| 1. |
- Mikhaylova, Maria, et al.
(författare)
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The effect of biocompatible coating layers on magnetic properties of superparamagnetic iron oxide nanoparticles
- 2004
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Ingår i: Hyperfine Interactions. - 0304-3843 .- 1572-9540. ; 156:1, s. 257-263:156/157, s. 257-263
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Tidskriftsartikel (refereegranskat)abstract
- The effect of the surface coating on the magnetic properties of superparamagnetic iron oxide nanoparticles (SPION) with 8 nm in size has been studied. Four different biocompatible coating layers are considered: poly L,L-lactic acid (PLLA), poly epsilon-caprolactone (PCL), bovine serum albumin (BSA) and gold. The presence of coating layer on the surface of SPION is confirmed by FT-IR spectroscopy. Mossbauer spectroscopy and magnetic susceptibility measurements show that for uncoated SPION and Au@SPION the superparamagnetic fraction is retained. The formation of clusters in the case of BSA@SPION and chain-like structure for PCL@SPION and PLLA@SPION increase the inter-particle interactions resulting in hyperfine magnetic structure observed in the Mossbauer spectra at ambient temperature.
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| 2. |
- Abdel-Karim, R., et al.
(författare)
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Electrodeposition and Characterization of Nanocrystalline Ni-Fe Alloys
- 2011
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Ingår i: Journal of Nanomaterials. - : Hindawi Limited. - 1687-4110 .- 1687-4129. ; , s. 519274-
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Tidskriftsartikel (refereegranskat)abstract
- Nanocrystalline Ni-Fe deposits with different composition and grain sizes were fabricated by electrodeposition. Deposits with iron contents in the range from 7 to 31% were obtained by changing the Ni(2+)/Fe(2+) mass ratio in the electrolyte. The deposits were found to be nanocrystalline with average grain size in the range 20-30 nm. The surface morphology was found to be dependent on Ni(2+)/Fe(2+) mass ratio as well as electroplating time. The grains size decreased with increasing the iron content, especially in case of short time electroplating. Increasing the electroplating time had no significant effect on grain size. The microhardness of the materials followed the regular Hall-Petch relationship with amaximum value (762 Hv) when applying Ni(2+)/Fe(2+) mass ratio equal to 9.8.
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| 3. |
- Abderrazek, K., et al.
(författare)
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Photocatalytic degradation of indigo carmine using [Zn-Al] LDH supported on PAN nanofibres
- 2015
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Ingår i: Clay minerals. - : Mineralogical Society. - 0009-8558 .- 1471-8030. ; 50:2, s. 185-197
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Tidskriftsartikel (refereegranskat)abstract
- Zn-Al layered double hydroxides (LDH), before and after calcination, were tested for the removal of indigo carmine (IC) dye from solution. These LDH photocatalysts were characterized by powder x-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry/differential thermogravimetry (TG/DTG), nitrogen physisorption at -196 degrees C, scanning electron microscopy (SEM) and diffuse reflectance spectrophotometry (DRS). The different photocatalysts were supported on polyacrylonitrile (PAN) nanofibres, so that filtration was unnecessary. The PXRD and FTIR analyses showed that the IC adsorption on c-Zn-Al-3-500 (LDH calcined at 500 degrees C) was enhanced by construction of the hydrotalcite matrix intercalated with the dye. The intercalation was clearly evidenced by the appearance of a peak at low degrees 2 theta values. All of the materials prepared exhibited photocatalytic activity, which for the c-Zn-Al-3-500 was comparable to that of commercial PAN-supported ZnO nanoparticles (100% degradation after 180 min). Kinetic studies showed that the degradation of the IC followed a pseudo-first order rate. The high activity and the ease of both synthesis and separation processes rendered this photocatalyst a promising candidate for environmental remediation.
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| 4. |
- Adamopoulos, Othon, et al.
(författare)
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A nanophase oxygen storage material : Alumina-coated metal-based ceria
- 2009
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Ingår i: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219 .- 1873-619X. ; 29:4, s. 677-689
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Tidskriftsartikel (refereegranskat)abstract
- Nanoparticles of Ce1-xMxO2-delta (M = Ca or Zr) coated with Al2O3 with average crystallite size of 10 nm have been synthesised via solution chemistry approach under controlled chemical and hydrodynamic conditions. Their synthesis has been accomplished in three major steps: (1) simultaneous co-precipitation of cations, (2) sequential precipitation of Al(OH)(3) over the former particles and (3) calcination of the precipitated precursors to the corresponding oxides. Several compositions have been synthesised and their physicochemical properties are compared with commercial state-of-the-art material. The Al2O3-coating hinders the particles growth at high temperatures, resulting in materials with a large specific surface area and a restrain in the decrease of their oxygen storage capacity.
