Safety of electrooxidation for urea removal in a wearable artificial kidney is compromised by formation of glucose degradation products

Abstract

A major challenge for the development of a wearable artificial kidney (WAK) is the removal of urea from the spent dialysate, as urea is the waste solute with the highest daily molar production and is difficult to adsorb. Here we present results on glucose degradation products (GDPs) formed during electrooxidation (EO), a technique that applies a current to the dialysate to convert urea into nitrogen, carbon dioxide, and hydrogen gas. Uremic plasma and peritoneal effluent were dialyzed for 8 hours with a WAK with and without EO‐based dialysate regeneration. Samples were taken regularly during treatment. GDPs (glyoxal, methylglyoxal, and 3‐deoxyglucosone) were measured in EO‐ and non‐EO‐treated fluids. Glyoxal and methylglyoxal concentrations increased 26‐ and 11‐fold, respectively, in uremic plasma (at [glucose] 7 mmol/L) and 209‐ and 353‐fold, respectively, in peritoneal effluent (at [glucose] 100 mmol/L) during treatment with EO, whereas no change was observed in GDP concentrations during dialysate regeneration without EO. EO for dialysate regeneration in a WAK is currently not safe due to the generation of GDPs which are not biocompatible.

Urea catalytic oxidation for energy and environmental applications

“…320 Electrooxidation is an attractive method for removing urea from dialysates, and its equipment is lightweight, durable, and reusable. 318,321 As discussed in Section 5, urea can be oxidized indirectly by oxidizing chlorine species, accompanied by toxic by-products chlorine, chloramine, and metal leaching from the electrode. 322 Thus, an efficient method to reduce chlorine by-products was explored by Wester et al They selected Pt, Ru, and graphite electrodes to compare urea removal, toxic chlorine release, and metal ion leaching.…”

Wearables in Nephrology: Fanciful Gadgetry or Prêt-à-Porter?

“…The altered effluent then undergoes refreshing through the addition of bicarbonate and other electrolytes, plus glucose in the case of PD, before a series of further safety checks and returns to the body [ 50 ]. Urea removal via electrooxidation has also been explored; however, is currently not suitable due to safety concerns [ 52 ].…”

Dialysate regeneration via urea photodecomposition with TiO2 nanowires at therapeutic rates

“…As a result, there is significant oxo-chlorine formation and a number of reaction byproducts are formed. 22,27 Needed is an oxidation system that is selective to urea over chloride.…”

“…However, dialysate is a complex mixture of electrolytes and sucrose to match blood plasma levels. As a result, there is significant oxo‐chlorine formation and a number of reaction by‐products are formed 22,27 . Needed is an oxidation system that is selective to urea over chloride.…”