Modified Polysulfone Membrane Research Articles

Interfacial Interaction between Functionalization of Polysulfone Membrane Materials and Protein Adsorption.

This study that modified polysulfone membranes with different end-group chemical functionalities were prepared using chemical synthesis methods and experimentally characterized. The molecular dynamics (MD) method were used to discuss the adsorption mechanism of proteins on functionalized modified polysulfone membrane materials from a molecular perspective, revealing the interactions between different functionalized membrane surfaces and protein adsorption. Theoretical analysis combined with basic experiments and MD simulations were used to explore the orientation and spatial conformational changes of protein adsorption at the molecular level. The results show that BSA exhibits different variability and adsorption characteristics on membranes with different functional group modifications. On hydrophobic membrane surfaces, BSA shows the least stable configuration stability, making it prone to nonspecific structural changes. In addition, surface charge effects lead to electrostatic repulsion for BSA and reduce the protein adsorption sites. These MD simulation results are consistent with experimental findings, providing new design ideas and support for modifying blood-compatible membrane materials.

Improving Hemocompatibility of Polysulfone Membrane by UV-Assisted Grafting of Sulfonated Chitosan.

The most prevalent type of hemodialysis membrane is polysulfone (PSf). However, due to inadequate biocompatibility, it significantly compromises the safety of dialysis for patients. In this study, we modify the surface of the PSf membrane with 2,4-dihydroxybenzophenone (DBPh) groups to serve as anchoring sites during UV irradiation. Subsequently, a tailored sulfonated dihydroxy propyl chitosan (SDHPCS) is grafted onto the modified PSf membrane to compensate for the deficiencies in hydrophilic additives. The modified PSf membrane exhibits outstanding hydrophilicity and stability, as demonstrated by its characterization and evaluation. This paper focuses on investigating the interaction between platelet membrane formation, protein adsorption, and anticoagulant activity. The results show that the modified PSf membrane exhibits remarkable enhancement in surface hydrophilicity, leading to a significant reduction in protein and platelet adsorption as well as adhesion.

Modified polysulfone membrane facilitates rapid separation of plasma from whole blood for an effective anti-SARS-CoV-2-IgM diagnosis

During the outbreak of coronavirus, RT-PCR was the premier gold standard method for severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) diagnosis. However, the sophisticated procedure of RT-PCR persuades researchers to develop sustainable point-of-need immunoassay methods for tracing unwitting carriers of SARSCoV-2. Herein, by fabricating a modified polysulfone (MPSF) membrane, we developed an integrated radial flow immunoassay (IRFIA) platform as a point-of-care system, capable of multiplying the immunoassays at a short run time. The target molecule is the SARSCoV-2 IgM in separated plasma. Although the lateral flow immunoassay kits for the rapid identification of Covid-19 have already been commercially developed but, the proposed method is superior to the conventional lateral flow immunoassay. In the newly designed membrane system, we have combined the five membranes of prevalent lateral flow immunoassay (LFIA) strips in one polymeric membrane. The MPSF membrane is capable of separating plasma from whole blood sample, which will reduce the interference of red colour of hemoglobin with generated signal and enhance the immunoassay precision. The efficiency of plasma separation, reached the mean value of 97.34 v/v% in 5 s. Furthermore, the gel electrophoresis results of the separated plasma contrasted with centrifuged plasma sample, demonstrated more efficient separation by the membrane. Using the MPSF membrane, signal generation time reduced from about 20 min in conventional rapid test strip for Covid-19 to about 7 min in IRFIA platform. The sensitivity and specificity of the membrane platform were determined to be 89% and 90%, respectively and a Kappa coefficient of 0.79 showed reliable agreement between the RT-PCR and the membrane system.

Ultrafiltration study of the polysulfone membrane modified with branched polyethyleneimine

Abstract This work discussed the fabrication of polysulfone (PSF) ultrafiltration membranes with hydrophilic behaviour by adding branched polyethyleneimine (PEI) as an additive. By directly blending the base polymer and the additive in the organic solvent, the casting solution is prepared. An asymmetric ultrafiltration membrane was fabricated by the phase inversion method. The presence of PEI was confirmed by comparing the IR spectra of the plain PSF membrane and the modified PSF membrane. A scanning electron microscope was used for the comparison of morphological changes in plain and modified membranes. The membrane was characterised with respect to bovine serum albumin (BSA) adsorption, pure water flux, permeability, compaction factor, humic acid (HA) rejection, and water uptake. The fouling resistance behaviour is prompted due to the presence of hydrophilic PEI chains in the membrane. As a result, pure water flux and flux recovery ratio increased from 28.84 to 326.54 L/m2h and from 0.526 to 0.954 L/m2hkPa for the modified membrane with respect to the plain membrane, respectively.

