Bilirubin Adsorption Capacity Research Articles

Functionalized SBA-15 materials for bilirubin adsorption

To investigate the driving force for bilirubin adsorption on mesoporous materials, a comparative study was carried out between pure siliceous SBA-15 and three functionalized SBA-15 mesoporous materials: CH 3-SBA-15 (MS), NH 2-SBA-15 (AS), and CH 3/NH 2-SBA-15 (AMS) that were synthesized by one-pot method. The obtained materials exhibited large surface areas (553–810 m 2/g) and pore size (6.6–7.1 nm) demonstrated by XRD and N 2-ad/desorption analysis. The SEM images showed that the materials had similar fiberlike morphology. The functionalization extent was calculated according to 29Si MAS NMR spectra and it was close to the designed value (10%). The synthesized mesoporous materials were used as bilirubin adsorbents and showed higher bilirubin adsorption capacities than the commercial active carbon. The adsorption capacities of amine functionalized samples AMS and AS were larger than those of pure siliceous SBA-15 and MS, indicating that electrostatic interaction was the dominant driving force for bilirubin adsorption on mesoporous materials. Increasing the ionic strength of bilirubin solution by adding NaCl would decrease the bilirubin adsorption capacity of mesoporous material, which further demonstrated that the electrostatic interaction was the dominant driving force for bilirubin adsorption. In addition, the hydrophobic interaction provided by methyl groups could promote the bilirubin adsorption.

Preparation of bovine serum albumin immobilized adsorbent for specific adsorption of bilirubin

Serum bilirubin concentration is greatly elevated in certain diseases such as hyperbilirubinemia and severe hepatitis. Lowering the level of bilirubin is one of the major targets of many therapies such as plasma exchange and hemoperfusion. In this study, a bilirubin specific adsorbent was prepared by covalently immobilizing bovine serum albumin (BSA) onto macroporous poly (glycidyl methacrylate-co-trimethylolpropane trimethacrylate) microspheres. The resulting BSA immobilized adsorbent (BIA) demonstrated good performance in adsorption of bilirubin with an adsorption capacity of 48.7 mg/g. Presence of BSA in bilirubin solution significantly lowered the adsorption capacity of the adsorbent due to the tight binding of bilirubin onto BSA. Adsorption performance of the adsorbent for bilirubin was improved with the elevation of temperature. The adsorbent demonstrated good stability even after 31 d of storage at - 80 degrees C in that there was almost no change in adsorption capacity for bilirubin. These results indicated that the prepared BSA immobilized adsorbent could be an alternative choice for specific adsorption of bilirubin.

Bilirubin adsorption property of mesoporous silica and amine-grafted mesoporous silica

Nephritic, hepatic and immune failures would lead to the overload of endogenous toxic molecules (e.g. bilirubin, cholic acid, uric acid, creatinine etc.) in human bodies. It is fatal in most cases and extracorporeal blood purification (ECBP) is powerful first-aid therapy. Adsorbents are key parts of ECBP apparatus. Mesoporous silicas should be promising candidates for these medical adsorbents, but there is no report about this. Herein, pure and amine-grafted mesoporous silicas have been applied to adsorb bilirubin, cholic acid, uric acid, creatinine and phenobarbital for the first time. These mesoporous materials show high adsorption capacities for bilirubin and uric acid in phosphate buffer solution (PBS). Effects of pore sizes, amine-modification, temperature and ionic strength on their bilirubin adsorption capacities have been studied in detail.

