Fabrication of a novel nitrogen-containing porous carbon adsorbent for protein-bound uremic toxins removal

Recent advances in cellulose-based sustainable materials for wastewater treatment: An overview

Water pollution presents a significant challenge, impacting ecosystems and human health. The necessity for solutions to address water pollution arises from the critical need to preserve and protect the quality of water resources. Effective solutions are crucial to safeguarding ecosystems, human health, and ensuring sustainable access to clean water for current and future generations. Generally, cellulose and its derivatives are considered potential substrates for wastewater treatment. The various cellulose processing methods including acid, alkali, organic & inorganic components treatment, chemical treatment and spinning methods are highlighted. Additionally, we reviewed effective use of the cellulose derivatives (CD), including cellulose nanocrystals (CNCs), cellulose nano-fibrils (CNFs), CNPs, and bacterial nano-cellulose (BNC) on waste water (WW) treatment. The various cellulose processing methods, including spinning, mechanical, chemical, and biological approaches are also highlighted. Additionally, cellulose-based materials, including adsorbents, membranes and hydrogels are critically discussed. The review also highlighted the mechanism of adsorption, kinetics, thermodynamics, and sorption isotherm studies of adsorbents. The review concluded that the cellulose-derived materials are effective substrates for removing heavy metals, dyes, pathogenic microorganisms, and other pollutants from WW. Similarly, cellulose based materials are used for flocculants and water filtration membranes. Cellulose composites are widely used in the separation of oil and water emulsions as well as in removing dyes from wastewater. Cellulose's natural hydrophilicity makes it easier for it to interact with water molecules, making it appropriate for use in water treatment processes. Furthermore, the materials derived from cellulose have wider application in WW treatment due to their inexhaustible sources, low energy consumption, cost-effectiveness, sustainability, and renewable nature.

Biobased chitosan-derived self-nitrogen-doped porous carbon nanofibers containing nitrogen-doped zeolites for efficient removal of uremic toxins during hemodialysis

Highly efficient adsorbents are needed to remove uremic toxins and reduce the economic and societal burden of the current dialysis treatments in resource-limited environments. In this study, nanostructured porous carbon nanofibers with nitrogen-doped zeolites (NZ-PCNF) were prepared, by electrospinning zeolites with chitosan-poly(ethylene oxide) blends, followed by a one-step carbonization process, without further activation steps or aggressive chemical additives for N-doping. The results showed that N-zeolites were successfully integrated into an ultrafine carbon nanofiber network, with a uniform nanofiber diameter of approximately 25 nm, hierarchical porous structure (micro- and mesopores), and high specific surface area (639.29 m2/g), facilitating uremic toxin diffusion and adsorption. The self-N-doped structure in the NZ-PCNF removed more creatinine (∼1.8 times) than the porous carbon nanofibers when using the same weight of precursor materials. Cytotoxicity and hemolysis tests were performed to verify the safety of NZ-PCNF. This study provides a novel strategy for transforming chitosan-based materials into state-of-the-art porous carbon nanofiber/zeolite self-N-doped composites, affording an efficient bioderived adsorbent for the removal of uremic toxins in patients with chronic kidney disease.

Derivation and elimination of uremic toxins from kidney-gut axis

Uremic toxins are chemicals, organic or inorganic, that accumulate in the body fluids of individuals with acute or chronic kidney disease and impaired renal function. More than 130 uremic solutions are included in the most comprehensive reviews to date by the European Uremic Toxins Work Group, and novel investigations are ongoing to increase this number. Although approaches to remove uremic toxins have emerged, recalcitrant toxins that injure the human body remain a difficult problem. Herein, we review the derivation and elimination of uremic toxins, outline kidney-gut axis function and relative toxin removal methods, and elucidate promising approaches to effectively remove toxins.

