Reversible immobilization of glycoamylase by a variety of Cu2+-chelated membranes

Glycoamylase (AMG) is an ?-amylase enzyme which catalyzes the breakdown of large a(1,4)-linked malto-oligosaccharides to glucose. It is an extracellular enzyme and is excreted to the culture medium. In this study, AMG was immobilized on a variety of metal affinity membranes, which were prepared by chelating Cu2+ ions onto poly(hydroxyethyl methacrylate) (PHEMA) using N-methacryloyl-(L)-histidine methyl ester (MAH), N-methacryloyl-(L)-cysteine methyl ester (MAC), and N-methacryloyl-(L)-phenylalanine methyl ester (MAPA) as metal-chelating comonomers for reversible immobilization of AMG. The PHEMAH, PHEMAC, PHEMAPA membranes were synthesized by UV-initiated photo-polymerization and Cu2+ ions were chelated on the membrane surfaces. Cu2+-chelated membranes were characterized by swelling tests, SEM, contact angle measurements, elemental analysis, and FTIR. AMG immobilization on the Cu2+-chelated membranes was performed by using aqueous solutions of different amounts of AMG at different pH values and Cu2+ loadings. Durability tests concerning desorption of AMG and reusability of the Cu2+-chelated membranes yielded acceptable results. It was computationally determined that AMG possesses four likely Cu2+/Zn2+ binding sites, away from the catalytic site, to which the metal-chelated membranes can be efficiently used. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 201

Cadmium removal out of human plasma using ion-imprinted beads in a magnetic column

The aim of this study is to utilize ion-imprinted magnetic beads in the selective removal of Cd2+ ions out of human plasma overdosed with Cd2+ ions. The Cd (2+) imprinted magnetic poly(HEMA-MAC) (mPHEMAC-Cd2+) beads were produced by suspension polymerization in the presence of magnetite Fe3O4 in a nano-powder form. The template Cd2+ ions could be reversibly detached from the matrix to form mPHEMAC-Cd2+ beads using 0.1 M thiourea solution. The specific surface area of the mPHEMAC-Cd2+ beads was found to be 24.7 m(2)/g. The MAC and Fe3O4 contents of the mPHEMAC-Cd2+ beads were found to be 41.8 mu mol/g polymer and 8.2% on the average. The Cd2+ adsorption capacity of mPHEMAC-Cd2+ columns decreased drastically from 48.8 mu mol/g to 20.0 mu mol/g as the flow rate is increased from 0.50 ml/min to 3.0 ml/min. The maximum adsorption capacity of the mPHEMAC-Cd2+ beads was determined to be 48.8 mu mol Cd2+/g on the average. The relative selectivity coefficients of the mPHEMAC beads for Cd2+/Pb2+ and Cd2+/Zn2+ were 22.6 and 160.7 times greater than those of the non-imprinted magnetic PHEMAC (mPHEMAC) beads, respectively. The mPHEMAC-Cd2+ beads are reusable for many times with no significant decrease in their adsorption capacities. (C) 2008 Elsevier B.V. All rights reserved

Development Of Ion-Imprinted Cryogels For Selective Removal Of Arsenic From Environmental Waters

Arsenic present by nature as metalloid, having transportability in the environment via diverse sources. Because of both natural processes and anthropogenic activities, arsenic is found in environmental water sources. The aim of this study is to design ion-imprinting-based cryogel adsorbents for the removal of arsenic species from environmental waters. Since trivalent arsenic exhibit a high afgfinity for sulfhydryl groups, cysteine-based functional monomer, i.e. MAC, was synthesized and MAC-As(III) complex was prepared. Ion-imprinted polymeric adsorbents were fabricated via cryopolymerization. Elemental analysis studies have shown that the cryogel monolith contains 192.8 mu mol/g mol MAC/g polymer. The maximum adsorption capacity of ion-imprinted cryogels at an initial arsenic concentration of 10 ppm was found to be 372.5 mu g/g at pH 8.0. Arsenic removal rate of the imprinted cryogels from environmental water sample was determined as 94.8% In the studies carried out for the removal of arsenic from the environmental waters, 94.8% removal efficiency was achieved. Reusability assays of ion-imprinted cryogels were performed and there was no significant decrease in adsorption capacity.WoSScopu

Composite Polymeric Cryogel Cartridges for Selective Removal of Cadmium Ions from Aqueous Solutions

