Optimization of the Urea Removal in a Wearable Dialysis Device Using Nitrogen-Doped and Phosphorus-Doped Graphene

Abstract

Dialysis has been recognized as an essential treatment for end-stage renal disease (ESRD). This therapy, however, suffers from several limitations leading to numerous complications in the patients. As dialysis cannot completely substitute healthy kidney functions, the health condition of an ESRD patient is ultimately affected. Wearable artificial kidney (WAK) can resolve the restrictions of blood purification by the dialysis method. However, absorbing large amounts of urea produced in the body is one of the main challenges of these WAK and overcoming this is necessary to improve both functionality and footprint of the device. This study investigates the adsorption capabilities of N- and P-doped graphene nanosorbents for the first time by using molecular dynamic simulation. Urea removal on carbon nanosheets was simulated with different percentages of phosphorus and nitrogen dopants along with the pristine graphene. Specifically, the effects of interaction energy, adsorption percentage, gyration radius, hydrogen bonding, and other molecular dynamic analyses on urea removal were also investigated. The results from this study match well with the existing research, demonstrating the accuracy of the model. The results further suggest that graphene nanosheets doped by 10% nitrogen are likely the most effective in removing urea given that it is associated with the maximum radial distribution function (RDF), the maximum reduction in gyration radius, a high number of hydrogen bonds, and the most negative adsorption energy. This molecular study offers attractive suggestions for the novel adsorbents of artificial kidney devices and paves the way for the development of novel and enhanced urea adsorbents.

A Perfluorocarbon-Coated ZrP Cation Exchanger with Excellent Ammonium Selectivity and Chemical Stability: An Oral Sorbent for End-Stage Kidney Disease (ESKD)

“…Oral sorbents have been clinically prescribed in CKD to mitigate the accumulation of toxic uremic retention solutes between dialysis treatments. The CKD-related uremic retention solutes capable of being clinically controlled are phosphate, − potassium, , cholesterol, and hydrogen ions. , However, no oral sorbents have been developed for removing accumulated Na + or urea from ESKD patients in between dialysis treatments. ,,− A coated ZrP sorbent with a high capacity for NH 4 + could be used to alleviate patients before starting dialysis as their diets are modified to avoid protein consumption that causes urea accumulation . The coated ZrP sorbent would be given in combination with other cation exchangers to remove Na + and K + and the anion exchanger zirconium oxide to control pH, phosphate, and other negatively charged toxic uremic solutes like oxalate.…”

“… 18 , 19 However, no oral sorbents have been developed for removing accumulated Na + or urea from ESKD patients in between dialysis treatments. 9 , 10 , 20 − 22 A coated ZrP sorbent with a high capacity for NH 4 + could be used to alleviate patients before starting dialysis as their diets are modified to avoid protein consumption that causes urea accumulation. 23 The coated ZrP sorbent would be given in combination with other cation exchangers to remove Na + and K + and the anion exchanger zirconium oxide to control pH, phosphate, and other negatively charged toxic uremic solutes like oxalate.…”

High-Throughput Preparation of Uncontaminated Graphene-Oxide Aqueous Dispersions with Antioxidant Properties by Semi-Automated Diffusion Dialysis

“…Robust membranes based on GO or rGO can be prepared for desalination, separation of gaseous mixtures, and water purification [ 5 ]. In biomedical applications, GO, especially aqueous GO dispersions (aqGO) can be used as a tunable material for wearable artificial kidneys [ 6 , 7 ] or thin-film nanofiltration purification systems [ 8 ]. GO and rGO have a potential in diagnosis and treatment of cancer [ 9 , 10 , 11 ], drug delivery [ 12 ], in tissue regeneration and immunomodulation [ 13 , 14 ].…”