Preparation of nano-CaCO3/polystyrene nanocomposite beads for efficient bilirubin removal

[Application of Modified Polyether Sulfone Microspheres in Hyperbilirubinemia]

Objective

To design and prepare a high efficiency bilirubin adsorbent with good mechanical properties and biocompatibility.

Methods

In this study, quaternary ammonium pyridine was designed and synthesized, and then modified polyether sulfone microspheres, or PES/p(4-VP-co-N-VP)@6 microspheres, were prepared by phase conversion and electrostatic spraying. The morphology of the polymer components and the microspheres were studied by means of nuclear magnetic resonance (NMR) spectroscopy and scanning electron microscopy. The basic properties of the microspheres and their bilirubin adsorption efficiency were tested, and the adsorption mechanism was further explored. Blood cell counts and the clotting time of the microspheres were also measured.

Results

The diameter of the modified polyether sulfone microspheres prepared in the study was approximately 700-800 μm. Compared with the original PES microspheres, the surface and internal structure of PES/p(4-VP-co-N-VP)@6 microspheres did not change significantly, and they also had a loose porous structure, with some micropores scattered around in addition to irregular large pores. Compared with the control group, the bilirubin removal effect of the modified microspheres was (94.91±0.73)% after static adsorption in bilirubin PBS buffer solution for 180 min, with the difference being statistically significant (P<0.0001). According to the findings for the clotting time, the activated partial thromboplastin time (APTT) of the blank plasma group, the control PES group, and the modified PES microsphere group were (27.57±1.25) s, (28.47±0.45) s, and (30.4±0.872) s, respectively, and the difference between the experimental group and the other two groups was statistically significant (P<0.01, P<0.05). There was no significant change in red blood cell and white blood cell counts.

Conclusion

The microspheres prepared in the study have high efficiency in bilirubin adsorption, excellent mechanical properties and thermal stability, and good blood biocompatibility, and are expected to be used in the clinical treatment of patients with liver failure.

TiO2/Polystyrene Nanocomposite Antibacterial Material as a Hemoperfusion Adsorbent for Efficient Bilirubin Removal and Prevention of Bacterial Infection

The use of hemoperfusion adsorbents for the removal of bilirubin in patients with liver failure has become a critical treatment. However, the insufficient clearance of bilirubin and the possibility of bacterial infection during hemoperfusion limit the application. In this work, we designed a novel antibacterial bilirubin adsorbent (PSVT) through the suspension polymerization reaction between double-bond functionalized TiO2 nanoparticles and styrene. PSVT showed an excellent bilirubin adsorption ability and antibacterial performance, ensuring efficient clearance of bilirubin in liver failure patients during hemoperfusion and preventing bacterial infection. The experimental results indicated that TiO2 was uniformly dispersed in the microspheres, which improved the mesoporous structure and increased the specific surface area. Composite adsorbent PSVT showed an exceptional bilirubin adsorption capacity, with the maximum adsorption capacity reaching 24.3 mg/g. In addition, the introduction of TiO2 endowed PSVT with excellent antibacterial ability; the ultimate antibacterial rates against Escherichia coli and Staphylococcus aureus reached 97.31 and 96.47%, respectively. In summary, PSVT served as a novel antibacterial bilirubin adsorbent with excellent bilirubin clearance capacity and antibacterial performance, providing excellent application prospects for treating liver failure patients.

Novel hemoperfusion adsorbents based on collagen for efficient bilirubin removal - A thought from yellow skin of patients with hyperbilirubinemia

Hemoperfusion is a well-developed method for removing bilirubin from patients with hyperbilirubinemia. The performance of adsorbents is crucial during the process. However, most adsorbents used for bilirubin removal are not suitable for clinical applications, because they either have poor adsorption performance or limited biocompatibility. Patients with hyperbilirubinemia usually have distinctive yellow skin, indicating that collagen, a primary component of the skin, may be an effective material for absorbing bilirubin from the blood. Based on this idea, we designed and synthesized collagen (Col) and collagen-polyethyleneimine (Col-PEI) microspheres and employed them as hemoperfusion adsorbents for bilirubin removal. The microspheres have an efficient adsorption rate, higher bilirubin adsorption capacity, and competitive adsorption of bilirubin in the bilirubin/bovine serum albumin (BSA) solution. The maximum adsorption capacities of Col and Col-PEI microspheres for bilirubin are 150.2 mg/g and 258.4 mg/g, respectively, which are higher than those of most traditional polymer microspheres. Additionally, the microspheres exhibit excellent blood compatibility originating from collagen. Our study provides a new collagen-based strategy for the hemoperfusion treatment of hyperbilirubinemia.

