| 1. |
- Andõn, F. T., et al.
(author)
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Biodegradation of Single-Walled Carbon Nanotubes by Eosinophil Peroxidase
- 2013
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In: Small. - : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 9:16, s. 2721-2729
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Journal article (peer-reviewed)abstract
- Eosinophil peroxidase (EPO) is one of the major oxidant-producing enzymes during inflammatory states in the human lung. The degradation of single-walled carbon nanotubes (SWCNTs) upon incubation with human EPO and H2O 2 is reported. Biodegradation of SWCNTs is higher in the presence of NaBr, but neither EPO alone nor H2O2 alone caused the degradation of nanotubes. Molecular modeling reveals two binding sites for SWCNTs on EPO, one located at the proximal side (same side as the catalytic site) and the other on the distal side of EPO. The oxidized groups on SWCNTs in both cases are stabilized by electrostatic interactions with positively charged residues. Biodegradation of SWCNTs can also be executed in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. Biodegradation is proven by a range of methods including transmission electron microscopy, UV-visible-NIR spectroscopy, Raman spectroscopy, and confocal Raman imaging. Thus, human EPO (in vitro) and ex vivo activated eosinophils mediate biodegradation of SWCNTs: an observation that is relevant to pulmonary responses to these materials. Human eosinophil peroxidase (EPO) is able to degrade SWCNTs in vitro in the presence of H2O2. EPO is one of the major oxidant-generating enzymes present in human lungs during inflammatory states. The biodegradation of SWCNTs is evidenced also in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. These results are relevant to potential respiratory exposure to carbon nanotubes.
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| 2. |
- Bhattacharya, Kunal, et al.
(author)
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Enzymatic 'stripping' and degradation of PEGylated carbon nanotubes
- 2014
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In: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 6:24, s. 14686-14690
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Journal article (peer-reviewed)abstract
- Single-walled carbon nanotubes (SWCNTs) coated or functionalized with PEG chains of different molecular weight were assessed for their propensity to undergo biodegradation under in vitro conditions using recombinant myeloperoxidase (MPO) or ex vivo using freshly isolated primary human neutrophils. Our findings suggest that under natural conditions, a combined process of 'stripping' (i.e., defunctionalization) and biodegradation of PEG-SWCNTs might occur and that PEG-SWCNTs are a promising-and degradable-nanomedicine vector.
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| 3. |
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| 4. |
- Bogren, Sara, et al.
(author)
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Classification of Magnetic Nanoparticle Systems—Synthesis, Standardization and Analysis Methods in the NanoMag Project
- 2015
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In: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 16:9, s. 20308-20325
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Journal article (peer-reviewed)abstract
- This study presents classification of different magnetic single- and multi-core particle systems using their measured dynamic magnetic properties together with their nanocrystal and particle sizes. The dynamic magnetic properties are measured with AC (dynamical) susceptometry and magnetorelaxometry and the size parameters are determined from electron microscopy and dynamic light scattering. Using these methods, we also show that the nanocrystal size and particle morphology determines the dynamic magnetic properties for both single- and multi-core particles. The presented results are obtained from the four year EU NMP FP7 project, NanoMag, which is focused on standardization of analysis methods for magnetic nanoparticles.
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| 5. |
- Booth, Andy, et al.
