Immobilization of biocatalysts for enzymatic polymerizations:Possibilities, advantages, applications

Biotechnology also holds tremendous opportunities for realizing functional polymeric materials. Biocatalytic pathways to polymeric materials are an emerging research area with not only enormous scientific and technological promise, but also a tremendous impact on environmental issues. Many of the enzymatic polymerizations reported proceed in organic solvents. However, enzymes mostly show none of their profound characteristics in organic solvents and can easily denature under industrial conditions. Therefore, natural enzymes seldom have the features adequate to be used as industrial catalysts in organic synthesis. The productivity of enzymatic processes is often low due to substrate and/or product inhibition. An important route to improving enzyme performance in non-natural environments is to immobilize them. In this review we will first summarize some of the most prominent examples of enzymatic polymerizations and will subsequently review the most important immobilization routes that are used for the immobilization of biocatalysts relevant to the field of enzymatic polymerizations. (C) 2011 Elsevier Ltd. All rights reserved

Multifunctionalized Self-supported (Nano) Membranes as Integrated Platform for Plasmonic Metamaterials

We considered the possibility to fabricate multifunctional nanocomposite membranes as a platform for plasmonic metamaterials, simultaneously incorporating pores, built-in functional groups and active nanoparticles. To this purpose we combined lamination and inclusion of nanofillers into the membrane host. For the basic material we chose macroporous crosslinked copolymers based on glycidyl methacrylate (GMA). The epoxy group present in GMA molecule is readily transformed into various functional groups that further serve as affinity enhancers, ensuring the usability of the membranes as pre-concentrators of selected agents in plasmonic sensors. To form GMA-based membranes we used a recently proposed method combining the traditional immersion precipitation with photopolymerization and crosslinking of functional monomers. Further functionalization is obtained by in-situ formation of noble metal nanoparticles directly within the GMA host. In this way membranes with simultaneous plasmonic, adsorbent and catalytic functionality are obtained. We considered the use of the our structures for plasmonic chemical sensors where separator, pre-concentrator and binding agent are integrated with the plasmonic crystal, as well as for plasmonic enhancement of photocatalytic reactions in microreactors. Our approach gives a highly tailorable element compatible with microelectromechanical systems (MEMS) technologies and readily transferable across platforms

Silver nanoparticles within functionalized hydrogels for plasmonic (bio)chemical sensors

Plasmonics is the basis for a novel generation of adsorption-based ultrasensitive (bio) chemical sensors. In nanoplasmonic sensors one utilizes nanocomposites typically in the form of thin films, comprising metal nanoparticles or ordered metal-dielectrics (plasmonic crystals). In this work we investigated thin functionalized hydrogel films with embedded silver nanoparticles. These films were prepared by copolymerizing glycidyl methacrylate with mono and multifunctional methacrylates using UV irradiation. The epoxy group in glycidyl methacrylate can then be converted by chemical means into a desired functionality to capture the targeted analyte. Silver nanoparticles were either photochemically generated in situ, or were introduced into hydrogels by chemical reduction. Differences in morphology and performance of these nanocomposites were investigated and will be discussed

Influence of bentonite filler on the thermal stability of glycidyl methacrylate based composite

Macroporous crosslinked copolymer of glycidyl methacrylate, GMA, and ethylene glycol dimethacrylate, EGDMA, poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) and its composites were synthesized by suspension copolymerization. Composites were obtained by introducing 10 mass % of either raw bentonite (S0) or acid modified bentonite (SA) into reaction system. The composite synthesized with SA as filer showed superior thermal stability comparing to starting copolymer and composite with S0 embedded in copolymer matrix

Adsorption isotherms of chloroform on macroporous copolymers determined by inverse gas chromatography

