Poly(HEMA-co-NBMI) Monolithic Cryogel Columns for IgG Adsorption

Supermacroporous poly(2-hydroxyethyl methacrylate-co-1,5-naphthalene bismaleimide) [poly(HEMA-co-NBMI)] monolithic cryogel column was prepared by free radical cryo-copolymerization of HEMA with NBMI as a hydrophobic functional comonomer and N,N′-methylene-bisacrylamide as cross-linker directly in a plastic syringe for adsorption of albumin. The monolithic cryogel contained a continuous polymeric matrix which has interconnected pores of 10–100 μm size. Poly(HEMA-co-NBMI) cryogel was characterized by swelling studies, FTIR and scanning electron microscopy. The equilibrium swelling degree of the poly(HEMA-co-NBMI) cryogel was 10.5 g of H₂O/g dry cryogel. Poly(HEMA-co-NBMI) cryogel was used in the adsorption/desorption of IgG from aqueous solutions. The maximum amount of IgG adsorption from aqueous solution in phosphate buffer was 98.20 mg/g polymer at pH 7.0. The nonspecific adsorption of IgG onto plain poly(HEMA) cryogel was very low (2.79 g/g polymer). It was observed that IgG could be repeatedly adsorbed and desorbed with the poly(HEMA-co-NBMI) cryogel without significant loss of adsorption capacity.     

单分散非多孔交联聚甲基丙烯酸环氧丙酯微球作为亲和色谱载体的研究

单分散、非多孔聚甲基丙烯酸环丙酯生球机械强度高,表面的环基易于修饰与键合,非常适宜于生物大分子的快速分离、纯化。对其表面环氧基浓度、非特异性地性能等进行了表征;并以胰蛋白酶抑制剂为配基,制备了胰蛋白酶抑制剂－交联聚甲基丙烯权环氧丙酯亲和色柱,考察了胰蛋白酶等蛋白南的亲和色谱行为,表明该基质适宜用作亲和色谱载体。提出以添加１％乙腈的方法,可有癣地消除此类载体的弱非特异性吸附,使人血清白蛋白的回收率     

Synthesis of Poly[(hydroxyethyl methacrylate)‐co‐(methacrylamidoalanine)] Membranes and Their Utilization as an Affinity Sorbent for Lysozyme Adsorption

Various adsorbent materials have been reported in the literature for protein separation. We have developed a novel and new approach to obtain high protein‐adsorption capacity utilizing a 2‐methacrylamidoalanine‐containing membrane. An amino acid ligand 2‐methacrylamidoalanine (MAAL) was synthesized from methacrylochloride and alanine. Then, poly[(2‐hydroxyethyl methacrylate)‐co‐(2‐methacrylamidoalanine)] [p(HEMA‐co‐MAAL)] membranes were prepared by UV‐initiated photopolymerization of HEMA and MAAL. The synthesized MAAL monomer was characterized by NMR spectrometry. p(HEMA‐co‐MAAL) membranes were characterized by swelling studies, porosimeter, scanning electron microscopy, FT‐IR spectroscopy and elemental analysis. These membranes have large pores; the micropore dimensions are around 5–10 μm. p(HEMA‐co‐MAAL) affinity membranes with a swelling ratio of 198.9%, and containing 23.9 (mmol MAAL)·m^–2 were used in the adsorption of lysozyme from aqueous media containing different amounts of lysozyme (0.1–3.0 mg·ml^–1) and at different pH values (4.0–8.0). The effect of Cu(II) incorporation on lysozyme adsorption was also studied. The non‐specific adsorption of lysozyme on the pHEMA membranes was 0.9 μg‐cm^–2. Incorporation of MAAL molecules into the polymeric structure significantly increased the lysozyme adsorption up to 2.96 mg·cm^–2. The lysozyme‐adsorption capacity of the membranes incorporated with Cu(II) (9.98 mg·cm^–2) was greater than that of the p(HEMA‐co‐MAAL) membranes. More than 85% of the adsorbed lysozyme was desorbed in 1 h in the desorption medium containing 1.0 M NaCl. The p(HEMA‐co‐MAAL) membranes are suitable for repeated use for more than 5 cycles without noticeable loss of capacity. These features make p(HEMA‐co‐MAAL) membrane a very good candidate for bioaffinity adsorption.     

