The iron/silica magnetic composite spheres were prepared by electrochemical method and reduced in hydrogen atmosphere at different temperatures. The morphology and structure of the composite were characterized by SEM,...The iron/silica magnetic composite spheres were prepared by electrochemical method and reduced in hydrogen atmosphere at different temperatures. The morphology and structure of the composite were characterized by SEM, TEM and XRD. The iron/silica microspheres exhibit essential ferromagnetic behavior characterized by magnetometry. After being coated with silica in sodium silicate solution by acidifying technology, the surface of these magnetic composite spheres is with amino-silane coupling agent for their attachment to affinity ligands. Bovine serum albumin (BSA) was covalently immobilized onto the amino-silane modified magnetic silica supports by the glutaraldehyde method. The influence of pH, ionic strength as well as the initial protein concentration on BSA immobilization was studied. The results show that such amino-silane modified magnetic composite spheres are the effective supports for bioseparation and the maximum BSA immobilization capacity (up to 87.4 mg/g) is obtained in 0.1 mol/L phosphate buffer at pH 5.0.展开更多
Superparamagnetic poly（styrene）-co-poly（2-acrylanmido-2-methyl propanesulfonic acid） （PSt-co-PAMPS） and poly（methylmethacrylate）-co-poly（glycidyl methacrylate） （PMMA-co-PGMA） microspheres with mean size of...Superparamagnetic poly（styrene）-co-poly（2-acrylanmido-2-methyl propanesulfonic acid） （PSt-co-PAMPS） and poly（methylmethacrylate）-co-poly（glycidyl methacrylate） （PMMA-co-PGMA） microspheres with mean size of 170 nm were prepared by emulsion polymerization in the presence of oleic acid-coated Fe3O4 nanoparticles. The structures, morphologies, diameter and diameter distribution of the as-prepared microspheres were identified by Fourier transform infrared spectroscopy （FT-IR） and transmission electron microscopy （TEM）. The saturation magnetizations of PSt-co-PAMPS and PMMA-co-PGMA microspheres are 21.94 and 25.07 emu/g, respectively. The as-synthesized magnetic microspheres were used for immobilization of Bovine serum albumin （BSA） by physical interaction and covalent interaction respectively. The equilibrium amount of BSA immobilized onto PMMA-co-PGMA microspheres was 86.48 mg/g microspheres in 90 min, while on PSt-co-PAMPS microspheres was 59.62 mg/g microspheres in 120 min.展开更多
A method for the two-step synthesis of magnetic composites with a γ-Fe 2 O 3 core, silica inner layer and numerous gold nanoparticles supported on the surface of the silica (γ-Fe 2 O 3 /SiO 2 /Au) is described. Firs...A method for the two-step synthesis of magnetic composites with a γ-Fe 2 O 3 core, silica inner layer and numerous gold nanoparticles supported on the surface of the silica (γ-Fe 2 O 3 /SiO 2 /Au) is described. First, thiol-functionalized γ-Fe 2 O 3 /SiO 2 composites and gold colloids are prepared by modifying γ-Fe 2 O 3 /SiO 2 composites with mercaptosilane and reduction of Au 3+ to Au 0 with citrate, respectively. Gold nanoparticles are then assembled on the surface of the thiol-functionalized γ-Fe 2 O 3 /SiO 2 composites to form γ-Fe 2 O 3 /SiO 2 /Au composites. The structure of the composite particles is confirmed by transmission electronic microscopy and powder X-ray diffraction. Immobilization studies with bovine serum albumin (BSA) demonstrate that the γ-Fe 2 O 3 /SiO 2 /Au composites can be used to immobilize BSA, making them useful for biomedical and biological applications.展开更多
基金Project(10676009) supported by the National Natural Science Foundation of ChinaProject(20080440750) supported by the Postdoctoral Science Foundation of China
文摘The iron/silica magnetic composite spheres were prepared by electrochemical method and reduced in hydrogen atmosphere at different temperatures. The morphology and structure of the composite were characterized by SEM, TEM and XRD. The iron/silica microspheres exhibit essential ferromagnetic behavior characterized by magnetometry. After being coated with silica in sodium silicate solution by acidifying technology, the surface of these magnetic composite spheres is with amino-silane coupling agent for their attachment to affinity ligands. Bovine serum albumin (BSA) was covalently immobilized onto the amino-silane modified magnetic silica supports by the glutaraldehyde method. The influence of pH, ionic strength as well as the initial protein concentration on BSA immobilization was studied. The results show that such amino-silane modified magnetic composite spheres are the effective supports for bioseparation and the maximum BSA immobilization capacity (up to 87.4 mg/g) is obtained in 0.1 mol/L phosphate buffer at pH 5.0.
基金Funded by the National Natural Science Foundation of China (20876070)Technology Innovation Team of Universities Funded Project of Jiangsu Province (2007-5)
文摘Superparamagnetic poly（styrene）-co-poly（2-acrylanmido-2-methyl propanesulfonic acid） （PSt-co-PAMPS） and poly（methylmethacrylate）-co-poly（glycidyl methacrylate） （PMMA-co-PGMA） microspheres with mean size of 170 nm were prepared by emulsion polymerization in the presence of oleic acid-coated Fe3O4 nanoparticles. The structures, morphologies, diameter and diameter distribution of the as-prepared microspheres were identified by Fourier transform infrared spectroscopy （FT-IR） and transmission electron microscopy （TEM）. The saturation magnetizations of PSt-co-PAMPS and PMMA-co-PGMA microspheres are 21.94 and 25.07 emu/g, respectively. The as-synthesized magnetic microspheres were used for immobilization of Bovine serum albumin （BSA） by physical interaction and covalent interaction respectively. The equilibrium amount of BSA immobilized onto PMMA-co-PGMA microspheres was 86.48 mg/g microspheres in 90 min, while on PSt-co-PAMPS microspheres was 59.62 mg/g microspheres in 120 min.
基金supported by the Research Program of the Education Department of Shaanxi Province (09JK765)
文摘A method for the two-step synthesis of magnetic composites with a γ-Fe 2 O 3 core, silica inner layer and numerous gold nanoparticles supported on the surface of the silica (γ-Fe 2 O 3 /SiO 2 /Au) is described. First, thiol-functionalized γ-Fe 2 O 3 /SiO 2 composites and gold colloids are prepared by modifying γ-Fe 2 O 3 /SiO 2 composites with mercaptosilane and reduction of Au 3+ to Au 0 with citrate, respectively. Gold nanoparticles are then assembled on the surface of the thiol-functionalized γ-Fe 2 O 3 /SiO 2 composites to form γ-Fe 2 O 3 /SiO 2 /Au composites. The structure of the composite particles is confirmed by transmission electronic microscopy and powder X-ray diffraction. Immobilization studies with bovine serum albumin (BSA) demonstrate that the γ-Fe 2 O 3 /SiO 2 /Au composites can be used to immobilize BSA, making them useful for biomedical and biological applications.
