Electrochemical polymerization of functionalized thiophene derivatives for the immobilization of proteins

The hydroxy group of 3-(2-hydroxyethyl)thiophene was protected as methyl ether 1 and as dimethyl tert-butyl silyl ether 5 before anodic polymerization. The poly[3-(2-methoxyethyl)thiophene] 2 was prepared by electrochemical homopolymerization of 1 . Ether cleavage was carried out in the polymer film 2 and the resulting poly [3-(2-hydroxyethyl)thiophene] ( 3 ) was activated with cyanogen bromide to immobilize alcohol dehydrogenase. Silylether 5 did not undergo homopolymerization but copolymerization of 5 with 3-methylthiophene ( 4 ) was successful. After cleavage of the protecting group the resulting copolymer 7 was activated by cyanuric chloride, and chymotrypsin was immobilized. Electrocopolymerization of thiophene-3-acetic acid ( 8 ) and 3-methylthiophene ( 4 ) under various conditions produces copolymer 9 . By activation of the carboxylic groups with N,N'-dicyclohexylcarbodiimide (DCC) lactate oxidase (LOD) was bond to the surface of the electrode to form a lactate sensor.     

HEMA与HEA辐射共聚制备固定化微生物载体的结构与性能

应用低温辐射技术辐射诱导甲基丙烯酸β-羟乙酯(HEMA)和丙烯酸羟乙酯(HEA)共聚合制备了高分子载体,用增殖细胞技术固定氨氧化细菌。利用红外光谱(FT-IR)、X射线光电子能谱(XPS)、X射线衍射(XRD)、扫描电子显微镜(SEM)以及接触角和含水率的测试对聚合物载体进行了性能表征。结果表明:经充分溶胀后的聚合物表面水接触角几乎为0,含水率为450%,润湿性能良好;聚合物表面具有极性官能团;聚合物的非晶结构有利于小分子尤其是水分子的渗透和扩散,多孔结构有利于微生物的生长和繁殖。以聚合物为载体固定化氨氧化细菌在处理含氨废水的过程中实现了短程硝化,在3种氨氮负荷(100、1502、00 mg/L)条件下,氨氮去除率和亚硝化率可分别达到95%和90%以上。     

SYNTHESIS OF POLY(METHYL METHACRYLATE)-graft-POLYSTYRENE BY ATOM TRANSFER RADICAL POLYMERIZATION

The radical copolymerization of methyl methacrylate and 2-hydroxyethyl methacrylate was carried out via atomtransfer radical polymerization (ATRP) initiated by ethyl 2-bromoisobutyrate and catalyzed by CuBr/2,2'-bipyridinecomplex. This polymerization proceeds in a living fashion with controlled molecular weight and low polydispersity. Theobtained copolymer was esterified with 2-bromoisobutylryl bromide yielding a macroinitiator, poly(methyl methacrylate-co-2-hydroxyethyl methacrylate-co-2-(2-bromoisobutyryloxy)ethyl methacrylate), and its structure was characterized by ~1H-NMR. This macroinitiator was used for ATRP of styrene to synthesize poly(methyl methacrylate)-graft-polystyrene. Themolecular weight of graft copolymer increased with the monomer conversion, and the polydispersity remained relatively low.The individual grafted polystyrene chains were cleaved from the macroinitiator backbone by hydrolysis and the hydrolyzed product was characterized by ~1H-NMR and GPC.     

Production of anomalous particles in the process of emulsifier-free emulsion copolymerization of styrene and 2-hydroxyethyl methacrylate

It was found that copolymer particles produced by emulsifier-free emulsion copolymerization of styrene and 2-hydroxyethyl methacrylate had an anomalous shape with uneven surface. The formation mechanism is discussed.     

Poly(N-isopropylacrylamide) with hydrolyzable lactic acid ester side groups: a new type of thermosensitive polymer

N-isopropylacrylamide (NIPAAm) was copolymerized with 2-hydroxyethyl methacrylate-monolactate (HEMA-monolactate). With increasing HEMA-monolactate content in the copolymer, the lower critical solution temperature (LCST) decreases. During incubation in an aqueous solution, the lactate groups are released by hydrolysis, by which the copolymer is converted into poly(NIPAAm-co-HEMA). By this process, the hydrophilicity of the copolymer increases, resulting in increased LCST values.     