(author)
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Freshwater dispersion stability of PAA-stabilised cerium oxide nanoparticles and toxicity towards Pseudokirchneriella subcapitata
- 2015
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 505, s. 596-605
-
Journal article (peer-reviewed)abstract
- An aqueous dispersion of poly (acrylic acid)-stabilised cerium oxide (CeO2) nanoparticles (PAA-CeO2) was evaluated for its stability in a range of freshwater ecotoxicity media (MHRW, TG 201 and M7), with and without natural organic matter (NOM). In a 15day dispersion stability study, PAA-CeO2 did not undergo significant aggregation in any media type. Zeta potential varied between media types and was influenced by PAA-CeO2 concentration, but remained constant over 15days. NOM had no influence on PAA-CeO2 aggregation or zeta potential. The ecotoxicity of the PAA-CeO2 dispersion was investigated in 72h algal growth inhibition tests using the freshwater microalgae Pseudokirchneriella subcapitata. PAA-CeO2 EC50 values for growth inhibition (GI; 0.024mg/L) were 2-3 orders of magnitude lower than pristine CeO2 EC50 values reported in the literature. The concentration of dissolved cerium (Ce3+/Ce4+) in PAA-CeO2 exposure suspensions was very low, ranging between 0.5 and 5.6μg/L. Free PAA concentration in the exposure solutions (0.0096-0.0384mg/L) was significantly lower than the EC10 growth inhibition (47.7mg/L) value of pure PAA, indicating that free PAA did not contribute to the observed toxicity. Elemental analysis indicated that up to 38% of the total Cerium becomes directly associated with the algal cells during the 72h exposure. TOF-SIMS analysis of algal cell wall compounds indicated three different modes of action, including a significant oxidative stress response to PAA-CeO2 exposure. In contrast to pristine CeO2 nanoparticles, which rapidly aggregate in standard ecotoxicity media, PAA-stabilised CeO2 nanoparticles remain dispersed and available to water column species. Interaction of PAA with cell wall components, which could be responsible for the observed biomarker alterations, could not be excluded. This study indicates that the increased dispersion stability of PAA-CeO2 leads to an increase in toxicity compared to pristine non-stabilised forms.
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| 6. |
- Fadeel, Bengt, et al.
(author)
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Keeping it real : The importance of material characterization in nanotoxicology
- 2015
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In: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 468:3, s. 498-503
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Research review (peer-reviewed)abstract
- Nanomaterials are small and the small size and corresponding large surface area of nanomaterials confers specific properties, making these materials desirable for various applications, not least in medicine. However, it is pertinent to ask whether size is the only property that matters for the desirable or detrimental effects of nanomaterials? Indeed, it is important to know not only what the material looks like, but also what it is made of, as well as how the material interacts with its biological surroundings. It has been suggested that guidelines should be implemented on the types of information required in terms of physicochemical characterization of nanomaterials for toxicological studies in order to improve the quality and relevance of the published results. This is certainly a key issue, but it is important to keep in mind that material characterization should be fit-for-purpose, that is, the information gathered should be relevant for the end-points being studied.
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| 7. |
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| 8. |
- Fornara, Andrea, 1980-
(author)
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Magnetic nanostructured materials for advanced bio-applications
- 2008
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Licentiate thesis (other academic/artistic)abstract
- In the recent years, nanostructured magnetic materials and their use in biomedical and biotechnological applications have received a lot of attention. In this thesis, we developed tailored magnetic nanoparticles for advanced bio-applications, such as direct detection of antibodies in biological samples and stimuli responsive drug delivery system. For sensitive and selective detection of biomolecules, thermally blocked iron oxide nanoparticles with specific magnetic properties are synthesized by thermal hydrolysis to achieve a narrow size distribution just above the superparamagnetic limit. The prepared nanoparticles were characterized and functionalized with biomolecules for use in a successful biosensor system. We have demonstrated the applicability of this type of nanoparticles for the detection of Brucella antibodies as model compound in serum samples and very low detection limits were achieved (0.05 mg/mL). The second part is concerning an in-depth investigation of the evolution of the thermally blocked magnetic nanoparticles. In this study, the formation of the nanoparticles at different stages during the synthesis was investigated by high resolution electron microscopy and correlated to their magnetic properties. At early stage of the high temperature synthesis, small nuclei of 3.5 nm are formed and the particles size increases successively until they reach a size of 17-20 nm. The small particles first exhibit superparamagnetic behavior at the early stage of synthesis and then transform to thermally blocked behavior as their size increases and passes the superparamagnetic limit. The last section of the Thesis is related to the development of novel drug delivery system based on magnetically controlled release rate. The system consists of hydrogel of Pluronic FP127 incorporating superparamagnetic iron oxide nanoparticles to form a ferrogel. The sol to gel formation of the hydrogel could be tailored to be solid at body temperature and thus have the ability to be injected inside living biological tissues. In order to evaluate the drug loading and release, the hydrophobic drug indomethacin was selected as a model compound. The drug could be loaded in the ferrogel owning to the oil in water micellar structure. We have studied the release rate from the ferrogel in the absence and presence of magnetic field. We have demonstrated that the drug release rate can be significantly enhanced by use of external magnetic field decreasing the half time of the release to more than 50% (from 3200 to 1500 min) upon the application of the external magnetic field. This makes the developed ferrogel a very promising drug delivery system that does not require surgical implant procedure for medical treatment and gives the possibility of enhancing the rate of release by external magnetic field.