The inverse gas chromatography (IGC) under finite surface coverage conditions was used for the determination of adsorption isotherms of chloroform on macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), PGME and copolymer modified with ethylene diamine, EDA, PGME-en. The specific surface areas of initial and modified copolymer samples calculated from IGC data are in fair agreement with those determined by the BET method from the low-temperature nitrogen adsorption isotherms.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Design of an amino-functionalized chelating macroporous copolymer poly(GMA-co-EGDMA) for the sorption of Cu(II) ions

Polymer-based, highly porous nanocomposites with functionalized ligands attached to the core structure are extremely efficient in the detection, removal and recovery of metals through the process of sorption. Quantum-chemical models could be helpful for sorption process analyses. The sorption of Cu(II) ions by amino-functionalized chelating macroporous copolymers poly(GMA-co-EGDMA)-amine and sorption selectivity of the subject copolymers, ethylenediamine (en), diethylenetriamine (dien) and triethylenetetramine (trien), were successfully modelled by quantum chemical calculations. Considering the crystal structures from CSD and experimental conditions during the formation of metal complexes, the most frequent mononuclear complexes are those with the tetradentate teta ligand, while binuclear complexes are formed when the metal ion is in large excess. Although the en-copolymer was the most effective functionalized one, higher maximum sorption capacities (Qmax) were observed for the dien- and trien-copolymers, due to their abilities to form binuclear complexes. The enthalpy term has the greatest contribution to the total Gibbs energy change of reaction for the formation of mononuclear Cu(II) complexes (ΔGaq), while the solvation energy of the reaction has the greatest contribution in the formation of binuclear complexes. The results of the study indicate that small amines with the ability to form binuclear complex are the best choice for functionalization of the considered copolymer

Funkcionalizovani makroporozni kopolimer na bazi glicidilmetakrilata - uticaj liganda i parametara poroznosti na sorpciju Cu(II) jona iz vodenih rastvora

The removal of heavy metals from hydro-metallurgical and other industries' wastewaters, their safe storage and possible recovery from waste- water streams is one of the greater ecological problems of modern society. Conventional methods, like precipitation, adsorption and biosorption, electrowinning, membrane separation, solvent extraction and ion exchange are often ineffective, expensive and can generate secondary pollution. On the other hand, chelating polymers, consisting of crosslinked copolymers as a solid support and functional group (ligand), are capable of selectively loading different metal ions from aqueous solutions. In the relatively simple process, the chelating copolymer is contacted with the contaminated solution, loaded with metal ions, and stripped with the appropriate eluent. Important properties of chelating polymers are high capacity, high selectivity and fast kinetics combined with mechanical stability and chemical inertness. Macroporous hydrophilic copolymers of glycidyl methacrylate and ethylene glycol dimethacrylate modified by different amines show outstanding efficiency and selectivity for the sorption of precious and heavy metals from aqueous solutions. In this study poly(GMA-co-EGDMA) copolymers were synthesized with different porosity parameters and functionalized in reactions with ethylene diamine (EDA), diethylene triamine (DETA) and triethylene tetramine (TETA). Under non-competitive conditions, in batch experiments at room temperature, the rate of sorption of Cu(II) ions from aqueous solutions and the influence of pH on it was determined for four samples of amino-functionalized poly(GMA-co-EGDMA). The sorption of Cu(II) for both amino-functionalized samples was found to be very rapid. The sorption half time, t1/2, defined as the time required to reach 50% of the total sorption capacity, was between 1 and 2 min. The maximum sorption capacity for copper (2.80 mmol/g) was obtained on SGE-10/12-deta sample. The sorption capacity of Cu(II) ions increases with increasing pH and has maximum at pH ~5. In the experimental pH range, the maximum sorption capacity of Cu(II) ions again is reached on SGE-10/12-deta. By comparing literature data and obtained results it is possible to conclude that amino-functionalized macroporous copolymers based on glycidyl methacrylate are efficient for sorption of Cu(II) ions from aqueous solutions and sorption capacity for copper mostly depends on type of amine with which the basic copolymer is functionalized.Makroporozni hidrofilni kopolimeri glicidilmetakrilata i etilenglikoldimetakrilata modifikovani različitim aminima poseduju izraženu efikasnost i selektivnost pri sorpciji plemenitih i teških metala iz vodenih rastvora. U ovom radu su sintetisani uzorci poli( GMA-co-EGDMA) sa različitom poroznošću i funkcionalizovani reakcijama sa etilendiaminom, dietilentriaminom i trietilentetraminom. Pri nekompetitivnim uslovima je, šaržnom metodom na sobnoj temperaturi, određena brzina sorpcije Cu(II) jona iz vodenih rastvora na četiri uzorka amino-funkcionalizovanog kopolimera, kao i uticaj pH. Pokazalo se da je sorpcija Cu(II) jona veoma brza, sa poluvremenom sorpcije ? 2 min, kao i da se sa povećanjem pH kapacitet sorpcije Cu(II) povećava i maksimalan je na ~pH 5

