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Hybrid Nanoparticles (hybrid + nanoparticle)
Selected AbstractsNanogel-Templated Mineralization: Polymer-Calcium Phosphate Hybrid NanomaterialsMACROMOLECULAR RAPID COMMUNICATIONS, Issue 6 2006Ayae Sugawara Abstract Summary: We report novel organic-inorganic hybrid nanomaterials that consist of polymer hydrogel nanoparticles (nanogels) and calcium phosphate. Hybrid nanoparticles that measure ca. 40 nm are synthesized from a dilute solution of hydroxyapatite using nanogels as templates for calcium phosphate mineralization. These nanoparticles show a narrow size distribution and high colloidal stability. Nanogel-adsorbed liposomes act as templates for hierarchical hybrid nanostructures. These nanohybrids can potentially be used as biocompatible drug carriers with controlled-release properties. TEM images of calcium phosphate nanoparticles formed in the presence of CHP nanogels (0.5 mg,·,mL,1) (left) and nanogel-liposomes (CHP 0.05 mg,·,mL,1, DPPC 0.08 mg,·,mL,1)(right). [source] Constrained Synthesis and Organization of Catalytically Active Metal Nanoparticles by Self-Assembled Protein TemplatesADVANCED MATERIALS, Issue 34 2009Silke Behrens Novel geometrical architectures of hybrid nanoparticle,protein complexes are generated by chemically synthesizing monodisperse metal nanoparticles in situ in the presence of a stable, stress-related protein. The catalytic activity of the protein,particle hybrids is examined for the reduction of 4-nitrophenol, providing future biofunctional nanoparticle labels for catalytic signal amplification in optical assays. [source] Bifunctional Eu3+ -doped Gd2O3 nanoparticles as a luminescent and T1 contrast agent for stem cell labelingCONTRAST MEDIA & MOLECULAR IMAGING, Issue 2 2010Zhilong Shi Abstract Magnetic resonance tracking of stem cells has recently become an emerging application for investigating cell,tissue interactions and guiding the development of effective stem cell therapies for regeneration of damaged tissues and organs. In this work, anionic Eu3+ -doped Gd2O3 hybrid nanoparticles were applied as a contrast agent both for fluorescence microscopy and T1 -weighted MRI. The nanoparticles were synthesized through the polyol method and further modified with citric acid to obtain anionic nanoparticles. These nanoparticles were internalized into human mesenchymal stem cells (hMSCs) as confirmed by confocal laser scanning microscopy and quantified by inductively coupled plasma,mass spectrometry. MTT assay of the labeled cells showed that the nanoparticles did not possess significant cytotoxicity. In addition, the osteogenic, adipogenic and chondrogenic differentiation of the hMSCs was not influenced by the labeling process. With MRI, the in vitro detection threshold of cells after incubation with nanoparticles at a Gd concentration of 0.5,mMfor 2,h was estimated to be about 10 000 cells. The results from this study indicate that the biocompatible anionic Gd2O3 nanoparticles doped with Eu3+ show promise both as a luminescent and T1 contrast agent for use in visualizing hMSCs. Copyright © 2010 John Wiley & Sons, Ltd. [source] A Versatile Solvent-Free "One-Pot" Route to Polymer Nanocomposites and the in situ Formation of Calcium Phosphate/Layered Silicate Hybrid NanoparticlesADVANCED FUNCTIONAL MATERIALS, Issue 11 2010Hans Weickmann Abstract Poly(methyl methacrylate) (PMMA), polystyrene (PS), and polyurethane (PU) nanocomposites containing well-dispersed calcium phosphate/layered silicate hybrid nanoparticles were prepared in a versatile solvent-free "one-pot" process without requiring separate steps, such as organophilic modification, purification, drying, dispersing, and compounding, typical for many conventional organoclay nanocomposites. In this "one-pot" process, alkyl ammonium phosphates were added as swelling agents to a suspension of calcium/layered silicate in styrene, methyl methacrylate, or polyols prior to polymerization. Alkyl ammonium phosphates were prepared in situ by reacting phosphoric acid with an equivalent amount of alkyl amines such as stearyl amine (SA) or the corresponding ester- and methacrylate-functionalized tertiary alkyl amines, obtained via Michael Addition of SA with methyl acrylate or