Carbon encapsulated Au@Fe nanoparticles (NPs) were synthesized by the hydrothermal method, and the palladium NPs (12 nm) were
immobilized on this hydroxyl-terminated support. The morphology, composition, content and magnetism of the samples were characterized.
Compared with the commercial carbon-supported Pd catalyst, high catalytic activity, recyclability and selectivity were evaluated
by the catalyst Pd/(C@(Au@Fe)) in the Heck reaction. Especially, in the Heck cross-coupling reactions of iodobenzene and methyl
acrylate, the catalyst was reused 10 times without significant loss of activity. In addition, the catalyst was simply recycled
by a magnetic field.
Maghemite nano-particles were synthesized by a solid-state chemical reaction for its highly selective use as, cyclotron-produced,
109Cd (462.9 days) purification method of choice. 109Cd radiochemical separation starts with Ag activities precipitated with HCl 0.0015 M followed by, on a second step, 109Cd separation from Cu carrier and 65Zn (243.8 days) using Ca (NO3)2 0.01 M. Experimental parameters such, pH and sorbent concentration, on 109Cd extraction efficiency were investigated. Phase morphology, nanostructure and size of nano-particles were studied by X-ray
diffraction (XRD) and scanning electron microscopy (SEM). A 10–20 nm average grain size was derived from XRD line broadening
and SEM data. Heat treatment on Fe3+:Fe2+ ratios equal to 2:1, produced powders, resulting in tetragonal (maghemite) structure at 300 °C and rhombohedra (hematite)
at 600 °C. 109Cd chemical and radionuclidic purity were determined by ICP-AES and HPGe detector gamma-ray spectrometry. The overall recovery
and radionuclide purity were 80.0% from obtained 129.63 kBq/C MeV (70 kBq/μAh) initial activity and 91.4%, respectively.
Authors:Amir Jalilian, Seyyedeh Hosseini-Salekdeh, Morteza Mahmoudi, Hassan Yousefnia, A. Majdabadi, and Majid Pouladian
In this study, superparamagnetic iron oxide nanoparticles (SPION) embedded by folic acid (SPION-folate) were prepared by a
modified co-precipitation method. The structure, size, morphology, magnetic property and relaxivity of the SPION-folate were
characterized systematically by means of XRD, VSM, HRSEM and TEM and the interaction between folate and iron oxide (Fe3O4) was characterized by FT-IR. The particle size was shown to be ≈5–10 nm. To ensure biocompatibility, the interaction of these
SPION with mouse connective tissue cells (adhesive) was investigated using an MTT assay. Consequently, gallium-67 labeled
nanoparticles ([67Ga]-SPION-folate) were prepared using 67Ga with a high labeling efficiency (over 96%, RTLC method) and they also showed an excellent stability at room temperature
for at least 2 days and were evaluated for their biodistribution in normal rats up to 24 h compared with free Ga3+ cation and [67Ga]-SPION biodistribution. The biodistribution of the tracer among 3 other folate tracers were compared, showing lower liver
uptake and higher blood circulation after 24 h leading to better bioavailability. The bone:muscle, kidney:muscle, lung:muscle,
stomach:muscle ratios were 9.3, 9.32, 7.6 and 5.83 respectively. The developed folate-containing nano-system can be an interesting
folate receptor tracer, capable of better cell membrane permeability while possessing paramagnetic properties for thermotherapy.
Authors:L. Gonsalves, S. Mojumdar, and V. Verenkar
The chemistry, structure, and properties of spinel ferrites are largely governed by the method of preparation. The metal carboxylato-hydrazinate
precursors are known to yield nanosized oxides at a comparatively lower temperature. In this study, we are reporting the synthesis
of one such precursor, cobalt nickel ferrous fumarato-hydrazinate which decomposes autocatalytically to give cobalt nickel
ferrite nanoparticles. The XRD study of this decomposed product confirms the formation of single-phase spinel, i.e., Co0.5Ni0.5Fe2O4. The thermal decomposition of the precursor has been studied by isothermal, thermogravimetric (TG), and differential scanning
calorimetric (DSC) analysis. The precursor has also been characterized by FTIR, EDX, and chemical analysis, and its chemical
composition has been determined as Co0.5Ni0.5Fe2(C4H2O4)3·6N2H4.
Authors:Mariam Khvedelidze, Tamaz Mdzinarashvili, Tamar Partskhaladze, Noha Nafee, Ulrich Schaefer, Claus-Michael Lehr, and Marc Schneider
The calorimetric investigation of non-coated and chitosan-coated PLGA nanoparticles (NP) shows that at initial temperatures
of heating particle swelling takes place what results in an internal architectural change at lower than physiological temperature.
It has shown that the temperature of NP tightness perturbing depends on solvent polarity: as more polar is the solvent more
stable are particles. The break of existing bonds in NP shell is accompanied with heat absorption peak which undergoes significant
changes depending on heating rate. In the wide pH 2–8 interval in transition temperature no changes occurred. The obtained
results show that such NP could be used in acidic area for drug transfer, which gives possibility to take medicine orally.