Preparation of poly(hydroxyethyl methacrylate) and poly(hydroxypropyl methacrylate) latices

Hydroxyethyl methacrylate and hydroxypropyl methacrylate (both having extremely high solubilities in water) were polymerized in aqueous medium to obtain the respective polymer latices with a solid content as high as 10 wt.-%. The initial state of the polymerization is in solution rather than in dispersion, and the polymer product is sparingly soluble in the aqueous phase. The polymerization was carefully controlled to avoid forming hydrogel by using an oil soluble initiator and a mixture of sodium dodecyl sulfate and poly(vinyl alcohol). Solubilities of both monomers and polymers in water were also investigated.     

Poly(hydroxyethyl methacrylate) membranes: as a hydrogel support for use in immobilized metal affinity chromatography

Lysozyme adsorption onto a dye ligand (Procion Red HE-3B) immobilized and Cu(II) incorporated poly(2-hydroxyethylmethacrylate) (pHEMA) membrane, were investigated. The membranes were prepared by UV initiated photopolymerization of HEMA in the presence of an initiator (α-α′-azoisobutyronitrile; AIBN). The amount of immobilized dye on the membrane was 112.2 μmol g⁻¹. Lysozyme adsorption on to these membranes from aqueous solutions containing different amounts of lysozyme at different pH was investigated in batch system. Lysozyme adsorption capacity of the dye-ligand immobilized membrane was 45.6 mg g⁻¹. Lysozyme adsorption capacity of the Cu(II) incorporated membranes (112.3 mg g⁻¹) was greater than that of the Procion Red HE-3B immobilized membranes. The non-specific adsorption of lysozyme on the pHEMA membranes was 0.14 mg g⁻¹. More than 97% of the adsorbed lysozyme were desorbed in 60 in the desorption medium containing 1.0 M KSCN at pH 8.0.     

High Performance Affinity Chromatography of Antithrombin III Based on Monodisperse Poly (glycidyl methacrylate) Beads

Antithrombin III, a (2-glycoprotein and one of the major proteinase inhibitors in mammalian plasma, shows specific interaction with heparin. Therefore, immobilized heparin has been widely used as an adsorbent for the separation and purification of plasma components in blood-coagulation systems. Traditionally, affinity chromatography has been carried out at low pressure using soft gels made of polysaccharide1,2. Soft gels, however, is flow rate limited, susceptible to microbial degradation, an…     

Poly(alkyl methacrylate) monolithic columns for HPLC

Several monolithic macroporous polymer sorbents (pore size 1–2 µm) based on alkyl methacrylates and ethylene glycol dimethacrylate as a cross-linking agent were prepared by free radical copolymerization in columns 3×150 mm. The influence of compositions of the reaction mixture and porogens and the nature of the alkyl radical in a mixture of monomers on the hydrodynamic and chromatographic characteristics of the monoliths was studied. The monoliths based on n-butyl methacrylate have rigid macroporous morphology and excellent hydrodynamic characteristics (flow rate up to 5 mL min^?1). The efficiency of separation of a mixture of benzene and its derivatives in the version of reversed-phase HPLC was shown to increase with an increase in the fraction of a lauryl methacrylate additive (LMA) in the reaction mixture. The maximum separation efficiency (number of theoretical plates (tp)) was 35 000 tp m^?1 for the monolith based on n-butyl methacrylate with 7% LMA in the reaction mixture.     

