Sorbent-based dialysate regeneration for the wearable artificial kidney: Advancing material innovation via experimental and computational studies

Hemodialysis is the primary renal replacement therapy for patients affected by end-stage renal disease, but it has a severe impact on the patient's lifestyle and wellbeing, and is extremely water intensive. A wearable dialysis device could solve most of the issues associated with the treatment, but the main obstacle to its realisation is an efficient and reliable system for dialysate regeneration, i.e. the purification of spent dialysate from uremic toxins. Several techniques have been proposed to this aim, such as enzymatic conversion, forward osmosis and electrochemical oxidation. One of the most promising and safe technologies is adsorption, in which toxins are captured onto nanoporous materials, polymers or their combinations (mixed matrix membranes). In this review, we first give a general overview of the hemodialysis processes and of the challenges associated to making it wearable. Subsequently, we use experimental data from the literature to rank different materials based on their ability to remove the typical uremic toxins present in dialysate, including considerations on their recyclability, stability and safety. Finally, we critically analyse different computational modelling techniques available to design and/or optimise adsorbent materials for dialysate regeneration, and their accuracy in predicting the materials performance and screen large databases of adsorbents.