Rough-Surface Implantable Membrane Construct for Cell Exclusion
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Solution Overview
Problem
Existing implantable devices face challenges in maintaining the viability and productivity of bioactive entities by minimizing the formation of non-functional mesenchymal cells, which interfere with nutrient and oxygen transport to therapeutic cells, leading to reduced therapeutic efficacy.
Innovation Solution
An implantable membrane construct with a maximum pore size of less than 2 microns and surface roughness of at least 0.5 microns on opposing sides, incorporating layers with specific properties to mitigate mesenchymal cell formation and enhance nutrient and oxygen access, including fluoropolymer membranes and reinforcing components for structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth membrane surface is used, then manufacturing is easier and material selection is simpler, but mesenchymal cell formation increases at the luminal interface, creating diffusional barriers and reducing therapeutic cell viability
Solution Approach 1:
The patent applies parameter changes by modifying the surface roughness parameter of the membrane to at least 0.5 microns. This physical parameter modification prevents mesenchymal cell formation at the luminal interface while maintaining manufacturing feasibility through established membrane fabrication techniques. The rough surface topology creates an environment that is unfavorable for mesenchymal cell adhesion and proliferation.
Solution Approach 2:
The patent applies local quality by implementing different surface roughness characteristics at different locations of the membrane. The luminal interface (first surface) has a roughness of at least 0.5 microns to prevent mesenchymal cell formation, while the opposite surface may have different properties optimized for its specific function. This spatial differentiation of surface properties addresses the local requirement to prevent harmful cell formation without compromising overall device function.
2Productivity
If the membrane pore size is increased to improve nutrient and oxygen transport, then diffusional barriers are reduced, but non-functional mesenchymal cells can penetrate and colonize the membrane, reducing therapeutic efficacy
Solution Approach 1:
The patent optimizes the pore size parameter to a specific range (0.03-2 microns) that balances two competing requirements: large enough pores to permit efficient nutrient and oxygen diffusion to therapeutic cells, but small enough pores to prevent mesenchymal cell penetration and colonization. This precise parameter control resolves the contradiction between transport efficiency and harmful cell exclusion.
Solution Approach 2:
The patent employs composite material structures combining the membrane with surface roughness modifications and potentially multiple layers or coatings. This composite approach allows the membrane to simultaneously achieve appropriate pore size for nutrient transport while the surface roughness feature prevents mesenchymal cell adhesion, resolving the contradiction through material composition rather than single-parameter adjustment.
3Reliability
If the membrane is made more permeable to allow better cell access to nutrients, then therapeutic cell viability improves, but the formation of non-therapeutic cell populations increases, reducing the functional cell density
Solution Approach 1:
The patent changes the surface roughness parameter to at least 0.5 microns on the luminal interface, which creates a physical barrier that prevents non-therapeutic mesenchymal cell formation while maintaining permeability for nutrient and oxygen transport. This parameter modification allows therapeutic cells to maintain viability through adequate nutrient access without the contamination of harmful cell populations.
Solution Approach 2:
The patent converts the potentially harmful effect of surface roughness (which could complicate manufacturing) into a beneficial feature that actively prevents mesenchymal cell formation. The rough surface topology, rather than being a manufacturing defect, becomes a functional feature that protects the therapeutic cell environment from harmful cell colonization while maintaining necessary permeability.
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 membrane construct effectively reduces mesenchymal cell formation, ensuring optimal nutrient and oxygen delivery to therapeutic cells, thereby maximizing therapeutic potential and minimizing diffusional barriers.
Implementation Method 1
the diffusion distance and time needed for transport of the oxygen and nutrients to the implanted, encapsulated cells is minimized
Data Source
AI summary
An implantable membrane construct including a maximum pore size (MPS) less than 2 microns and opposing sides, each side of the construct having a surface roughness (Sa) greater than about 0.5 microns is disclosed. When the luminal surface of the implantable membrane construct has a surface roughness (Sa) greater than about 0.5 microns, mesenchymal cells do not form at the interface of the lumen and the first layer (i.e., luminal interface) such that the mesenchymal cells do not impede the flow of oxygen and nutrients to the graft cells (when implanted). When implanted, the outermost layer of the implantable membrane construct enables cellular penetration, vascularization, and anchoring of the construct. The implantable membrane construct includes single layer embodiments and multiple layer embodiments. Encapsulation devices utilizing the implantable membrane constructs to encapsulate biological entities (e.g., cells) into a patient are also provided.