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| 5. |
- Afrasiabi, Roodabeh, et al.
(författare)
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Microwave mediated synthesis of semiconductor quantum dots
- 2012
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Ingår i: Physica Status Solidi. C, Current topics in solid state physics. - : Wiley. - 1610-1634 .- 1610-1642. ; 9:7, s. 1551-1556
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Tidskriftsartikel (refereegranskat)abstract
- Colloidal quantum dots (QD) have tuneable optoelectronic properties and can be easily handled by simple solution processing techniques, making them very attractive for a wide range of applications. Over the past decade synthesis of morphology controlled high quality (crystalline, monodisperse) colloidal QDs by thermal decomposition of organometallic precursors has matured and is well studied. Recently, synthesis of colloidal QDs by microwave irradiation as heating source is being studied due to the inherently different mechanisms of heat transfer, when compared to solvent convection based heating. Under microwave irradiation, polar precursor molecules directly absorb the microwave energy and heat up more efficiently. Here we report synthesis of colloidal II-VI semiconductor QDs (CdS, CdSe, CdTe) by microwave irradiation and compare it with conventional synthesis based on convection heating. Our findings show that QD synthesis by microwave heating is more efficient and the chalcogenide precursor strongly absorbs the microwave radiation shortening the reaction time and giving a high reaction yield.
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| 6. |
- Asem, Heba, et al.
(författare)
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Biodistribution of biodegradable polymeric nano-carriers loaded with busulphan and designed for multimodal imaging
- 2016
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Ingår i: Journal of Nanobiotechnology. - : BioMed Central (BMC). - 1477-3155. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Multifunctional nanocarriers for controlled drug delivery, imaging of disease development and follow-up of treatment efficacy are promising novel tools for disease diagnosis and treatment. In the current investigation, we present a multifunctional theranostic nanocarrier system for anticancer drug delivery and molecular imaging. Superparamagnetic iron oxide nanoparticles (SPIONs) as an MRI contrast agent and busulphan as a model for lipophilic antineoplastic drugs were encapsulated into poly (ethylene glycol)-co-poly (caprolactone) (PEG-PCL) micelles via the emulsion-evaporation method, and PEG-PCL was labelled with VivoTag 680XL fluorochrome for in vivo fluorescence imaging. Results: Busulphan entrapment efficiency was 83% while the drug release showed a sustained pattern over 10 h. SPION loaded-PEG-PCL micelles showed contrast enhancement in T-2*-weighted MRI with high r(2)* relaxivity. In vitro cellular uptake of PEG-PCL micelles labeled with fluorescein in J774A cells was found to be time-dependent. The maximum uptake was observed after 24 h of incubation. The biodistribution of PEG-PCL micelles functionalized with VivoTag 680XL was investigated in Balb/c mice over 48 h using in vivo fluorescence imaging. The results of real-time live imaging were then confirmed by ex vivo organ imaging and histological examination. Generally, PEG-PCL micelles were highly distributed into the lungs during the first 4 h post intravenous administration, then redistributed and accumulated in liver and spleen until 48 h post administration. No pathological impairment was found in the major organs studied. Conclusions: Thus, with loaded contrast agent and conjugated fluorochrome, PEG-PCL micelles as biodegradable and biocompatible nanocarriers are efficient multimodal imaging agents, offering high drug loading capacity, and sustained drug release. These might offer high treatment efficacy and real-time tracking of the drug delivery system in vivo, which is crucial for designing of an efficient drug delivery system.
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| 7. |
- Asem, Heba, et al.
(författare)
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Development and biodistribution of a theranostic aluminum phthalocyanine nanophotosensitizer
- 2016
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Ingår i: Photodiagnosis and Photodynamic Therapy. - : Elsevier BV. - 1572-1000 .- 1873-1597. ; 13, s. 48-57
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Tidskriftsartikel (refereegranskat)abstract
- Background: Aluminum phthalocyanine (AlPc) is an efficient second generation photosensitizer (PS) with high fluorescence ability. Its use in photodynamic therapy (PDT) is hampered by hydrophobicity and poor biodistribution. Methods: AlPc was converted to a biocompatible nanostructure by incorporation into amphiphilic polyethylene glycol-polycaprolactone (PECL) copolymer nanoparticles, allowing efficient entrapment of the PS in the hydrophobic core, water dispersibility and biodistribution enhancement by PEG-induced surface characteristics. A series of synthesized PECL copolymers were used to prepare nanophotosensitizers with an average diameter of 66.5-99.1 nm and encapsulation efficiency (EE%) of 66.4-78.0%. One formulation with favorable colloidal properties and relatively slow release over 7 days was selected for in vitro photophysical assessment and in vivo biodistribution studies in mice. Results: The photophysical properties of AlPc were improved by encapsulating AlPc into PECL-NPs, which showed intense fluorescence emission at 687 nm and no AlPc aggregation has been induced after entrapment into the nanoparticles. Biodistribution of AlPc loaded NPs (AlPc-NPs) and free AlPc drug in mice was monitored by in vivo whole body fluorescence imaging and ex vivo organ imaging, with in vivo imaging system (IVIS). Compared to a AlPc solution in aqueous TWEEN 80 (2 w/v%), the developed nanophotosensitizer showed targeted drug delivery to lungs, liver and spleen as monitored by the intrinsic fluorescence of AlPc at different time points (1 h, 24 h and 48 h) post iv. administration. Conclusions: The AlPc-based copolymer nanoparticles developed offer potential as a single agent multifunctional theranostic nanophotosensitizer for PDT coupled with imaging-guided drug delivery and biodistribution, and possibly also fluorescence diagnostics.
