Chitosan Porous Layer Compression Neutralization
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Solution Overview
Problem
Chitosan-based porous layers used for reinforcing staple zones or lines face issues with neutralization and washing, leading to re-solubilization and destruction when compressed and high in density, making them unsuitable for use as effective implants.
Innovation Solution
A method involving the preparation of a chitosan solution, lyophilization, compression, neutralization using an NH4OH solution, and subsequent washing steps to create high-density, compressively stable chitosan-based porous layers with excellent tensile strength and suturing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If chitosan-based porous layers are strongly compressed to achieve high density and good mechanical strength, then the mechanical properties and tensile strength are improved, but the neutralization step becomes ineffective and the layers dissolve completely in washing medium
Solution Approach 1:
The patent changes the chemical parameter of the neutralization agent from conventional bases (NaOH, KOH) to ammonium hydroxide (NH4OH). This parameter change allows effective neutralization of compressed chitosan layers without causing dissolution, as ammonium hydroxide neutralizes the chitosan salts while maintaining structural integrity during the washing step.
Solution Approach 2:
Ammonium hydroxide acts as an intermediary substance that facilitates the neutralization process. It temporarily interacts with the chitosan salts during compression, then allows complete removal during washing without leaving residual salts that would cause dissolution, thus mediating between the compression stability requirement and the neutralization effectiveness requirement.
2Strength
If chitosan concentration is increased to improve mechanical properties, then tensile strength and density are improved, but the neutralization step becomes ineffective
Solution Approach 1:
The patent changes the chemical parameter of the neutralization agent to ammonium hydroxide, which has different interaction properties with high-concentration chitosan compared to conventional bases. This allows effective neutralization even at high chitosan concentrations where conventional bases fail, enabling the use of high chitosan content for improved mechanical properties.
3Shape
If compression is applied before neutralization to achieve permanent deformation and prevent re-inflation, then thickness control is improved, but the subsequent neutralization and washing steps cause complete dissolution
Solution Approach 1:
The patent changes the chemical parameter of the neutralization agent to ammonium hydroxide, which maintains the structural stability of compressed layers during neutralization. This allows the compression step to be performed before neutralization with permanent deformation and controlled thickness, while avoiding the dissolution problem that occurs with conventional bases.
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 effectively neutralizes and washes chitosan-based porous layers, maintaining their structural integrity and mechanical properties, enabling their use as effective implants for reinforcing staple zones or lines with enhanced tensile strength and suturing resistance.
Implementation Method 1
Lyophilization involves a first step during which a solution is frozen in a particular structure
Implementation Method 2
a second step, during which a controlled pressure is applied in order to cause sublimation of the water present in the frozen structure
Data Source
AI summary
Method for preparing a chitosan-based porous layer The present invention relates to a method or preparing a chitosan-based, neutralized compressed porous layer, comprising the following steps: —a) a chitosan solution is prepared, —b) said solution is poured into a mold in order to form a layer, —c) the layer obtained in b) is lyophilized so as to obtain a porous layer, —d) said porous layer obtained in c) is compressed, —e) the compressed porous layer obtained in d) is neutralized by means of an NH4OH solution. It also relates to an implant comprising a layer obtained according to such a method.