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| 9. |
- Fornara, Andrea, 1980-
(author)
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Multifunctional nanomaterials for diagnostic and therapeutic applications
- 2010
-
Doctoral thesis (other academic/artistic)abstract
- In the past few years, the use of nanostructured materials in medical applications hasdramatically increased, both in the research phase and for clinical purposes, due to thepeculiar properties and the ability of such materials to interact at a similar scale withbiological entities. In this thesis, we developed tailored magnetic multifunctionalnanoparticles for diagnostic and therapeutic applications, such as detection ofbiomolecules, simultaneous enhanced magnetic resonance imaging (MRI), fluorescentvisualization and controlled drug release.For sensitive and selective detection of specific biomolecules, thermally blocked ironoxide nanoparticles with tailored magnetic properties were developed. The formation ofsuch nanoparticles has been studied both in terms of size and magnetic behavior in liquidsuspension or in polymer matrixes. These particles with narrow size distribution (averagediameter of 19 nm) were surface functionalized by antigen molecules and were used forthe detection of Brucella antibodies in biological samples. The binding of biomoleculesresults in an increase in the particle’s hydrodynamic diameter, affecting the relaxationbehavior that was monitored by magnetic measurements. This sensing system is a fastand sensitive biosensor with very low detection limits (0.05 μg/mL).Superparamagnetic iron oxide nanoparticles (SPION) have been synthesized withaverage diameter of 10-12 nm, narrow size distribution, high crystallinity and superiormagnetic properties as liquid suspensions or embedded in a bulk transparent magneticnanocomposite. These nanoparticles were synthesized in organic solvents and, after phasetransfer with Pluronic F127 amphiphilic copolymer, show excellent relaxivity properties(high r2/r1 ratio) and great contrast enhancement in T2 weighted MRI, confirmed by invivostudies of rat inner ear.SPION have been used as a component for different multifunctional nanostructures. Thefirst system based on poly (L,L lactide)-methoxy polyethylene glycol (PLLA-mPEG)copolymer has been prepared by an emulsion/evaporation process that lead to polymericnanoparticles containing several imaging agents, such as SPION, quantum dots (QDs)and gold nanorods as well as indomethacin (IMC) as therapeutic payload. With a similarprocedure, but using poly (lactide-co-glycolide) (PLGA-PEG-NH2) copolymer, a secondtype of multifunctional nanoparticles has been obtained. Their size can be tailored from70 to 150 nm varying synthesis parameters, such as the surfactant concentration or waterto oil ratio. Both these polymer-based multifunctional nanoparticles can be visualized byfluorescence microscopy (QDs photoemission) and MRI (SPION magnetization) and theycan be used for photothermal therapy (gold nanorods) and drug delivery. The last systemconsists of SPION nanoparticles coated with PLLA directly on the surface by an in-situpolymerization process. A hydrophobic drug was loaded before the phase transfer withPluronic F127 and these nanoparticles show simultaneous MRI T2 contrast enhancementas well as high drug loading and sustained delivery.Controlling the drug release rate is also a critical parameter for tailored therapeutictreatments, and for this reason we developed a novel drug delivery system based on theintegration of SPION and Pluronic F127 gels. IMC was loaded in the ferrogel (with atailored gelation temperature) and its release rate was triggered by applying an externalmagnetic field owing to the SPION magnetic properties.
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| 10. |
- Fornara, Andrea, et al.
