Preparation of sulfonated porous carbon nanotubes/activated carbon composite beads and their adsorption of low density lipoprotein

Mesoporous activated carbon derived from Chinese herbal medicine residues for hemoperfusion removal of uremia toxins from progressive chronic kidney diseases patients

Hemoperfusion is one of the most important therapies for progressive chronic kidney disease (CKD) and is effective at removing toxins from the blood. Increasing the efficiency of adsorbents applied in hemoperfusion is crucial. In the present study, shell of areca nut, one of the most common waste Chinese herb medicine residue with a porous structure was carbonized and activated at different temperatures to obtain two kinds of porous materials. The biocompatibility of the as-prepared porous materials was estimated via a hemolytic test, and the removal efficiency of the materials toward toxins was tested via an adsorption experiment in solution and blood samples from CKD patients, simulated hemoperfusion and in vivo hemoperfusion. After 4 h of adsorption, free and protein-bound toxins in solution were efficiently removed by the prepared porous materials, and the removal efficiency was better than that of commonly used hemoperfutor adsorbents. Most of the tested toxins can be removed from CKD blood samples and simulated hemoperfusion samples. Blood uremic toxins from CKD mice were also efficiently and safely removed after in vivo hemoperfusion using the as-prepared adsorbent. This work highlights promising adsorbents for hemoperfusion that could increase the therapeutic efficacy in patients with progressive CKD.

Photorenewable Azobenzene Polymer Brush-Modified Nanoadsorbent for Selective Adsorption of LDL in Serum

The elevated concentration of low-density lipoprotein (LDL) is recognized as a leading factor of hyperlipidemia (HLP), and selective adsorption of serum LDL is regarded as a practical therapy. Based on the superior structure-function characteristics of stimuli-responsive materials, a photorenewable nanoadsorbent (SiO₂@Azo@Gly) with high selectivity and reusability was developed using azobenzene as the functional ligand. Its principle was certified by the preparation of silicon nanoparticles with atom transfer radical polymerization (ATRP)-initiating groups via a sol-gel reaction and their subsequent grafting of azobenzene polymer brushes by surface-initiated ATRP, followed by modification with glycine. Immobilization of carboxylated azobenzene polymer brushes onto the nanoparticles endowed SiO₂@Azo@Gly with high adsorption selectivity and reusability. The advanced nanoadsorbent exhibited excellent LDL adsorption capacity at about 27 mg/g and could be regenerated by illumination with high efficiency (circulations ≥ 5); this was further verified by transmission electron microscopy (TEM) and Fourier-transform infrared (FTIR) analysis. SiO₂@Azo@Gly also demonstrated superior adsorption efficiency and selectivity in serum from HLP patients, the respective adsorption capacities of LDL, triglyceride, and total cholesterol were about 15.65, 24.48, and 28.36 mg/g, and the adsorption to high-density lipoprotein (cardioprotective effect) was only about 3.66 mg/g. Green regeneration of the nanoadsorbent could be achieved completely through a simple photoregeneration process, and the recovery rate was still 97.9% after five regeneration experiments.

Biomembrane-mimetic hemoperfusion adsorbent for efficient removal of low-density lipoprotein from hyperlipemia blood

Lowering of low-density lipoprotein (LDL) levels in blood of patients with hyperlipidaemia can effectively prevent the progression of atherosclerosis and coronary heart disease. The present study demonstrated a facile synthesis strategy to prepare biomembrane-mimetic LDL adsorbent (PVA@COOH-PE) via directional immobilization of phospholipid onto macro-porous cross-linked poly(vinyl alcohol) spheres. The binding between the prepared adsorbent and LDL particles simulates the cytosolic lipid droplets to form a lipid-packing structure. The adsorbent possesses satisfactory removal efficiency for LDL and total cholesterol (TCH) in hyperlipemia serum, while remains high-density lipoprotein (HDL) concentration within the normal range. The adsorption capacities for LDL and TCH are about 1.13 and 1.74 mg/ml respectively, which are nearly three and four times higher than that of HDL (0.42 mg/ml). The adsorbent also possesses satisfactory anticoagulant properties, causes negligible effect on blood cells and produces low hemolysis ratios. The excellent blood compatibility plus LDL removal efficiency of PVA@COOH-PE indicates its good application prospect as hemoperfusion adsorbent in the treatment of hyperlipidaemia.