Synthesis and properties of electroactive polyaniline-graft-poly(2-hydroxy ethyl metacrylate) copolymers

In this paper we report on the synthesis of a polyaniline-graft-poly(2-hydroxy ethyl metacrylate), which was obtained by atom-transfer radical polymerization of 2-hydroxy ethyl metacrylate using polyaniline as a macroinitiator. The latter was prepared by chemical oxidation (interfacial method) and further modification. Macroinitiator and graft copolymer were characterized by FTIR and ¹H NMR spectroscopy. The scanning electron microscopy and atomic force microscopy images showed the growing of poly(2-hydroxy ethyl metacrylate) chains on polyaniline backbone. The solubility test revealed that the polyaniline-graft-poly(2-hydroxyethyl metacrylate) copolymer is water soluble and some organic solvents soluble. The cyclic voltammetry study confirmed the electroactivity of the copolymer.     

Grafting of Polystyrene-b-Poly(2-hydroxyethyl methacrylate) onto Carbon Fiber

Carbon fiber (CF) was subjected to oxidation and acyl chlorination, resulting in CF functionalized with acyl chloride (CF-COCl). The block copolymer polystyrene-b-poly (2-hydroxyethyl methacrylate) (PSt-b-PHEMA) was synthesized by atom-transfer radical polymerization (ATRP). According to the reaction between hydroxyl groups of block copolymer and acyl chloride groups on CF, the block copolymer was successfully grafted onto the surface of CF. Fourier-transform infrared spectra (FTIR), Gel permeation chromatography (GPC) were used to determine the chemical structure and molecular weight of block copolymer; Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR), Scanning electron microscopy (SEM) and thermal gravimetric analyses (TGA) were used to determine the chemical property and structure of grafted CF.     

Vinyl 2-hydroxyethyl sulfide polymers and their sorption properties with respect to transition metals

Vinyl 2-hydroxyethyl sulfide (VHES) homopolymer and the homopolymer and vinyl 2-hydroxyethyl sulfide-acryl amide copolymer cross-linked by bisacrylamide were prepared by radical polymerization. The sorption of Au(III), Ag(I), Pd(II), Pt(IV), Hg(II), Pb(II), Fe(III), Ni(II), Cu(II) on these polymers under the static conditions was studied in relation to the solution pH. The polymers are highly selective and efficient sorbents for Au(III), Ag(I) and Hg(II).     

Preferential adsorption of bovine serum albumin dimer onto polymer microspheres having a heterogeneous surface consisting of hydrophobic and hydrophilic parts

The adsorption behaviors of bovine serum albumin (BSA) containing both dimeric and monomeric species onto polymer microspheres were examined using various homopolymers and poly(2-hydroxyethyl methacrylate)/polystyrene composite microspheres which were produced by the emulsifier-free (seeded) emulsion polymerization technique. The preferential adsorption of the BSA dimer was clearly observed in an optimum region of the surface hydrophilicities of the polymer microspheres. The preferential adsorption of the BSA dimer onto the composite polymer microspheres having heterogeneous surfaces consisting of hydrophilic and hydrophobic parts was more marked than those onto the homopolymer and copolymer microspheres having homogeneous surfaces.     

Novel hydrogel membrane based on copoly(hydroxyethyl methacrylate/p-vinylbenzyl-poly(ethylene oxide)) for biomedical applications: properties and drug release characteristics

The aim of this study was to synthesize and characterize a novel biocompatible polymeric membrane system and demonstrate its potential use in various biomedical applications. Synthetic hydrogels based on poly(hydroxyethyl methacrylate), poly(HEMA), have been widely studied and used in biomedical fields. A novel copolymer hydrogel was prepared in the membrane form using 2-hydroxyethyl methacrylate monomer (HEMA) and a macromonomer p-vinylbenzyl-poly(ethylene oxide) (V-PEO) via photoinitiated polymerization. A series of poly(HEMA/V-PEO) copolymer membranes with different compositions was prepared. The membranes were characterized using infrared, thermal and SEM analysis. The thermal stabilities of the copolymer membranes were found to be lowered by an increase in the ratio of macromonomer (V-PEO) in the membrane structure. Because of the incorporation of PEO segments, the copolymers exhibited significantly higher hydrophilic surface properties than pure poly(HEMA), as demonstrated by contact angle measurements. Equilibrium swelling studies were conducted to investigate the swelling behavior of the membranes. The equilibrium water uptake was reached in about 4 h. Moreover, the blood protein adsorption and platelet adhesion were significantly reduced on the surface of the PEO containing copolymer membranes compared to control pure poly(HEMA). Drug release experiments were performed in a continuous release system using model drug (vancomycin) loaded copoly(HEMA/V-PEO) membranes. A specific poly(HEMA/V-PEO) membrane formulation possessing the highest PEO content (with a HEMA:V-PEO (mmol:mmol) feed ratio of 112:1 and loaded with 40 mg antibiotic/g polymer) released about 81% of the total loaded drug in 24 h at pH 7.4. This membrane composition provided the best results and can be considered as a potential candidate for a transdermal antibiotic carrier and various biomedical and biotechnological applications.     