Wastewater Management Using Coagulation and Surface Adsorption through Different Polyferrics in the Presence of TiO2-g-PMAA Particles

For the surface adsorption process, a wide range of studies have been carried out to describe the adsorption process. However, no extensive study has been carried out to investigate the pre-treatment method effect on the separation process. The purpose of the present study is to improve the performance of the membrane process in the treatment of oily wastewater. For this purpose, the effects of pre-treatment, membrane modification, and operational parameters were investigated on the microfiltration membrane system. Two methods of coagulation and surface adsorption were used as pre-treatment, and then a modified polysulfone (PSf) membrane containing TiO2 nanoparticles was applied in the microfiltration process. In order to reduce the membrane fouling and increase the permeate flux, the surface of the nanoparticle was modified. In order to check the performance of coagulation, pretreatments of polyferric sulfate (PFS) and polyferric chloride (PFC) were applied. The results showed that the Chemical Oxygen Demand (COD) reduction of 98% can be obtained using 1 g/L of PFS coagulant at pH = 6, while only 81% of COD was removed using 1 g/L PFC. It was also found that the best pH for the performance of this type of coagulant was measured as pH = 10 and the removal efficiency for 1 and 2 g/L of PFC coagulant was obtained as 96.1% and 91.7%, respectively. The results show that in the case of using a coagulant of less than 1 g/L, using PFS is more efficient than PFC; meanwhile, in more than 1 g/L of coagulant, this effect is reversed and the use of PFS will be less efficient than PFC. The performance of the PSf-TiO2 membrane fabricated by the Nonsolvent-induced phase separation (NIPS) method was investigated using modified nanoparticles with an initial size of 10 nm at different operating conditions. The results show that the permeate flux and the rejection can be increased to 563 L/h m2 and 99%, respectively, using the modified PSf membrane. The results of this paper showed that the performance of the adsorption process can be improved by using the coagulation process as a pre-treatment method.

Structured nano materials derived from MOF

At the present time, zeolitic imidazolate framework-8 is used in multiple areas from wastewater treatment, membranes, drug delivery and catalysis to photo electronics owing to their inherent exclusive pore structure and high specific surface area as well as their advanced thermal and chemical stability. The molecular differentiation qualities of the product that is ZIF-8 will affect by porosity and pore size distribution and this affects the membrane performance in terms of permeability. Systematic porous materials are broadly achieved by classical hard and soft templating techniques leading to diverse pore size distributions and morphologies. In recent years, ZIF-8 derived from Metal-organic frameworks (MOFs) which is a subclass of Metal-organic frameworks (MOFs) and these MOFs are growing as a novel category of nanoporous materials with large surface areas and small pore size distributions. In the present work, we have synthesized and characterized carbonized metal–organic framework, in the case of ZIF-8 for wastewater treatment processes. Nano ZIF-8 is prepared via a single step room temperature crystallizationwith 2-MIM and zinc nitrate hexahydrate as precursor materials. Prepared ZIF-8 materials were characterized by DLS, XRD, and SEM analysis for identifying morphological and compositional changes. Carbonized ZIF-8 (CZIF-8) is produced via the single-step carbonization technique by decomposing ZIF-8 in an inert atmosphere at 1000 °C. Parent material is compared with the carbonized material for morphological and elemental composition changes. ZIF-8 and CZIF-8 were utilized as an additive in the fabrication of a mixed matrix membrane to modified polysulfone membrane for wastewater treatment. As a result, compared with plain polysulfone membrane has a pure water flux of 50.5L/m2h and ZIF-8/PSF Mixed Matrix Membrane has a pure water flux is 456.09 L/m2h, but CZIF-8/PSF MMM is 521.12 L /m2 h, which is much greater than that of pure PSF and 4 wt% ZIF-8/PSF membranes. as shown in Fig 0.7.

