Surface modification of polycarbonate urethane by grafting polyethylene glycol and bivalirudin drug for improving hemocompatibility

As the clinical demand for blood-contacting materials increases, higher requirements are placed on their physicochemical properties, durability and hemocompatibility in vivo. In this work, a multiple functionalized material was developed through a facile modification process. Herein, polycarbonate urethane (PCU) surface was co-modified with polyethylene glycol (PEG) and bivalirudin (BVLD). PCU provides excellent physical and mechanical properties, PEG and BVLD, especially BVLD, enable the surface with outstanding anticoagulant capacity. Specifically, PCU surface was first treated with hexamethylene diisocyanate to introduce active isocyanate groups onto the surface, followed by hydroxy-PEG grafting to improve the hydrophilicity. Finally, BVLD was immobilized on the surface via Michael addition reaction to improve antithrombotic properties. Attenuated total reflection Fourier transforms infrared spectroscopy and UV spectrophotometers were used to confirm the modified surfaces. The hydrophilicity was characterized by static water contact angle measurement, the morphology of the modified surfaces was observed by scanning electron microscopy. Blood compatibility of the modified surfaces was characterized by the hemolysis rate, platelet adhesion assay and cell culture test. The results showed that the BVLD immobilized surface has excellent anticoagulant properties, good fibrin-bound thrombin inhibition, and good resistance against non-specific adhesion of proteins. Hence, the co-modification with PEG and BVLD was proved an encouraging strategy for improving hemocompatibility.     

Studies on polyethylene glycol/polyethersulfone composite membranes for FCC gasoline desulphurization by pervaporation

A polyethylene glycol (PEG)/polyethersulfone (PES) composite membrane that can be applied on a commercial (or scale up) plant for fluid catalytic cracking (FCC) gasoline desulphurization was prepared through pre-wetting combined with double-layer coating methodology. Preparation methodology, morphologies characterization and performance test for the composite membranes were conducted. The results indicated that the pre-wetting method effectively confined the intrusion of PEG solution to porous PES support layer in coating process. The composite membrane had a clear-cut boundary surface between the dense active layer and the porous support layer, which was examined by scanning electron microscope (SEM). Pervaporation (PV) experiments indicated that the membrane, with the crosslinking agent amount of 17% and solids content in active layer solution of 16%, had a stable performance for FCC desulphurization. The sulphur enrichment factor came to 3.63, and the total permeation flux was 3.37 kg/m² h. It was found that the PV performance of the composite membrane changed slightly when the thickness of active layer varied from 4.25 μm to 33.26 μm.     

聚四氟乙烯膜分离技术在含油废水处理中的应用进展

世界生态环境逐渐恶化,为保护生态环境,含油废水的无害化处理排放成为保护生态环境的必要做法。膜处理技术作为20世纪最具发展前景的污水处理技术之一,具备低能耗,分离效率高等特点。聚四氟乙烯薄膜（PTFE）膜由于其具有的极高化学稳定性、良好的力学性能、过滤速度高、使用寿命长等特点,被广泛应用于水处理领域。为此本文概述膜分离原理,结合膜本身特点和改性方法,重点对PTFE膜及其改性膜在含油废水中的应用进行综述,并探讨了PTFE膜在应用过程中亟待解决的问题,为PTFE膜及其改性膜在水处理中的应用提供技术和理论支持。     

Heparin-like surface modification of polyethersulfone membrane and its biocompatibility

Sulfonated polyethersulfone (SPES) and poly (acrylonitrile-co-acrylic acid-co-vinyl pyrrolidone) (P(AN-AA-VP)), which provided sulfonic acid (SO(3)H) and carboxylic acid groups (COOH), respectively, were used to modify polyethersulfone (PES) membrane with a heparin-like surface by blending method. The SPES was prepared by sulfonation of PES using chlorosulfonic acid as the sulfonating agent, while the P(AA-AN-VP) was prepared through a free radical polymerization. The PES and modified PES membranes were prepared by a phase-inversion technique; the modified membranes showed lowered protein (bovine serum albumin, BSA; bovine serum fibrinogen, FBG) adsorption and suppressed platelet adhesion. For the modified membranes, significant decreases in thrombin-antithrombin (TAT) generation, percentage platelets positive for CD62p expression, and the complement activation on C3a and C5a levels were observed compared with those for the pure PES membrane. Due to the similar negatively charged groups as heparin, the modified membranes effectively prolonged the activated partial thromboplastin time (APTT). Furthermore, the modified membranes showed good cytocompatibility. Hepatocytes cultured on the modified materials exhibited improved functional profiles in terms of scanning electron microscope (SEM) observation and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay compared with those on the pure PES membrane. It could be concluded that the modified membranes with sulfonic acid and carboxylic acid groups were endowed with excellent biocompatibility, and the heparin-like surface modification seemed to be a promising approach to improve the biocompatibility of materials.     

