Sulfonation of polyethersulfone sheets effects on adsorbability of beta 2-microglobulin: Whether the adsorbability changes with increased sulfonation degree? / 中国组织工程研究

BACKGROUND: Dialysis-related amyloid may occur during long-term dialysis for patients with uraemia, of which the main evocator is β_2-microglobulin (β_22M); therefore, how to eliminate 132M from blood is always the focus of research. OBJECTIVE: To observe ability of removal of β_2-microglobulin (β_2M) from serum using two kinds of polyethersulfone (PES) membrane materials with various degrees of sulfonation.METHODS: These materials were incubated in radio-labeled β_2M (~(125)Ⅰ-β_2M) solution and human serum respectively at appointed time at 37 ℃, and then the amounts of ~(125)Ⅰ-β_2M and serumβ_2M adsorbed by materials were measured by radio immunoassay. RESULTS AND CONCLUSION: In the ~(125)Ⅰ-β_2M system, amounts of ~(125)Ⅰ-β_2M adsorbed by the materials decreased in the following sequence PES with high degree of sulfonation > PES with low degree of sulfonation > PES, whatever the source of PES was. In the serum system, amounts of β_2M adsorbed reached maximums at 30 minutes and the final adsorptions decreased in sequence of PES with high degree of sulfonation > PES with low degree of sulfonaUon > PES. Sulfonated PES removed β_2M more than PES did and the adsorption of β_2M increases with the increase in the degree of sulfonation. Its ability to remove significant amount of β_2M may result in less β_2M available for incorporation into amyloid. The use of sulfonated PES membranes may lessen the likelihood of development of dialysis-related amyloidosis, which remains a major source of morbidity for patients treated with long-term hemodialysis.

Study on adsorption of methylene blue by sulfonated polyethersulfone II. The adsorption of methylene blue by sulfonated polyethersulfone in plasma / 生物医学工程学杂志

The evaluation of the adsorption of methylene blue (MB) in plasma by sulfonated polyethersulfone (SPES) adsorbent column was carried out in this study. The results indicated the adsorption of MB by SPES adsorbent column was more efficient than that by polyethersulfone (PES). In addition, the changes of the concentration of BSA solution passing through adsorbent column along with the time and the biochemical indices of plasma before and after adsorption treatment were also investigated. The results showed that the adsorption amount of BSA by PES adsorbent column was larger than that by SPES, and the biochemical parameters such as total protein, albumin, glucose, triglyceride and total cholesterol in plasma varied slightly before and after passing through the column, which were still within the clinical indices.

Study on adsorption of methylene blue by sulfonated polyethersulfone I. The preparation of sulfonated polyethersulfone and its adsorption of methylene blue in water / 生物医学工程学杂志

The evaluation of the adsorption of methylene blue (MB) in water by the sulfonated polyethersulfone (SPES) adsorbent column was carried out in this study after the SPES was prepared by gassy SO3 method. The polyethersulfone (PES) adsorbent column was used as control. The results indicated that the adsorption of MB by adsorbent column of SPES was more efficient than that of PES. In addition, the effect of the flow rate or ionic intensity on the adsorption and desorption of MB in water by SPES adsorbent column were also investigated. The results showed that the removal rate in water by SPES adsorbent column was larger than that in saline. However, the desorption experiment revealed that the desorption amount of the SPES adsorbent column in saline was larger than that in water.

Grafting and characterization of poly (ethylene glycol) on polysulfone sheets / 生物医学工程学杂志

Grafting of poly (ethylene glycol) (PEG) on the surface of polysulfone (PSF) sheets by simultaneous or sequential UV irradiation with 4-azidobenzoic acid as the photocoupler was carried out. Water contact angle measurements showed that there was a great improvement of hydrophilicity on the grafted surface. X-ray photoelectron spectroscopy suggested that the area covered by PEG be 77.3% and 41.9% respectively after grafting by simultaneous and sequential pathways. With atomic force microscope (AFM), obvious difference in the shape and the phase mode was observed between surfaces of PEG-g-PSF sheets made by these two pathways. Evidences implied that simultaneous pathway would produce a branched PEG layer on the surface, while sequential pathway was coupled with a "pan-cake" PEG layer on it. This study provides the foundation for further advancement in tethering brush-like PEG on PSF hollow fiber membranes.