(author)
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PLGA-PEG multifunctional nanoparticles for simultaneous drug delivery and imaging by MRI and fluorescence microscopy
- 2012
-
In: Technical Proceedings of the 2012 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2012. - 9781466562769 ; , s. 4-7
-
Conference paper (peer-reviewed)abstract
- This work deals with the synthesis of multifunctional nanoparticles based on biocompatible di-block copolymer (PLGA-PEG) via an emulsion-evaporation method. To enable their visualization, these nanoparticles can be loaded with iron oxide nanoparticles for Magnetic Resonance Imaging (MRI) and/or quantum dots for fluorescent microscopy. A therapeutic agent, Indomethacin, can also be loaded and released. The influence of synthesis parameters on nanoparticle size (in the range 70-150 nm) has been controlled to achieve specific cellular interactions avoiding possible immuno-response. These multifunctional nanoparticles possess excellent photoemission properties for fluorescent microscopy and enhanced contrast efficiency for T 2 MRI imaging compared to available agents used today. In-vitro experiments confirm the low cytotoxicity of such nanoparticles and their excellent visualization properties by MRI and fluorescence microscopy in cells and biological tissues.
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| 11. |
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| 12. |
- Fornara, Andrea, 1980-, et al.
(author)
-
Polymeric/inorganic multifunctional nanoparticles for simultaneous drug delivery and visualization
- 2010
-
In: Materials Research Society Symposium Proceedings. - 0272-9172 .- 1946-4274. ; 1257
-
Journal article (peer-reviewed)abstract
- Nanoparticles consisting of different biocompatible materials are attracting a lot of interest in the biomedical area as useful tools for drug delivery, photo-therapy and contrast enhancement agents in MRI, fluorescence and confocal microscopy. This work mainly focuses on the synthesis of polymeric/inorganic multifunctional nanoparticles (PIMN) based on biocompatible di-block copolymer poly(L,L-lactide-co-ethylene glycol) (PLLA-PEG) via an emulsion-evaporation method. Besides containing a hydrophobic drug (Indomethacin), these polymeric nanoparticles incorporate different visualization agents such as superparamagnetic iron oxide nanoparticles (SPION) and fluorescent Quantum Dots (QDs) that are used as contrast agents for Magnetic Resonance Imaging (MRI) and fluorescence microscopy together. Gold Nanorods are also incorporated in such nanostructures to allow simultaneous visualization and photodynamic therapy. MRI studies are performed with different loading of SPION into PIMN, showing an enhancement in T2 contrast superior to commercial contrast agents. Core-shell QDs absorption and emission spectra are recorded before and after their loading into PIMN. With these polymeric/inorganic multifunctional nanoparticles, both MRI visualization and confocal fluorescence microscopy studies can be performed. Gold nanorods are also synthesized and incorporated into PIMN without changing their longitudinal absorption peak usable for lased excitation and phototherapy. In-vitro cytotoxicity studies have also been performed to confirm the low cytotoxicity of PIMN for further in-vivo studies.
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| 13. |
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| 14. |
- Fornara, Andrea, et al.
(author)
-
Tailored Magnetic Nanoparticles for Direct and Sensitive Detection of Biomolecules in Biological Samples
- 2008
-
In: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 8:10, s. 3423-3428
-
Journal article (peer-reviewed)abstract
- We developed nanoparticles with tailored magnetic properties for sensitive detection of biomolecules directly in biological samples in a single step. Thermally blocked nanoparticles obtained by thermal hydrolysis are mixed with sample solutions and the variation of the magnetic relaxation due to surface binding is used to detect the presence of biomolecules. The binding events significantly increase the hydrodynamic volume of nanoparticles, thus changing their Brownian relaxation frequency which is measured by a specifically developed AC-susceptometer.The system was tested for the presence of Brucella antibodies in serum samples from infected cows and the surface of the nanoparticles was functionalized with lipopolysaccarides (LPS) from Brucella abortus. The hydrodynamic volume of functionalized particles increased by 25-35% as a result of the binding of the antibodies, as measured by changes in the susceptibility in an alternating magnetic field. The method has shown high sensitivity, with detection limit of 7 nmol·L-1 in serum without any pre-treatment of the biological samples.The detection method is very sensitive, cost-efficient and versatile, giving a direct indication if the animal is infected or not, making it suitable for point-of care applications. The functionalization of tailored magnetic nanoparticles can be modified to suit numerous homogenous assays for a wide range of applications.
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| 15. |
- Gavilán, Helena, et al.
