China Part.

Magnetic particles have numerous applications in biotechnology and biomedicine. In this paper we reviewed the synthesis, surface modification and some applications of magnetic particles with focus on their synthesis and surface modification. Various methods have been developed for the production of magnetic particles (magnetic nanoparticles and magnetic composite particles). For future application magnetic particles must be modified to obtain stability and surface functional groups. Finally, the application of magnetic particles in magnetic separation, drug delivery, hyperthermia, and magnetic resonance imaging are discussed. (C) 2007 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.Magnetic particles have numerous applications in biotechnology and biomedicine. In this paper we reviewed the synthesis, surface modification and some applications of magnetic particles with focus on their synthesis and surface modification. Various methods have been developed for the production of magnetic particles (magnetic nanoparticles and magnetic composite particles). For future application magnetic particles must be modified to obtain stability and surface functional groups. Finally, the application of magnetic particles in magnetic separation, drug delivery, hyperthermia, and magnetic resonance imaging are discussed. (C) 2007 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved

Synthesis and surface modification of magnetic particles for application in biotechnology and biomedicine

Magnetic particles have numerous applications in biotechnology and biomedicine. In this paper we reviewed the synthesis, surface modification and some applications of magnetic particles with focus on their synthesis and surface modification. Various methods have been developed for the production of magnetic particles (magnetic nanoparticles and magnetic composite particles). For future application magnetic particles must be modified to obtain stability and surface functional groups. Finally, the application of magnetic particles in magnetic separation, drug delivery, hyperthermia, and magnetic resonance imaging are discussed

preparationandcharacterizationofnonporoussuperparamagneticmicrosphereswithepoxygroupsbydispersionpolymerization

Non-porous superparamagnetic polymer microspheres with epoxy groups were prepared by dispersion polymerization of glycidyl methacrylate (GMA) in the presence of magnetic iron oxide (Fe3O4) nanoparticles coated with oleic acid. The polymerization was carried out in the ethanol/water medium using polyvinylpyrrolidone (PVP) and 2,2 '-azobisisobutyranitrile (AIBN) as stabilizer and initiator, respectively. The magnetic microspheres obtained were characterized with scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy (FTIR). The results showed that the magnetic microspheres had an average size of similar to 1 mu m with superpararnagnetic characteristics. The saturation magnetization was found to be 4.5 emu.g(-1). There was abundance of epoxy groups with density of 0.028 mmol-g(-1) in microspheres. The magnetic PGMA microspheres have extensive potential uses in magnetic bioseparation and biotechnology

Ind. Eng. Chem. Res.

As a general protocol for transferring mineral acids from an aqueous solution to an organic phase, mineral acids are extracted with secondary carbon primary amine (C9-11)(2)CHNH2 (commercial code: NI923) into an organic phase (e.g., heptane or benzene) because of the complexation reaction and the formation of typical reversed micelles. Based on this principle, a novel approach for a large-scale synthesis of highly nanoporous iron phosphate particles is developed via the formed RNH3+/H2PO4- (H2O)/oil reversed micelle system and ethanol-Fe3+ solutions. Synthetic conditions, such as H3PO4 concentration in reversed micelles and Fe3+ concentration in ethanol-Fe3+ solution are investigated and optimized. The product is characterized using transmission electron microscopy, Brunauer-Emett-Teller, thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. The as-obtained iron phosphate is flocculent and highly porous, exhibiting a high reported surface area of 144 m(2)/g. The synthetic procedure is relatively simple and is suitable for large-scale fabrication, and the used organic amines can be recycled. The power of this approach is demonstrated using other kinds of organic amines, such as tri-n-octylamine (TOA) and tri-C8-10-alkylmethyl ammonium chloride (N263), as phase-transfer reagents exhibiting promising application in the synthesis of highly nanoporous materials.As a general protocol for transferring mineral acids from an aqueous solution to an organic phase, mineral acids are extracted with secondary carbon primary amine (C9-11)(2)CHNH2 (commercial code: NI923) into an organic phase (e.g., heptane or benzene) because of the complexation reaction and the formation of typical reversed micelles. Based on this principle, a novel approach for a large-scale synthesis of highly nanoporous iron phosphate particles is developed via the formed RNH3+/H2PO4- (H2O)/oil reversed micelle system and ethanol-Fe3+ solutions. Synthetic conditions, such as H3PO4 concentration in reversed micelles and Fe3+ concentration in ethanol-Fe3+ solution are investigated and optimized. The product is characterized using transmission electron microscopy, Brunauer-Emett-Teller, thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. The as-obtained iron phosphate is flocculent and highly porous, exhibiting a high reported surface area of 144 m(2)/g. The synthetic procedure is relatively simple and is suitable for large-scale fabrication, and the used organic amines can be recycled. The power of this approach is demonstrated using other kinds of organic amines, such as tri-n-octylamine (TOA) and tri-C8-10-alkylmethyl ammonium chloride (N263), as phase-transfer reagents exhibiting promising application in the synthesis of highly nanoporous materials

Ind. Eng. Chem. Res.