Reusable Zwitterionic Porous Organic Polymers for Bilirubin Removal in Serum

Herein, we report a straightforward strategy to construct reusable, hemocompatible, and highly efficient bilirubin adsorbents by installing zwitterionic modules into a porous organic polymer (POP) for hemoperfusion application. Three types of zwitterions with different amounts are used to evaluate their impacts on the characteristics of POPs, including carboxybetaine methacrylate (CB), sulfobetaine methacrylate (SB), and 2-methacryloyloxyethyl phosphorylcholine (MPC). Results show that zwitterions can improve hemocompatibility, hydrophilicity, and bilirubin uptake of the POP. Among all zwitterionic POPs, POP-CB-40% exhibits the best bilirubin uptake, ∼46.5 times enhancement compared with the non-zwitterionic POP in 100% serum. This enhancement can be attributed to the improved hydrophilicity and protein resistance ability in biological solutions. More importantly, the reusability test shows that POP-CB-40% maintains ∼99% of bilirubin uptake capacity at fifth recycling in 100% serum. Findings in this work provide a guideline for the design of biocompatible and efficient POP-based bilirubin adsorbents for hemoperfusion therapy.

Preparation of chitin/MXene/poly(L-arginine) composite aerogel spheres for specific adsorption of bilirubin

Currently, hemoperfusion is clinically the most rapid and effective treatment for removing toxins from the blood. The core of hemoperfusion is the sorbent inside the hemoperfusion device. Due to the complex composition of the blood, adsorbents tend to adsorb substances such as proteins in the blood (non-specific adsorption) while adsorbing toxins. Hyperbilirubinemia is caused by excessive levels of bilirubin in the human blood, causing irreversible damage to the patient's brain and nervous system, and even leading to death. High adsorption and high biocompatibility adsorbents with specific bilirubin adsorption are urgently needed to treat hyperbilirubinemia. Herein, poly(L-arginine) (PLA) which can specifically adsorb bilirubin, was introduced into chitin/MXene (Ch/MX) composite aerogel spheres. Ch/MX/PLA prepared by supercritical CO₂ technology had higher mechanical properties than Ch/MX and can withstand 50,000 times its own weight. The in vitro simulated hemoperfusion test showed that the adsorption capacity of Ch/MX/PLA was as high as 596.31 mg/g, which was 15.38 % higher than that of Ch/MX. Binary and ternary competitive adsorption tests showed that Ch/MX/PLA also had good adsorption capacity in the presence of a variety of interfering molecules. In addition, hemolysis rate testing and CCK-8 testing confirmed that Ch/MX/PLA had better biocompatibility and hemocompatibility. Ch/MX/PLA can meet the required properties of clinical hemoperfusion sorbents and has the ability to produce mass production. It has good application potential in the clinical treatment of hyperbilirubinemia.

Enhanced adsorption and colorimetric detection of tetracycline antibiotics by using functional phosphate/carbonate composite with nanoporous network coverage

This work presents efficient tetracycline (TC) antibiotics adsorption using a functional porous phosphate/carbonate composite (PCC). The PCC was fabricated by anion-exchange of phosphate on the surface of vaterite-phase calcium carbonate particle scaffolds. The PCC, having dense nanoporous network coverage with large surface area and pore volume, exhibited excellent TC adsorption in solution. Its adsorption isotherm fitted well to the Freundlich model, with a maximum adsorption capacity of 118.72 mg/g. The adsorption process was spontaneous, endothermic, and followed pseudo-second-order kinetics. From the XPS analysis, the hydrogen bonding and surface complexation were the key interactions in the process. In addition, a colorimetric TC detection method was developed considering its complexation with phosphate ions, originating from PCC dissolution, during adsorption. The method was used to detect TC in mg/L concentrations in water samples. Thus, the multifunctional PCC exhibited potential for use in TC removal and environmental remediation.

