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Dialysis membranes are not hemocompatible with human blood, as the patients are suffering from the blood–membrane interactions' side effects. Zwitterionic structures have shown improved hemocompatibility; however, their complicated synthesis hinders their commercialization. The goal of the study is to achieve fast functionalization for carboxybetaine and sulfobetaine zwitterionic immobilization on PES membranes while comparing the stability and the targeted hemocompatibility. The chemical modification approach is based on an aminolysis reaction. Characterization, computational simulations, and clinical analysis were conducted to study the modified membranes. Atomic force microscopy (AFM) patterns showed a lower mean roughness for carboxybetaine-modified (6.3 nm) and sulfobetaine-modified (7.7 nm) membranes compared to the neat membrane (52.61 nm). The pore size of the membranes was reduced from values above 50 nm for the neat PES to values between 2 and 50 nm for zwitterionized membranes, using Brunauer–Emmett–Teller (BET) analysis. More hydrophilic surfaces led to a growth equilibrium water content (EWC) of nearly 6% for carboxybetaine and 10% for sulfobetaine-modified membranes. Differential scanning calorimetry (DSC) measurements were 12% and 16% stable water for carboxybetaine- and sulfobetaine-modified membranes, respectively. Sulfobetaine membranes showed better compatibility with blood with respect to C5a, IL-1a, and IL-6 biomarkers. Aminolysis-based zwitterionization was found to be suitable for the improvement of hemodialysis membranes. The approach introduced in this paper could be used to modify the current dialysis membranes with minimal change in the production facilities. [ABSTRACT FROM AUTHOR]

ESRD patients suffer from side effects of the dialysis process. Comprehension of different operational parameters' effect on the hemocompatibility profiles of the separative membranes, i.e. dialyzers, could result in designing more compatible materials. This study includes a computational approach to assess the effect of pH by assessing different uremic metabolites' behavior. The pH effect was assessed by comparing the water interaction ability of different uremic metabolites (which appear at different bloodstream pH levels) using molecular dynamics (MD) simulations. Based on the findings of the studies, a new class of zwitterionic materials is introduced. The proposed modification, containing guanidine (GNDM) was experimentally implemented on poly ether sulfone (PES) membranes. Aminolysis and sultone-ring opening reactions were used to immobilize the zwitterionic structure. Attuned total reflectance-Furrier transmission infrared spectroscopy (ATR-FTIR) was used to characterize the functional groups of the modified membrane. Gravimetry was used to measure the amount of modification layer added to the membrane as well as the equilibrium water content (EWC). Atomic force microscopy (AFM) was used to measure the roughness patterns of the neat and modified membranes. Zeta potential analyzer was used to check the trend of surface charge variations. Differential scanning calorimetry (DSC) was used to assess the stable water content of the membranes. A filtration test was performed to check the stability of the immobilized materials on the membranes. The newly modified PES membranes were nearly 50 % smoother and negatively charged. DSC reflects a 16 % higher content of stable water for the modified membranes. Computational assessments also reflected that the modified structure created more hydrogen bonds and could keep the water molecules more stable on the surface of the membrane. As the new membrane owned a higher capability to keep the water more stable on its surface, it could be a perfect candidate for a hemocompatible dialysis membrane. [Display omitted] • A uremic metabolite-attached zwitterionic dialysis membrane was fabricated. • The stability of the hydration layer on the modified membranes was measured. • Standard membrane characterizations were performed to confirm the structure. • The behavior of the water molecules on the modified membrane was assessed computationally. • The durability of the modification layer was assessed using filtration and ATR-FTIR-assisted functional group tracking. [ABSTRACT FROM AUTHOR]

