Porous 3D Polymer Matrix with Supercritical CO2 Drying
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Solution Overview
Problem
Existing biodegradable polymer matrices for cell culture and tissue therapy lack sufficient mechanical strength and porosity, with alginate xerogels exhibiting low mechanical resistance and polysaccharide sponges having limited control over porosity and structural integrity.
Innovation Solution
A method involving the preparation of a biocompatible and biodegradable polymer matrix through steps of forming an aqueous solution with anionic and cationic polysaccharides, mechanical agitation, freezing, gelling, dehydration, and drying with supercritical CO2 to create a matrix with open and interconnected pores, ensuring mechanical resistance and elasticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If alginate xerogels are prepared by air drying at 80°C to achieve high porosity favorable to cell culture, then porosity is improved, but mechanical resistance deteriorates
Solution Approach 1:
The patent combines alginate with chitosan and gelatin to create a composite material system. The chitosan provides structural support and mechanical strength, while gelatin contributes to porosity and biocompatibility. This composite approach allows the material to simultaneously achieve high porosity (60-90%) and sufficient mechanical resistance for implantation, resolving the contradiction between porosity and mechanical strength.
Solution Approach 2:
The patent employs supercritical CO2 drying instead of conventional air drying to preserve the foam structure. By changing the drying parameter from atmospheric air drying to supercritical fluid drying, the material maintains its highly porous structure without collapsing, thereby achieving both high porosity and mechanical integrity that would otherwise be mutually exclusive.
2Strength
If polysaccharide sponges are prepared by freezing and lyophilization to improve mechanical strength, then mechanical strength is improved, but porosity control and structural integrity deteriorate
Solution Approach 1:
The patent incorporates a foaming agent into the polysaccharide solution before gelation, creating a pre-formed foam structure. This preliminary action of foam formation allows subsequent freezing and lyophilization to preserve the desired porous architecture rather than creating random ice-crystal patterns, thereby maintaining both mechanical strength and controlled porosity.
Solution Approach 2:
The patent uses a foaming agent as an intermediary substance that templates the porous structure during gel formation. This intermediary creates a stable foam matrix that guides the subsequent freezing and drying processes to produce uniform, controlled porosity while maintaining mechanical strength, overcoming the limitations of direct freezing methods.
3Ease of manufacture
If direct cell injection is performed into the affected organ to treat ischemic heart disease, then cell therapy is administered, but cell mortality increases and side effects occur
Solution Approach 1:
The patent utilizes a highly porous biomaterial scaffold (with 60-90% porosity) that serves as a protective carrier for mesenchymal stem cells. The porous structure allows cell encapsulation and maintenance in a biomimetic environment, protecting cells from mechanical stress and immune rejection during implantation. This approach dramatically improves cell survival rates compared to direct injection while enabling localized delivery to the affected cardiac tissue.
Solution Approach 2:
The patent introduces a biomimetic porous matrix as an intermediary carrier between the cells and the target tissue. This matrix protects cells during transplantation, maintains their viability, and facilitates controlled release at the implantation site. The intermediary structure eliminates the harmful effects of direct injection while preserving the therapeutic benefits of cell therapy.
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 resulting polymer matrix exhibits sufficient mechanical properties and porosity, supporting cell culture and therapy applications, particularly in cardiac cell therapy, by maintaining cell viability and functionality.
Implementation Method 1
the gelling of said frozen foam, by adding to said foam at least one gelling agent in solution in a solvent, to obtain a gelled foam
Implementation Method 2
the freezing of the foam obtained above in the previous step, to obtain a frozen foam
Implementation Method 3
the dehydration of the gelled foam obtained above in the previous step, to obtain a dehydrated gelled foam
Implementation Method 4
the drying of the dehydrated gelled foam obtained above in the previous step, by treatment with supercritical CO2, to obtain said polymer matrix
Data Source
Figure 1a~1d
Figure 2a~3
Figure 4~5
AI summary
The present invention relates to a process for preparing a biocompatible and biodegradable porous three-dimensional polymer matrix comprising a network of open and interconnected pores, to the porous polymer matrix obtained by means of such a process, and also to the uses thereof, in particular as a support and for culturing cells or in regenerative medicine, and in particular for cell therapy, in particular cardiac cell therapy. The process for preparing said matrix comprises the following steps: 1) preparing an aqueous solution comprising at least one biocompatible anionic polysaccharide and at least one biocompatible cationic polymer, 2) mechanically stirring said solution obtained above in the preceding step, in the presence of a foaming agent or of a gas under pressure, so as to form a foam, 3) freezing the foam obtained above in the preceding step, so as to obtain a frozen foam, 4) gelling the frozen foam obtained above in the preceding step, by adding to said foam at least one gelling agent in solution in a solvent, so as to obtain a gelled foam, 5) dehydrating the gelled foam obtained above in the preceding step, so as to obtain a dehydrated gelled foam, then 6) drying the dehydrated gelled foam obtained above in the preceding step, by treatment with supercritical CO2, so as to obtain said polymer matrix.