Gradient Pore Immunoisolation Membrane for Transplantation
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Solution Overview
Problem
Existing membranes for immunoisolation in transplantation are costly to manufacture and prone to deterioration in substance permeability due to protein adsorption, especially when they have small pore diameters, which can lead to immune rejection and reduced functionality over time.
Innovation Solution
A membrane with a porous structure that has a layered compact portion with a minimum pore diameter of 0.02 μm to 1.5 μm, where the pore diameter continuously increases from the compact portion towards the surface, made from polysulfone and polyvinylpyrrolidone, reducing protein adsorption and enhancing permeability while inhibiting immune cell infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous membrane with small pore diameter is used for immunoisolation, then immune cell infiltration is inhibited, but substance permeability deteriorates due to protein adsorption
Solution Approach 1:
The membrane structure transitions from uniform pores to a gradient structure where pore size varies by location. The compact portion has small pores (0.02-1.5 μm) for immunoisolation, while the spongy portion has larger pores for substance permeability. This local differentiation resolves the contradiction between blocking immune cells and allowing substance exchange.
Solution Approach 2:
The invention moves from considering only pore diameter (one dimension) to incorporating pore size gradient in the thickness direction (adding another dimension). The continuous increase in pore diameter from the compact portion toward the surface creates a three-dimensional pore size distribution that simultaneously achieves immunoisolation at the base and high permeability at the surface.
2Reliability
If a porous membrane with small pore diameter is used, then immune rejection is prevented, but manufacturing cost increases and substance permeability deteriorates
Solution Approach 1:
The invention changes the pore diameter parameter from a fixed small value to a gradient distribution ranging from 0.02-1.5 μm in the compact portion to larger values in the spongy portion. This parameter transformation allows the membrane to maintain immunoisolation effectiveness while improving substance permeability and reducing manufacturing complexity compared to ultrafine uniform pore membranes.
3Reliability
If pore diameter is small to prevent immune rejection, then immune cell infiltration is inhibited, but manufacturing precision requirements increase leading to defective products
Solution Approach 1:
The membrane is segmented into two functional portions: a compact portion with small pores for immunoisolation and a spongy portion with larger pores for permeability. This segmentation allows each portion to be optimized independently, with the compact portion providing the necessary immune barrier without requiring the entire membrane to have ultrafine uniform pores, thus reducing manufacturing precision requirements.
Solution Approach 2:
By introducing the thickness direction as an additional dimension for pore size variation, the invention creates a pore size gradient that transitions from small pores at the base to larger pores toward the surface. This dimensional approach allows the membrane to achieve immunoisolation with smaller pores only where necessary while maintaining manufacturability.
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 is manufactured at lower costs, maintains substance permeability, and reduces immune rejection, allowing for long-term functionality by preventing immune cell infiltration and protein adsorption, thus ensuring effective nutrient and physiologically active substance exchange.
Implementation Method 1
A membrane for immunoisolation is a selectively permeable membrane which allows water, oxygen, glucose, or the like to permeate
Implementation Method 2
a deterioration in substance permeability is likely to occur in general due to adsorption of proteins or the like
Data Source
AI summary
According to the present invention, there are provided a membrane for immunoisolation, including: a porous membrane that contains a polymer, in which the porous membrane includes a layered compact portion where a pore diameter is the smallest within the membrane, and a pore diameter continuously increases in a thickness direction from the compact portion toward at least one surface of the porous 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, including the above-described chamber for transplantation enclosing the biological constituent therein. In the membrane for immunoisolation of the present invention which can be manufactured at low costs, a deterioration in substance permeability is unlikely to occur.