• PAES hemodialysis membrane was selected for blood-membrane interaction study. • Blood- membrane interactions were investigated using spectroscopy analyses. • PAES morphological variation and blood attachments clots were investigated. • Binding energy between human serum proteins and PAES was studied using MDS. Patients with end-stage renal diseases (ESRD) require specific health cares as the accumulation of toxins due to the lack of kidney functionality would affect their lives. However, the mortality rate is still high due to cardiovascular diseases, socks, etc. A majority of patients with chronic kidney disease (CKD) require hemodialysis services. Blood purifying membranes, as the main component of hemodialysis setups, however, still suffer from lack of optimum biocompatibility, which results in morbidity and mortality of hemodialysis service receiving patients. The goal of the present case study is to have an in-depth understanding of the current blood-hemodialysis membrane interactions occurring during hemodialysis sessions using poly (aryl ether sulfone)-poly (vinyl pyrrolidone) (PAES-PVP) membrane. Attenuated total reflectance-Fourier transmission infrared (ATR-FTIR) spectroscopy, Raman spectroscopy, and solid-state nuclear magnetic resonance (SSNMR) spectroscopy were used to assess the initial chemical structure of the PAES-PVP membrane along with the variations after with the infections with human blood. Furthermore, scanning electron microscopy (SEM) and Transition electron microscopy (TEM) were used to visualize the structural variation of the membrane, blood aggregations, and blood clots on the membrane surface. Besides, Molecular dynamics (MD) simulation was used to assess the interaction of PAES-PVP with major human blood proteins, in terms of interaction energy, which is a novel contribution to the area. The macromolecules (human serum albumin (HSA), human serum transferrin (TRF), and human fibrinogen (HFG)) were chosen from the plasma protein component. These protein structures were chosen based on their different molecular size. Three advanced spectroscopy techniques and two advanced visualization techniques were used for the assessment of the membranes. Spectroscopy studies revealed amine related peak displacement and intensity shifts as indices for attachment of biological species to the polymeric membrane surfaces. Raman peaks around 370, 798, and 1299 cm−1, which experienced significant shifts that were related to carbon-nitrogen and sulfur-oxygen bonds due to protein adhesion. Visualization techniques illustrated blood protein fouling patterns and extracellular vesicles' presence in the pore structures into membranes. The findings highlight the importance of whole structure biocompatibility improvement, rather than only focusing on surface modifications of hemodialysis membranes. Molecular dynamics simulation assessment showed various interaction behaviors for different proteins suggesting molecular weight and active residues of the protein macromolecules play an important role in interacting with polymeric structure. FB had the highest interaction (4,274,749.07 kcal/mol) and binding (10,370.90 kcal/mol) energy with the PAES-PVP structure. TRF owned the lowest interaction energy with respect to its lower molecular weight and fewer active residue count. Image, graphical abstract Computational and experimental assessment of poly aryl ether sulfone structure for hemodialysis application. [ABSTRACT FROM AUTHOR]

Abstract: In this research, the surface of poly (vinylidene fluoride) (PVDF)/sulfonated polyethersulfone (SPES) blend membrane prepared via immersion precipitation was modified by depositing of TiO2 nano-particles followed by UV irradiation to activate their photocatalytic property. The membranes were characterized by FTIR, SEM, AFM, contact angle, dead end filtration (pure water flux and BSA solution flux), antifouling analysis and antibacterial activity. The FTIR spectrum confirmed the presence of OH functional groups on the PVDF/SPES membrane structure, which was the key factor for deposition, and self-assembly of TiO2 nanoparticles on the membrane surface. The SEM and AFM images indicated that the TiO2 nanoparticles were deposited on the PVDF/SPES membrane. The contact angle measurements showed that the hydrophilicity of PVDF/SPES membrane was strongly improved by TiO2 deposition and UV irradiation. The filtration results indicated that the initial flux of TiO2 deposited PVDF/SPES membranes was lower than the initial flux of neat PVDF/SPES membrane. However, the former membranes showed lower flux decline compared to the neat PVDF/SPES membrane. The BSA rejection of modified membranes was improved. The fouling analysis demonstrated that the TiO2 deposited PVDF/SPES membranes showed the fewer tendencies to fouling. The results of antibacterial study showed that the UV irradiated TiO2 deposited PVDF/SPES membranes possess high antibacterial property. [Copyright &y& Elsevier]

Amine functionalized Multi-walled carbon nanotubes (F-MWCNTs)/polyethersulfone (PES) membranes were prepared using phase inversion induced by immersion precipitation. Crude MWCNTs were chemically treated using strong acids (H2SO4/HNO3) and 1,3-phenylenediamine (mPDA) to produce the functional amine groups (NH2) on their surfaces. F-MWCNTs with different concentration were blended in the casting solution containing PES, polyvinylpyrrolidone (PVP) and dimethylacetamide (DMAC). Pure water was used as non-solvent. The FTIR spectra indicated that the amine functional groups were produced on the surface of MWCNTs. The membranes prepared with different concentrations of F-MWCNTs were characterized using contact angle, field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM), atomic force microscopy (AFM) and permeation tests. The surface hydrophilicity of membranes was significantly improved by addition of F-MWCNTs in the casting solution. An increment in the porosity, pore size and surface roughness of the membranes was observed by increasing F-MWCNTs content up to 1 wt.%. Further addition of F-MWCNTs caused a reduction in porosity and roughness of formed membrane. The membranes prepared with 0.5 and 1 wt.% of F-MWCNTs showed higher performance than neat membrane. Addition of F-MWCNTs in the casting solution improved the BSA rejection and antifouling properties of PES membrane. [ABSTRACT FROM AUTHOR]