Chemical modification of hyperbranched ultrathin films on gold and polyethylene

Synthetic methods for modifying the carboxylic acid groups of hyperbranched thin film grafts were studied. Amidation, esterification, reduction, and alkylation reactions of carboxylic acid derivatives that proceed in high conversion (>90%) are described. The stability of ultrathin, hyperbranched film grafts attached to self‐assembled monolayers on gold to conditions of strong base, strong acid, heat, and organic solvents is detailed. Practical procedures that can be used to prepare and modify poly(acrylic acid) hyperbranched grafts on gold, polyethylene film, and powder for use in the synthesis of cationic polyelectrolyte grafts, for use in the synthesis of poly(allyl alcohol) grafts, for use in the synthesis of poly(allyl ester) grafts, and for use as substrates for organometallic chemistry and further graft chemistry are discussed. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3944–3953, 2000     

SPC/PVDF membranes for emulsified oily wastewater treatment

New membranes based on sulfonated polycarbonate (SPC) and polyvinylidene fluoride (PVDF) were prepared. SPC was obtained by treating polycarbonate (PC) with acetyl sulfate. The ion exchange capacity (IEC) of the sulfonated polymer was 0.6753 meq/g. Scanning electron microscopy revealed that the SPC/PVDF membranes constituted heterogeneous blends. Porosimetric measurements by liquid–liquid displacement indicated that there is no substantial change in pore-size distribution due to growing SPC content. Membrane performance was assessed using an oil–water emulsion. Results indicated that the membranes present lower fouling as SPC content increases. When using the resistances-in-series model to quantify fouling, membranes containing 20% of SPC did not present irreversible fouling.     

Surface modification of polyethersulfone membranes by blending triblock copolymers of methoxyl poly(ethylene glycol)-polyurethane-methoxyl poly(ethylene glycol)

The surface of polyethersulfone (PES) membrane was modified by blending triblock copolymers of methoxyl poly(ethylene glycol)-polyurethane-methoxyl poly(ethylene glycol) (mPEG-PU-mPEG), which were synthesized through solution polymerization with mPEG Mns of 500 and 2000, respectively. The PES and PES/mPEG-PU-mPEG blended membranes were prepared through spin coating coupled with liquid-liquid phase separation. FTIR and (1)H NMR analysis confirmed that the triblock copolymers were successfully synthesized. The functional groups and morphologies of the membranes were studied by ATR-FTIR and SEM, respectively. It was found that the triblock copolymers were blended into PES membranes successfully, and the morphologies of the blended membranes were somewhat different from PES membrane. The water contact angles and platelet adhesion were decreased after blending mPEG-PU-mPEG into PES membranes. Meanwhile, the activated partial thromboplastin time (APTT) for the blended membranes increased. The anti-protein-fouling property and permeation property of the blended membranes improved obviously. SEM observation and 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay proved the surfaces of the blended membranes promoted human hepatocytes adhesion and proliferation better than PES membrane.     

