ECM Medical Graft Devices With Compressed Laminated Regions
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Solution Overview
Problem
Traditional lyophilization methods for preparing medical graft devices from extracellular matrix (ECM) tissues are limited in creating larger area and thicker sheets due to the inability to laminate tissue layers with sufficient strength, restricting their size and thickness, and thus, their application in wound management.
Innovation Solution
The method involves preparing at least two hydrated sheets of ECM, compressing specific overlapping regions without drying, freezing to bond them, and then lyophilizing to create a medical graft device with a combination of collapsed and open matrix structures, allowing for larger area and thickness by stacking or staggering the sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional lyophilization method is used, then open matrix structure is achieved, but device area and thickness are limited
Solution Approach 1:
The device is divided into multiple discrete ECM sheets that can be independently processed and then assembled. Each sheet maintains its structural integrity while allowing for flexible arrangement in stacked or staggered configurations to achieve desired device area and thickness.
Solution Approach 2:
Multiple ECM sheets are combined through compression bonding to form a laminated structure. The compression process creates strong inter-laminar bonds while preserving the open matrix structure within each sheet, enabling the creation of large-area devices with controlled thickness.
2Volume of moving object
If multiple sheets are stacked to increase thickness, then device thickness is improved, but lamination strength is insufficient
Solution Approach 1:
The ECM sheets are pre-compressed before final device assembly. This preliminary compression creates initial bonding surfaces that facilitate strong inter-laminar adhesion during subsequent lamination steps, ensuring adequate lamination strength in the final multi-layer device.
Solution Approach 2:
The compression force and duration are optimized to achieve the desired balance between lamination strength and preservation of open matrix structure. By controlling compression parameters, strong bonds form at interfaces while the internal porosity of each sheet is maintained.
3Strength
If vacuum pressing is used, then tensile strength is improved, but matrix structure becomes overly compressed
Solution Approach 1:
Different regions of the device have different compression levels. The inter-laminar regions are compressed to create strong bonds, while the intra-laminar regions maintain their open matrix structure. This local differentiation of compression quality achieves both strength and structural integrity.
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
This approach enables the production of larger area and thicker medical graft devices with a combination of high tensile strength and rapid resorption, addressing the limitations of traditional lyophilization by creating laminated regions with a collapsed matrix structure and non-laminated regions with an open matrix structure, enhancing integration and interaction with local cells and tissues.
Implementation Method 1
Lyophilization, on the other hand, comprises drying tissue by sublimation, a process of changing ice crystals from a solid directly to a gas without passing through an intermediate liquid phase. During lyophilization, a vacuum applied to frozen tissue at low temperatures causes the ice crystals to sublimate from the frozen tissue, leaving behind small pockets of open space formerly occupied by the ice.
Implementation Method 2
Vacuum pressing comprises compressing hydrated, remoldable material while subjecting the material to a vacuum. Tissue compressed by vacuum pressing generally has a higher tensile strength and lower strain value compared to tissue compressed by other methods because of its more compressed matrix structure.
Implementation Method 3
The sheets of ECM have overlapping regions that are compressed together during a non-drying process, and other overlapping regions that are not compressed together. Once the appropriate overlapping regions of the sheets are compressed together, the entire device is lyophilized to bond the compressed regions together
Data Source
AI summary
Large-area medical graft devices comprise at least two sheets of extracellular matrix material (ECM). The sheets of ECM have overlapping regions that are compressed together during a non-drying process, and other overlapping regions that are not compressed together. The compressed overlapping regions have a more collapsed matrix structure, while the non-compressed overlapping regions having a more open matrix structure. The sheets of ECM can have a stacked orientation to create a desired thickness, or a staggered orientation to create a desired surface area, or combinations of both orientations.