Le Quoc Minh

Surface modification of iron oxide nanoparticles and their conjuntion with water soluble polymers for biomedical application

Superparamagnetic iron oxide nanoparticles (SPION) coated with suitable bio-compatible substances have been used in biomedicine, particularly in magnetic resonance imaging (MRI), tissue engineering, and hyperthermia and drug delivery. In this study, we describe the synthesis of SPION and its surface modification for in-vitro experiments. The particle diameter and structure were estimated by FESEM, TEM, XRD analyses. The saturation magnetization was characterized. SPION with a mean size of 12 nm have been prepared under N2 atmosphere, with support of natural polymeric starch, by controlling chemical coprecipitation of magnetite phase from aqueous solutions containing suitable salts ratios of Fe2+ and Fe3+. The surface of SPION-nanoparticles was treated with a coordinatable agent for higher dispersion ability in water and remaining the superparamagnetic behavior. The prepared iron oxide nanoparticles were coated with starch, dextran, PEG or MPEG to extend the application potential in the quite different engineering field of nano biomedicine.

Fabrication and properties of highly luminescent materials from Tb(OH)3@SiO2 and Tb(OH)3@SiO2:Eu3+ nanotubes

Luminescent nanomaterials with one-dimensional (1D) structures have attracted much attention due to their unique properties and potential applications in nanophotonics and nanobiophotonics. In this paper, we report a synthesis of terbium – hydroxide – at – silica Tb(OH)3@SiO2 and Tb(OH)3@SiO2:Eu3+ nanotubes. Terbium – hydroxide tubes were synthesized by soft template method. The size of the tubes can be controlled precisely and have outer diameters ranging from 80 to 120 nm, wall thickness of about 30 nm, and lengths ranging from 300 to 800 nm. To fabricate core/shell materials, the seed growth method is used. FESEM, X-ray diffraction, Raman spectra of Tb(OH)3 and Tb(OH)3@SiO2 nanotubes were investigated. The photoluminescence (PL) spectrum of Tb(OH)3 under 325 nm excitation consists of four main peaks at 488, 542, 582, and 618 nm. Furthermore, a preliminary suggestion for the mechanism of growth of the Tb(OH)3 nanotubes using the soft – template synthesis technique has been proposed. The PL intensity from Tb(OH)3@SiO2 or Tb(OH)3@SiO2:Eu3+ nanotubes is much stronger than that of Tb(OH)3.

Wet Chemical Preparation of Nanoparticles ZnO:Eu3

ZnO doped with Eu3+ and Tb3+ had been successfully prepared by wet chemical method with the assistance of microwave. The influence of reaction conditions such as temperature, time, content of Eu3+, Tb3+ ion, and annealing treatment on the structure and luminescent characteristics was studied. The analysis of energy dispersive spectroscopy (EDS) and photoluminescence spectra measurements indicated that Eu3+ and Tb3+ exist in host lattice and create the new emission region compared to ZnO crystalline host lattice. The field emission scanning electron microscope (FE-SEM) studies show the Eu3+, Tb3+ doped ZnO nanoparticles have a pseudohexagonal shape. The particle size was 30–50u2009nm for ZnO:Eu3+ and 40–60u2009nm for ZnO:Tb3+. Photoluminescence excitation (PLE) and photoluminescence (PL) spectra at room temperature have been studied to recognize active centers for characteristic luminescence of ZnO:Eu3+ and ZnO:Tb3+. The characteristic luminescent lines of Eu3+ (5D0-7Fj) and Tb3+ (5D4-7Fj) were determined. It has been demonstrated that the wet chemical synthesis method with microwave assistance can strongly enhance the luminescent intensity of nanoparticles ZnO:Eu3+ in red and ZnO:Tb3+ in green.

Preparation and optical properties of ZnO, ZnO: Al nanomaterials

ZnO nanorods were prepared by different methods of MOCVD, CVD and ZnO: Al nanomaterials were synthesized by the hydrothermal method. Their structure was investigated using X-ray diffraction XRD and field emission scanning electron microscopy FESEM. The diameter of the nanorods is from 40 to 90 nm and the length is from 500 nm to 1000 nm dependent on the growth conditions. Optical properties were studied by photoluminescent with different excited of 325 and 266 nm. A dominant photoluminescent peak 380 nm was observed at room temperature. At low temperature, five peaks were observed at 3.347, 3.321, 3.301, 3.208, and 3.111 eV. The nature of luminescent peaks will be investigated. ZnO:Al nanomaterials have strong luminescent intensity in visible range dependent on Al concentration, optimal molar concentration is 7%.

Preparation, optical properties of ZnO, ZnO:Al nanorods and Y(OH)3:Eu nanotube

ZnO, ZnO:Al nanorods and Y(OH)3 nanotubes have been prepared by the chemical vapor deposition and liquid phase synthesis. ZnO nanorods with diameter of 50 ? 100 nm and length of 5 ?m have been obtained by the CVD method. ZnO:Al nanorods were synthesized by the hydrothermal method from ZnSO4. and Al2(SO4)3. Nanorods and nanotubes of Y(OH)3 with diameter of 200 nm and length of several micrometers were prepared by the soft template method. The crystal structure and morphology of rods and tubes were analyzed by the X-Ray diffraction and FE-SEM. The influence of fabrication conditions and Al, Eu concentration have been discussed.

New nanomaterials for photonic application

A brief survey of the development of new nanomaterials for photonic application will be presented. Based on the photoresponsive sol gel nanohybrid of polymethamethyl acrylate, silica, and zirconia (ASZ) or titania (AST) have been fabricated some planar light guiding structures and devices. The lanthanide containing nanosphere with core/shell structures have been synthesized in using a modified solgel process. The opal like photonic crystal structures have been fabricated by self assembling technique.

Nanosciences and Nanotechnology of Vietnamese Women: Fabrication, Characterization, and Application of Rare Earth Nanocompounds for Photonics

Nanorods Y(OH)3:Eu, nanotubes Tb (OH)3, and nanocomposites silica‐titania‐ and silica‐zirconia‐doped erbium and ytterbium were prepared by liquid‐phase methods. Structures and photonic properties such as long decay time (7.4 ms) and waveguide loss were studied in detail in the concentration and temperature dependence. The application of the nanocomposites for planar waveguide systems is presented.

Preparation, characterization and optical properties of ZrO2:Er3+, Yb3+ nanomaterials

Luminescent nanomaterials from lanthanide are one of most promising materials for applications in medical diagnostics. In this paper, we present for the first time the ZrO2 nanomaterials with capsule like nanostructure with the sizes of 150 nm in length and 50 nm in width. These nanocapsule like ZrO2 doped with Er3+, Yb3+ ions were prepared by soft template methods. Morphological characterization of nano – ZrO2:Er3+, Yb3+ was performed by using FESEM, X-ray diffraction, micro Raman. Up conversion luminescence and photoluminescence have been also studied with IR-laser excitation at 940 nm and UV excitation at 365 nm.