Simulation-based assessment of zwitterionic pendant group variations on the hemocompatibility of polyethersulfone membranes

Hemodialysis is a lifesaving treatment for end-stage renal disease (ESRD) that exploits semipermeable membranes to remove fluids and uremic toxins from ESRD patients. Polyethersulfone (PES) is the most common membrane that is currently used in Canadian hospitals and represents 93% of the market. Nevertheless, PES membranes have limited hemocompatibility, which triggers blood activation cascades, as the rate of morbidity and mortality in ESRD patients is still unacceptably high. Surface modification with zwitterionic (ZW) materials, which are well known for their strong dipole–dipole interactions and exceptional antifouling properties, has recently received increased attention in improving PES characteristics like roughness, wettability, and biocompatibility, which are crucial factors in dialysis efficiency. The hydration structures, dynamics, and interactions of ZWs are significantly dependent on the backbone structures, such as differences in carbon space length [CSL], conformation, functional groups, pendant groups, and charge distributions, and even minor changes in ZW structure can drastically alter their behavior. However, a systematic investigation of the impact of dipole orientation of ZW on the hemocompatibility of the membranes has not yet been investigated. This study offers a comprehensive exploration of the interactions between hemodialysis membranes and human serum proteins, emphasizing the pivotal role of the zwitterion dipole orientation. We utilize molecular docking techniques to predict protein–ligand interactions, offering insights into the binding sites and binding energy of these complexes. The effect of dipole orientation on the hemocompatibility of various ZW-modified PES membranes compared to the pristine PES has been investigated using 2-methacryloyloxyethyl phosphorylcholine (MPC), 2-((2-(methacryloyloxy)ethyl)dimethylammonio)ethyl methyl phosphate (MMP), and butyl (2-((2-(methacryloyloxy)ethyl)dimethylammonio)ethyl) phosphate (MBP) zwitterions with opposite dipole orientations. Results showed that the protein–ligand interactions and affinity energies displayed by the reverse dipole moment structures are remarkably different. It was demonstrated that the MBP–PES ligand had the lowest affinity energy to interact with all examined human serum proteins compared to the structure, which had an opposite dipole moment. As a result, this membrane surface has better antifouling properties and, thus, higher hemocompatibility, which directly correlates with greater efficiency of hemodialysis in patients.

This paper presents the performance of the modified nanoporous polyethersulfone (PES) membrane for dialysis system in terms of long term diffusion capability of low molecule ions and blood compatibility (platelets adhesion). Surface modification on PES membrane by parylene film has significantly reduced the number of platelet adhered to the membrane surface after long term diffusion test (0-28 days), without degrading the diffusivity performance of the membranes. After 28 days, the diffusivity PES membrane was decreasing, whilst, the PES membranes coated by parylene have shown the consistent diffusion coefficient value. In addition, the membrane coated by parylene has less platelet adhered on its surfaces, showing the improvement of bio compatibility and blood compatibility of the coated membrane. The results indicated that our modified PES membrane has a potential use for application in hemodialysis system.

In this study, multifunctional polyethersulfone (PES) membranes are prepared via in situ cross-linked copolymerization coupled with a liquid–liquid phase separation technique. Acrylic acid (AA) and N-vinylpyrrolidone (VP) are copolymerized in PES solution, and the solution is then directly used to prepare PES membranes. The infrared and X-ray photoelectron spectroscopy testing, scanning electron microscopy, and water contact angle measurements confirm the successful modification of pristine PES membrane. Protein adsorption, platelet adhesion, plasma recalcification time, and activated partial thromboplastin time assays convince that the modified PES membranes have a better biocompatibility than pristine PES membrane. In addition, the modified membranes showed good protein antifouling property and significant adsorption property of cationic dye. The loading of Ag nanoparticles into the modified membranes endows the composite membranes with antibacterial activity.