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| 8. |
- Ashour, Radwa M., et al.
(författare)
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Rare Earth Ions Adsorption onto Graphene Oxide Nanosheets
- 2017
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Ingår i: Solvent extraction and ion exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 35:2, s. 91-103
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Tidskriftsartikel (refereegranskat)abstract
- Graphene oxide (GO) was synthesized and used as a coagulant of rare earth elements (REEs) from aqueous solution. Stability and adsorption capacities were exhibited for target REEs such as La(III), Nd(III), Gd(III), and Y(III). The parameters influencing the adsorption capacity of the target species including contact time, pH, initial concentration, and temperature were optimized. The adsorption kinetics and thermodynamics were studied. The method showed quantitative recovery (99%) upon desorption using HNO3 acid (0.1 M) after a short contact time (15 min).
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| 9. |
- Ashour, Radwa M., et al.
(författare)
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Selective separation of rare earth ions from aqueous solution using functionalized magnetite nanoparticles : kinetic and thermodynamic studies
- 2017
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 327, s. 286-296
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Tidskriftsartikel (refereegranskat)abstract
- Separation of rare earth ions (RE3+) from aqueous solution is a tricky problem due to their physico-chemical similarities of properties. In this study, we investigate the influence of the functionalized ligands on the adsorption efficiency and selective adsorption of La3+, Nd3+, Gd3+ and Y3+ from aqueous solution using Magnetite (Fe3O4) nanoparticles (NPs) functionalized with citric acid (CA@Fe3O4 NPs) or L-cysteine (Cys@Fe3O4 NPs). The microstructure, thermal behavior and surface functionalization of the synthesized nanoparticles were studied. The general adsorption capacity of Cys@Fe3O4 NPs was found to be high (98 mg g−1) in comparison to CA@Fe3O4 NPs (52 mg g−1) at neutral pH 7.0. The adsorption kinetic studies revealed that the adsorption of RE3+ ions follows a pseudo second-order model and the adsorption equilibrium data fits well to the Langmuir isotherm. Thermodynamic studies imply that the adsorption process was endothermic and spontaneous in nature. Controlled desorption within 30 min of the adsorbed RE3+ ions from both Cys@Fe3O4 NPs and CA@Fe3O4 NPs was achieved with 0.5 M HNO3. Furthermore, Cys@Fe3O4 NPs exhibited a higher separation factor (SF) in the separation of Gd3+/La3+, Gd3+/Nd3+, Gd3+/Y3+ ions compared to CA@Fe3O4 NPs.
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| 10. |
- Avila, Marta, et al.
(författare)
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Surface functionalized nanofibers for the removal of chromium(VI) from aqueous solutions
- 2014
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 245, s. 201-209
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Tidskriftsartikel (refereegranskat)abstract
- Polyacrylonitrile (PAN) nanofibers functionalized with amine groups (PAN-NH2) were prepared using a simple one-step reaction route. The PAN-NH2 nanofibers were investigated for the removal of chromium(VI) from aqueous solutions. The adsorption and the kinetic characteristics were evaluated in batch process. The adsorption process showed pH dependence and the maximum Cr(VI) adsorption occurred at pH = 2. The Langmuir adsorption model described well the experimental adsorption data and estimated a maximum loading capacity of 156 mg/g, which is a markedly high value compared to other adsorbents reported. The kinetics studies indicated that the equilibrium was attained after 90 min and the experimental data followed a pseudo-second order model suggesting a chemisorption process as the rate limiting step. X-ray Photoelectron Spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) revealed that the adsorption of Cr(VI) species on PAN-NH2 was facilitated through both electrostatic attraction and surface complexation. High desorption efficiency (> 90%) of Cr(VI) was achieved using diluted base solutions that may allow the reuse of PAN-NH2 nanofibers.
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