Bilirubin Removal by Polymeric Adsorbents for Hyperbilirubinemia Therapy

Hyperbilirubinemia, presenting as jaundice, is a life-threatening critical illness in newborn babies and acute severe hepatic failure patients. Over the past few decades, extracorporeal hemoadsorption by adsorbent therapy has been widely applied in the treatment of hyperbilirubinemia. The capability of hemoadsorption depends on the adsorbents. Most of the clinically used bilirubin adsorbents are made up of styrene/divinylbenzene copolymer and quaternary ammonium salt, which usually have poor biocompatibility and weak mechanical strength. To overcome the drawbacks of commercial polymer adsorbents, advanced synthetic and natural polymers with/without nanomaterials have been designed, and novel adsorbent fabrication technologies have also been developed. In this review, the adsorption mechanism of bilirubin adsorbents has been summarized, which is the basic criterion in adsorbent development. Furthermore, the preparation method, adsorption mechanism, relative merits and practicability of the emerging bilirubin adsorbents have been evaluated. Based on the existing studies, this work highlights the future direction of the efforts on how to design and develop bilirubin adsorbents with good overall clinical performance. Perhaps this study can change traditional perspectives and propose new strategies for bilirubin clearance from the aspects of pathogenic mechanisms, metabolic pathways, and material-based innovation.

Engineering Antioxidative Cascade Metal-Phenolic Nanozymes for Alleviating Oxidative Stress during Extracorporeal Blood Purification

Oxidative stress is a compelling risk factor in chronic kidney diseases and is further aggravated for individuals during extracorporeal blood purification, ultimately leading to multiple complications. Herein, antioxidative cascade metal-phenolic nanozymes (metal-tannic acid nanozymes, M-TA NMs) are synthesized via metal ions-mediated oxidative coupling of polyphenols; then M-TA NMs engineered hemoperfusion microspheres (Cu-TAn@PMS) are constructed for alleviating oxidative stress. M-TA NMs show adjustable broad-spectrum antioxidative activities toward multiple reactive nitrogen and oxygen species (RNOS) due to the adjustable catalytic active centers. Importantly, M-TA NMs could mimic the cascade processes of superoxide dismutase and catalase to maintain intracellular redox balance. Detailed structural and spectral analyses reveal that the existence of a transition metal could decrease the electronic energy band gaps of M-TA NMs to offer better electron transfers for RNOS scavenging. Notably, dynamic blood experiments demonstrate that Cu-TAn@PMS could serve as an antioxidant defense system for blood in hemoperfusion to scavenge intracellular reactive oxygen species (ROS) effectively even in the complex blood environment and further protect endogenous antioxidative enzymes and molecules. In general, this work developed antioxidative cascade nanozymes engineered microspheres with excellent therapeutic efficacy for the treatment of oxidative stress-related diseases, which exhibited potential for clinical blood purification and extended the biomedical applications of nanozymes.

Freezing-triggered gelation of quaternized chitosan reinforced with microfibrillated cellulose for highly efficient removal of bilirubin

The highly efficient removal of bilirubin from blood by hemoperfusion for liver failure therapy remains a challenge in the clinical field due to the low adsorption capacity and poor hemocompatibility of currently used carbon-based adsorbents. Polysaccharide-based cryogels seem to be promising candidates for hemoperfusion adsorbents owing to their inherited excellent hemocompatibility. However, the weak mechanical strength and relatively low adsorption capacity of polysaccharide-based cryogels limited their application in bilirubin adsorption. In this work, we presented a freezing-triggered strategy to fabricate QCS/MFC cryogels, which were formed by quaternized chitosan (QCS) crosslinked with divinylsulfonyl methane (BVSM) and reinforced with microfibrillated cellulose (MFC). Ice crystal exclusions triggered the chemical crosslinking to generate the cryogels with dense pore walls. The obtained QCS/MFC cryogels were characterized by FTIR, SEM, stress-strain test, and hemocompatibility assay, which exhibited interconnected macroporous structures, excellent shape-recovery and mechanical performance, and outstanding blood compatibility. Due to the quaternary ammonium functionalization of chitosan, the QCS/MFC showed a high adsorption capacity of 250 mg g^-1 and a short adsorption equilibrium time of 3 h. More importantly, the QCS/MFC still exhibited high adsorption efficiency (over 49.7%) in the presence of 40 g L^-1 albumin. Furthermore, the QCS/MFC could also maintain high dynamic adsorption efficiency in self-made hemoperfusion devices. This facile approach provides a new avenue to develop high-performance hemoperfusion adsorbents for bilirubin removal, showing great promise for the translational therapy of hyperbilirubinemia.