Synergetic effect of graphene oxide and poly(MMA-co-GMA) copolymer on PSF ultrafiltration membrane for the remediation of potential environmental contaminants

A novel hydrophilic polysulfone (PSF) membranes integrated with graphene oxide (GO) and bifunctional based poly(methyl methacrylate-co-glycidyl methacrylate) (poly(MMA-co-GMA)) copolymer were prepared. The functional groups of synthesized GO, poly(MMA-co-GMA) and PSF membranes were justified using FTIR spectroscopy. The variety of physicochemical analysis helped to demonstrate the presence GO (1.5 wt%) and poly(MMA-co-GMA) (0–2 wt%) and also its impact on morphology and performance of the membranes. Embedding of the pristine GO, affected the pore forming mechanism due to which the modified membrane exhibited uniform finger-like pores as a result of its hydrophilic filler property. PGC-1 membrane was endowed with maximum pore density, porosity and permeability. There was a significant decline in CA and the amount of BSA adsorbed from 81.2° and 0.22 mg/cm2 for pristine membrane to 59.7° and 0.06 mg/cm2, respectively for PGC-2 membrane. By increasing the amount of the copolymer from 0 wt% to 2 wt% the irreversible fouling and total fouling were decreased, which resulted to high flux recovery ratio (Frr) for the modified PSF membrane. Besides, the o/w emulsion flux obtained for PGC-2 membrane was 6 times greater than that of the unmodified PSF membrane signifying that the foulants were unable to affect the modified membrane. In general, PSF/GO/poly(MMA-co-GMA) membrane with improved fouling resistance and high separation efficiency open up a way for its great potential for protein separation, oil/water emulsion separation and various other similar domains.

Enhanced hydrophilicity and anticoagulation of polysulfone materials modified via dihydroxypropyl, sulfonic groups and chitosan

A novel modified polysulfone (PSF) is successfully prepared for hemodialysis by grafting with a well-defined heparin-like polymer, sulfonated dihydroxypropyl chitosan (SDHPCS), which is obtained in proper sequence via alkalization of chitosan, etherification and sulfonation. PSF is modified via chloroacetyl chloride, and then, the chloroacylated polysulfone (CAPSF) with pristine PSF is transformed into CAPSF/PSF blend membrane via the phase inversion, followed introducing amino group into CAPSF on the surface and taking glutaraldehyde as bridge between modified PSF membrane and SDHPCS. The result of 1H NMR spectrum of prepared CAPSF indicates that the degree of the substitution of chloroacetyl group. The SEM, EDS mapping, FTIR and XPS show that SDHPCS-g-PSF membranes are successfully prepared. The hydrophilicity of the membrane modified by SDHPCS is improved obviously, and the contact angle remarkably reduced from 87 ° to below 45°, exhibiting much better hydrophilicity. The hemocompatibility characterizations including BSA adsorption, Plasma recalcification time (PRT), hemolysis ratio (HR), activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) also certificates that SDHPCS-g-PSF possesses lower BSA adsorption and enhanced blood compatibility.

Construction of electro-neutral surface on dialysis membrane for improved toxin clearance and anti-coagulation/inflammation through saltwater fish inspired trimethylamine N-oxide (TMAO)

Dialysis membranes capable of preventing coagulation and inflammation and achieving high toxin clearances are highly desired for clinical hemodialysis. Here, we constructed an electro-neutral and hydrophilic surface on Polysulfone (PSf) membrane, which both improved the hemocompatibility and toxin clearance. The membrane surface was modified with trimethylamine N-oxide (TMAO) through Michael addition reaction and subsequent crosslinking with glycidyl ether oxypropyl trimethoxysilane (KH560). Saltwater fish inspired zwitterionic monomer TMAO without spacers between positive and negative headgroups is thought to generate a hydrated and net-charged layer that prevents non-specific plasma proteins and platelets adsorption and activation. Coagulation time, serine protease Factor XIIa, bradykinin (BK), kallikrein (KLK) and anaphylatoxins (C3, C5 and SC5b-9) were examined to explore blood compatibility. All results showed that the highly hydrated and electro-neutral surface could efficiently alleviate the activation of the coagulation cascade, kallikrein-kinin system (KKS) and complement system simultaneously. Furthermore, the modified PSf membrane is favorable to toxins clearance (e.g., urea, creatine, lysozyme and vitamin B12) during simulated dialysis process. It is manifested that the TMAO based surface modification is feasible for improving the hemocompatibility and toxin clearance of dialysis membranes.