Structure changes on polymer blends by means of phase growth on microheterophase surface

We have studied the structural changes on poly(2-hydroxyethyl methacrylate) (PHEMA)/polystyrene (PS) blends by means of phase growth of microheterophase pattern on a template surface composed of poly[2-hydroxyethyl methacrylate (HEMA)-g-styrene (S)] graft copolymer (lamellar shape). The PS macromonomer was synthesized by free radical polymerization of S monomer initiated by a functional initiator [2,2'-azobis(2-(2-imidazolin-2-yl)propane: VA-061] in the presence of a degradative chain transfer agent, followed by an end-capping reaction with p-chloromethylstyrene (CMS). Poly(HEMA-g-S) graft copolymers were prepared by free radical copolymerization of these vinylbenzyl-terminated PS macromonomers with HEMA comonomer.     

丙磺舒药物键合两亲共聚物的制备

丙磺舒药物键合两亲共聚物的制备;丙磺舒; 两亲共聚物; 高分子药物     

Resolution of lymphocyte subpopulations derived from rat spleen by polyamine-graft-PHEMA copolymer

The retention behavior of lymphocyte subpopulations, B cell, T cell and null cell, derived from rat spleen to polyamine-graft-poly(2-hydroxyethyl methacrylate) copolymer (HA) surface was investigated, focusing on the conformational transition of the polyamine side chain as well as the protonation of amino groups in the polyamine grafts. Furthermore, the availability of HA was discussed as a column adsorbent for separation of lymphocyte subpopulations derived from spleen. The conformational transition of polyamine grafts significantly influenced the mode of retention of lymphocyte subpopulations. When polyamine grafts existed in an aggregated conformation (protonatin degree α < 0.5), the retention of lymphocyte subpopulations was decreased in the order B cell> null cell> T cell. On the other hand, when polyamine existed in an extended conformation into the aqueous interior from the matrix interface (α > 0.5), T cell retention became greater than null cell retention, resulting in a decreased B cell> T cell> null cell order. These results indicate that the differential retention of spleen lymphocyte subpopulations is attributed to their differential responses to the change in matrix interface accompanied by the protonation of amino groups. Furthermore, spleen lymphocytes were compared with lymph node lymphocytes in terms of resolution efficacy by an HA copolymer column.     

Synthesis and characterization of tapered copolymer brushes via surface-initiated atom transfer radical copolymerization

Tapered copolymer brushes of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) were synthesized via surface-initiated atom transfer radical polymerization (ATRP) by gradual addition of HEMA to a reaction mixture that originally only had MMA as monomer. The copolymer brush grew linearly with polymerization time. The tapered copolymer brushes responded to selective solvent treatments. For the same tapered copolymer brush, pretreating the surface with methylene chloride made the surface more hydrophobic; pretreating the surface with methanol increased the surface hydrophilicity. This change in surface properties was reversible and considered to be caused by the solvent induced rearrangement of the polymer brushes, which is supported by atomic force microscopy images of the surface. Our work demonstrates that the properties of the tapered copolymer brush could be finely tuned by careful control of the composition profile.     

Controlled Activity Polymers. IV. Copolymers of 2-(1-Naphthylacetyl)Ethyl Acrylate With Hydrophilic Comonomers: Synthesis and Characterization

2-(1-Naphthylacetyl)ethyl acrylate (NAEA) was synthesized by esterification of 1-naphthylacetic acid (NAA) and 2-hydroxyethyl acrylate (HEA) and then polymerized to obtain the polymer-bound auxin NAA. The resulting polymer is potentially useful as a plant growth regulator through hydrolytic release of NAA. Copolymers of NAEA with hydrophilic comonomers were prepared by solution polymerization. The copolymer compositions were determined from elemental analysis, ¹³C-NMR, and UV spectroscopy. The copolymer microstructure was predicted from the reactivity ratios in order to investigate the influence on the behavior of controlled release. These model structures will be utilized for assessment of structure/hydrolysis relationships in a subsequent paper.     