The application of ultrafiltration for treatment of ships generated oily wastewater

The wastewaters collected from ships were preliminary separated in harbour installation into an oil fraction (slop oil) and the aqueous phase. The oil phase was then separated from slop oil, and the resulting water phase was subjected to the treatment in a coagulation/flotation process. The effluent (oil content 7–13 ppm) from these processes was further purified in biological wastewater treatment plant. A composition of bilge water is variable what affects the efficiency of coagulation/flotation process and the effluents may contain a significant amount of oil residues. The purification of effluents from coagulation/flotation process was performed in this work with ultrafiltration (UF), using FP100 membranes. The turbidity of obtained UF permeate was varied in the range of 0.08–0.26 NTU and the oil content was at a level of 0.9–1.1 ppm. Such purified water can be utilized for rinsing the oil–water separation devices located in the wastewater treatment plant, instead of tap water used so far. The obtained UF retentate contained 30 ppm of oil can be recycled to the coagulation/flotation process. Fouling of UF membranes was observed during the separation process, however, the FP100 membranes were effective cleaned with alkaline cleaning agents P3 Ultrasil 11.     

MBA接枝聚丙烯微孔膜的亲水改性研究

运用表面吸附法使聚丙烯微孔膜表面覆盖上引发剂,然后浸入氮氮亚甲基双丙烯酰胺(MBA)水溶液在一定温度下进行接枝反应。研究了引发剂用量,单体浓度,反应时间与温度对接枝率的影响,并用红外、扫描电镜对聚丙烯膜接枝前后的微孔膜进行了表征。同时对膜的亲水性和水通量进行了测试,发现其亲水性能有了极大的提高,其中接枝改性后接触角与未接枝的相比降低了90°以上,吸水率最多提高了12%,但是水通量有所下降。还对改性微孔膜的抗污染性能进行了探究。     

Alteration of bacterial nanocellulose structure by in situ modification using polyethylene glycol and carbohydrate additives

Bacterial nanocellulose (BC) is characterized by an exciting interconnection of the important and well-known cellulose properties with the outstanding features of nano-scale materials. As a remarkable benefit of BC the property-controlling fiber network and pore system formed by self-assembly of the cellulose molecules can be modified in situ using additives during biosynthesis. The addition of polyethylene glycol (PEG) 4000 causes a pore size decrease. In presence of β-cyclodextrin or PEG 400 remarkably increased pores can be achieved. Surprisingly, these co-substrates act as removable auxiliaries not incorporated in the BC samples. In contrast, carboxymethyl cellulose and methyl cellulose as additives lead to structural modified composite materials. Using cationic starch (2-hydroxy-3-trimethylammoniumpropyl starch chloride, TMAP starch) double-network BC composites by incorporation of the starch derivative in the BC prepolymer were obtained.     

Preparation of silica-supported porous sorbent for heavy metal ions removal in wastewater treatment by organic-inorganic hybridization combined with sucrose and polyethylene glycol imprinting

A new porous sorbent for wastewater treatment of metal ions was synthesized by covalent grafting of molecularly imprinted organic-inorganic hybrid on silica gel. With sucrose and polyethylene glycol 4000 (PEG 4000) being synergic imprinting molecules, covalent surface coating on silica gel was achieved by using polysaccharide-incorporated sol-gel process starting from the functional biopolymer, chitosan and an inorganic epoxy-precursor, gamma-glycidoxypropyltrimethoxysiloxane (GPTMS) at room temperature. The prepared porous sorbent was characterized by using simultaneous thermogravimetry and differential scanning calorimeter (TG/DSC), scanning electron microscopy (SEM), nitrogen adsorption porosimetry measurement and X-ray diffraction (XRD). Copper ion, Cu²⁺, was chosen as the model metal ion to evaluate the effectiveness of the new biosorbent in wastewater treatment. The influence of epoxy-siloxane dose, buffer pH and co-existed ions on Cu²⁺ adsorption was assessed through batch experiments. The imprinted composite sorbent offered a fast kinetics for the adsorption of Cu²⁺. The uptake capacity of the sorbent imprinted by two pore-building components was higher than those imprinted with only a single component. The dynamic adsorption in column underwent a good elimination of Cu²⁺ in treating electric plating wastewater. The prepared composite sorbent exhibited high reusability. Easy preparation of the described porous composite sorbent, absence of organic solvents, cost-effectiveness and high stability make this approach attractive in biosorption.     