Fabrication of a Modified Polysulfone Membrane Using Molecular Imprinting Technique for Selective Separation of Tetracycline from the Environment

AbstractIn recent years, the environmental contamination and ecological poisons of antibiotics have possessed great challenges for human health. Versatile methods have been developed in enhanced de...

Enhanced adsorption and biocompatibility of polysulfone hollow fibre membrane via the addition of silica/alpha-mangostin hybrid nanoparticle for uremic toxins removal

In this study, a highly biocompatible adsorptive membrane is developed for haemodialysis application. Silica/α-mangostin hybrid nanoparticle was incorporated into polysulfone (PSf) based membrane to enhance the biocompatibility and the adsorption capacity of the membrane. The PSf based membranes were fabricated via dry-wet phase inversion technique and characterised based on scanning electron microscopy and contact angle measurement. The effects of silica/α-mangostin nanoparticle incorporation into PSf membrane were evaluated in terms of permeability, p-cresol adsorption capacity, urea, and creatinine removal capabilities, bovine serum albumin rejection and p-cresol dynamic adsorption. The biocompatibility assessment was done based on platelet adhesion, antioxidant properties, and complement activation of the membrane. The incorporation of the nanoparticle into PSf based membrane helped to smoothen the surface of the membrane and enhanced its hydrophilicity of the membrane by 12.54%. The presence of silica/α-mangostin in the membrane enhanced the adsorption capacity of the membrane by 20.92% with adsorption capacity of 55.64 mg/g at 500 mg/L initial concentration. The modified PSf membrane had also successfully improved the biocompatibility of the membrane by enhancing the scavenging activity of hydrogen peroxide and nitrogen oxide by 61.8% and 36%, respectively and inhibited the formation of C5a by 27.27%. The developed biocompatible PSf based adsorptive membrane has a good potential to be used for haemodialysis application.

Facile synthesis and characterization of Zno-HNT additive for enhancement of polysulfone membrane for Oil-In-Water separation

In this study, a novel nanocomposite of Zinc Oxide-Halloysite Nanotubes (ZnO-HNT) has been synthesized and incorporated into polysulfone membrane for the purpose of oily wastewater separation and purification. ZnO-HNT nanocomposite was synthesized as additives that can improve the hydrophilicity as well as the oleophobicity of the membrane. The nanocomposite was incorporated into PSf membrane in three different loading of ZnO and HNT. The novel nanocomposite has been characterized for its morphological characteristics using SEM, TEM and its physicochemical properties were also analyzed by FTIR and XRD. The performance of the modified polysulfone membrane was studied in terms of hydrophilicity, oil rejection and antifouling properties. The FTIR spectra recorded significant –OH peak at 3200 to 3500 cm−1 which contributes to the improve hydrophilicity of the membrane. XRD analysis shown that there are significant peaks at 2θ that attributes to both ZnO and HNT in which the nanocomposite exhibited more intense peak at 56.7° denoting increased amount of hydroxide groups. Additionally, the modified PSf membrane with ZnO-HNT additives has shown improved oil contact angle of 165°, water contact angle of 48.6° and 99% total rejection for oily wastewater indicating the improve performance of PSf through incorporation of ZnO-HNT.

CQDs/Au NPs Modified Polysulfone Membrane with Antibacterial Function and Photocatalytic Activity for Degradation of Methylene Blue

Herein, carbon quantum dots (CQDs) and gold nanoparticles (Au NPs) were synthesized and deposited on the surface of Polysulfone (PSF) membrane using polydopamine as the sublayer, resulting in excellent antibacterial property and photocatalytic activity for degradation of organic dyes. Water contact angle (WCA) of the membrane before and after surface modification dropped from [Formula: see text] to [Formula: see text], due to outstanding hydrophilicity of CQDs. The antibacterial test against [Formula: see text]. [Formula: see text] found that the CQDs/Au NPs were beneficial to improve the antibacterial property of the membrane, and the antibacterial rate could reach 90%, effectively prolonging the service life of the membrane. In addition, the adsorption of bovine serum albumin (BSA) molecules on the membrane was significantly reduced, and the irreversible fouling ratio also decreased from 41.3% to 10.7%. On the other hand, the CQDs/Au NPs layer was used as a photocatalytic material for degradation of methylene blue.

