polysaccharides
Implementation Method 2
improved adhesion and secretion absorption capacity, allowing for controlled exudate uptake
Data Source
AI summary
The method for the production of a layered-wound pad with a biocompatible material and polysaccharides, comprises providing a dispersion of polysaccharides in a fluid dispersion agent, hardening the dispersion under layered formation of polysaccharides through the reception of water from fluid dispersion agent and/or the reception of the dispersion agent in the polysaccharides and/or through evaporation of the dispersion agent, swelling the hardened polysaccharides through the supply of water under formation of gel. The method for the production of a layered-wound pad with a biocompatible material and polysaccharides, comprises providing a dispersion of polysaccharides in a fluid dispersion agent, hardening the dispersion under layered formation of polysaccharides through the reception of water from fluid dispersion agent and/or the reception of the dispersion agent in the polysaccharides and/or through evaporation of the dispersion agent, swelling the hardened polysaccharides through the supply of water under formation of gel and/or adjusting its thickness and pore structure, applying a suspension or solution of biocompatible material on the swollen gel or the layered, hardened polysaccharides, and simultaneously cooling off and freeze-drying of gel with the suspension or solution of biocompatible materials or the hardened polysaccharides with the suspension or solution of the biocompatible material under formation of solid compound between the layers. The fluid dispersion agent consists of organic water-containing fluid and/or fluids such as ethanol, isopropanol or glycerin, and/or the organic fluid consists of 15 wt.% of water. The polysaccharide dispersion consists of 20 wt.% of polysaccharide and/or 1.0 wt.% of collagen related to the total weight of the suspension. The wound-pad is produced with a thickness of 2-4 mm. The polysaccharides and/or the biocompatible materials are dyed by riboflavin for the identification of the wound pad. The wound pad consists of antimicrobial and/or anti-inflammatory material and/or the surface of the wound pad is modified or structured in wave-like manner. The wound pad is produced under use of a cross-linker such as aldehyde and/or plasticizer such as 1,2-propanediol. A new layer is applied on the frozen wound pad having a layered biocompatible material and polysaccarides and is formed under freeze-drying to a three-layered wound pad. Porcine is used as collagen. An independent claim is included for a layered-wound pad.