Functionalized Polymer Membranes for Plasmonic Sensing with Enhanced Selectivity

We investigate theoretically and experimentally the concept of enhancing the selectivity of chemical, biochemical and biological (nano)plasmonic sensors utilizing multifunctionalized polymer membranes. Membrane nanocompositing is done by lamination and surface/pore immobilization. A separator/filter and an affinity-based adsorption enhancer are integrated into a single multifunctional membrane structure. Functionalized membrane may be transferred across platforms and even used for different types of sensing devices

Comparative study of W(VI) and Cr(VI) oxyanions binding ability with magnetic polymer nanocomposite

Magnetite particles are widely used as sorbents for removal of heavy metal ions, organic dyes, drug delivery, cell labelling, magnetic resonance imaging, sensing, etc. [1,2]. Also, the functionalization of polymer by specific ligands enables customizing these composites for specific applications. Magnetic crosslinked macroporous copolymer of glycidyl methacrylate, GMA, and ethylene glycol dimethacrylate, EGDMA, mPGME was synthesized by suspension copolymerisation of GMA and EGDMA, in the presence of inert component (mixture of cyclohexanol and aliphatic alcohol) [3] and magnetite nanoparticles coated with (3-aminopropyl)trimethoxysilane (APTMS) as silanization agent. The sample was additionally functionalized with diethylene triamine mPGME-deta. Magnetic amino-functionalized copolymer was fully characterized in terms of its structural and magnetic properties using: FTIR analysis, SEM/EDX, XRD and SQUID magnetometry. Synthesized magnetic macroporous copolymer mPGME-deta was tested as sorbent of W(VI) and Cr(VI) oxyanions from diluted aqueous solutions (Ci=25 ppm) in a batch system, under uncompetitive conditions, at room temperature (T=25 °C). The oxyanions concentrations in solution after 60 min of sorption, were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The maximal experimental values of oxyanions sorption capacities (Qmax μmol/g) were compared with theoretically values determined by theoretical modeling, using quantum-chemical methods: Density Functional Theory (DFT), statistic analysis of the crystal structure extracted from the Cambridge Structural Database (CSD) and by implicit solvation model (SMD). It was found that the process is spontaneous and exothermic, and that the active sites of magnetic copolymer sorbent are amino groups (of diethylenetriamine and APTMS) which forms electrostatic interactions with oxianions W(VI) and Cr(VI)

Novel asymmetric polyethersulfone membranes for ultrafiltration application

Ultrafiltration has recently become popular as a promising separation method in many industrial processes covering fractionation and concentration steps in the food, pharmaceutical and biotechnology industries as much as in water and wastewater treatments. This paper presents the synthesis of novel asymmetric polyethersulfone membranes containing an interpenetrating network of poly(glycidyl methacrylate) (PGMA). In order to improve the properties and application range of membranes, the epoxy groups from PGMA are converted to amine groups by ring opening under alkaline conditions. Membranes before and after functionalization are characterized by FTIR-ATR, elememtal analysis and water permeability