Material, process, and computational developments for polymeric membrane-assisted decarbonization.

Hemodialysis (HD) is a filtration vital process through which the bloods’ toxins and contaminations are removed. However, several immune system activations occur during dialysis, which can result in morbidity and mortality. The efficiency of the currently available blood purification process is hindered, on one hand, by the deficient toxins and middle molecule removal, and on the other hand, with the loss of valuable blood components (such as plasma and its constituents). This chapter offers an overview of the challenges and advances in HD membranes. It includes an introduction of the end stage renal disease, concepts of dialysis, its historical background, and the path through which the configurations and materials evolved. The interactions between membrane polymeric materials with human blood is also discussed. The aspect of material modification is one of the critical areas in HD technology as it targets to solve the most immediate and prevalent HD issue of membrane bioincompatibility. High flux dialysis (HFD) and hemofiltration (HF) are introduced and discussed. This class of membranes was introduced to solve middle molecule (such as β2- microglobulin) related challenges. This chapter highlights the question of why the issue of incompatible materials still exists along with current membrane modifications.

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.

Fibrinogen (FB) can trigger several biological reactions and is one of the critical proteins targeted during hemodialysis (HD). A better understanding of the thermal behavior of FB and its interactions with polymeric membranes during the HD process is needed in both normal and fever temperature conditions. This study calculated the thermal behavior of FB along with its interaction energy with polyarylethersulfone (PAES) clinical HD membranes using molecular dynamics (MD) approaches. The Dreiding force field was used for the MD simulations. The influence of temperature on the thermal conductivity (TC) and the interaction energy of the FB structure was assessed to understand the activation trends in fever conditions. Based on the MD simulation, the TC of FB at normal body temperature was 0.044 and 0.084 W/m·K according to equilibrium and non-equilibrium approaches, respectively. The elevation of temperature from normal to fever conditions increased the thermal conduction of FB to 0.577 and 0.114 W/m·K for equilibrium and non-equilibrium approaches, respectively. In addition, the elevation of patient blood temperature resulted in nearly 32 kcal/mol higher total interaction energy between FB and the PAES model. When end-stage renal disease (ESRD) patients have a HD session and experience fever and elevated temperature as a side effect, the interaction between FB and the membrane increases. More importantly, FB is exposed to more heat passage and accordingly more temperature-induced confirmation and activation compared to other human serum proteins such as albumin.