Assessment of polyethersulfone and polyacrylonitrile hemodialysis clinical membranes: In situ synchrotron-based imaging of human serum proteins adsorption, interaction analyses, molecular docking and clinical inflammatory biomarkers investigations

Superhydrophobic polyether sulfone (PES) dialysis membrane with enhanced hemocompatibility and reduced human serum protein interactions: Ex vivo, in situ synchrotron imaging, experimental, and computational studies

We incorporated zwitterionic materials into light-curable fluoride varnish (LCFV) in order to inhibit biofilm accumulation and prevent dental caries, and the properties of LCFV with three different zwitterionic materials, namely, 2-methacryloyloxyethyl phosphorylcholine (MPC), carboxybetaine methacrylate (CBMA), and sulfobetaine methacrylate (SBMA) polymers (each at a weight percentage of 3%), were compared; unmodified LCFV without any zwitterionic material was used as a control. Material properties including film thickness and degree of conversion (DC) of each type of LCFV were evaluated. In addition, protein-repellent effects and inhibitory effects on Streptococcus mutans adhesion and saliva-derived biofilm accumulation of LCFV were estimated. Finally, the preventive effect of LCFV on enamel demineralization was assessed in vitro on extracted human teeth specimens stored in S. mutans-containing medium. The film thickness of LCFV significantly decreased with the incorporation of zwitterionic materials compared to the control LCFV, whereas there were no significant differences in the DC among all of the LCFV groups. Furthermore, the amount of adsorbed protein, adherent S. mutans colony-forming unit (CFU) counts, and saliva-derived biofilm thickness and biomass were all significantly lower for LCFV with incorporated zwitterionic materials compared with the control. All LCFV groups including the control showed certain preventive effects against enamel demineralization during a 14-day immersion in the medium with S. mutans and sucrose, and the depth of demineralization was significantly lower in LCFV with zwitterionic materials than in the control. Thus, the incorporation of zwitterionic materials such as MPC, CBMA, and SBMA appears to confer superior antifouling effects to LCFV.

The studies focused on plasma surface modification of poly(ether)sulfone (PES) ultrafiltration (UF) membrane show its potent effect on antifouling propensity but there are few data on the pH dependence of superior surface character achieved. This study examined UF performance and cleaning efficiency of atmospheric pressure argon jet plasma (AP‐AJP) modified PES membrane in whey concentration at various operation pH compared to the plain membrane (UP020). The highest initial permeate flux for the UP020 at pH of 6.4 increased the cake layer formation and the irreversible fouling resistance. The plasma action led to greater intrinsic membrane resistance causing low water permeability compared with the UP020. This effect reduced cake layer resistance despite the fact that the irreversible fouling was more severe at all operation pH. The increase in pH caused to decrease in contribution of fouling to total resistance. For the UP020, the shift in operation pH from acidic point to neutral reduced the recovery in hydraulic permeability after chemical cleaning. The plasma action induced greater cleaning efficiency, which is the most obvious at pH of 6.4. The overall results showed that the AP‐AJP may have the potential to maintain profit‐making UF process in whey concentration at broad range of pH.Practical ApplicationsIn the industrial point of view, cost friendly, and sustainable operation in valorization of whey can be achieved by fouling resistant membranes. Atmospheric pressure argon jet plasma provides extremely hydrophilic character to poly(ether)sulfone membrane. The plasma action decreases fouling resistance and especially cake layer formation. This effect broadens the operating pH of whey without any pre‐adjustment and results in easy to clean membrane surfaces.

In this work, surface grafting modification technology was combined with reverse thermally induced phase separation (RTIPS) method in order to improve the structure and permanent hydrophilicity of polyethersulfone (PES) membranes. Acrylic solution with different concentrations was grafted on the surface of PES membranes while grafting temperature and grafting time were also varied. The modified PES membranes were characterized in all aspects. Attenuated total reflectance Fourier transform‐infrared confirmed successful modification of the PES membrane by grafting acrylic acid. Scanning electron microscopy revealed that homogeneous porous top surface as well as spongy‐like cross‐section structure appeared in the membrane by RTIPS procedure. Moreover, porosity was affected by changes of acrylic acid concentration, grafting temperature, and grafting time. Atomic force microscopy showed that grafting acrylic acid gave a reduction in roughness of PES membrane. Combined with the decreased values of contact angle, the hydrophilicity and antifouling performance of the PES membrane were improved. The pure water flux and BSA rejection rate of the grafted PES membranes were remarkably improved for pure PES membrane and attained a maximum, which was 1,646.24 L/(m2h) and 94.5%, respectively. The long‐term test demonstrated that grafting membranes exhibited outstanding elevated water flux recovery ratio (>85%).