Bilirubin adsorption property of mesoporous silica and amine-grafted mesoporous silica

Abstract Nephritic, hepatic and immune failures would lead to the overload of endogenous toxic molecules (e.g. bilirubin, cholic acid, uric acid, creatinine etc.) in human bodies. It is fatal in most cases and extracorporeal blood purification (ECBP) is powerful first-aid therapy. Adsorbents are key parts of ECBP apparatus. Mesoporous silicas should be promising candidates for these medical adsorbents, but there is no report about this. Herein, pure and amine-grafted mesoporous silicas have been applied to adsorb bilirubin, cholic acid, uric acid, creatinine and phenobarbital for the first time. These mesoporous materials show high adsorption capacities for bilirubin and uric acid in phosphate buffer solution (PBS). Effects of pore sizes, amine-modification, temperature and ionic strength on their bilirubin adsorption capacities have been studied in detail.

Preparation of grafted polytetrafluoroethylene fibers and adsorption of bilirubin

AbstractBACKGROUND: A successful hemoperfusion technique requires that the adsorbent for bilirubin should have a high specificity, adsorption capacity and adsorption rate, blood compatibility and no toxicity. Compared with polymer microbeads, polytetrafluoroethylene (PTFE) fibers have many advantages. The aim of the work reported here was to prepare a new polytetrafluoroethylene‐graft‐poly(glycidyl methacrylate)‐block‐polyethyleneimine (PTFE‐g‐PGMA‐b‐PEI) adsorbent for bilirubin based on PTFE fibers by the 60Co radiation‐induced graft polymerization of GMA followed by the chemical modification of the epoxy groups on the PTFE‐g‐PGMA fibers with PEI. In addition, the adsorption properties of this novel adsorbent for bilirubin were examined.RESULTS: The highest content of amino groups obtained on the PTFE‐g‐PGMA‐b‐PEI fibers was 1.87 mmol g−1. The maximum adsorption capacity of the grafted fibers was 9.6 mg g−1 at pH = 6.5. Bilirubin adsorption on these fibers obeyed the Langmuir model. Also, these fibers possessed the ability to selectively adsorb bilirubin in the presence of bovine serum albumin.CONCLUSION: The PTFE‐g‐PGMA‐b‐PEI fibers have a high adsorption capacity for bilirubin and excellent adsorption properties. In addition, this new adsorbent is inexpensive, easy to prepare and has no toxicity. So the PTFE‐g‐PGMA‐b‐PEI fibers as a biomedical adsorbent are promising for the removal of bilirubin through the hemoperfusion technique. Copyright © 2009 Society of Chemical Industry

Fabrication of carbon nanotube sheets and their bilirubin adsorption capacity

Bilirubin adsorption on carbon nanotube surfaces has been studied to develop a new adsorbent in the plasma apheresis. Powder-like carbon nanotubes were first examined under various adsorption conditions such as temperatures and initial concentrations of bilirubin solutions. The adsorption capacity was measured from the residual concentrations of bilirubin in the solution after the adsorption process using a visible absorption spectroscopy. We found that multi-walled carbon nanotubes (MWCNTs) exhibit greater adsorption capacity for bilirubin molecules than that of single-walled carbon nanotubes (SWCNTs). To guarantee the safety of the adsorbents, we fabricated carbon nanotube sheets in which leakage of CNTs to the plasma is suppressed. Since SWCNTs are more suitable for robust sheets, a complex sheet consisting of SWCNTs as the scaffolds and MWCNTs as the efficient adsorbents. CNT/polyaniline complex sheets were also fabricated. Bilirubin adsorption capacity of CNTs has been found to be much larger than that of the conventional materials because of their large surface areas and large adsorption capability for polycyclic compound molecules due to their surface structure similar to graphite.

Hollow mesoporous carbon spheres—an excellent bilirubin adsorbent

Hollow mesoporous carbon spheres (HMCSs) were used for the first time as a bilirubin adsorbent, which showed an extraordinarily high bilirubin adsorption capacity as compared with commercial activated carbon for haemoperfusion, high bilirubin adsorption selectivity and negligible hemolytic activity. The results are very attractive and promising for blood purification applications.