Cysteine functionalized poly(hydroxyethyl methacrylate) monolith for heavy metal removal

The aim of this study was to investigate the performance of monoliths composed of hydroxyethyl methacrylate (HEMA) to which N-methacryloyl-(L)-cysteine methyl ester (MAC) was polymerized for removal of heavy metal ions. Poly(HEMA-MAC) monolith was produced by bulk polymerization. Poly(HEMA-MAC) monolith was characterized by FTIR and scanning electron microscopy (SEM). The poly(HEMA-MAC) monolith with a swelling ratio of 89%, and containing 69.4 μmol MAC/g were used in the adsorption studies. Adsorption capacity of the monolith for the metal ions, i.e., Cu²⁺, Cd²⁺, Zn²⁺, Hg²⁺, and Pb²⁺ were investigated in aqueous media containing different amounts of the ions (10–750 mg/L) and at different pH values (3.0–7.0). The maximum adsorption capacities of the poly(HEMA-MAC) monolith were 68.2 mg/g for Zn²⁺, 129.2 mg/g for Cu²⁺, 245.8 mg/g for Pb²⁺, 270.2 mg/g for Hg²⁺, and 284.0 mg/g for Cd²⁺. pH significantly affected the adsorption capacity of MAC incorporated monolith. The competitive adsorption capacities were 587 μmol/g for Zn²⁺, 1646 μmol/g for Cu²⁺, 687 μmol/g for Pb²⁺, 929 μmol/g for Hg²⁺, and 1993 μmol/g for Cd²⁺. The chelating monolith exhibited the following metal ion affinity sequence on molar basis: Cd²⁺ > Cu²⁺ > Hg²⁺ > Pb²⁺ > Zn²⁺. The formation constants of MAC–metal ion complexes have been investigated applying the method of Ruzic. The calculated values of stability constants were 5.28 × 10⁴ L/mol for Cd²⁺, 4.16 × 10⁴ L/mol for Cu²⁺, 2.27 × 10⁴ L/mol for Hg²⁺, 1.98 × 10⁴ L/mol for Pb²⁺, and 1.25 × 10⁴ L/mol for Zn²⁺. Stability constants were increased with increasing binding affinity. The chelating monoliths can be easily regenerated by 0.1 M HNO₃ with higher effectiveness. These features make poly(HEMA-MAC) monolith a potential adsorbent for heavy metal removal.     

Hydrogels of poly(hydroxyethyl methacrylate) and hydroxyethyl methacrylate—glycerol monomethacry-late copolymers

Hydrophilic three-dimensional polymer networks (hydrogels) were prepared from hydroxyethyl methacrylate (HEMA) and the copolymer HEMA and glycerol monomethacrylate (GMMA). The equilibrium water content of the hydrogels in water was investigated as a function of the initial dilution of the polymerization mixture, the type of solvent, and the hydrophilicity of the polymer. The initial dilution was found to have a decisive effect on the swelling or deswelling of hydrogels after the completion of the gel formation. With relatively less hydrophilic hydrogels, there is a critical initial dilution to produce the gel which does not swell or deswell in water after the gel formation. This “isovolumic” initial dilution shifts toward a higher dilution as the hydrophilicity of the hydrogels increases; however, when hydrophilicity of the polymer rises above a certain point, gels always swell in water. Permeability of oxygen through hydrogels was also studied.     

Creatinine imprinted poly(hydroxyethyl methacrylate) based cryogel cartridges

Creatinine imprinted cryogel (MIP) cartridge was prepared with functional monomer N-methacryloyl-(L)-histidinemethylester (MAH) under frozen conditions. Creatinine adsorption studies and selectivity of MIP cryogel were evaluated in aqueous solution and artificial urine sample. Maximum adsorbed amount of creatinine was calculated as 6.83 mg/g polymer for MIP cryogel. Langmuir and Freundlich adsorption isotherm models were used to investigate the adsorption behaviour of creatinine. In the artificial urine sample; recovery amounts of creatinine were found 34.7–46.2%. Creatinine imprinted cryogel (MIP) cartridge recognized creatinine, 4.58 and 4.37 times greater competitive molecules. MIP cryogel catridge was repeatedly used many times for adsorption desorption cycles.     

