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Size Controlled Magnetite Nanoparticles and Their Drug Loading Ability
C. V. Thach,N. H. Hai,N. Chau 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5
Magnetite nanoparticles (MNPs) were synthesized by using coprecipitation method with a reaction between the FeCl₂/FeCl₃ solution and the ammonia water. The size of the MNPs could be controlled from 10.0 to 14.6 nm by changing the concentration of the solutes. The particles were superparamagnetic at room temperature. The saturation magnetization of the MNPs increased with increasing concentration of reactants. The magnetite nanoparticles were coated with a single layer of oleic acid (OA) to have a hydrophobic surface or with a double layer of oleic acid/sodium dodecyl sulfate (OA/SDS) to have hydrophilic surface. The coated particles could be dispersed in n-Hexane or water. The OA/SDS-coated nanoparticles were used to load an antibiotic drug, chloramphenicol (Cm). Three weight percent of Cm could be loaded onto the OA/SDS coated nanoparticles, which is much higher than amount that can be loaded using the traditional drug loading method. Magnetite nanoparticles (MNPs) were synthesized by using coprecipitation method with a reaction between the FeCl₂/FeCl₃ solution and the ammonia water. The size of the MNPs could be controlled from 10.0 to 14.6 nm by changing the concentration of the solutes. The particles were superparamagnetic at room temperature. The saturation magnetization of the MNPs increased with increasing concentration of reactants. The magnetite nanoparticles were coated with a single layer of oleic acid (OA) to have a hydrophobic surface or with a double layer of oleic acid/sodium dodecyl sulfate (OA/SDS) to have hydrophilic surface. The coated particles could be dispersed in n-Hexane or water. The OA/SDS-coated nanoparticles were used to load an antibiotic drug, chloramphenicol (Cm). Three weight percent of Cm could be loaded onto the OA/SDS coated nanoparticles, which is much higher than amount that can be loaded using the traditional drug loading method.
Mechanism for Sustainable Magnetic Nanoparticles under Ambient Conditions
N. H. Hai,N. D. Phu,N. H. Luong,N. Chau,H. D. Chinh,L. H. Hoang,D. L. Leslie-Pelecky 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5
Iron-based magnetic fluids are widely used in physical applications. Recently, they have been extended to many biological applications due to their magnetic and biocompatible properties. However, their stability under an ambient environment still has not been systematically investigated. In this report, we present the oxidation process of magnetic fluids. The oxidation process depends on the materials that make the nanoparticles, the diffusion of oxygen atoms from the environment to the magnetic nanoparticles, which mainly depends on the viscosity of the solution and the surfactant that coats the nanoparticles. We suggest three ways to protect nanoparticles from oxidation: (a) using highly viscous carrier liquid (b) using relevant surfactants and (c) substitution of Ni²+ and Co²+ for Fe²+ in magnetite. Methods (a) and (b) are general, so they can be applied for many environmentally sensitive magnetic fluids. Method (c) is specific for a magnetite fluid. Iron-based magnetic fluids are widely used in physical applications. Recently, they have been extended to many biological applications due to their magnetic and biocompatible properties. However, their stability under an ambient environment still has not been systematically investigated. In this report, we present the oxidation process of magnetic fluids. The oxidation process depends on the materials that make the nanoparticles, the diffusion of oxygen atoms from the environment to the magnetic nanoparticles, which mainly depends on the viscosity of the solution and the surfactant that coats the nanoparticles. We suggest three ways to protect nanoparticles from oxidation: (a) using highly viscous carrier liquid (b) using relevant surfactants and (c) substitution of Ni²+ and Co²+ for Fe²+ in magnetite. Methods (a) and (b) are general, so they can be applied for many environmentally sensitive magnetic fluids. Method (c) is specific for a magnetite fluid.