Supermacroporous poly(hydroxyethyl methacrylate) based cryogel with embedded bilirubin imprinted particles

Molecular imprinted polymers are artificial, template-made materials with the ability to recognize and to specifically bind the target molecule. The aim of this study is to prepare supermacroporous cryogel with embedded bilirubin-imprinted particles which can be used for the selective removal of bilirubin from human plasma. N-methacryloyl-( l)-tyrosinemethylester (MAT) was chosen as the pre-organization monomer. In the first step, bilirubin was complexed with MAT and the bilirubin-imprinted poly(hydroxyethyl methacrylate- N-methacryloly-( l)-tyrosine methyl-ester) [MIP] monolith was produced by bulk polymerization. MIP monolith was smashed and the particles ground and sieved through 100 μm sieves. In the second step, the supermacroporous poly(hydroxyethyl methacrylate) (PHEMA) cryogel with embedded MIP particles [PHEMA/MIP composite cryogel] was produced by free radical polymerization initiated by N, N, N′, N′-tetramethylene diamine (TEMED) and ammonium persulfate (APS) pair in an ice bath. After that, the template (i.e., bilirubin) molecules were removed using sodium carbonate and sodium hydroxide. Compared with the PHEMA cryogel (0.2 mg/g polymer), the bilirubin adsorption capacity of the PHEMA/MIP composite cryogel (10.3 mg/g polymer) was improved significantly due to the embedded MIP particles into the polymeric matrix. The relative selectivity coefficients of PHEMA/MIP composite cryogel for bilirubin/cholesterol and bilirubin/testosterone were 8.6 and 4.1 times greater than the PHEMA cryogel, respectively. The PHEMA/MIP composite cryogel could be used many times without decreasing the bilirubin adsorption capacity significantly.

Bilirubin removal performance of immobilized albumin in a magnetically stabilized fluidized bed

Human serum albumin (HSA)-immobilised magnetic poly(2-hydroxyethyl methacrylate) (mPHEMA) particles were investigated as an adsorbent for selective bilirubin removal from human plasma in a magnetically stabilized fluidized bed system. mPHEMA particles were prepared by suspension polymerization in the presence of Fe3O4 particles. mPHEMA particles were characterized by scanning electron microscopy (SEM), surface area and pore size measurements. The mPHEMA beads have a spherical shape and porous structure. The specific surface area of the mPHEMA particles was found to be 50 m2/g with a size range of 80–120 μm in diameter and the swelling ratio was 45%. Then, HSA was covalently coupled to the cyanogen bromide (CNBr)-activated mPHEMA particles. The amount of coupled HSA was arranged by changing the activation degree of particles (i.e., CNBr concentration). In vitro bilirubin removal was investigated from hyperbilirubinemic human plasma on the mPHEMA particles containing different amounts of immobilised HSA (between 11 and 100 mg/g). The non-specific bilirubin adsorption on the bare mPHEMA particles was 0.47 mg/g. Higher bilirubin adsorption capacities, up to 88.3 mg/g, were obtained with the HSA-immobilised magnetic particles. Bilirubin capacity decreased significantly from 75.0 mg/g to 40.0 mg/g polymer with the increase of the flow-velocity from 0.5 ml/min to 4.0 ml/min. Bilirubin adsorption increased with increasing temperature. Adsorption behavior of bilirubin could be modelled using the Langmuir isotherm.

Bilirubin removal from human plasma by Cibacron Blue F3GA using immobilized microporous affinity membranous capillary method

A novel affinity sorbent system for direct bilirubin removal from human plasma was developed. These new adsorbents comprise Cibacron Blue F3GA as the specific ligand, and microporous membranous poly(tetrafluoroethylene) capillary (modified by coating with a hydrophilic layer of poly(vinyl alcohol) after activation) as the carrier matrix. The affinity adsorbents carrying 126.5 μmol Cibacron Blue F3GA/g polymer was then used to remove bilirubin in a flow-injection system. Non-specific adsorption on the poly(vinyl alcohol) coated capillary remains low, and higher affinity adsorption capacity, of up to 76.2 mg/g polymer was obtained after dye immobilization. The bilirubin adsorption capacity of the affinity capillary decreased with increase in the recirculation rate of plasma. The adsorption capacity increased with increase the temperature while decreased with increase the ionic strength. The maximum adsorption was only observed in neutral solution (pH 6–7). The adsorption isotherm fitted the Langmuir model well. These new adsorbents have higher velocity of mass transfer, better adsorption capacity, less fouling, longer service life and good reusability. The results of blood tests suggested the dye affinity capillary has good blood compatibility.