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

Bioaffinity 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.     

聚甲基丙烯酸甲酯型高分子染料的合成

高分子染料的合成研究起于６０年代初［１］．１９７３年，Ｍａｒｅｃｈａｌ等实现了无色高分子材料与有色染料分子的化学键合［２～３］．目前，高分子染料已广泛应用于化妆品、涂料、填料、食品等领域并开始探索在液晶显示、半导体材料、激光记录、非线性光学材料、亲和...     

Poly(3-hexylthiophene)/Poly(methyl methacrylate) Core-Shell Electrospun Fibers for Sensory Applications

New electrospun (ES) sensory fibers consisted of poly(methyl methacrylate) (PMMA) core and poly(3-hexylthiophene-2,5-diyl) (P3HT) shell were successfully prepared using a two-fluid coaxial electrospinning process. Field-emission scanning electron microscope (FE-SEM) studies showed that the prepared ES fibers had diameters of 500–700 nm and worm-like surface structure of P3HT on the fiber. Red emission fibers were exhibited from the laser confocal microscope. Upon exposed to air under light for two weeks, significant blue-shifting on both absorption and luminescence spectra was found on the prepared ES fibers. It was probably due to the chain scission occurred in the P3HT and led to the reduced conjugated length. The sensitivity of the ES fibers was much better than that of the spin-coated P3HT film from the comparison on the variation of photophysical properties. Besides, the EPR result indicated the formation of the P3HT · O₂ charge transfer complex (CTC), leading to the fiber conductivity of 10⁻⁶ S/cm without an external doping. The present study demonstrates that conjugated polymer based ES core-shell fibers may have potential applications for oxygen-sensing devices.     

RGDS‐ and SIKVAVS‐Modified Superporous Poly(2‐hydroxyethyl methacrylate) Scaffolds for Tissue Engineering Applications

Three‐dimensional hydrogel supports for mesenchymal and neural stem cells (NSCs) are promising materials for tissue engineering applications such as spinal cord repair. This study involves the preparation and characterization of superporous scaffolds based on a copolymer of 2‐hydroxyethyl and 2‐aminoethyl methacrylate (HEMA and AEMA) crosslinked with ethylene dimethacrylate. Ammonium oxalate is chosen as a suitable porogen because it consists of needle‐like crystals, allowing their parallel arrangement in the polymerization mold. The amino group of AEMA is used to immobilize RGDS and SIKVAVS peptide sequences with an N‐γ‐maleimidobutyryloxy succinimide ester linker. The amount of the peptide on the scaffold is determined using ¹²⁵I radiolabeled SIKVAVS. Both RGDS‐ and SIKVAVS‐modified poly(2‐hydroxyethyl methacrylate) scaffolds serve as supports for culturing human mesenchymal stem cells (MSCs) and human fetal NSCs. The RGDS sequence is found to be better for MSC and NSC proliferation and growth than SIKVAVS.

     

Poly(styrene peroxide) and Poly(methyl methacrylate peroxide) for Grafting on Unsaturated Bacterial Polyesters

A new soluble terephthaloyl oligoperoxide (OTP) was synthesized by the reaction of terephthaloyl peroxide and 2,5‐dimethyl 2,5‐dihydroperoxy hexane. Thermal polymerization of vinyl monomers (styrene, methyl methacrylate) with OTP yielded poly(styrene peroxide) (PS‐P) and poly(methyl methacrylate peroxide) (PMMA‐P) which are used in the grafting reactions onto medium chain length unsaturated bacterial polyester obtained from soybean oily acids with Pseudomonas oleovorans poly(3‐hydroxy alkanoate), (PHA). PS‐g‐PHA and PMMA‐g‐PHA graft copolymers isolated from related homopolymers were characterizated by ¹H NMR spectrometry, FT‐IR spectroscopy, thermal analysis and gel permeation chromatographic (GPC) techniques. Swelling measurement of the crosslinked graft copolymers were also measured to calculate q_v values.     