色谱固定相的超支化和聚酰胺-胺树状大分子接枝修饰方法研究进展

随着色谱固定相制备技术深入发展,固定相填料的修饰方法日渐成熟,主要包括固定相表面直接化学反应、表面附聚、共价接枝和超支化修饰。其中,以缩聚反应为主的超支化修饰方法自提出以来备受研究者的青睐,已经被应用于多种阴离子交换色谱固定相填料的制备。近些年来,和超支化聚合物具有相似结构的树状大分子由于其独特的物理性能、完美的树状结构和大量活性官能团,也逐渐被应用于各种色谱固定相填料的修饰,并有望进一步完善固定相填料的结构和分离性能。该文主要总结了超支化修饰方法和以聚酰胺-胺为主的树状大分子接枝修饰方法在色谱固定相填料制备中的应用,并对其未来发展进行展望。     

喜树碱及其衍生物的聚乙二醇化学修饰药物研究进展

目的：喜树碱及其衍生物药物是一类重要的抗肿瘤药物,但其存在水溶性差、生物利用度低、毒副作用大等问题,喜树碱及其衍生物的聚乙二醇化学修饰具有十分诱人的前景,但目前国内研究较少,本文综述近年来喜树碱及其衍生物药物的聚乙二醇化学修饰研究进展。方法：以喜树碱（Camptothecin, CPT）、伊立替康（Irinotecan, CPT-11）、7-乙基-10-羟基喜树碱（7-ethyl-10-hydroxycamptothecin, SN38）、聚乙二醇（Polyethylene glycol, PEG）、聚乙二醇化喜树碱（PEG-CPT）等为关键词,查阅近几年国内外相关研究文献。结果与结论：综述了喜树碱及其衍生物的聚乙二醇化学修饰药物的研究进展与临床研究报道,为发掘结构明确、组成稳定的新型化学修饰药物提供理论基础和技术支撑。     

Hydrophilic modification of polyethersulfone membranes by low temperature plasma-induced graft polymerization

A complete and permanent hydrophilic modification of polyethersulfone (PES) membranes is achieved by argon plasma treatment followed by polyacrylic acid (PAA) grafting in vapor phase. Both Ar plasma treatment alone and post-PAA grafting rendered a complete hydrophilicity to the PES membranes. The hydrophilicity of the membranes treated with only the Ar plasmas is not, however, permanent. In contrast, the PES membranes treated with Ar plasma and subsequent acrylic acid (AA) grafting are permanently hydrophilic. High energy resolution X-ray photoelectron spectroscopy (XPS) confirmed the grafting of PAA to all surfaces of the membrane. Furthermore, water bubble point measurements remain unaffected. The pore sizes of the grafted membranes at higher grafting yield are slightly decreased. The modified membranes are less susceptible to protein fouling than the unmodified membranes and the pure water flux for the modified membranes was tremendously increased by plasma treatment. Furthermore, the modified membranes are easier to clean and required little caustic to recover permeation flux.     

A novel method of surface modification on thin-film-composite reverse osmosis membrane by grafting hydantoin derivative

Membrane degradations by biofouling and free chlorine oxidation are the major obstacles for aromatic polyamide thin-film-composite (TFC) reverse osmosis (RO) membranes to realize high performance over a long period of operation. In this work, a hydantoin derivative, 3-monomethylol-5,5-dimethylhydantoin (MDMH), was grafted onto the nascent aromatic polyamide membrane surfaces by the reactions with active groups (e.g., acyl chloride groups) in the surfaces. The grafted MDMH moieties with high reaction activity and free chlorine could play as sacrificial pendant groups when membranes suffer from chlorine attacks, and the chlorination products N-halamines with strong antimicrobial function could sterilize microorganisms on membrane surfaces and then regenerate to MDMH. This was designed as a novel means to improve both chlorine resistances and anti-biofouling properties of the aromatic polyamide TFC RO membranes.Attenuated total reflectance mode Fourier transform infrared spectroscopy (ATR-FTIR) revealed that the MDMH-modified membranes had two characteristic bands at 1772 and 1709 cm⁻¹ corresponding to two carbonyl groups in hydantoin ring. This suggested the successful grafting of MDMH onto the membrane surfaces, which was further confirmed and quantified by X-ray photoelectron spectroscopy (XPS) analysis. After modification with MDMH, the membrane surface hydrophilicity increased obviously as contact angles decreased from 57.7° to 50.4–31.5°. But, there was no obvious change in membrane surface roughness after modification. The MDMH-modified membranes were shown to possess high chlorine resistances with small changes in water fluxes and salt rejections after chlorination with 100–2000 ppm h chlorine at pH 4. The chlorinated MDMH-modified membranes demonstrated obvious sterilization effects on Escherchia coli and substantial preventions against microbial fouling. Therefore, the MDMH-modified membranes offer a potential use as a new type of chlorine resistance and anti-biofouling TFC RO membranes.     