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

Blood purification is a commonly used method to remove excess metabolic waste in the blood in renal replacement therapy. The sufficient removal of these toxins from blood can reduce complications and improve survival lifetime in dialysis patients. However, the current biological blood purification materials in clinical practice are not ideal, where there is an unmet need for producing novel materials that have better biocompatibility, reduced toxicity, and, in particular, more efficient toxin clearance rates and a lower cost of production. Given this, this review has carefully summarized newly developed engineered different structural biomedical materials for blood purification in terms of types and structure characteristics of blood purification materials, the production process, as well as interfacial chemical adsorption properties or mechanisms. This study may provide a valuable reference for fabricating a user-friendly purification device that is more suitable for clinical blood purification applications in dialysis patients.

Multi-Functional Hypercrosslinked Polystyrene as High-Performance Adsorbents for Artificial Liver Blood Purification

In artificial liver blood purification system, highly efficient removal of multiple toxic metabolites from whole blood by hemoperfusion still remains a challenge in the clinical field, due to the limited unspecific absorptive capacity and low biocompatibility of adsorbents. In this work, a new pyridinyl-modified hypercrosslinked polystyrene (HCP) adsorbent, named HCP(St-DVB-VP), was constructed directly through a Friedel-Crafts post-crosslinking reaction using a small-molecule crosslinking agent for the first time. The preparation method provides in this study can avert the problem posed by the use of the toxic carcinogenic chloromethyl ether reagent in the traditional HCP resin synthesis process. The results indicated that HCP(St-DVB-VP) had a highly porous structure with a specific surface area of 761 m² g⁻¹. Notably, the adsorbent demonstrated excellent adsorptive properties towards both protein-bound toxins (bilirubin) and medium- and large-sized molecular toxins (PTH, IL-6) in vitro experiments simultaneously. More importantly, the obtained adsorbent showed acceptable hemocompatibility. Taken together, the low-cost and ecofriendly fabrication method, broad-spectrum adsorption performance and hemocompatibility makes the HCP(St-DVB-VP) promising for whole blood perfusion in artificial liver blood purification in clinical practice.

Uremic Toxins: An Alarming Danger Concerning the Cardiovascular System

The kidneys and heart share functions with the common goal of maintaining homeostasis. When kidney injury occurs, many compounds, the so-called "uremic retention solutes" or "uremic toxins," accumulate in the circulation targeting other tissues. The accumulation of uremic toxins such as p-cresyl sulfate, indoxyl sulfate and inorganic phosphate leads to a loss of a substantial number of body functions. Although the concept of uremic toxins is dated to the 1960s, the molecular mechanisms capable of leading to renal and cardiovascular injuries are not yet known. Besides, the greatest toxic effects appear to be induced by compounds that are difficult to remove by dialysis. Considering the close relationship between renal and cardiovascular functions, an understanding of the mechanisms involved in the production, clearance and overall impact of uremic toxins is extremely relevant for the understanding of pathologies of the cardiovascular system. Thus, the present study has as main focus to present an extensive review on the impact of uremic toxins in the cardiovascular system, bringing the state of the art on the subject as well as clinical implications related to patient's therapy affected by chronic kidney disease, which represents high mortality of patients with cardiac comorbidities.

Polymyxin B engineered polystyrene-divinylbenzene microspheres for the adsorption of bilirubin and endotoxin

Hemoperfusion is an important strategy for liver disease treatment. Polystyrene-divinylbenzene (PS-DVB) microspheres are widely applied as absorbents in hemoperfusion to efficiently remove the important toxin bilirubin. However, as another common toxin, endotoxin will remain during this process and cause endotoxemia. Therefore, simultaneous removal of both bilirubin and endotoxin is highly desirable. In the present study, we engineered PS-DVB microspheres with polymyxin B sulfate (PMB) to meet this goal. After modification, the novel PMB-engineered (P-PMB) microspheres displayed excellent biocompatibility and hemocompatibility. Notably, compared to PS-DVB microspheres, P-PMB microspheres exhibited markedly stronger detoxification of both bilirubin and endotoxin, increasing by 17.03% and 42.57%, respectively. Overall, we believe that the novel P-PMB microspheres have considerable potential for liver disease treatment in clinical practice.

A new adsorbent for hemoperfusion was successfully prepared by grafting polymyxin B (PMB) on the surface of polystyrene divinylbenzene (PS-DVB) microspheres. It showed good biocompatibility and could adsorb both bilirubin and endotoxin.