Synthesis and Characterization of Novel Adsorbents with Different Ligand Composition for Bilirubin Conjugated with Albumin

The chemical composition and conformation of ligand immobilized on bilirubin adsorbent have been proposed as the key factors to determine the affinity and specificity for bilirubin in patients' plasma. However, up to now, the effects of ligand composition on bilirubin removal are not clear. In this study, we selected human serum albumin (HSA), long carbolic chain and amino groups as the functional groups of ligand immobilized on Sepharose CL‐4B to discuss the effects. The results showed that amino groups and hydrophobic carbonic chains could be very important factors to adsorb bilirubin conjugated with albumin. The contribution of HSA to the adsorption may be owing to its dimensional obstruction for macromolecules approaching, thereby nonspecific adsorption was decreased in plasma. The adsorption capacity for bilirubin increased obviously with the rise of initial concentration of bilirubin in plasma. The adsorption capacity was 7.52 mg/mL gel for bilirubin in albumin phosphate buffer (pH 7.0) with bilirubin concentration of 377 mg/L, while it only got to 3.64 mg/mL in human plasma at the same concentration. The adsorption microenvironment with pH 7.0–8.0, higher temperature (30–40°C) and lower ionic strength were beneficial to the bilirubin adsorption.

Bilirubin removal by Cibacron Blue F3GA attached nylon-based hydrophilic affinity membrane

Covalent coupling of chitosan to the activated membrane was performed after the reaction of the microporous nylon membrane with formaldehyde. Covalent linkage of chitosan was essential to improve the hydrophilicity and consequently reduced the non-specific interactions of the membranes. Cibacron Blue F3G A (CB F3GA) was then covalently immobilized onto the composite membrane to prepare affinity membrane for bilirubin removal. Different amounts of CB F3GA were attached on the composite membranes by changing the dye-attachment conditions, i.e. initial dye concentration, addition of sodium carbonate, and sodium chloride. The maximum CB F3GA content was obtained at 142.9 μmol/g membrane. Dye release in buffers showed a tight covalent bound of CB F3GA on the composite membrane. Bilirubin molecules interacted with the absorbents directly. Non-specific adsorption on the unmodified nylon membrane remains low, and higher bilirubin adsorption capacity, of up to 63.4 mg/g was obtained after CB F3GA immobilization. The effects of the CB F3GA content, temperature, ionic strength, and pH, as well as the adsorption isotherm were investigated in this study. The adsorption capacity increased with increasing the temperature while decreased with increasing the NaCl concentration and a peak at about pH 6.0 was observed during the corresponding experiment. The adsorption isotherm fitted the Freundlich model well. Experiments on regeneration and dynamic adsorption were also performed.

Bilirubin Removal from Human Plasma with Albumin Immobilised Magnetic Poly(2‐hydroxyethyl methacrylate) Beads