ethylene 2-methacryloxyethyl acrylate. Upon contact with the calcium bentonite suspension, the cation exchange of Ca2+ in the silicate interlayers for alkyl ammonium cations rendered the bentonite organophilic and enabled effective swelling in the monomer accompanied by intercalation and in situ precipitation of calcium phosphates. According to energy dispersive X-ray analysis, the calcium phosphate precipitated exclusively onto the surfaces of the bentonite nanoplatelets, thus forming easy-to-disperse calcium phosphate/layered silicate hybrid nanoparticles. Incorporation of 5,15,wt% of such hybrid nanoparticles into PMMA, PS, and PU afforded improved stiffness/toughness balances of the polymer nanocomposites. Functionalized alkyl ammonium phosphate addition enabled polymer attachment to the nanoparticle surfaces. Transmission electron microscopy (TEM) analyses of PU and PU-foam nanocomposites, prepared by dispersing hybrid nanoparticles in the polyols prior to isocyanate cure, revealed the formation of fully exfoliated hybrid nanoparticles. [source] Nanoparticle Electroluminescence: Controlling Emission Color Through Förster Resonance Energy Transfer in Hybrid ParticlesADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Christopher F. Huebner Abstract Electroluminescent (EL) polymers are attractive for developing all-organic light-emitting devices (OLEDs) due to the potential advantages that polymeric systems may offer in the large-scale manufacturing of electronics. Nonetheless, many of these EL , -conjugated polymers are inherently insoluble in the solvents employed in the intended solution-based manufacturing processes. One such polymer is poly(2,5-dioctyl-1,4-phenylenevinylene) (POPPV), where the inherent lack of solubility of POPPV in organic solvents has frustrated its widespread application in devices and no OLEDs have been presented that exploit its electroluminescence characteristics. In this effort, a unique strategy is presented for the preparation of hybrid nanoparticles composed of POPPV, a green emitter (,em,=,505,nm) and poly(9,9-di- n -octylfluorenyl-2,7-diyl) (PFO), a blue emitter (,em,=,417,nm). The aqueous-based nanoparticle dispersion composed of these hybrid particles is stable to aggregate and can be employed in the construction of OLEDs. The color characteristics of the electroluminescence for the devices can be tuned by exploiting the Förster resonance energy transfer between the polymers within a particle, while suppressing energy transfer between the particles. These aqueous-based nanoparticle dispersions are amenable to being printed into devices through high-throughput manufacturing techniques, for example, roll-to-roll printing. [source] Synthesis and properties of organic/inorganic hybrid nanoparticles prepared using atom transfer radical polymerizationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Tzong-Liu Wang Abstract The synthesis of organic/inorganic hybrid materials was conducted by atom transfer radical polymerization (ATRP) of styrene and methyl methacrylate (MMA) from the surface of silica colloids. Colloidal initiators were prepared by the functionalization of silica nanoparticles with (3-(2-bromoisobutyryl)propyl) dimethylethoxysilane (BIDS). Well-defined polymer chains were grown from the nanoparticle surfaces to yield individual particles composed of a silica core and a well-defined outer polystyrene (PS) or poly(methyl methacrylate) (PMMA) layer. Fourier transform infrared (FTIR) and solid state 13C and 29Si-NMR spectroscopy confirmed the successful modification of nanosilica surfaces. Subsequent grafting of polymers on silica surfaces by ATRP was also performed with success based on FTIR and NMR data. Scanning electron microscopy (SEM) and silicon mapping showed both hybrid materials were homogeneous dispersion systems. Energy dispersive X-ray spectrometer (EDS) analysis indicated that the BIDS initiator was covalently attached on surfaces of silica nanoparticles and ATRP of styrene and MMA were accomplished. Thermogravimetric analysis (TGA) results displayed higher thermal stabilities for both nanohybrids in comparison with the linear-type vinyl polymers. Contact angle measurements revealed the nanomaterials character for both silica-based hybrid materials. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis of magnetic, reactive, and thermoresponsive Fe3O4 nanoparticles via surface-initiated RAFT copolymerization of N -isopropylacrylamide and acroleinJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2010Zhong-Peng Xiao Abstract A reversible addition-fragmentation chain transfer (RAFT) agent was directly anchored onto Fe3O4 nanoparticles in a simple procedure using a ligand exchange reaction of S -1-dodecyl- S,-(,,,,-dimethyl-,,-acetic acid)trithiocarbonate with oleic acid initially present on the surface of pristine Fe3O4 nanoparticles. The RAFT agent-functionalized Fe3O4 nanoparticles were then used for the surface-initiated RAFT copolymerization of N -isopropylacrylamide and acrolein to fabricate structurally well-defined hybrid nanoparticles with reactive and thermoresponsive poly(N -isopropylacrylamide- co -acrolein) shell and magnetic Fe3O4 core. Evidence of a well-controlled surface-initiated RAFT copolymerization was gained from a linear increase of number-average molecular weight with overall monomer conversions and relatively narrow molecular weight distributions of the copolymers grown from the nanoparticles. The resulting novel magnetic, reactive, and thermoresponsive core-shell nanoparticles exhibited temperature-trigged magnetic separation behavior and high ability to immobilize model protein BSA. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 542,550, 2010 [source] Surface-graft hyperbranched polymer via self-condensing atom transfer radical polymerization from zinc oxide nanoparticlesPOLYMER ENGINEERING & SCIENCE, Issue 9 2007Peng Liu We present the synthesis of hyperbranched polymer grafted zinc oxide (ZnO) hybrid nanoparticles by self-condensing vinyl polymerization (SCVP) via surface-initiated atom transfer radical polymerizations (SI-ATRP) from ZnO surfaces. ATRP initiators were covalently linked to the surfaces of ZnO particles, followed by SCVP of an initiator-monomer ("inimer") which has both a polymerizable group and an initiating group in the same molecule. Well-defined polymer chains were grown from the surfaces to yield hybrid nanoparticles comprised of ZnO cores and hyperbranched polymer shells having multifunctional chlorobenzyl functional end groups. The percentage of grafting (PG%) achieved 429% in 6 h, calculated from the elemental analysis results. The hybrid nanoparticles were also characterized using Fourier transform infrared spectroscopy, UV,vis absorption spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy. POLYM. ENG. SCI., 47:1296,1301, 2007. © 2007 Society of Plastics Engineers [source] A General Approach to Fabricate Diverse Noble-Metal (Au, Pt, Ag, Pt/Au)/Fe2O3 Hybrid NanomaterialsCHEMISTRY - A EUROPEAN JOURNAL, Issue 27 2010Jun Zhang Dr. Abstract A novel, facile, and general one-pot strategy is explored for the synthesis of diverse noble-metal (Au, Pt, Ag, or Pt/Au)/Fe2O3 hybrid nanoparticles with the assistance of lysine (which is a nontoxic, user friendly amino acid that is compatible with organisms) and without using any other functionalization reagents. Control experiments show that lysine, which contains both amino and carboxylic groups, plays dual and crucial roles as both linker and capping agents in attaching noble metals with a small size and uniform distribution onto an Fe2O3 support. Considering the perfect compatibility of lysine with organism, this approach may find potentials in biochemistry and biological applications. Furthermore, this novel route is also an attractive alternative and supplement to the current methods using a silane coupling agent or polyelectrolyte for preparing hybrid nanomaterials. To demonstrate the usage of such hybrid nanomaterials, a chemical gas sensor has been fabricated from the as-synthesized Au/Fe2O3 nanoparticles and investigated for ethanol detection. Results show that the hybrid sensor exhibits significantly improved sensor performances in terms of high sensitivity, low detection limit, better selectivity, and good reproducibility in comparison with pristine Fe2O3. Most importantly, this general approach can be further employed to fabricate other hybrid nanomaterials based on different support materials. [source] | |||||||||||||||||||