Dye attached poly(hydroxyethyl methacrylate) cryogel for albumin depletion from human serum

Cibacron Blue F3GA was immobilized on poly(hydroxyethyl methacrylate) cryogel and it was used for selective and efficient depletion of albumin from human serum. The poly(hydroxyethyl methacrylate) was selected as the basic component because of its inertness, mechanical strength, chemical and biological stability, and biocompatibility. Cibacron Blue F3GA was covalently attached to the poly(hydroxyethyl methacrylate) cryogel to produce poly(hydroxyethyl methacrylate)-Cibacron Blue F3GA cryogel affinity column. The poly(hydroxyethyl methacrylate)-Cibacron Blue F3GA cryogel was characterized with respect to gelation yield, swelling degree, total volume of macropores, Fourier Transform Infrared spectroscopy, and scanning electron microscopy. It was found that the maximum amount of adsorption (343 mg/g of dry cryogel) obtained from experimental results is very close to the calculated Langmuir adsorption capacity (345 mg/g of dry cryogel). The maximum adsorption capacity for poly(hydroxyethyl methacrylate)-Cibacron Blue F3GA cryogel column was obtained as 950 mg/g of dry cryogel for nondiluted serum. The adsorption capacity decreased with increasing dilution ratios while the depletion ratio of albumin remained as 77% in serum sample. Finally, the poly(hydroxyethyl methacrylate)-Cibacron Blue F3GA cryogel was optimized for using in the fast protein liquid chromatography system for rapid removal of the high abundant proteins from the human serum.     

High capacity binding of antibodies by poly(hydroxyethyl methacrylate) nanoparticles

Poly(hydroxyethyl methacrylate) (PHEMA) nanoparticles with an average size of 150 nm in diameter and with a poly-dispersity index of 1.171 were produced by a surfactant free emulsion polymerization. Specific surface area of the PHEMA nanoparticles was found to be 1779 m(2)/g. Reactive imidazole containing 3-(2-imidazoline-1-yl)propyl(triethoxysilane) (IMEO) was used as a pseudo-specific ligand. IMEO was attached covalently onto the nanoparticles. PHEMA-IMEO nanoparticles were used for the affinity binding of immunoglobulin-G (IgG) from human plasma. To evaluate the degree of IMEO loading, the PHEMA nanoparticles were subjected to Si analysis by using flame atomizer atomic absorption spectrometer and it was estimated as 64.5 mg/g of polymer. The nanoparticles were characterized by transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). IgG binding onto the PHEMA nanoparticles was found to be 5.2 mg/g. Much higher binding values (up to 843 mg/g) were obtained for the PHEMA-IMEO nanoparticles. IgG could be repeatedly bound and eluted on PHEMA-IMEO nanoparticles without noticeable loss in the IgG binding capacity.     

Stereocomplex Formation of Atactic Poly(methyl methacrylate)

Stereocomplexes formed in atactic poly(methyl methacrylate) (a-PMMA) films cast form different solvents were studied by means of Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The growth of stereocomplex was a function of annealing temperature and annealing time, respectively.     

Cross‐Linking and Degradation Properties of Plasma Enhanced Chemical Vapor Deposited Poly(2‐hydroxyethyl methacrylate)

Plasma Enhanced Chemical Vapor Deposition (PECVD) of poly‐2‐hydroxyethyl methacrylate (pHEMA) biocompatible, biodegradable polymer films were produced alone and cross‐linked with ethylene glycol diacrylate (EGDA). Degree of cross‐linking was controlled via manipulation of the EGDA flow rate, which influenced the amount of swelling and the extent of degradation of the films in an aqueous solution over time. Noncross‐linked pHEMA films swelled 10% more than cross‐linked films after 24 h of incubation in an aqueous environment. Increasing degree of film cross‐linking decreased degradation over time. Thus, PECVD pHEMA films with variable cross‐linking properties enable tuning of gel formation and degradation properties, making these films useful in a variety of biologically significant applications.