Virus Removal Membrane with Porosity Gradient
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Solution Overview
Problem
Conventional virus removal membranes face challenges in maintaining high filtration efficiency while maintaining high virus removal performance, especially when pressure or flow velocity conditions change, leading to potential clogging and reduced virus removal capability.
Innovation Solution
A virus removal hollow fiber membrane is developed using a hydrophilized polyvinylidene fluoride (PVDF) resin with a specific structure and composition, where gold colloids are used to evaluate the uniformity and thickness of the capture layer, ensuring uniform virus capture and high filtration efficiency even under varying pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a virus removal membrane is used to remove viruses from protein-containing solutions, then virus removal capability is improved, but filtration efficiency deteriorates due to clogging and pressure changes
Solution Approach 1:
The patent employs a porous hollow fiber membrane with specifically controlled pore size distribution and porosity gradient. The membrane contains a dense structure layer with controlled pore size (10-30 nm) and a coarse structure layer with higher porosity (50-80%), creating an optimized porous structure that maintains virus removal capability while reducing clogging and improving filtration efficiency
Solution Approach 2:
The patent creates a porosity gradient within the membrane structure, with the dense structure layer having lower porosity (20-50%) near the feed side and the coarse structure layer having higher porosity (50-80%) toward the permeate side. This local variation in pore density and size allows different regions to perform specialized functions: virus capture at the dense layer and efficient flux at the coarse layer, resolving the contradiction between removal capability and filtration efficiency
2Reliability
If the membrane structure is made denser to improve virus removal performance, then virus removal capability is improved, but protein filtration efficiency deteriorates due to increased resistance
Solution Approach 1:
The patent divides the membrane into two distinct functional layers: a dense structure layer (10-50 μm thick) with pore size 10-30 nm for virus removal, and a coarse structure layer for maintaining flux. This segmentation allows each layer to be optimized for its specific function without compromising the other, enabling high virus removal performance while maintaining low protein filtration resistance
Solution Approach 2:
The patent utilizes a porous polymer matrix with controlled pore size distribution. The dense structure layer has tightly controlled small pores (10-30 nm) that exclude viruses while the overall membrane maintains sufficient porosity (20-50% in dense layer, 50-80% in coarse layer) to allow protein passage, resolving the contradiction between virus removal performance and protein filtration resistance
3Reliability
If a hydrophilic polymer is added to improve virus removal performance, then virus removal capability is improved, but membrane complexity increases due to material composition
Solution Approach 1:
The patent achieves virus removal capability by precisely controlling physical parameters of a single polymer material (PVDF) rather than relying on complex multi-component compositions. Key parameters include pore size (10-30 nm in dense layer), porosity gradient (20-50% to 50-80%), and layer thickness ratio. This parameter-based approach simplifies material composition while maintaining high virus removal capability
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 achieves high virus removal capability and filtration efficiency with uniform virus capture and reduced leakage, maintaining performance across different pressure and flow conditions, thus addressing the limitations of existing membranes.
Implementation Method 1
the composition is heated to a temperature not lower than the crystal melting point of the PVDF resin and uniformly dissolved
Implementation Method 2
a virus removal method by filtration with a virus removal membrane
Implementation Method 3
the thickness of a portion where gold colloids having a diameter of 20 nm or more and 30 nm or less are captured
Data Source
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AI summary
A virus removal membrane 10 for removing viruses from a protein-containing solution, the virus removal membrane 10 including a primary surface 1 to which the protein-containing solution is applied, and a secondary surface 2 from which a liquid that permeates through the virus removal membrane 10 is flowed, wherein the virus removal membrane is formed from a hydrophilized synthetic polymer, in which, when a solution containing gold colloids having a diameter of 20 nm is applied through the primary surface to the virus removal membrane to allow the virus removal membrane 10 to capture the gold colloids for measurement of brightness in a cross section of the virus removal membrane 10, a value obtained by dividing a standard deviation of a value of an area of a spectrum of variation in the brightness by an average of the value of the area is 0.01 or more and 1.5 or less; and a thickness of a portion, where gold colloids having a diameter of 20 nm or more and 30 nm or less are captured, in the cross section of the virus removal membrane 10 in a wet state is 10 µm or more and 30 µm or less.