AbstractBioaffinity separation has a unique and powerful role as a support tool in the removal of toxic substances from human plasma. Magnetic beads have advantages as supports in comparison to conventional nonmagnetic beads because of low pressure drop, high mass transfer rates, and good fluid‐solid contact. In addition, they eliminate internal diffusion limitations. Human serum albumin (HSA) immobilised onto magnetic poly(2‐hydroxyethyl methacrylate) (mPHEMA) beads were investigated as an adsorbent for the selective bilirubin removal from human plasma. The mPHEMA beads were prepared by a modified suspension polymerisation. HSA was covalently coupled to the mPHEMA beads. Bilirubin adsorption was investigated from hyperbilirubinemic human plasma on the mPHEMA beads containing different amounts of immobilised HSA, (between 11–100 mg/g). The nonspecific bilirubin adsorption on the unmodified mPHEMA beads was 0.47 mg/g. Higher bilirubin adsorption capacities, up to 64.7 mg/g, were obtained with the HSA‐immobilised magnetic beads. Bilirubin adsorption increased with increasing temperature.Effect of HSA loading on bilirubin adsorption.magnified imageEffect of HSA loading on bilirubin adsorption.

Synthesis, characterization and properties of methylaminocellulose

Homogeneously prepared tosylcelluloses (TC) with degrees of substitution (DS) of DSTos 0.1–1.8 were used as intermediates for the synthesis of methylaminocelluloses (MAC) by nucleophilic substitution with methylamine. TC with DSTos up to 1.1 were shown to be valuable intermediates for selective synthesis of MAC with DSMA varying from 0.1 to approximately 1. No nucleophilic substitution was observed at higher DSTos. At the chosen reaction conditions (60 °C, 48 h) residual tosyl moieties remained unchanged and little hydrolysis took place. The samples obtained were characterized by means of elemental analysis, FTIR and 13C CP/MAS NMR spectroscopy. 13C CP/MAS NMR spectroscopy was found to be an efficient tool for quantification of DSMA. Furthermore, the swelling behaviour in water was investigated and preliminary tests concerning the bilirubin adsorption capacity of MAC were carried out.

Bilirubin removal from human plasma by dye affinity microporous hollow fibers

Bioaffinity adsorption has a unique and powerful role as a support tool in the removal of toxic substances from human plasma. Synthetic hollow-fiber membranes have advantages as support matrices in comparison to conventional hemoperfusion columns because they are not compressible and they eliminate internal diffusion limitations. In this study, Cibacron Blue F3GA was covalently attached onto commercially available microporous polyamide hollow-fiber membranes for bilirubin removal from hyperbilirubinemic human plasma. Different amounts of Cibacron Blue F3GA were attached on the polyamide hollow-fibers by changing the dye-attachment conditions, i.e., initial dye concentration, addition of sodium carbonate, and sodium chloride. The maximum amount of Cibacron Blue F3GA attachment was obtained at 42.5 μmol g−1 when the hollow fibers were treated with 3 M HCl for 30 min before performing the dye attachment. The nonspecific bilirubin adsorption on the unmodified polyamide hollow-fiber membranes was 0.65 mg g−1 from human plasma. Higher bilirubin adsorption capacities, of up to 39.7 mg g−1, were obtained with the Cibacron Blue F3GA-attached polyamide hollow-fiber membranes. Further increase in bilirubin adsorption was obtained as 48.9 mg g−1. Bilirubin molecules interacted with these adsorbents directly. Contribution of albumin adsorption on the bilirubin adsorption was much pronounced. Bilirubin adsorption increased with increasing temperature and maximum adsorption was observed at 37°C.

Bilirubin removal from human plasma in a packed-bed column system with dye-affinity microbeads

A dye-ligand, Cibacron Blue F3GA, was covalently coupled with the poly(EGDMA-HEMA) microbeads. The affinity sorbent carrying 16.5 μmol Cibacron Blue F3GA per gram polymer was then used to remove bilirubin from human plasma in a packed-bed column system. Bilirubin adsorption from human plasma on the unmodified poly(EGDMA-HEMA) microbeads was 0.32 mg/g, while much higher adsorption values, up to 24.2 mg/g, were obtained with the dye-attached microbeads. The bilirubin adsorption capacity of the microbeads decreased with an increase in the recirculation rate of plasma. Bilirubin adsorption increased with increasing temperature, and the maximum adsorption achieved at 37°C (32.5 mg bilirubin/g polymer). Bilirubin molecules interacted directly with the immobilized Cibacron Blue F3GA molecules. Contribution of albumin adsorption on bilirubin adsorption was also significant.