In this study, composite polymeric cryogel cartridges were achieved by using Cd(II) imprinted poly(hydroxyethyl methacrylate N-methacryloly-(L)-cysteine methylester) beads and poly(hydroxyethyl methacrylate) cryogel cartridges with two different mole ratios of functional monomer. The N-methacryloly-(L)-cysteinemethylester was used as a functional monomer and Cd(II) 1:1 and 2:1, which were then notated as MIP1 and MIP2, respectively. Various characterization methods have confirmed the structural transformation on the MIP1 and MIP2 composite cryogel cartridges by scanning electron microscopy, Fourier-transform infrared spectroscopy-Attenuated Total Reflectance, and swelling tests. The maximum amount of Cd(II) adsorption with composite cryogel cartridges was determined by altering the Cd(II) initial concentration, temperature, and pH values. The maximum adsorption capacity of MIP1 and MIP2 composite cryogel cartridges obtained was 76.35 and 98.8 µmol/g of composite cryogels, respectively. The adsorption studies revealed that the MIP2 possessed a good adsorption performance for Cd(II). The obtained composite cryogel cartridges have a selective, reusable, and cost-friendly potential for the removal of Cd(II) from aqueous solutions, and are used many times without decreasing their adsorption capacities significantly. The Cd(II) removal rate of the MIP1 and MIP2 composite cryogel cartridges from synthetic wastewater samples was determined as 98.8%. The obtained cryogel cartridges’ adsorption material exhibited a good directional removal performance for Cd(II) from wastewater samples

Molecularly imprinted composite cryogels for hemoglobin depletion from human blood

A molecularly imprinted composite cryogel (MICC) was prepared for depletion of hemoglobin from human blood prior to use in proteome applications. Poly(hydroxyethyl methacrylate) based MICC was prepared with high gel fraction yields up to 90%, and characterized by Fourier transform infrared spectrophotometer, scanning electron microscopy, swelling studies, flow dynamics and surface area measurements. MICC exhibited a high binding capacity and selectivity for hemoglobin in the presence of immunoglobulin G, albumin and myoglobin. MICC column was successfully applied in fast protein liquid chromatography system for selective depletion of hemoglobin for human blood. The depletion ratio was highly increased by embedding microspheres into the cryogel (93.2%). Finally, MICC can be reused many times with no apparent decrease in hemoglobin adsorption capacity. Copyright (C) 2014 John Wiley & Sons, Ltd

Highly selective ion-imprinted particles for solid-phase extraction of Pb2+ ions

WOS: 000271256700024The Pb2+-imprinted (PHEMAC-Pb2+)particles were prepared by bulk polymerization as a solid-phase extraction (SPE) adsorbent. N-methacryloyl-(L)-cysteine (MAC) was used as functional monomer to have a well-shaped molecular geometry between MAC monomer and Pb2+ ions that provide molecular recognition based on well fitted cavities for Pb2+ ions after removal of template ions. The PHEMAC-Pb2+ particles were characterized and the applicability of these particles was investigated for the solid-phase extraction of Pb2+ ions from aqueous solutions and environmental samples. The PHEMAC-Pb2+ particles with a size range of 50-200 mu m have a rough surface and macropores in bulk structure. The adsorption capacity of the PHEMAC-Pb2+ particles is relatively low (2.01 mg/g). However, the high selectivity towards competitive ions (Cd2+, Ni2+ and Cu2+) promises the PHEMAC-Pb2+ particles an alternative SPE adsorbent in literature. The relative selectivity coefficients of PHEMAC-Pb2+ particles for Pb2+/Ni2+, Pb2+/Cd2+ and Pb2+/Cu2+ were almost 71, 117 and 192 times greater than that of non-imprinted (PHEMAC) particles, respectively. Moreover, the reusability of the PHEMAC-Pb2+ particles was tested for several times and no significant loss in adsorption capacity was observed. The accuracy of the proposed procedure was also verified by the determination of Pb2+ ions in the certified reference material, LGC 6137 Estuarine sediment. (C) 2009 Elsevier B.V. All rights reserved

Synthesis and characterization of amino acid containing Cu(II) chelated nanoparticles for lysozyme adsorption

WOS: 000313155500073PubMed ID: 25428106Immobilized metal ion affinity chromatography (IMAC) is a useful method for adsorption of proteins that have an affinity for transition metal ions. In this study, poly( hydroxyethyl methacrylate-methacryloyl-L-tryptophan) (PHEMATrp) nanoparticles were prepared by surfactant free emulsion polymerization. Then, Cu(II) ions were chelated on the PHEMATrp nanoparticles to be used in lysozyme adsorption studies in batch system. The maximum lysozyme adsorption capacity of the PHEMATrp nanoparticles was found to be 326.9 mg/g polymer at pH 7.0. The nonspecific lysozyme adsorption onto the PHEMA nanoparticles was negligible. In terms of protein desorption, it was observed that adsorbed lysozyme was readily desorbed in medium containing 1.0 M NaCl. The results showed that the metal-chelated PHEMATrp nanoparticles can be considered as a good adsorbent for lysozyme purification. (C) 2012 Elsevier B.V. All rights reserved