Effect of sulfonation of polyethersulfone sheets on the adsorption of beta2-microglobulin / 生物医学工程学杂志

This study was performed to evaluate the adsorption of beta2-microglobulin(beta2 M) by blood dialysis membrane materials which are polyethersulfone (PES), sulfonated polyethersulfones, (PES-SO3Na-I and PES-SO3Na-I ) in vitro incubated in human serum and radiolabeled beta2M (125I-beta2 M) solution respectively. In these experiments, the materials were incubated in 125I-beta2 M solution and human serum at the appointed time ranging from 15 minutes to four hours at 37 degrees C, and then the amounts of 125I-beta2M and serum beta2M adsorbed by materials were measured by radioimmunoassay (RIA). In the 125I-beta2 M system, amounts of 125I-beta2M adsorbed by the materials decreased in sequence of PES-SO3 Na-II > PES-SO3Na-I > PES. In the serum system, amounts of beta2M adsorbed reached maximums at 30 minutes and the final adsorptions decreased in sequence of PES-SO3Na-II > PES-SO3Na-I > PES. Sulfonated PES removes beta2M more than PES does and the adsorption of beta2M increases with the increase in the degree of sulfonation. Its ability to remove significant amount of beta2M may result in less beta2M available for incorporation into amyloid. The use of PES-SO3Na membranes lessens the likelihood of dialysis-related amyloidosis (DRA) development, which remains a major source of morbidity for patients treated with long-term hemodialysis.

Synthesis and application of the polyacrylamide beads acting as LDL adsorbent's matrices / 生物医学工程学杂志

This study in pursuit of the synthetic technologies and structure characterization of polyacrylamide-based matrices (PAM beads) for low density lipoprotein (LDL) adsorbent and their adsorbability for LDL was intended for an experimental evidence of developing advanced matrices for LDL adsorbent. PAM beads were synthesized by inverse suspension polymerization, and their structure characterization was characterized by SEM, image analyzer and small angle X-ray scattering. The tripeptide serine-aspartic-glutamic acid (SDE) was coupled on the PAM beads to prepare the LDL adsorbents whose adsorbability for LDL was determined in vitro. The results showed that the PAM beads with the average size diameter 142.1 microm and the average pore diameter 119.8 nm could act as the matrices in accordance with the requirement of adsorbent for LDL. When the amount of acrylamide and the crosslinking agent N,N'-methylene-bis(acrylamide) was fixed, the average pore diameter decreased with the increase of the crosslinking agent content. Although the nonspecific binding of PAM beads for LDL was low, they could selectively adsorb LDL after coupling the SDE on the PAM beads.

Peptides used in lowering the level of LDL in plasma when treating familial hypercholesterolemia / 生物医学工程学杂志

While introducing the indications of low-density lipoprotein (LDL) apheresis, LDL absorption systems were reviewed generally. As the key components for binding LDL, four kinds of ligands which are synthesized by different principles are: 1. Positively charged peptides designed according to state charge force between ligand and LDL; 2. Peptides designed according to structural characteristics of the binding site between LDL and its receptors; 3. Antibody of Lp (a) obtained by immunizing mammals with designed peptides with the characteristics of Lp (a); 4. Segments of LDL binding proteins (LBPs) synthesized with genetic engineering method based on the specific binding of LBPs to LDL. Requirements of matrices carrying these ligands are also considered. Finally, future developments in treatments of familial hypercholesterolemia by means of blood purification using synthesized peptides are overlooked.