A critical review of recent advances in hemodialysis membranes hemocompatibility and guidelines for future development

Hemodialysis is a life-sustaining procedure for patients with end-stage renal disease (ESRD). The efficiency of hemodialysis is limited by the dialysis membrane biocompatibility and the poor clearance of middle-molecule uremic toxins. As a result, hemodialysis is associated with acute chronic side-effects that threaten patients' lives. During hemodialysis, interfacial interactions of blood-polymeric membranes result in several consequences. These interactions lead to the body's various system activations, including the coagulation of blood components, leukocytes (i.e., immune system activation) and complement activations, thrombogenesis, cytokine production, and appearance of radicals with free oxygen. Despite advances in research, the most vital issue in dialysis therapies is the biocompatibility and hemoincompatibility of the membranes. The process of enhancing membrane hemocompatibility is currently posing a global challenge. Reactions to incompatibility can cause severe injuries to the patients and result in morbidity and mortality. This critical review offers a focused analysis of the latest efforts to enhance the hemodialysis membrane's hemocompatibility as well as emphasize current research gaps. Recent innovations (since 2014) in hemodialysis membranes are analyzed in correlation to categories of modified polymer structure chemistry tuning, and surface modifications and their influences on membrane hemocompatibility. Particular attention is paid to: (1) chemical immobilization of functional groups (surface grafting); (2) layer-by-layer chemical attachment of species (LBL); (3) covalent attachment of super hydrophilic-hydrogel; (4) mixed matrix membranes (MMM); and (5) base polymer membrane modification (blending method). This critical review provides an overview of the effects the modification methods can have on biocompatibility and how they can pave the way for optimum enhancement of hemodialysis membrane biocompatibility.