Ultraefficiently Calming Cytokine Storm Using Ti3C2T x MXene

During the global outbreak of COVID-19 pandemic, "cytokine storm" conditions are regarded as the fatal step resulting in most mortality. Hemoperfusion is widely used to remove cytokines from the blood of severely ill patients to prevent uncontrolled inflammation induced by a cytokine storm. This article discoveres, for the first time, that 2D Ti3C2T x MXene sheet demonstrates an ultrahigh removal capability for typical cytokine interleukin-6. In particular, MXene shows a 13.4 times higher removal efficiency over traditional activated carbon absorbents. Molecular-level investigations reveal that MXene exhibits a strong chemisorption mechanism for immobilizing cytokine interleukin-6 molecules, which is different from activated carbon absorbents. MXene sheet also demonstrates excellent blood compatibility without any deleterious side influence on the composition of human blood. This work can open a new avenue to use MXene sheets as an ultraefficient hemoperfusion absorbent to eliminate the cytokine storm syndrome in treatment of severe COVID-19 patients.

3D hierarchical porous hybrid nanostructure of carbon nanotubes and N-doped activated carbon

In this work, carbon nanotubes (CNTs)/nitrogen-doped activated carbon (AC) hybrids were designed and fabricated using a facile and one-step synthesis. The synthesis of CNTs is based on the recently discovered phenomenon of thermally-induced polyfurfuryl alcohol (PFA) conversion. Hybrid materials are fabricated through the in-situ free growth of closed carbon nanotubes on low-cost activated carbon substrates which were obtained from green algae or amino acids. Herein, three types of carbon nanotubes were observed to freely grow on an activated carbon background from Chlorella vulgaris or l-lysine, types such as multiwalled carbon and bamboo-like nanotubes, whose structure depends on the background used and conditions of the synthesis. Structure type is identified by analyzing transmission electron microscopy images. HRTEM images reveal the tubes’ outer diameter to be in the range of 20–120 nm. Because the carbon surface for the growth of carbon tubes contains nitrogen, the final hybrid materials also possess pyridinic-N and quaternary-N groups, as indicated by X-ray photoelectron spectra.

Functionalized Carbon Nanotube-Embedded Poly(vinyl alcohol) Microspheres for Efficient Removal of Tumor Necrosis Factor-α

Tumor necrosis factor (TNF)-α has an important role in the pathogenesis of autoimmune and inflammatory diseases such as rheumatoid and septic arthritis. Removal of excess tumor necrosis factor-α (TNF-α) is a promising treatment. In this study, a series of functionalized carbon nanotube-embedded poly(vinyl alcohol) (PVA) nanocomposite adsorbents were prepared for TNF-α removal for the first time. The resulting nanocomposites were characterized by scanning electron microscopy and Raman spectroscopy, which demonstrated that carbon nanotubes were well-dispersed on the surface of PVA macroporous microspheres. Adsorption tests showed that the carboxylated carbon nanotube-embedded composite microspheres (PVA/MWCNTs-COOH) possessed much better adsorption capacity for TNF-α in both simulated serum solution and rat plasma compared to the aminated (PVA/MWCNTs-NH₂) and raw carbon nanotube-embedded microspheres (PVA/MWCNTs-raw). In addition, the effects on hemolytic activity, the anticoagulant property, and the components of blood were negligible, indicating the excellent blood compatibility of composite beads. Our findings suggest that the carboxylated carbon nanotube-embedded composite microspheres may be potentially useful for the treatment of autoimmune and inflammatory diseases by removing TNF-α from the blood.

Chondroitin-analogue decorated magnetic nanoparticles via a click reaction for selective adsorption of low-density lipoprotein

Chondroitin-analogue polymers are synthesized to anchor on Fe₃O₄ nanoparticle surfaces to achieve efficient, selective and reusable adsorption of low-density lipoprotein.