A new type of ALSS — the preparation of crosslinked chitosan resins and its adsorption properties for bilirubin

With chitosan as a raw material, a new type of ALSS-CHP was prepared by the reaction of glutaric dialdehyde with chitosan. This type of resin has high adsorption capacity for bilirubin and good blood compatibility. The adsorption capacity was related to the degree of crosslinking of beads; phosphate buffer concentration; bilirubin concentration; pH value; BSA concentration and the size of resins.

Sorption of unconjugated bilirubin by means of novel immobilized β-cyclodextrin polymers

Three kinds of novel β-cyclodextrin (β-CyD) polymers were synthesized by immobilization of β-CyD onto the crosslinked polystyrene supports with different functional groups such as CH 2Cl, SO 2Cl and ▪. biomedical adsorbents, they were tested for their removal capacity of unconjugated bilirubin (BR). The results indicate that the adsorption capacity for BR is due to the inclusion interaction between β-CyD and BR. Many factors such as the adsorption time, the pH value of the adsorption medium, the concentrations of BR and albumin, the amount of β-CyD immobilized on the supports and the degree of crosslinking may affect the adsorption capacity. The adsorption mechanism was also studied.

Assessment of bilirubin clearance capacity of a newly developed ion‐exchange adsorption column and its possible use as a supportive therapy in hepatorenal syndrome

We assessed the bilirubin reduction capacity of three different types of devices in vitro: a high-permeable membrane column for double-filtration plasmapheresis (DFP) (Evaflux 2A, Kuraray, Japan), and non-coated charcoal column for hemoperfusion (HP) (N-180, Asahi Medical, Japan), and ion-exchange columns for plasma adsorption (PA) (BR-350, Asahi Medical, Japan, and B-001, Kuraray, Japan). A column for DFP reduced the concentration of low-molecular proteins effectively such as plasma bilirubin and bile acids in an albumin-dependent manner. A charcoal column adsorbed low-molecular substances preferentially. But in these two columns, the loss of fibrinogen is a limiting factor for determining the processing plasma volume. Ion-exchange columns for PA adsorbed bile acids, disconjugated bilirubin, and monoconjugated bilirubin more efficiently compared with delta-bilirubin and unconjugated bilirubin. Pretreatment of the column with heparin reduced the loss of fibrinogen to less than 10%. We applied the BR-350 ion-exchange column in vivo for treatment of three patients with hyperbilirubinemia. After treatment, an alcoholic hepatitis patient with the hepatorenal syndrome (HRS) recovered from acute renal failure. However, in a patient with primary biliary cirrhosis and in a patient with fulminant hepatitis, the decrease of serum bilirubin was transient and no obvious beneficial responses were noted. The capacity and ability of the BR-350 column to adsorb plasma bilirubin was shown sufficient to treat deeply jaundiced patients, because 4 liters of the plasma of a patient with 108 mg/dl of initial total bilirubin concentration was able to be processed continuously without an obvious decrease in bilirubin adsorption capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Preparation of a biocompatible albumin-coated ion exchange resin for bilirubin removal from the blood of jaundiced newborns.

Removal of bilirubin by hemoperfusion with ion exchange resin particles is suggested to replace exchange transfusion of blood of jaundiced infants in some cases of unconjugated hyperbilirubinemia. The hemoperfusion system developed here consists of a packed bed of a macroreticular resin which is made biocompatible by a coating of a monomolecular layer of albumin. The choice of the appropriate ionic form of the resin and the proper albumin coating and crosslinking procedure assures a high bilirubin adsorption capacity and excellent blood compatibility of the resin. The albumin coated resin removes in vitro 80-90% of the bilirubin initially present in the plasma. The results encourage in vivo clinical studies.