Novel uremic metabolite-based zwitterionic polyethersulfone (PES) hemodialysis membrane for improved hemocompatibility: Towards the fourth generation of hemodialysis modifiers

Abstract

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.