Here, we have reported a new approach for utilizing oleic acid-Pluronic L-64 block copolymer coated iron oxide nanoparticles as supports for enzyme immobilization. Iron oxide nanoparticles were prepared by a coprecipitation method and were coated with oleic acid and Pluronic to achieve higher stability and dispersibility. The surface morphology and size of the particle, as determined by transmission electron microscopy (TEM), was +/- 10 nm. X-ray diffraction (XRD) patterns were taken over a range from 10 degrees to 90 degrees 20, using Cu K alpha radiation. Saturation magnetization values, measured at 300 K, varied from 34.6 emu/g to 60.8 emu/g. The possible interaction behavior of oleic acid and Pluronic was observed by Fourier transform infrared (FTIR) analysis and nuclear magnetic resonance (NMR) studies. Further potential of this material as a support for lipase immobilization and enzymatic hydrolysis at the oil/water interface was also investigated. The features of the surface-coated magnetic particles enable the adsorption of lipase from Candida cylindraces via strong hydrophobic interactions, which enhances the stability of the adsorbed enzyme molecules. The stability of the catalyst and, hence, its industrial applicability was tested by performing subsequent reaction cycles for the hydrolysis of olive oil. The activity of the immobilized lipase, pretreated with its substrate, was 510 U/g-matrix and was observed to be maintained at levels as high as 90% of its original activity for up to at least seven reuses.Here, we have reported a new approach for utilizing oleic acid-Pluronic L-64 block copolymer coated iron oxide nanoparticles as supports for enzyme immobilization. Iron oxide nanoparticles were prepared by a coprecipitation method and were coated with oleic acid and Pluronic to achieve higher stability and dispersibility. The surface morphology and size of the particle, as determined by transmission electron microscopy (TEM), was +/- 10 nm. X-ray diffraction (XRD) patterns were taken over a range from 10 degrees to 90 degrees 20, using Cu K alpha radiation. Saturation magnetization values, measured at 300 K, varied from 34.6 emu/g to 60.8 emu/g. The possible interaction behavior of oleic acid and Pluronic was observed by Fourier transform infrared (FTIR) analysis and nuclear magnetic resonance (NMR) studies. Further potential of this material as a support for lipase immobilization and enzymatic hydrolysis at the oil/water interface was also investigated. The features of the surface-coated magnetic particles enable the adsorption of lipase from Candida cylindraces via strong hydrophobic interactions, which enhances the stability of the adsorbed enzyme molecules. The stability of the catalyst and, hence, its industrial applicability was tested by performing subsequent reaction cycles for the hydrolysis of olive oil. The activity of the immobilized lipase, pretreated with its substrate, was 510 U/g-matrix and was observed to be maintained at levels as high as 90% of its original activity for up to at least seven reuses

J. Phys. Chem. B

Aggregation and disaggregation of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers, Pluronics P103 and P104, in aqueous solutions during a heating and cooling cycle were investigated by dynamic laser scattering (DLS) and H-1 NMR spectroscopy. Temperature hysteresis was observed by DLS when cooling the copolymer aqueous solutions because larger aggregates existed at temperatures lower than critical micellization temperature (CMT), but no temperature differences were observed by NMR. This phenomenon was explained as the forming of water-swollen micelles at temperatures lower than CMT during the cooling process.Aggregation and disaggregation of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers, Pluronics P103 and P104, in aqueous solutions during a heating and cooling cycle were investigated by dynamic laser scattering (DLS) and H-1 NMR spectroscopy. Temperature hysteresis was observed by DLS when cooling the copolymer aqueous solutions because larger aggregates existed at temperatures lower than critical micellization temperature (CMT), but no temperature differences were observed by NMR. This phenomenon was explained as the forming of water-swollen micelles at temperatures lower than CMT during the cooling process