The hemocompatibility of the modified polysulfone membrane with 4-(chloromethyl)benzoic acid and sulfonated hydroxypropyl chitosan

Polysulfone (PSf) membrane is widely employed in blood purification fields, but the blood compatibility of PSf membrane is not adequate. To improve the hemocompatibility of PSf membrane, 4-(chloromethyl)benzoic acid (CMBA) and sulfonated hydroxypropyl chitosan (SHPCS) were grafted onto PSf membrane surface. In our strategy, CMBA was firstly grafted on the PSf membrane surface through the Friedel-Crafts alkylation reaction, and the product was named BAPSf membrane. Then, SHPCS was grafted onto the BAPSf membrane surface by esterification, and the product was named SHPCS-BAPSf membrane. The effects of temperature and reaction time on the productivity of BAPSf and the grafting density of carboxyl and the effects of reaction time on the grafting density of SHPCS grafted onto the BAPSf membrane surface were studied. The SHPCS-BAPSf membranes are investigated by ATR-FTIR, XPS, contact angle measurements and evaluated by blood compatibility in vitro. The results reveal that the hydrophilicity of SHPCS-BAPSf membranes were grealy improved and the evaluation of protein adsorption, hemolysis test, platelet adhesion plasma recalcification time(PRT), activated partial thromboplastin time(APTT), prothrombin time(PT) and thrombin time(TT) confirmed that the SHPCS-BAPSf membranes have remarkable blood compatibility.

Construction of Antifouling Membrane Surfaces through Layer-by-Layer Self-Assembly of Lignosulfonate and Polyethyleneimine.

Lignin is the second most abundant and low-cost natural polymer, but its high value-added utilization is still lack of effective and economic ways. In this paper, waste lignosulfonate (LS) was introduced to fabricate antifouling membrane surfaces via layer-by-layer self-assembly with polyethyleneimine (PEI). The LS/PEI multilayers were successfully deposited on the polysulfone (PSf) membrane, as demonstrated by ATR-FTIR, XPS, Zeta potential measurements, AFM, and SEM. Meanwhile, the effect of the number of bilayers was investigated in detail on the composition, morphologies, hydrophilicity, and antifouling performance of the membrane surface. As a result, with the bilayer numbers increase to 5, the PSf membrane shows smooth surface with small roughness, and its water contact angle reduces to 44.1°, indicating the improved hydrophilicity. Accordingly, the modified PSf membrane with 5 LS/PEI bilayers repels the adsorption of protein, resulting in good antifouling performance. This work provides a green, facile, and low-cost strategy to construct antifouling membrane surfaces.

Alleviating membrane fouling of modified polysulfone membrane via coagulation pretreatment/ultrafiltration hybrid process

In this study, ultrafiltration membrane fouling was alleviated by hydrophilic modification and coagulation pretreatment. A polydopamine (PDA) layer was used as a bridge to introduce the nano titanium dioxide (TiO2) onto the polysulfone (PSf) membranes, forming a hydrophilic modified layer. A relationship model was established between the coagulation efficiencies and floc properties and membrane fouling of the modified PSf membranes during the coagulation/ultrafiltration (C-UF) process. The combination styles of flocculants, poly dimethyldiallylammonium chloride (PDMDAAC) and polyaluminum chloride (PAC) were used in C-UF hybrid process. The characterization results indicated that the hydrophilicity was significantly enhanced in the modified PSf membranes. Scanning electron microscopy (SEM) tests proved that the PDA layer could be tightly bound to TiO2 by coordination bond onto PSf membrane surface. In the acidic conditions, more TiO2 nano-particles were adhered on the PDA particles surface as the pH of (NH4)2TiF6 solution was increased, which resulted in higher hydrophilicity of membranes. In addition, the C-UF tests exhibited that the coagulation efficiency was greatly improved in the PAC/PDMDAAC system, and the PSf membrane modified by PDA/TiO2 in UF tests significantly reduced the membrane fouling, this was partially due to the formation of TiO2 modified coating with higher hydrophilicity.

