(675g) A New Generation of Materials for Sustainable and Wearable Hemodialysis: Tests and Molecular Screening.

Hemodialysis (HD) is a life-supporting treatment for 2 million patients with chronic kidney failure, affecting 697.5 million people worldwide. HD replaces kidney functionality, based on the exchange of uremic toxins (UT) present in blood through a semipermeable membrane with a buffered solution, called dialysate. The treatment is time-consuming and discontinuous causing health issues and a low quality of life. Furthermore, the water consumption is assessed around 400 L per session. The last 40 years have witnessed many attempts to design a wearable artificial kidney (WAK), which is a miniaturized HD unit where the dialysate is purified and recirculated back to the dialysis unit. Such a device, not yet on the market, would boost sustainability, accessibility, delivery of hemodialysis with huge improvement of the patients’ lifestyle.

Previous attempts to build a wearable kidney involved a chemical conversion of urea, that is the most difficult toxin to remove from dialysate. However, such process releases by-products that can be harmful for the patient, while a technology involving only urea capture with adsorbent materials is intrinsically safe. Previous works have shown that adsorbents like activated carbon and zeolites could be efficiently embedded into porous polymeric supports made of cellulose acetate with optimal fluid dynamics and low energy consumption, building the so-called Mixed Matrix Membrane Adsorbers (MMMAs) [1-3]. However, the systems fabricated so far only employed conventional adsorbers like activated carbon and zeolites, with limited urea removal capacity.

In this work we propose to accelerate the deployment of adsorbent materials for uremic toxins removal with an in silico screening on existing and new crystal adsorbent structures. Such a methodology will allow to score promising materials for hemodialysis applications and contaminant removal, reducing the experimental efforts required and simultaneously providing better understanding of UTs adsorption on nanoporous materials.

The pipeline developed and presented mines crystal structures from databases applying constrains on selection of crystals according to rules of acceptability. Subsequently, a set of general or local descriptors of topological and physiochemical features is calculated, while binding capacity and strength toward UTs, together with selectivity, are investigated by means of molecular mechanics simulations. This protocol allows to score and rank the structures according to their suitability as adsorbers toward UTs. Furthermore, a quantitative structure-property relationship is devised for describing UTs adsorption by Covalent Organic Frameworks COFs, for the first time.

The in-house developed pipeline is versatile enough to describe other compounds and totally based on open-source tools and resources, such as RASPA as environment for molecular simulations. The optimal adsorbents selected in the screening will be embedded into porous polymeric supports to develop MMMAs for wearable hemodialysis.

[1] De Pascale, M. G. De Angelis and C. Boi, Membranes, 12(2), 203 (2022) https://www.mdpi.com/2077-0375/12/2/203

[2] De Pascale, M. G. De Angelis and C. Boi, Chemical Engineering Transactions, 74, 781–786, (2019)

[3] De Pascale, "Novel membranes for hemodialysis application," PhD Thesis, University of Bologna, 202