Complex formation of amphiphilic polymers with azo dyes and their photoviscosity behavior

The hydrophobic interaction of amphiphilic copolymers, which contain 2-hydroxyethyl methacrylate(HEMA) and 1vinyl-2-pyrrolidone (VPy), with Methyl Orange (MO) was compared with that of HEMA-acrylamide (AAm) copolymers to deduce the correlation between their complexation ability in a photochromic azo dye and the photoviscosity effect in aqueous copolymer/dye complex solution. On the basis of the dialysis data and fluorometric analysis it appeared that the complexation dependence on HEMA content in the copolymers was due to the hydrophobic interaction between the polymer and the dye. For a comparable HEMA content AAm copolymers bound less MO than VPy copolymers. It was confiied by photoviscosity measurements that the conformation of the complex composed of photochromic azo dye and HEMA copolymer changed reversibly in response to the photo- and thermal isomerization of the dye. In HEMA-AAm copolymer systems the photoviscosity effect was small compared with that of HEMA-VPy copolymer systems. From these results it was concluded that the complexation ability of polymers due to the hydrophobic interaction was an important factor in producing a large photoinduced conformational change in water.     

Effect of copolymer type and composition on separation characteristics of pervaporation membranes—A case study with separation of acetone–water mixtures

Five different copolymer membranes, i.e. copolymer of acrylonitrile with 2-hydroxyethyl methacrylate (PANHEMA), vinyl acetate (PANVAC) and methyl methacrylate (PANMMA) and styrene with vinyl acetate PSTYVAC) and methyl methacrylate (PSTYMMA) were synthesized, each with two different copolymer compositions (i.e. PANHEMA-1, PANHEMA-2, etc.). The copolymer membranes were synthesized on the basis of their relative solubility parameters with respect to acetone and hydrophilicity with respect to water. These membranes were used for pervaporative dehydration of acetone over the entire concentration range of 0–100 wt% water as well as acetone separation over 0–44 wt% acetone in feed. The acrylonitrile copolymers showed water selectivity with maximum water flux and selectivity for PANHEMA-2 copolymer (29.3 g/(m² h), 16.73, respectively, for 2.5 wt% water in feed) while the styrene copolymers showed maximum acetone selectivity with reasonable acetone flux for PSTYMMA-1 copolymer (7.12 g/(m² h), 12.61, respectively, for 1.6 wt% acetone in feed) membrane. The influence of one permeant on permeation of the other permeant was also studied in terms of permeation factor.     

Synthesis and properties of polymeric and organo-inorganic amphiphilic sorbents molecularly imprinted with cholesterol

Polymeric and organo-inorganic sorbents molecularly imprinted with cholesterol were synthesized to create selective hemosorbents for efferent therapy of hypercholesterlemia. These sorbents are block copolymers of 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate and granulated organo-inorganic sorbents in which the imprinting was performed in the layer of the above copolymer on the surface of selenium (Se) nanoparticles stabilized with polyvinyl pyrrolidone. The physicochemical and sorption properties of the sorbents were studied.     

Spectroscopic investigations into degradation of polymer membranes for fuel cells applications

The research was focused on synthesis of proton conductive, easily degradable polymer membranes, which can be used as a model system to verify the efficiency of transition metal ions (TMI) in prevention of polymer degradation. Two polymers composed of 2-hydroxyethyl methacrylate (HEMA), 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS), and styrenesulfonic acid (SS) were synthesized. The copolymers were characterized by gel permeation chromatography (GPC), elementary analysis, and FTIR and fluorescence spectroscopies. The results allowed determination of weight-average molecular weight and the copolymer composition. The protons of sulfonic groups were substituted by paramagnetic transition metal ions of various spin states (Cr(3+), S=3/2 and Mn(2+), S=5/2) with the loading varying from 0.5 up to 10 mol%. The effectiveness of spin catalysis was checked by EPR. The results obtained indicate enhancement of polymer stability in the presence of Mn(2+).     

Conformational studies of copoly (N 5-ω-hydroxyalkyl-L-glutamine-L-glutamic acid)s

Copoly (α-amino acid)s consisting ofL-glutamic acid residue andN ⁵-ω hydroxyalkyl-L-glutamine residue, i.e., 2-hydroxyethyl, 3-hydroxypropyl, and di-2-hydroxyethyl derivatives were prepared by the reactions of copoly (L-glutamic acid) containing succinimide ester with corresponding amino alcohols. The conformation of these copolymers was examined by the CD and infrared measurements. These three copolymers containing about 20–30% hydroxyalkyl groups undergo a methanol-induced and a pH-induced conformational transitions. The copolymer containing about 50% 3-hydroxypropyl group assumes the α-helical conformation in the pH region from 2.5 to 11.6, and in a methanol-water mixture (9∶1). On the other hand, the copolymer containing about 60% di-2-hydroxyethyl groups does not allow any helical conformation even at lower pH and also even in a trifluoroethanol-water mixture (9∶1), suggesting that the branched hydroxyalkyl group is unfavorable for the formation of α-helix. Furthermore, the poly(N ⁵-di-2-hydroxyethyl-L-glutamine) is shown to have a rather disordered structure in the solid state.