Hydroxyapatite reinforced inorganic-organic hybrid nanocomposite as high-performance adsorbents for bilirubin removal in vitro and in pig models

Highly efficient removal of bilirubin from whole blood directly by hemoperfusion for liver failure therapy remains a challenge in the clinical field due to the low adsorption capacity, poor mechanical strength and low biocompatibility of adsorbents. In this work, a new class of nanocomposite adsorbents was constructed through an inorganic-organic co-crosslinked nanocomposite network between vinyltriethoxysilane (VTES)-functionalized hydroxyapatite nanoparticles (V-Hap) and non-ionic styrene-divinylbenzene (PS-DVB) resins (PS-DVB/V-Hap) using suspension polymerization. Notably, our adsorbent demonstrated substantially improved mechanical performance compared to the pure polymer, with the hardness and modulus increasing by nearly 3 and 2.5 times, respectively. Moreover, due to the development of a mesoporous structure, the prepared PS-DVB/V-Hap3 exhibited an ideal adsorption capacity of 40.27 mg g-1. More importantly, the obtained adsorbent beads showed outstanding blood compatibility and biocompatibility. Furthermore, in vivo extracorporeal hemoperfusion verified the efficacy and biosafety of the adsorbent for directly removing bilirubin from whole blood in pig models, and this material could potentially prevent liver damage and improve clinical outcomes. Taken together, the results suggest that PS-DVB/V-Hap3 beads can be used in commercial adsorption columns to threat hyperbilirubinemia patients through hemoperfusion, thus replacing the existing techniques where plasma separation is initially required.

Hierarchical core-shell nanoplatforms constructed from Fe3O4@C and metal-organic frameworks with excellent bilirubin removal performance

Hemoperfusion has become the third-generation treatment strategy for patients suffering from hyperbilirubinemia, but adsorbents used for bilirubin removal mostly face intractable problems, such as unsatisfactory adsorption performance and poor hemocompatibility. Metal-organic frameworks (MOFs) are promising adsorbents for hemoperfusion due to their high specific surface areas and easily modified organic ligands. However, their microporous properties and separation have hampered their application. Here, a novel hierarchical core-shell nanoplatform (named Double-PEG) with tailored binding sites and pore sizes based on Fe3O4@C and Uio66-NH2 was constructed. Notably, Double-PEG showed excellent bilirubin uptake of up to 1738.30 mg g-1 and maintained excellent bilirubin removal efficiency in simulated biological solutions. A study on the adsorption mechanism showed that the adsorption of Double-PEG towards bilirubin tended to be chemical adsorption and in accordance with the Langmuir model. Besides, the good separability, recyclability, cytotoxicity and hemocompatibility of Double-PEG show great potential in hemoperfusion therapy. The finding of this study may provide a novel insight into the application of MOF materials in the field of hemoperfusion.

Continuous renal replacement therapy and extended indications

Extracorporeal blood purification (EBP) techniques provide support for critically ill patients with single or multiple organ dysfunction. Continuous renal replacement therapy (CRRT) is the modality of choice for kidney support for those patients and orchestrates the interactions between the different artificial organ support systems. Intensive care teams should be familiar with the concept of sequential extracorporeal therapy and plan on how to incorporate new treatment modalities into their daily practices. Importantly, scientific evidence should guide the decision-making process at the bedside and provide robust arguments to justify the costs of implementing new EBP treatments. In this narrative review, we explore the extended indications for CRRT as an adjunctive treatment to provide support for the heart, lung, liver, and immune system. We detail practicalities on how to run the treatments and how to tackle the most frequent complications regarding each of the therapies, whether applied alone or integrated. The physicochemical processes and technologies involved at the molecular level encompassing the interactions between the molecules, membranes, and resins are spotlighted. A clinical case will illustrate the timing for the initiation, maintenance, and discontinuation of EBP techniques.

A novel anticoagulant affinity membrane for enhanced hemocompatibility and bilirubin removal

Affinity membrane is widely employed to promote specific adsorption of toxins and reduce the blood purification therapeutic time. However, it suffers from insufficient toxin binding and low hemocompatibility. Herein, a novel anticoagulant affinity membrane (AAM) was developed to clear bilirubin from human blood in a pore-flow-through way. Firstly, a nylon net membrane with a regularly arranged pore as the matrix was coated with poly(pyrrole-3-carboxylic acid) via chemical vapor deposition (CVD) method. Then, poly(L-arginine) (PLA) as a highly specific ligand of bilirubin, was immobilized onto the surface of the composited membrane after the modification of heparin. Owing to the 3-dimensional molecular architecture of PLA, up to 86.1 % of bilirubin was efficiently cleared. Besides, the AAM exhibited effective anticoagulant activity in the measurement of clotting time, with suppressed thrombus formation, low hemolysis ratio, minimized platelet and leukocyte adhesion, and excellent biosafety. Therefore, the AAM has enormous potential in blood purification therapy for enhancing hemocompatibility and bilirubin removal.