Synthesis of amphiphilic linear‐hyperbranched graft‐copolymers via grafting based on linear polyethylene backbone

The synthesis of amphiphilic linear‐hyperbranched graft‐copolymers in a grafting‐from approach is reported. The linear polyethylene with terminated hydroxyls, prepared by copolymerization of ethylene and 10‐undecen‐1‐ol, was used as macroinitiator for ring‐opening multibranching polymerization of glycidol by a typical slow monomer addition approach. Successful attachment of the hyperbranched grafts to the linear polyethylene backbone was confirmed by ¹H/¹³C NMR, GPC, and TGA. The degree of polymerization and M_w/M_n of hyperbranched grafts were efficiently controlled by temperature, deprotonation ratio as well as the molar ratio of glycidol/hydroxyl (N_glycidol/N_OH). The complicated microstructures caused by unsymmetric glycidol structure were analyzed by DEPT and 2D HSQC spectra, the degree of branching of 0.63–0.66 were calculated, indicating the extent of branch is close to theoretical values. The thermal analysis of linear‐hyperbranched copolymers via TGA and DSC is also presented. To our knowledge, this is the first report of a linear‐hyperbranched graft‐copolymer with a crystalline and nonpolar linear‐polyethylene segment. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2146–2154     

Poly (methyl methacrylate) grafted wheat straw for economical and eco-friendly treatment of oily wastewater

Cellulose - The sustainable development of oil–gas and petrochemical industries necessitates the development of cost-effective and eco-friendly technologies to treat mass-produced oily...     

Purification and modification by polyethylene glycol of a new human basic fibroblast growth factor mutant-hbFGF(Ser25,87,92)

The mutant of human basic fibroblast growth factor (hbFGF), hbFGF(Ser25,87,92), which was constructed by replacing the cysteine residues at the positions of the 25th, the 87th and the 92nd with serine residues, was coupled to polyethylene glycol (PEG) with a molecular size of 20 kDa (20K) (PEG(20K)) to obtain hbFGF derivative, PEG(20K)-hbFGF(Ser25,87,92). The optimal modified reaction was conducted at 12 degrees C for 12h with the molar ratio of PEG(20K) to hbFGF(Ser25,87,92) of 30:1. The result of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that the modification rate was up to 60%. The PEGylated product retained binding affinity to heparin and could be purified by heparin affinity chromatography. Compared to hbFGF mutant, purified PEG(20K)-hbFGF(Ser25,87,92) retained about 34% of mitogenic activity. Heat-stability assay indicated that the modified product was more stable than the native protein at the temperature of 37 degrees C.     

Changes in enzymatic and membrane-adsorbing activities of sphingomyelinase from Bacillus cereus by modification with a polyethylene glycol derivative.

Sphingomyelinase (SMPLC) from Bacillus cereus was modified with a polyethylene glycol (PEG) derivative, methoxypolyethylene glycol-succinimidyl succinate (ss-PEG). The molecular weight of the ss-PEG-modified SMPLC was calculated to be approx. 150 kDa by gel-filtration whereas that of the native enzyme, was 25 kDa. By this modification, the enzyme increased its thermostability and retained its hydrolytic activity toward 2-(N-hexadecanoylamino)-4-nitrophenylphosphocholine (HNP) and sphingomyelin (SM) in the mixed micelles with the surfactants such as Triton X-100 and sodium deoxycholate (SDC). However, the activity toward liposomal SM was significantly decreased, and all the enzyme activities toward bovine erythrocytes, including membraneous SM-hydrolyzing and hemolytic activities as well as the enzyme adsorption onto the erythrocyte membranes, were completely lost.