UV photo-grafting of hydrophilic monomers onto the surface of nano-porous PES membranes for improving surface properties

In this study, we evaluated a porous and single-layer skin polyethersulfone (PES) membrane as a material for use in hybrid bioartificial liver support systems. The PES membrane has been characterized as a single-layer skin structure, with a rough porous surface. Specifically, we studied the ability of the human hepatoblastoma cell lines (HepG2) to adhere, grow, and spread on the PES membrane. Furthermore, we examined albumin secretion, low-density lipoprotein uptake, and CYP450 activity of HepG2 cells that grew on the membrane. HepG2 cells readily adhered onto the outer surfaces of PES membranes. Over time, HepG2 cells proliferated actively, and confluent monolayer of cells covered the available surface area of the membrane, eventually forming cell clusters and three-dimensional aggregates. Furthermore, HepG2 cells grown on PES membranes maintained highly specific functions, including uptake capability, biosynthesis and biotransformation. These results indicate that PES membranes are potential substrates for the growth of human liver cells and may be useful in the construction of hollow fiber bioreactors. Porous and single-layer skin PES membranes and HepG2 cells may be potential biomaterials for the development of biohybrid liver devices.

ABSTRACTA variety of plasma treatments have been employed to achieve permanent hydrophilic surfaces throughout the membrane structure. Specifically, we have modified microporous polyethersulfone (PES) membranes using H2O, CO2, and N2 plasma treatments to implant polar functional groups; alternatively, Ar-plasma treatment followed by grafting of hydrophilic monomers (acrylic acid and acrylamide) in the vapor phase has also been successful at modifying PES membranes. PES membranes treated with H2O and CO2 plasmas as well as the grafted membranes are found to be permanently hydrophilic (for a minimum of six months), and the entire membrane cross-section is modified. Chemical changes to the modified PES membranes were determined with FTIR and XPS measurements. Furthermore, water bubble point measurements and electron microscopy results reveal that pore sizes of the modified membranes are only slightly affected, depending on the treatment. Incorporation of polar functionalities results in an increase in the glass transition temperature (Tg) and a moderate change in tensile strength of the modified membranes. Most importantly, the surfaces of the modified membrane are less susceptible to absorption by bovine serum albumin (BSA) proteins.

Biocompatibility enhancement of hemodialysis membranes using a novel zwitterionic copolymer: Experimental, in situ synchrotron imaging, molecular docking, and clinical inflammatory biomarkers investigations.

The main disadvantage of membrane bioreactor (MBR) technology, which is an important alternative for advanced wastewater treatment, is fouling. In this regard, polyether sulfone (PES) membranes were prepared by adding bismuth 2,3‐dimercapto‐1‐propanol (BisBAL) chelate to the dope solution for biofouling control. BisBAL was synthesized using bismuth metal and a thiol. The bare and BisBAL‐doped PES membranes were tested for their physical properties and biofouling resistance properties using xanthan gum solution as a model foulant and real activated sludge. The results showed that the BisBAL‐doped PES membrane has a lower absorptive surface and fouling tendency when compared to the bare PES membrane. Bismuth release from BisBAL‐doped PES membrane during pure water filtration was measured using inductive‐coupled plasma spectrometry and the results showed that bismuth release from BisBAL‐doped PES membrane was quite low. According to the MBR operation results, it can be said that the rate of transmembrane pressure increase, total fouling and biofilm creation could be decreased with BisBAL‐doped PES membrane usage without any effect on activated sludge structure and microbial community population in the MBR. BisBAL‐doped PES membranes did not lose their durability and anti‐biofouling activities in time and could be chemically washed. The novelty of this study was the application of a microfiltration membrane manufactured with bismuth metal in MBR operation.

Heparin-like surface modification of polyethersulfone membrane and its biocompatibility

The development of polyethersulfone (PES) membranes to improve membrane performance can be done in various ways; one is by combining two types of additives (organic and inorganic) in one dope polymer solution. In this study, researchers analyzed the effect of combining polyethylene glycol hexadecyl ether (PEG-HE) as an organic additive and nanocarbon as an inorganic additive on the characteristics and performance of PES membranes. The membrane performance test includes analysis of pure water flux and rejection of synthetic fertilizer factory wastewater (Mg2+) with a concentration of 300 ppm. The membrane characterization was carried out by analyzing the morphology of the membrane structure using Scanning Electron Microscopy (SEM), water contact angle (WCA), porosity, and membrane pore size. Ultrafiltration experiment showed that the modified PES membrane with PEG-HE and Nanocarbon had the highest pure water flux. The most significant rejection coefficient of 96.88% was found in an ultrafiltration experiment using pure PES membranes. The characteristic of other membranes will be described in detail in this article.