Novel Sorbent Platform for Selective Urea Capture in Portable Dialysis

Background: Minimizing dialysate consumption while maintaining hemodialysis efficacy is imperative for portable, remote therapy. Dialysate regeneration is a promising pathway to solving this, yet conventional approaches remain constrained in their ability to safely and efficiently remove urea. Enzymatic removal suffers from challenges with byproduct generation, leaching, fouling and reusability; electro- and photo-chemical removal lacks selectivity and struggles with off-target degradation and byproduct generation. To overcome these limitations, we have developed an approach to safe and effective urea removal in dialysate regeneration through mechanically-assisted, ultra-efficient chemical sorption. Methods: OLI sorbent was exposed to a urea-containing dialysate solution (300mg/dL initial urea concentration) in 15-minute sorption intervals (sorption uptime), each followed by a reconditioning process that recovered their binding capacity. Urea concentration was measured every 30 minutes of sorption uptime for 2 hours of total uptime. Comparative evaluation was performed using SBA-15, MXene, and oxidized starch, selected based on reported urea binding properties in literature. These comparative test articles leveraged no reconditioning process and were analyzed at the same time points. Urea concentrations were quantified via a colorimetric BUN assay using a SpectraMAX 190 plate reader at 450 nm. Calibration was performed using a serial dilution of urea standards provided with the assay kit. Controls included urea-free dialysate and the initial urea solution. Results: Under the specified conditions (2h sorption uptime, 250mL dialysate volume, 300mL/min flow, 300mg/dL initial urea, 2g sorbent), the OLI sorbent achieved urea removal rate that was up to 70-times greater than that of competing sorbent technologies. Conclusion: The OLI sorbent shows a superior urea-binding capacity compared to SBA-15, MXene, and oxidized starch under clinically relevant flow and concentration conditions. This effecient, regenerable synthetic system addresses the principal barrier to compact dialysate reclamation by enabling selective, biocompatible urea removal without large-scale water-treatment infrastructure. These findings support development of OLI-based platforms for portable and home hemodialysis devices, with the potential to improve treatment frequency, patient convenience, and healthcare cost. Funding: Commercial Support - OLI Technologies