The wearable artificial kidney can deliver continuous ambulatory dialysis for more than 3 million patients with end-stage renal disease. However, the efficient removal of urea is a key challenge in miniaturizing the device and making it light and small enough for practical use. Here, we show that two-dimensional titanium carbide (MXene) with the composition of Ti 3 C 2 T x , where T x represents surface termination groups such as −OH, −O−, and −F, can adsorb urea, reaching 99% removal efficiency from aqueous solution and 94% from dialysate at the initial urea concentration of 30 mg/dL, with the maximum urea adsorption capacity of 10.4 mg/g at room temperature. When tested at 37 °C, we achieved a 2-fold increase in urea removal efficiency from dialysate, with the maximum urea adsorption capacity of 21.7 mg/g. Ti 3 C 2 T x showed good hemocompatibility; it did not induce cell apoptosis or reduce the metabolizing cell fraction, indicating no impact on cell viability at concentrations of up to 200 μg/mL. The biocompatibility of Ti 3 C 2 T x and its selectivity for urea adsorption from dialysate open a new opportunity in designing a miniaturized dialysate regeneration system for a wearable artificial kidney.

No abstract

A new water-soluble polysaccharide (longan polysaccharide 1 (LP1)) was extracted and successfully purified from Dimocarpus longan pulp via diethylaminoethyl (DEAE)-cellulose anion-exchange and Sephacryl S-300 HR gel chromatography. The chemical structure was determined using Infrared (IR), gas chromatography (GC) and nuclear magnetic resonance (NMR) analysis. The results indicated that the molecular weight of the sample was 1.1 × 105 Da. Monosaccharide composition analysis revealed that LP1 was composed of Glc, GalA, Ara and Gal in a molar ratio of 5.39:1.04:0.74:0.21. Structural analysis indicated that LP1 consisted of a backbone of →4)-α-d-Glcp-(1→4)-α-d-GalpA-(1→4)-α-d-Glcp-(1→4)-β-d-Glcp-(1→ units with poly saccharide side chains composed of →2)-β-d-Fruf-(1→2)-l-sorbose-(1→ attached to the O-6 position of the α-d-Glcp residues. In vitro experiments indicated that LP1 had significantly high antitumor activity against SKOV3 and HO8910 tumor cells, with inhibition percentages of 40% and 50%, respectively. In addition, LP1 significantly stimulated the production of the cytokine interferon-γ (IFN-γ), increased the activity of murine macrophages and enhanced B- and T-lymphocyte proliferation. The results of this study demonstrate that LP1 has potential applications as a natural antitumor agent with immunomodulatory activity.

There is a range of medical conditions, which include acute organ failure, bacterial and viral infection, and sepsis, that result in overactivation of the inflammatory response of the organism and release of proinflammatory cytokines into the bloodstream. Fast removal of these cytokines from blood circulation could offer a potentially efficient treatment of such conditions. This study aims at the development and assessment of novel biocompatible graphene-based adsorbents for blood purification from proinflammatory cytokines. These graphene-based materials were chosen on the basis of their surface accessibility for small molecules further facilitated by the interlayer porosity, which is comparable to the size of the cytokine molecules to be adsorbed. Our preliminary results show that graphene nanoplatelets (GnP) exhibit high adsorption capacity, but they cannot be used in direct contact with blood due to the risk of small carbon particle release into the bloodstream. Granulation of GnP using poly(tetrafluoroethylene) as a binder eliminated an undesirable nanoparticle release without affecting the GnP surface accessibility for the cytokine molecules. The efficiency of proinflammatory cytokine removal was shown using a specially designed flow-through system. So far, GnP proved to be among the fastest acting and most efficient sorbents for cytokine removal identified to date, outperforming porous activated carbons and porous polymers.