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A feasible and fast method for glucose oxidase (GOx) study was developed by covalent attachment of GOx to gold-coated magnetic iron oxide nanoparticles (Fe@Au).GOx molecules were oxidized with metaperiodate to form aldehyde group. The prepared Fe@Au composite nanoparticles with 60 nm diameter were used as a carrier for the immobilization of GOx. Fe@Au nanoparticles were modified by cysteamine to produce amine groups at the surface. The GOx was covalently attached to the amine-modified Fe@Au nanoparticles through its aldehyde groups. The direct electrochemistry of GOx showed a quasi-reversible cyclic voltammogram corresponding to the flavin adenine dinucleotide (FAD/FAD[H.sub.2]) redox couple with a formal potential of -270 mV in 0.1 M phosphate buffer. The apparent charge transfer rate constant ([k.sub.s]) and transfer coefficient for electron transfer between the electrode surface and enzyme were calculated as 2.23 [s.sup.-1] and 0.45, respectively. The linear concentration range of the biosensor is 2.4-54 mM with detection limit of 0.51 mM at S/N = 3. The apparent Michaelis-Menten constant was measured to be 8.59 mM, indicating that the immobilized GOx on Fe@Au preserved its native activity. The life time of biosensor is more than 2 weeks. Keywords: biosensor, direct electrochemistry, glucose oxidase, gold-coated iron oxide nanoparticles, immobilization DOI: 10.1134/S1061934815100123, The determination of glucose concentration is very important in clinical, biological and chemical samples, as well as food processing and fermentation [1]. Chiefly glucose sensors have been studied most extensively [...]

In this work, an in situ reduction method was used to prepare nanosilver-modified polyethersulfone (PES-Ag) ultrafiltration membranes by mixing up the reducing agent ethylene glycol and the protective agent polyvinylpyrrolidone to reduce AgN[O.sub.3] in the casting solution. The effects of coagulation bath temperature (CBT) on the separation performances, antifouling property, tensile strength, and stability of the nanosilver particles were researched. The results indicated that when the PES-Ag membranes were prepared in 40°C coagulation bath, the loss rate of nanosilver particles during preparation was minimum, only 18.5%. With the CBT increasing from 20 to 60°C, the water flux of the PES and PES-Ag membranes increased, whereas the rejection rate decreased. The largest flux reached 471 L*[m.sup.-2]*[h.sup.-1] for PES-Ag membranes prepared at 60°C and the rejection was over 90%. The results of contact angle and flux recovery ratio showed that PES-Ag membranes had better hydrophilicity and antifouling property. Furthermore, the PES-Ag membranes could inhibit Escherichia coli from growing. POLYM. ENG, SCl., 53:1614-1622, 2013. © 2012 Society of Plastics Engineers, INTRODUCTION Compared with conventional separation techniques such as distillation, absorption and extraction, membrane separation technology is a highly efficient separation technique with many advantages (1). Ultrafiltration (UF) technology is widely [...]

Low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), and polyvinyl chloride (PVC) (1:1:1:0.5) were solution blended by using a mixture of solvents consisting of xylene and tetrahydrofuran (THF) (70:30). [Si0.sub.2] nanoparticles were modified by cetyl trimethyl ammonium bromide (CTAB). Wood polymer composites (WPC) were prepared by using polymer mixture, polyethylene-co-glycidyl methacrylate (PE -co-GMA), wood flour, and modified [Si0.sub.2]. X- ray diffraction (XRD) studies showed that the intensity of the peaks of polymer mixture decreased due to incorporation of [Si0.sub.2]. The dispersion of [Si0.sub.2] nanoparticles and morphological characteristics were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The interaction between [Si0.sub.2] nanoparticles, PE-co-GMA, polymer mixture, and wood was studied by Fourier transform infra-red spectroscopy (FTIR). Tensile and flexural properties of the composites improved significantly due to the incorporation of [Si0.sub.2] nanoparticles. Thermal stability, hardness, flame retardancy, and water resistance capacity were also found to enhance. Maximum improvement in properties was observed by the inclusion of 3 phr modified [Si0.sub.2] in WPC. POLYM. ENG. SCI., 52:1516-1523, 2012. © 2012 Society of Plastics Engineers, INTRODUCTION Wood polymer composite (WPC) covers a wide range of area in composite field (1). These are eco friendly, low cost consuming, biodegradable, and renewable (2). The consumption of plastic [...]

Gold nanoparticles (Au NPs) stabilized with six different thiolate-functionalized ionic liquids (TFILs) were synthesized in an organic solvent. The size and optical properties of the TFIL-stabilized Au NPs can be rationally controlled by altering the N-alkyl chain length and (or) the counteranion of the TFIL-stabilizing ligand. Au NPs were prepared from the reduction of a gold precursor (HAu[Cl.sub.4] or [[Au-C[equivalent to]C-t-Bu].sub.4]) employing NaB[H.sub.4] in the presence of the different disulfide precursors. A model, based on Israelachvili theory, is proposed to account for the dependence of NP size on the N-alkyl chain length and the counteranion of the surfactantlike TFIL stabilizers. Key words: gold nanoparticles, functionalized ionic liquids, gold(I) complexes, surface plasmon band, imidazolium salts. Des nanoparticules d'or (NPAu) stabilisees par six ioniques liquides fonctionnalises par un thiolate (ILFT) ont ete synthetisees dans un solvant organique. La taille et les proprietes optiques de ces NPAu stabilisees par des ILFT peuvent etre controlees rationnellement en modifiant la longueur de la chaine N-alkyle et (ou) le contre-anion du ILFT. Les NPAu ont ete preparees par reduction d'un precurseur d'or, HAu[Cl.sub.4] ou [[Au-C≍C-t-Bu].sub.4], a l'aide de NaBH4, en presence de chacun des six precurseurs de disulfure. Un modele, base sur la theorie de Israelachvili, est avance pour rendre compte de la relation entre la taille des NPAu et la longueur de la chaine N-alkyle et la taille du contre-anion du ILFT, qui agit comme stabilisant de la NP et surfactant. Mots-cles : nanoparticules d'or, liquides ioniques fonctionnels, complexe d'or(I), bande plasmon de surface, sels d'imidazolium., Introduction Gold nanoparticles (Au NPs) are subject to intensive research because of their application in optical sensing, (1) surface-enhanced Raman spectroscopy, (2) and catalysis. (3,4) Optical1 and catalytic (4) properties [...]

The effect of alumina nanoparticles on the viscosity and curing behavior of a bisphenol E cyanate ester monomer suspension was investigated by rheometry and differential scanning calorimetry. The viscosity was found to increase with solids content and was fit well by the Mooney equation. Cure experiments indicate that alumina particles catalyze the curing of the suspensions. The viscosity reduction achieved at high particle loadings by the addition of benzoic acid was also investigated by nuclear magnetic resonance. POLYM. ENG. SCI., 51:1409-1417, 2011. © 2011 Society of Plastics Engineers, INTRODUCTION Bisphenol E cyanate ester (bis(4-cyanatophenyl)-l,l-ethane) or BECy is a low viscosity monomer with a reported viscosity of 0.09-0.12 Pa s [1]. As shown in Fig. 1 [2], BECy cures [...]