UV-Cured Polyethersulfone Membrane Coating for Low Protein Binding
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Solution Overview
Problem
Existing polymeric membranes, such as polyethersulfone, suffer from hydrophilicity loss over time due to leaching of hydrophilic polymers, leading to protein contamination and reduced effectiveness in filtration applications, particularly in biopharmaceutical processes.
Innovation Solution
A polymeric membrane is modified by coating with hydrophilic monomers comprising amino, polyoxyalkylene, and (meth)acrylate moieties, followed by actinic irradiation, preferably using UV light, to create a stable hydrophilic surface that extends into the membrane pores, reducing protein adsorption and maintaining long-term hydrophilicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrophilic polymers are blended with polyethersulfone to render the membrane surface hydrophilic, then hydrophilicity is improved, but the membrane exhibits leaching of hydrophilic polymers leading to contamination and decreased long-term hydrophilicity
Solution Approach 1:
The patent applies preliminary action by pre-coating the membrane surface with hydrophilic monomers before final membrane formation. This ensures that the hydrophilic layer is established in advance, preventing leaching issues that occur when hydrophilic polymers are simply blended into the membrane matrix. The surface modification is performed as a separate preliminary step rather than relying on bulk blending.
Solution Approach 2:
The patent replaces mechanical blending of hydrophilic polymers with a chemical coating approach. Instead of physically mixing hydrophilic polymers into the polyethersulfone matrix (mechanical system), the invention uses surface coating followed by UV irradiation to create a chemically bonded hydrophilic layer, substituting the mechanical blending process with a chemical deposition and curing process.
2Object-affected harmful factors
If hydrophilic polymers are used to reduce protein binding tendency, then protein resistance is improved, but the application scope and duration are limited due to leaching
Solution Approach 1:
The patent replaces physical entrapment of hydrophilic polymers in the membrane matrix with chemical bonding through UV-cured surface coating. This substitution ensures that the hydrophilic layer remains firmly attached to the membrane surface, maintaining protein resistance over extended application durations without leaching that would limit the membrane's service life.
Solution Approach 2:
The patent applies parameter changes by transforming the hydrophilic polymers from a bulk-blended state to a surface-coated state, and further changing their physical state from liquid monomers to crosslinked polymer networks through UV irradiation. These parameter changes (location and molecular state) ensure the hydrophilic layer remains stable and functional throughout the membrane's operational lifetime.
3Productivity
If photoinitiators are used in photo-grafting processes to modify membrane surface, then grafting efficiency is improved, but residual photoinitiators may cause contamination and stability issues
Solution Approach 1:
The patent applies the extraction principle by completely removing photoinitiators from the formulation. Instead of using conventional photoinitiators that leave harmful residues, the invention uses UV irradiation of hydrophilic monomers that polymerize through a mechanism that does not require traditional photoinitiators, thereby extracting the harmful component from the system while maintaining grafting efficiency.
Solution Approach 2:
The patent employs a disposable approach by using fresh hydrophilic monomers that are polymerized in situ through UV irradiation. The monomers are applied as a coating, cured rapidly, and any unreacted monomers can be easily removed by rinsing. This approach replaces long-lived photoinitiators that persist in the membrane with short-lived monomers that are consumed during the curing process and do not leave harmful residues.
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 modified membrane exhibits low protein binding, increased hydrophilicity, and reduced extractables, making it suitable for microfiltration and nanofiltration, especially in biopharmaceutical applications, with improved stability and performance over multiple sterilization cycles.
Implementation Method 1
curing the hydrophilic monomers with actinic irradiation, preferably UV light
Implementation Method 2
U.S. Pat. No. 5,468,390 describes the modification of an aryl polysulfone membrane using a photo-grafting process without the use of a photoinitiator. The membrane is UV-irradiated for a certain time at wavelengths of about 254 nm in the presence of hydrophilic vinyl monomers.
Data Source
AI summary
The present disclosure is related to a polymeric membrane, comprising a modified surface obtained from coating with hydrophilic monomers and curing the hydrophilic monomers with actinic irradiation, preferably UV light, wherein the hydrophilic monomers comprise at least one amino moiety; at least one polyoxyalkylene unit; and at least one (meth)acrylate moiety.