Immunoisolation Membrane Sustaining Bioaffinity via Nitrogen Surface Gradients
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Solution Overview
Problem
Existing membranes for immunoisolation used in transplantation do not maintain high bioaffinity over time, leading to potential immune rejection and reduced efficacy in long-term transplantation applications.
Innovation Solution
A membrane for immunoisolation with a porous structure that satisfies specific elemental ratios (B/A ≤ 0.7 and A ≥ 0.015) on its surface, containing 0.05% to 8.0% nitrogen-containing compounds like polyvinylpyrrolidone, and having a thickness of 10 μm to 250 μm with a layered compact portion for controlled pore diameter distribution, enhancing bioaffinity and permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a synthetic polymer membrane is used for immunoisolation, then the membrane provides immune protection, but the bioaffinity decreases over time leading to immune rejection
Solution Approach 1:
The invention changes the chemical composition parameters of the membrane by incorporating nitrogen-containing compounds (0.05% to 8.0% by mass) and controlling the N/C ratio (0.015 ≤ A < 0.1) to achieve sustained bioaffinity. This parameter optimization prevents immune rejection while maintaining long-term functionality of the membrane.
Solution Approach 2:
The invention creates a composite membrane structure combining synthetic polymer base material with nitrogen-containing compounds (such as polyvinylpyrrolidone). This composite approach maintains the mechanical properties of synthetic polymers while adding bioaffinity characteristics that prevent immune rejection over time.
2Productivity
If the membrane allows permeation of nutrients, then the transplanted cells remain functional, but immune cells may also permeate causing rejection
Solution Approach 1:
The invention creates different functional zones within the membrane structure. The surface layer with controlled nitrogen content and N/C ratio provides immune protection, while the bulk material maintains nutrient permeability. This local differentiation allows selective permeation properties throughout the membrane.
Solution Approach 2:
The invention utilizes a porous membrane structure with controlled pore size distribution. The pores allow passage of small molecules like nutrients and oxygen while the surface chemistry (controlled N/C ratio and nitrogen content) prevents adhesion and passage of larger immune cells, achieving size-based and chemistry-based selectivity.
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 provides sustained bioaffinity and prevents immune rejection, allowing for long-term use in transplantation by selectively permeating nutrients while blocking immune cells, thereby maintaining the functionality of transplanted biological constituents like insulin-secreting cells.
Implementation Method 1
a selectively permeable membrane which allows water, oxygen, glucose, or the like to permeate, and which, at the same time, performs immunoisolation by inhibiting permeation of immune cells
Implementation Method 2
a porous membrane that contains a polymer, in which Formulas (I) and (II) are satisfied for at least one surface of the porous membrane
Data Source
AI summary
According to the present invention, there is provided a membrane for immunoisolation, including a porous membrane that contains a polymer, in which Formulas (I) and (II) are satisfied for at least one surface of the porous membrane, B/A≤0.7 (I) and A≥0.015 (II) (in the formula, A represents a ratio of an N element to a C element on a surface of the membrane, and B represents a ratio of the N element to the C element at a depth of 30 nm from the surface of the membrane); a chamber for transplantation for enclosing a biological constituent therein, including the above-described membrane for immunoisolation on at least a part of a surface forming an inside and an outside of the chamber for transplantation; and a device for transplantation includes the above-described chamber for transplantation enclosing the above-described biological constituent therein. The membrane for immunoisolation of the present invention has a high bioaffinity.