Plant protein modified natural cellulose with multiple adsorption effects used for bilirubin removal

In this study, bacterial cellulose (BC)/soy protein isolate (SPI) composite membranes were prepared by in situ cross-linked polymerization, and used as efficient blood compatible adsorbents to remove bilirubin. The obtained composite membranes were successively characterized by FTIR, SEM, AFM, contact angle test and hemolysis assay, which exhibited unique protein coated 3D fibrous network structures, hydrophobic surfaces and outstanding blood compatibility due to the incorporation of SPI. The BC/SPI membranes with high SPI content showed high adsorption efficiency, short adsorption equilibrium time (2 h) and multiple adsorption effects on bilirubin. The adsorption rate for free bilirubin of BC/SPI5 membrane could reach 78.8% when the bilirubin concentration was 100 mg L^-1, while it increased to over 96.5% when the initial bilirubin concentration exceeded 400 mg L^-1. More importantly, the BC/SPI5 membrane still exhibited high adsorption rate (over 70%) in presence of albumin. Furthermore, the composite membrane could also maintain high dynamic adsorption efficiency in self-made hemoperfusion devices. This novel naturally-derived membrane is an economical and efficient absorbent for the remove of bilirubin, and will provide new ideas for therapy of hemoperfusion without plasma separation process.

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.

MOF-Based Antibiofouling Hemoadsorbent for Highly Efficient Removal of Protein-Bound Bilirubin

A metal-organic framework (MOF)-based antibiofouling hemoadsorbent (PCB-MIL101) was developed through a facile encapsulation of MIL-101(Cr) in zwitterionic poly carboxybetaine (PCB) hydrogel. PCB-MIL101 possessed strong mechanical strength and superior hemocompatibility, ensuring its safety in hemoperfusion applications. In addition, it showed efficient and effective adsorption toward bilirubin (BR), and its maximum adsorption capacity was ∼583 mg g^-1. Moreover, due to the protection of antibiofouling PCB hydrogel, PCB-MIL101 showed ability to resist protein adsorption, thus working effectively to remove BR molecules from their binding albumin in biological solutions. The finding in this study provides a novel insight into developing MOF-based hemoadsorbents for the improvement of hemoperfusion therapies.

Polydopamine decorated ordered mesoporous carbon for efficient removal of bilirubin under albumin-rich conditions

Excess bilirubin in the body will lead to serious health problems; however, its efficient removal remains a challenge in the clinical field because the available sorbent materials still suffer from serious performance issues, performance declining in a high-content albumin environment. Herein, we prepared a novel polydopamine (PDA) decorated ordered mesoporous carbon (OMC) material for the efficient removal of bilirubin in albumin-rich conditions. OMC was used as the supporting material due to its high specific surface area and its good affinity to hydrophobic analytes. PDA was then decorated on the OMC material through a facile self-assembly process to form a surface-imprinted layer. The obtained PDA-coated OMC material (OMC@PDA) exhibited excellent adsorption performance towards bilirubin in albumin-free conditions, in which its theoretical maximum adsorption amount was calculated to be 513.54 mg g^-1. The imprinted PDA layer, for which the association constant towards bilirubin reached 4.51 × 10⁴ M^-1, endowed OMC@PDA with a competitive affinity compared to albumin. Therefore the materials showed good adsorption capacity and efficiency even in an albumin-rich environment (the adsorption equilibrated at 122.7 mg g^-1 in 30 min). In addition, the good biocompatibility of OMC@PDA was demonstrated by hemolysis assay and protein fouling evaluation, which indicated the feasibility of applying this material in clinical situations.

