Polysulfone Blood Purifier Membrane Sterilization
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Solution Overview
Problem
Conventional blood purifiers using polysulfone-based membranes face issues with hydrophobicity, leading to air lock phenomena and poor blood compatibility, and existing methods to enhance hydrophilicity, such as adding polyvinyl pyrrolidone, result in elution of hydrophilic polymers into the blood, causing side effects and complicating long-term storage stability.
Innovation Solution
A method involving polysulfone-based permselective hollow fiber membranes with controlled polyvinyl pyrrolidone content, deaerated water, and inert gas-saturated packaging, exposed to a radioactive ray after sealing, to inhibit hydrogen peroxide formation and maintain low water content, ensuring safety and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyvinyl pyrrolidone is added to polysulfone-based resin to enhance hydrophilicity, then blood compatibility is improved, but the hydrophilic polymer elutes into blood during hemodialysis causing side effects
Solution Approach 1:
The patent changes the molecular weight parameter of polyvinyl pyrrolidone from conventional ranges to 10,000-1,000,000 (preferably 50,000-500,000), and controls its content at 1-20% by weight. This parameter optimization reduces elution while maintaining hydrophilicity and blood compatibility. The high molecular weight PVP forms a more stable network structure that resists leaching into blood during dialysis.
Solution Approach 2:
The patent creates a composite membrane structure combining polysulfone-based resin with polyvinyl pyrrolidone at optimized ratios and molecular weights. This composite material integrates the mechanical strength and selectivity of polysulfone with the hydrophilicity and blood compatibility of PVP, while the specific composition controls PVP elution. The composite structure allows synergistic effects where PVP improves blood compatibility without excessive elution.
2Productivity
If polysulfone-based membranes are used for high water permeability, then dialysis efficiency is improved, but hydrophobicity causes air lock phenomena
Solution Approach 1:
The patent optimizes the molecular weight and content parameters of polyvinyl pyrrolidone to control the hydrophilicity of the membrane. By selecting PVP with molecular weight 10,000-1,000,000 and content 1-20% by weight, the membrane achieves sufficient hydrophilicity to prevent air lock phenomena while maintaining the high water permeability characteristic of polysulfone-based membranes. This parameter optimization balances hydrophilicity and permeability.
3Reliability
If hydrogen peroxide is present in the blood purifier, then sterilization is achieved, but it causes deterioration and decomposition of polyvinyl pyrrolidone over time
Solution Approach 1:
The patent performs preliminary action by controlling the manufacturing process to minimize hydrogen peroxide formation before the membrane is put into service. By optimizing the phase separation conditions and drying processes, and by selecting appropriate PVP molecular weights (10,000-1,000,000), the membrane structure is pre-stabilized to resist hydrogen peroxide-induced decomposition during storage and use, preventing PVP deterioration before it occurs.
Solution Approach 2:
The patent accepts that some hydrogen peroxide may be present from sterilization but designs the membrane with sufficient PVP stability margin through molecular weight optimization. The high molecular weight PVP (10,000-1,000,000) acts as a more resilient component that can withstand the temporary hydrogen peroxide exposure from sterilization without significant decomposition, effectively treating the sterilization as a controlled, temporary stressor.
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 method provides a sterilized blood purifier with improved blood compatibility, sustained performance, and enhanced storage stability, preventing hydrogen peroxide-induced deterioration and eliminating the need for radical-trapping agents, thus ensuring safety and efficiency.
Implementation Method 1
subjecting the polysulfone-based permselective hollow fiber membranes containing polyvinyl pyrrolidone to a radioactive ray exposure treatment
Implementation Method 2
adjusted in water content to 5 to 600 mass % by the use of deaerated water
Implementation Method 3
packaged in a state where a content of polyvinyl pyrrolidone... is sealed in a packaging bag capable of shutting out an external air and water vapor
Data Source
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AI summary
[PURPOSE] To provide a blood purifier which has high levels of blood compatibility, performance-retaining property when in contact with blood, and safety, and which shows an excellent water permeability-exhibiting rate after a priming treatment and has high reliability in long-term storage. [SOLUTION] A blood purifier assembled using a polyvinyl pyrrolidone-containing polysulfone-based permselective hollow fiber membrane bundle, characterized in that the amount of polyvinyl pyrrolidone which elutes from the hollow fiber membrane bundle is 10 ppm or less, the amounts of hydrogen peroxide which elute from extracts from all the sites of the hollow fiber membrane bundle are 5 ppm or less, when the hollow fiber membrane bundle is divided into 10 portions in the lengthwise direction to test the sites of all the 10 portions according to the method regulated in the Approval Standard for Dialysis-Type Artificial Kidney Apparatus, and the water permeability of the blood purifier found at a point of time when 10 minutes has passed since the priming treatment of the blood purifier is 90% or more of the water permeability of the same found at a point of time when 24 hours has passed since the priming treatment thereof.