Chitosan Matrix Fiber Embedding Shrinkage Prevention
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Solution Overview
Problem
Chitosan matrices with fiber reinforcement members face damage and shrinkage during neutralization, affecting their integrity and mechanical properties, which is detrimental for use as surgical implants.
Innovation Solution
A method involving the preparation of two separate chitosan porous layers, neutralization, acidification of one face of each layer, embedding a fiber reinforcement member between the acidified layers, and allowing them to dry, ensuring the reinforcement member is securely sandwiched without deformation or delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a fiber reinforcement member is embedded in a chitosan matrix by lyophilization, then the mechanical properties are improved, but the matrix shrinks and damages the fiber during neutralization
Solution Approach 1:
The patent applies preliminary action by acidifying the chitosan solution before lyophilization and embedding the fiber reinforcement member in the acidified state. This preliminary acidification prevents shrinkage during subsequent neutralization, as the fiber is already positioned and secured in the matrix before the dimensional changes occur during pH adjustment.
Solution Approach 2:
The patent inverts the conventional sequence by first acidifying the chitosan solution and embedding the fiber, then neutralizing afterward. Traditionally, neutralization is performed before fiber embedding, but this reversal prevents the shrinkage-induced damage, as the fiber is secured when the matrix is in its acidified, non-shrinking state.
2Reliability
If the chitosan matrix is neutralized after lyophilization, then the biological compatibility is improved, but high constraints are induced in the embedded mesh causing deformation
Solution Approach 1:
The patent applies preliminary action by performing the fiber embedding operation before neutralization, when the chitosan matrix is still in its acidified state. This ensures the fiber reinforcement member is securely positioned before the neutralization process begins, preventing deformation during the pH adjustment that would otherwise occur after embedding.
3Stability of the object's composition
If the chitosan solution is frozen and lyophilized, then the porous structure is created favorable for cell growth, but the matrix remains loaded with salts requiring neutralization
Solution Approach 1:
The patent utilizes phase transitions by freezing the chitosan solution and then performing lyophilization (freeze-drying). This process transforms the liquid water in the solution into ice, then sublimates it directly to vapor, creating a porous structure while preserving the embedded fiber reinforcement member and allowing subsequent neutralization to remove salts.
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 results in chitosan matrices with embedded fiber reinforcement members that maintain integrity and mechanical properties, preventing shrinkage and delamination, leading to effective surgical implants for tissue reinforcement.
Implementation Method 1
Lyophilization involves a first step during which a solution is frozen in a particular structure
Implementation Method 2
then a second step, during which a controlled pressure is applied in order to cause sublimation of the water present in the frozen structure
Implementation Method 3
a face of each chitosan porous layer is acidified with an acid... a fiber reinforcement member is provided and positioned between the two acidified faces... the two chitosan porous layers and the fiber reinforcement member are let to dry to obtain a matrix having the fiber reinforcement member embedded therein
Data Source
AI summary
The present invention relates to a method for preparing a chitosan-based matrix (4) comprising the following steps:a) two separate chitosan porous layers (1, 2) obtained from lyophilisation of layers of one or more solutions of chitosan are provided,b) the chitosan porous layers of a) are neutralized and washed,c) a face (1a, 2a) of each chitosan porous layer is acidified with an acid,d) a fiber reinforcement member (3) is provided and positioned between the two acidified faces of the two chitosan porous layers,e) the two chitosan porous layers and the fiber reinforcement member are let to dry to obtain a matrix having the fiber reinforcement member embedded therein.The invention also relates to an implant comprising a matrix obtained according to such a method.