It was shown that DNA attaches only to chitosan-coated NP. The optimal ratio for DNA loading onto the NP was found to be 7:1
Authors:Zack Varve, Edward Lai, Chunsheng Li, Baki Sadi, and Gary Kramer
A rapid bioassay for 90Sr was developed involving preconcentration of 90Sr/90Y from human urine samples with a cation exchange polymer (poly–acrylamido–methyl–propanesulfonic acid) coated onto magnetic
nanoparticles, followed by selective elution of 90Sr (over 90Y) with phosphate for determination by liquid scintillation analysis. The minimum detectable activity for this method (4.9 ± 0.5 Bq/L)
is lower than the required sensitivity of 19 Bq/L for 90Sr in human urine samples, as defined in the requirements for radiation emergency bioassay techniques for the public and first
responders based on the dose threshold for possible medical attention recommended by the International Commission on Radiological
Protection. The relative bias was 9.2%, the relative precision was 3.2%, and the linear dynamic range covered 12–600 Bq/L.
This simple and rapid bioassay method is found to be in compliance with the HPS ANSI N13.30 performance criteria for radiobioassay.
Authors:Weijuan Jia, Jessica McLachlan, Jiayan Xu, and S. Eichhorn
Gold nanoparticles (Au-NPs) were prepared by a surfactant-free single-phase reduction of hydrogen tetrachloroaurate(III) hydrate
in the presence of different organic thiol ligands. Sizes, size distributions, and crystallinity of the Au-NPs were determined
by high-resolution transmission electron microscopy and powder X-ray diffraction, whereas thermogravimetric analysis provided
information on the organic ligand-to-gold ratios as well as amounts of contaminants. A systematic decrease in size with increasing
conical bulk of the thiolate ligand is observed but large size distributions and contamination of the generated Au-NPs prohibit
detailed mechanistic studies. A first-generation Fréchet dendron thiol produced the smallest and cleanest Au-NPs of the narrowest
Authors:Isabelle Kraus, Shuning Li, Andrea Knauer, Marc Schmutz, Jacques Faerber, Christophe A. Serra, and Michael Köhler
This paper presents a new route to the synthesis of uniform and size-controlled inorganic/organic composite microparticles by means of microreaction technology. Au-nanoparticles in the range of 3 to 14 nm are synthesized by reduction of tetrachloroauric acid, while ZnO-nanoparticles (200–2000 nm) are synthesized in a continuous-flow two-step process using microtube arrangements for microsegmented flow. Both inorganic nanoparticles have a well-controlled size and narrow size distribution. Upon surface modification, the nanoparticles are then mixed on one hand with an acrylate-based monomer and, on the other hand, with an aqueous solution of acrylamide. Both solutions were then emulsified into uniform core-shell droplets by means of a capillary-based microfluidic device. Droplet's shell was hardened through UV-induced polymerization, whereas the core led to a hydrogel upon thermal-induced polymerization. Core-shell polymer microparticles (200–300 µm) with inorganic nanoparticles selectively incorporated into the core and the shell are thus obtained as proven by extensive morphological characterizations using electronic and optical microscopies.
Authors:Marek Wojnicki, Magdalena Luty-Błocho, Krzysztof Mech, Justyna Grzonka, Krzysztof Fitzner, and Krzysztof Kurzydłowski
A composite material consisting of metallic platinum nanoparticles and reduced graphene oxide was successfully obtained in microflow reactor. Moreover, subnanometric platinum particles were observed. Reduced graphene oxide plays an important role as a stabilizing agent for platinum nanoparticles. Reduced graphene oxide coverage and platinum particle size as well as size distribution depend mainly on initial concentration of platinum(IV) ions. High level of reduced graphene oxide coverage by platinum nanoparticles (PtNPs) was obtained and is equal to 71%. This in turn effects significantly the mass ratio of reduced graphene oxide to PtNPs which is equal to 49% (w/w). Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) analysis of the obtained materials were performed. Also, catalytic properties of the obtained composite material consisting of PtNPs at reduced graphene oxide surface, towards electrochemical glucose oxidation, were investigated. It was found that the studied materials exhibit high catalytic activity for glucose electro-oxidation process.
Authors:S. Papp, L. Kőrösi, B. Gool, T. Dederichs, P. Mela, M. Möller, and I. Dékány
Gold nanoparticles (Au NPs) were prepared by the reduction of HAuCl4 acid incorporated into the polar core of poly(styrene)-block-poly(2-vinylpyridine) (PS-b-P2VP) copolymer micelles dissolved in toluene. The formation of Au NPs was controlled using three reducing agents with different
strengths: hydrazine (HA), triethylsilane (TES), and potassium triethylborohydride (PTB). The formation of Au NPs was followed
by transmission electron microscopy, UV–Vis spectroscopy, isothermal titration calorimetry (ITC), and dynamic light scattering
(DLS). It was found that the strength of the reducing agent determined both the size and the rate of formation of the Au NPs.
The average diameters of the Au NPs prepared by reduction with HA, TES, and PTB were 1.7, 2.6, and 8 nm, respectively. The
reduction of Au(III) was rapid with HA and PTB. TES proved to be a mild reducing agent for the synthesis of Au NPs. DLS measurements
demonstrated swelling of the PS-b-P2VP micelles due to the incorporation of HAuCl4 and the reducing agents. The original micellar structure rearranged during the reduction with PTB. ITC measurements revealed
that some chemical reactions besides Au NPs formation also occurred in the course of the reduction process. The enthalpy of
formation of Au NPs in PS-b-P2VP micelles reduced by HA was determined.