Green Synthesis of Porous Cocoon-like rGO for Enhanced Microwave-Absorbing Performances

A novel porous cocoon-like reduced graphene oxide (rGO) with high porosity and low density was fabricated by a simple and green reduction reaction using ascorbic acid as the reductant in combination with a freeze-drying process without annealing. The bulk density of porous cocoon-like rGO is only 28.49 mg/cm³, and the porosity reaches 94.57%. The reaction times have an important influence on the formation of porous cocoon-like rGO and the reduction degree of rGO. The porous cocoon-like rGO exhibits an excellent microwave-absorbing property with a low mass filling ratio of 7.0 wt %; its minimum reflection loss (RL) is -29.05 dB at 15.96 GHz with a sample thickness of 2.0 mm and the effective absorption bandwidth (RL < -10 dB) is 5.27 GHz. The microwave-absorbing property of porous cocoon-like rGO is much better than that of GO and other porous rGO. The in-depth analyses of the reduction degree, porosity, and microwave-absorbing performance illustrate that the microwave-absorbing performance of rGO is significantly related to the reduction degree and porosity. In addition, the synthetic route for porous cocoon-like rGO is simple, has low energy consumption, and is environmentally friendly. Our work demonstrates that the porous cocoon-like rGO is a promising lightweight microwave absorber with high performance.

Preparation of PVA/amino multi-walled carbon nanotubes nanocomposite microspheres for endotoxin adsorption

A novel polyvinyl alcohol-amino multi-walled carbon nanotube (PVA-AMWCNT) nanocomposite microsphere was prepared successfully for the first time and used for endotoxin removal. The resulting AMWCNT modified PVA microsphere was characterized by SEM, Raman spectrum and fluorescence image, which indicated AMWCNT was dispersed into the macropores of PVA microsphere uniformly. The PVA-AMWCNT microspheres showed better adsorption capability and faster adsorption equilibrium for endotoxin in aqueous solution when compared to the PVA microsphere with polymyxin B (PMB) as ligand. More noteworthy, the PVA based microspheres had little nonspecific adsorption in simulated serum. Therefore, PVA-AMWCNT nanocomposite microsphere with an excellent haemocompatibility has a great potential application in clinical blood purification.

Fe₃O₄@ZnO core-shell nanocomposites for efficient and repetitive removal of low density lipoprotein in plasma and on blood vessel

Low density lipoprotein (LDL)-apheresis therapy, which directly removes LDL from plasma by LDL-adsorbents in vitro is found to be clinically effective and safe to lower the LDL content in blood to prevent cardiovascular disease. Thus, developing excellent LDL adsorbents are becoming more and more attractive. Herein, functional Fe3O4@ZnO core-shell nanocomposites have been synthesized by a facile and eco-friendly two-step method. Not only do they possess high LDL adsorption (in PBS/plasma as well as on blood vessels) and favorable magnetic targeting ability but they can also be reused conveniently, which offer the Fe3O4@ZnO core-shell nanocomposites significant potential in the removal of LDL in vitro and in vivo.

Analysis of medical use of carbon adsorbents in China and additional possibilities in this field achieved in Ukraine

The review is devoted to analysis of the use of carbon sorbents for medicinal purposes in China and description of some innovative technologies in this field in Ukraine. The review underlines the presence of common roots of sorption therapy development in these two countries determined by pioneer works of Prof. T.M.S. Chang, created to the concept of artificial cells. High level of works of Chinese scientists on sorption purification of blood and combined extracorporeal methods has been mentioned. At the same time, by author's opinion, two other methods of sorption therapy, namely enterosorption and sorption therapy of wounds and burns, has not been properly developed in China. In the review, there are also described the essential results of Ukrainian scientists in the field of blood purification from protein-bound toxins and other harmful compounds what is important for treatment of many serious human pathologies, and also the important data on the use of oral sorbents and dressings from activated carbon materials, which could be considered as a useful addition to achievements of Chinese scientists in the field of the development and use of sorbents for medicinal purposes.