Fouling characteristics of humic substances on tight polysulfone-based ultrafiltration membrane

Fouling characteristics of humic substances on tight ultrafiltration (UF) membrane have been investigated. The tight UF membrane was prepared by blending polysulfone (PSf) in N.N-dimethylacetamide (DMAc) with 25%wt of Polyethylene glycol (PEG400) and 4%wt of acetone. Fouling characteristic of the modified PSf membrane was observed during peat water filtration in different trans-membrane pressure (TMP). It was found that the acetone modified membrane provided 13% increase in TMP during five hours of peat water filtration, where a stable flux was reached within 150 minutes. Meanwhile, the increase of TMP from 10 psig to 30 psig resulted in a fouling resistance enhancement of 60%. Furthermore, based on the fouling analysis, fouling mechanism at the first phase of filtration was attributed to intermediate blocking while the second phase was cake formation.

The Biocompatibility Comparison of Modified Polysulfone by 2-Methoxyethylacrylate and the Sulfonated Hydroxypropyl Chitosan

In this paper, polysulfone materials were modified with 2-methoxyethylacrylate and the sulfonated hydroxypropyl chitosan in different graft method respectively. After being through chloromethylation and amination reaction of polysulfone, polysulfone-graft-poly (2-methoxyethylacrylate) (PSF-g-PMEA) was synthesized via Michael addition reaction, while the sulfonated hydroxypropyl chitosan (SHPCS) was grafted from polysulfone membrane material by Schiff-Base reaction. Scanning electron microscopy (SEM), water contact angles (WCA) measurement, protein adsorptions, hemolysis assay of the membranes were characterized and tested. The results showed that the water contact angle of modified polysulfone materials decreased to 60.5 °C and 31.8 °C, and the amount of protein adsorption declined at least 83.3%. Furthermore, the hemolysis ratios changed from 2.89% to 1.08%. All of results exhibited that modified polysulfone membrane materials have better biocompatibility than pure polysulfone materials and have potential application in biomedical materials.

The Effect of TiO2 Particles Addition on The Characteristics of Polysulfone Membrane

T he aim of this study was to characterize the modified Polysulfone-TiO 2 membrane via hydrophilic character, the molecular weight cutoff of the membrane and surface morphology of the membrane. Flat sheet modified Polysulfone membrane was prepared by using the phase inversion technique . N-methylene-2-pyrrolidone (NMP) was used as a solvent to dilute Polysulfone pellets. Titanium dioxide (TiO 2 ) and polyvinylpyrrolidone (PVP) were added to enhance the hydrophobic character of the Polysulfone membrane. The hydrophilic characteristic of the modified Polysulfone-TiO 2 membrane was analyzed by contact angle and was compared with conventional Polysulfone membrane. It was found that the addition of TiO 2 in Polysulfone membrane has improved the hydrophilic performance of Polysulfone membrane toward water flux. The membranes also were tested with molecular weight cut off (MWCO) using different weights of polyethylene glycol (PEG) which are 200, 400, 600 and 1000 Da. For membrane with the addition of TiO 2 , a decreased in pore sizeswas determined. The membranes also were analyzed under scanning electron microscope (SEM) in order to determine the morphology of the surface and cross-section. It was found that pore sizes of Polysulfone with TiO 2 membrane has become smaller, which contain more nano in size and formation of finger-like voids compared to the Polysulfone membrane.

Synthesis and biocompatibility of an argatroban-modified polysulfone membrane that directly inhibits thrombosis.

Anticoagulation therapy plays a vital role in the prevention of blood clot formation during hemodialysis and hemofiltration, especially for critical care patients. Here, we synthesized a novel argatroban (Arg)-modified polysulfone (PSf) membrane for anticoagulation. Arg was grafted onto the PSF membrane via chemical modification to increase membrane hydrophilicity. Protein adsorption, coagulation, as well as activation of platelets and complement systems were greatly reduced on the Arg-modified PSf membrane. Thus, the recalcification time and the activated partial thrombin time (APTT) were increased after the modification. In comparison with the pristine PSf membrane, the Arg-modified PSf membrane showed better hemocompatibility and anticoagulation properties, indicating its potential for applications in hemodialysis and hemofiltration. Modification of the PSf membrane has been investigated in attempts to further enhance the anticoagulation properties of the hemodialysis membranes, including a heparin-modified PSf membrane. However, heparin can inhibit plasma-free thrombin, and cause the occurrence of heparin-induced thrombocytopenia (HIT), which increases the risk of bleeding during dialysis in critical care patients. To address this problem, we modified PSf membrane with as a novel direct thrombin inhibitors, argatroban (Arg). It can reversibly bind to thrombin, inhibiting not only the plasma-free thrombin in the blood, but also clot-bound thrombin.