Magnetic Properties and Magnetic Viscosity of Pr4Fe76Co10B6Nb3Cu1 Nanocomposite Magnet
N. D. The,N. H. Hai,C. X. Huu,H. D. Anh,L. V. Vu,N. Chau,V. V. Hiep 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5
The nanocomposite magnet Pr4Fe76Co10B6Nb3Cu1 has been obtainedbynanocrystallizationofa rapidly-quenchedamorphous ake. Thein uenceoftheannealingprocessonthestructuralandthe magnetic properties are investigated. High magnetic hardness was reached with of large coercivity of Hc = 3.65 kOe, a remanent induction of Mr = 12.0 kG, Mr=Ms = 0.79 and maximum energy product (BH)max = 17.6 MGOe at optimal annealing conditions. The multiphase structures of Fe3B as soft phases and of Pr2Fe14B as hard phase were conrmed by X-ray diraction data. The magneticviscosityasafunctionofthereverseeldwasevaluatedforallspecimen. Theresultsshow thatthemagneticviscositycoecientpeaksatacriticalnucleationeld,atwhichthemagnetization reversal of the specimens becomes irreversible.
Magnetic Properties of (FePt)100-xCux Thin Films
N. T. T. Van,N. H. Hai,N. H. Luong,V. V. Hiep,N. Chau 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5
A series of (FePt)100-xCux (x = 0, 5, 8 and 11) thin films have been prepared by RF sputtering. The as-deposited films are nanocrystalline with fine particles. Upon annealing, the films transfer to the ordered fct FePt phase, which is hard magnetic. The influences of the Cu content, as well as the heat treatment conditions, on the magnetic properties of the films have been studied. Addition of 5 -- 8 at.% Cu lowers the optimum annealing temperature and improves the magnetic squareness and convexity of the hysteresis loop. Addition of a higher Cu content weakens the hard magnetic properties of the films. The dependence of the hard phase formation on the annealing conditions is investigated. A series of (FePt)100-xCux (x = 0, 5, 8 and 11) thin films have been prepared by RF sputtering. The as-deposited films are nanocrystalline with fine particles. Upon annealing, the films transfer to the ordered fct FePt phase, which is hard magnetic. The influences of the Cu content, as well as the heat treatment conditions, on the magnetic properties of the films have been studied. Addition of 5 -- 8 at.% Cu lowers the optimum annealing temperature and improves the magnetic squareness and convexity of the hysteresis loop. Addition of a higher Cu content weakens the hard magnetic properties of the films. The dependence of the hard phase formation on the annealing conditions is investigated.
Sorting CD4+ T Cells in Blood by Using Magnetic Nanoparticles Coated with Anti-CD4 Antibody
N. T. Khuat,V. T. A. Nguyen,T. N. Phan,L. H. Hoang,C. V. Thach,N. H. Hai,N. Chau 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.6
We used Fe3O4 magnetic nanoparticles (MNPs) which are coated with antiCD4 monoclonal antibody to bind selectively onto membranes of CD4+ T cells (hereafter antiCD4-MNPs). The antiCD4-MNPs were prepared through direct covalent interaction between the carboxyl group of the antiCD4 antibody and the amino group of amino-modified MNPs. The antiCD4-MNPs were mixed with human blood cells, followed by bursting the red blood cells with hypotonic buffer; then, the antiCD4-MNPs coated cells were separated by using a magnet. We observed the number of cells bound with magnetite clusters and particles. When fluorescence isothiocyanate labeled antiCD4- MNPs was used to observe the CD4+ T cells, the fluorescent intensity was improved by about two times compared to that when cells were labeled with the antiCD4 antibody only. This is a potential method to sort helper CD4+ T cells for observation under conventional microscopes. We used Fe3O4 magnetic nanoparticles (MNPs) which are coated with antiCD4 monoclonal antibody to bind selectively onto membranes of CD4+ T cells (hereafter antiCD4-MNPs). The antiCD4-MNPs were prepared through direct covalent interaction between the carboxyl group of the antiCD4 antibody and the amino group of amino-modified MNPs. The antiCD4-MNPs were mixed with human blood cells, followed by bursting the red blood cells with hypotonic buffer; then, the antiCD4-MNPs coated cells were separated by using a magnet. We observed the number of cells bound with magnetite clusters and particles. When fluorescence isothiocyanate labeled antiCD4- MNPs was used to observe the CD4+ T cells, the fluorescent intensity was improved by about two times compared to that when cells were labeled with the antiCD4 antibody only. This is a potential method to sort helper CD4+ T cells for observation under conventional microscopes.