Adsorption of Uremic Toxins Using Ti₃C₂T_x MXene for Dialysate Regeneration

Abstract

The COVID-19 pandemic has become a major worldwide crisis. Although respiratory symptoms are a key feature of the disease, many people who are hospitalized with COVID-19 also suffer acute kidney injury, a condition that exacerbates patient mortality and may have to be treated through renal replacement therapy. Much of the focus on hospital capacity during the pandemic has centered on the availability of ventilators. However, supplies for dialysis treatment, including dialysate, have also run dangerously low in hospitals at the epicenter of the pandemic. Therefore, there is an urgent need to develop materials that can efficiently and rapidly regenerate dialysate, removing toxins and restoring electrolyte concentrations so that this vital resource remains readily available. In this work, Ti3C2T x , a two-dimensional transition-metal carbide (MXene) that is known to efficiently adsorb urea, was used to remove creatinine and uric acid from an aqueous solution and dialysate, with a maximum adsorption capacity of 45.7 and 17.0 mg/g, respectively. We systematically analyzed and modeled the adsorption kinetics, isotherms, and thermodynamics, thus determining the rate-limiting step and adsorption mechanism. A fixed-bed column loaded with Ti3C2T x was designed to further evaluate the adsorption performance under continuous fluid-flow conditions, mirroring conditions of continuous renal replacement therapy modalities. The maximum capacity and 50% breakthrough volume were calculated to further approach the practical application of Ti3C2T x for removal of uremic toxins. Our findings suggest that Ti3C2T x has the potential to be used as an efficient sorbent for the regeneration of dialysate, allowing for accelerated dialysate regeneration by removing filtered toxins and leading to more portable dialysis devices.

Insights and Perspectives Regarding Nanostructured Fluorescent Materials toward Tackling COVID-19 and Future Pandemics

“…Therefore, the current work based on MXene to regenerate dialysate becomes very important to combat against COVID-19. 278 In another work, Wang et al anchored Cu 2 O nanospheres on a Ti 3 C 2 T x MXene nanosheet ( Figure 18 E) and tested their antibacterial ability against S. aureus and P. aeruginosa , observing a sharp enhancement in bacteriostasis efficiencies to 97.04% and 95.59%, respectively, in comparison with bare MXene, Cu 2 O and a mixture of MXene, and Cu 2 O ( Figure 18 F). PL investigations suggest that the recombination of electron–hole pairs of Cu 2 O is greatly prevented on introducing MXene.…”

Recent trends in therapeutic application of engineered blood purification materials for kidney disease

“…MXenes are a family of two-dimensional carbides and nitrides of transition metals with the general structure M n+1 X n T x (M is early transition metal, such as Ti, V, Nb, etc. ; n+1=1-3; X is C and/or N; T x represents the surface terminations, such as O, OH, F, and/or Cl) [ 58 , 59 ]. MXenes have a unique combination of properties, including hydrophilic due to functionalized surfaces and stable colloidal solutions in water owing to high negative zeta-potential, and have been extensively researched in the biomedical field in recent years [ 58 ].…”

“…And Ti 3 C 2 T x has been strongly demonstrated to have relatively high biocompatibility and low biotoxicity in previous in vivo studies [ 60 ]. In the work of Zhao et al, Ti 3 C 2 T x (Ti 3 C 2 -F, Ti 3 C 2 -O, Ti 3 C 2 -OH, fabricated from precursor Ti 3 AlC 2 using 10 wt % hydrofluoric acid) was used as adsorbents in aqueous solution, and it performed the rapid adsorption rate and higher adsorption capacity towards creatinine and uric acid compared with conventional activated carbon [ 59 ]. The high affinity between Ti 3 C 2 T x and creatinine in adsorption process is ascribed to hydrophilic surface terminations of Ti 3 C 2 T x and intraparticle diffusion of creatinine between Ti 3 C 2 T x layer.…”

Dialysate Regeneration with Urea Selective Membrane Coupled to Photoelectrochemical Oxidation System

“…A number of adsorbent materials have shown >10 mg g −1 urea binding capacity in simple saline solutions but diminished to <0.5 mg g −1 when exposed to serum samples with a diverse set of interfering chemistries. [17,18] Oxidation based urea removal has been shown to be efficient and led to the production of gaseous products of N 2 and CO 2 . [19,20] We have previously developed a photo-oxidation urea removal (POUR) device to remove urea.…”