Hemocompatible hemoadsorbent for effective removal of protein-bound toxin in serum

Resin hemoperfusion is a life-saving treatment for drug intoxication or hepatic failure of patients. However, current resin adsorbents exhibit a limited hemocompatibility or low adsorption efficiency, representing a major roadblock to successful clinical applications. In this work, we developed a hemocompatible and effective hemoadsorbent based on polystyrene resin (H103) microparticles encapsulated in anti-biofouling zwitterionic poly(carboxybetaine) (PCB) hydrogels. Apart from a strong mechanical stability, this PCB-based adsorbent (PCB-H103) exhibited excellent hemocompatibility (hemolysis ratio was ∼0.64%), which was attributed to the anti-biofouling property of PCB hydrogel. In addition, it can efficiently adsorb both small and middle molecular weight molecules in phosphate-buffered saline, and the efficiencies were significantly higher than poly(ethylene glycol) methacrylate-based and poly(2-hydroxyethyl methacrylate)-based adsorbent counterparts, indicating the favorable permeability of PCB hydrogel coating. More importantly, PCB-H103 could effectively remove protein-bound toxins including phenol red and bilirubin in bovine serum albumin solution or even in 100% fetal bovine serum (FBS). In 100% FBS, the adsorption capacity of PCB-H103 towards bilirubin was 8.3 times higher than that of pristine clinical-scale resin beads. Findings in this work may provide a new strategy for the development of modern resin hemoperfusion technology.

Selective adsorption of bilirubin against albumin to alkylamine functionalized PVA microspheres

Adsorbents are widely used in hemoperfusion for bilirubin removal. However, their performance is often compromised by the presence of plasma proteins. In this study, the bilirubin adsorption capacity of polyvinyl alcohol microspheres (PVAm) functionalized with different amino-alkane ligands has been investigated, with the aim of gaining binding selectivity over albumin. Octylamine-functionalized PVA microspheres (PVAm-8) exhibited an excellent adsorption capacity for bilirubin (75% and 3.95 mg/mL in PBS vs 72% and 3.84 mg/mL in albumin solution) when compared to the clinical adsorbent BPR (92% and 4.84 mg/mL in PBS vs 71%, and 3.80 mg/mL in albumin solution). The bilirubin adsorption capacities of PVAm-8 were largely unaffected by the presence of albumin. Adsorption of bilirubin to PVAm-8 occurs mainly through hydrophobic effects, with adsorption consistent with the monolayer model and the pseudo-first-order model operating in both PBS and albumin solution. The effects of PVAm-8 on hemolytic activity, blood component stability and coagulant activity were negligible, indicating that PVAm-8 has good potential as a high-affinity bilirubin adsorbent for hemoperfusion applications.

Fabrication of Organic Hec Nanocomposites Modified with Lysine as a Potential Adsorbent for Bilirubin Removal

As one of the typical phyllosilicate clays, hectorite (Hec) has some excellent characteristics and has been greatly applied in adsorption field for the removal of dye, endotoxin, etc. In this study, organic Hec nanocomposites modified with L-Lysine (Lys/Hec NCs) were prepared via solution intercalation method for BR removal. The effects of ionic strength, pH values, initial concentration of BR, and BSA concentration on the adsorption capacity for BR of Lys/Hec NCs were investigated. Results indicated that the adsorption capacity for BR of nanocomposites could reach 40 mg/g when the initial bilirubin concentration was 200 mg/L. However, the adsorption amount of Lys/Hec NCs decreased with increasing the concentration of BSA, but Lys/Hec NCs could still maintain a higher adsorption rate. The adsorption kinetics and adsorption isotherms indicated that the adsorption process of Lys/Hec NCs agreed well with the pseudo-second-order model and the Langmuir isotherm, respectively. Moreover, Lys/Hec NCs also exhibited excellent cytocompatibility. These obtained results demonstrate that Lys/Hec NCs prepared in this study had great potential to be used in hemoperfusion.

Synergistic effect of lignin incorporation into polystyrene for producing sustainable superadsorbent

Lignin has gained intensive interest as an excellent raw material for the generation of advanced green products. Polystyrene (PS) is known for its worldwide application in water purification processes. To induce a sustainable PS, kraft lignin (KL) and polystyrene were polymerized via free radical polymerization in a facile aqueous emulsion process. KL enhanced surface area and porosity of PS. The physicochemical properties of induced KL–PS were analyzed, and the fate of lignin in KL–PS was discussed fundamentally. Wettability and surface energy analyses were implemented to monitor the surface properties of KL, PS and KL–PS. Incorporation of KL in PS (40 wt%) boosted its surface energy and oxygen content, which led to KL–PS with better compatibility than PS with copper ions in aqueous systems. A quartz crystal microbalance with dissipation (QCM-D) confirmed the noticeably higher adsorption performance of copper ion on KL–PS than on PS and KL. The sorption mechanism, which was revealed by FTIR studies, was primarily attributed to the coordination of Cu(ii) and hydroxyl group of KL–PS as well as the quadrupolar system of KL–PS.

Lignin has gained intensive interest as an excellent raw material for the generation of advanced green products.