(author)
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Colloidal Flower-Shaped Iron Oxide Nanoparticles : Synthesis Strategies and Coatings
- 2017
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In: Particle & particle systems characterization. - : Wiley. - 0934-0866 .- 1521-4117. ; 34:7
-
Journal article (peer-reviewed)abstract
- The assembly of magnetic cores into regular structures may notably influence the properties displayed by a magnetic colloid. Here, key synthesis parameters driving the self-assembly process capable of organizing colloidal magnetic cores into highly regular and reproducible multi-core nanoparticles are determined. In addition, a self-consistent picture that explains the collective magnetic properties exhibited by these complex assemblies is achieved through structural, colloidal, and magnetic means. For this purpose, different strategies to obtain flower-shaped iron oxide assemblies in the size range 25–100 nm are examined. The routes are based on the partial oxidation of Fe(OH)2, polyol-mediated synthesis or the reduction of iron acetylacetonate. The nanoparticles are functionalized either with dextran, citric acid, or alternatively embedded in polystyrene and their long-term stability is assessed. The core size is measured, calculated, and modeled using both structural and magnetic means, while the Debye model and multi-core extended model are used to study interparticle interactions. This is the first step toward standardized protocols of synthesis and characterization of flower-shaped nanoparticles.
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| 16. |
- Gustafsson, Stefan, 1976, et al.
(author)
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Evolution of Structural and Magnetic Properties of Magnetite Nanoparticles for Biomedical Applications
- 2010
-
In: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 10:5, s. 2278-2284
-
Journal article (peer-reviewed)abstract
- We have investigated the evolution of microstructure and magnetic properties of thermally blocked magnetite nanoparticles, aimed for immunoassay applications, during their synthesis. High-resolution transmission electron microscopy (HRTEM) investigations of the size, size distribution, morphology, and crystal structure of particles reveal that particles at an early stage of the reaction process are either single crystals or polycrystals containing planar faults and they grow via a combination of reactant (monomer) consumption and oriented attachment at specific crystallographic surfaces because of the strong dipolar character of the < 111 > surfaces of magnetite. At a later stage of the synthesis reaction, the magnetic attraction strives to align contacting particles with their < 111 > axis of easy magnetization in parallel and this may also be an active driving force for crystal growth. At latter stages, the crystal growth is dominated by Ostwald ripening leading to smoother crystalline particles with a mean diameter of 16.7 +/- 3.5 nm and a narrow size distribution. The magnetic properties of the particles measured using static and dynamic magnetic fields are consistent with the evolution of particle size and structure and show the transition from superparamagnetic to thermally blocked behavior needed for magnetic relaxation-based immunoassay applications.
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| 17. |
- Gutiérrez, Lucía, et al.
(author)
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Synthesis methods to prepare single- and multi-core iron oxide nanoparticles for biomedical applications
- 2015
-
In: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 44:7, s. 2943-2952
-
Journal article (peer-reviewed)abstract
- We review current synthetic routes to magnetic iron oxide nanoparticles for biomedical applications. We classify the different approaches used depending on their ability to generate magnetic particles that are either single-core (containing only one magnetic core, i.e. a single domain nanocrystal) or multi-core (containing several magnetic cores, i.e. single domain nanocrystals). The synthesis of single-core magnetic nanoparticles requires the use of surfactants during the particle generation, and careful control of the particle coating to prevent aggregation. Special attention has to be paid to avoid the presence of any toxic reagents after the synthesis if biomedical applications are intended. Several approaches exist to obtain multi-core particles based on the coating of particle aggregates; nevertheless, the production of multi-core particles with good control of the number of magnetic cores per particle, and of the degree of polydispersity of the core sizes, is still a difficult task. The control of the structure of the particles is of great relevance for biomedical applications as it has a major influence on the magnetic properties of the materials.
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| 18. |
- Li, Shanghua, et al.
(author)
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Synthesis and magnetic properties of bulk transparent PMMA/Fe-oxide nanocomposites
- 2009
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In: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 20:18
-
Journal article (peer-reviewed)abstract
- PMMA/Fe-oxide nanocomposites are fabricated by a chemical method. Monodispersed Fe-oxide nanoparticles are well dispersed in the PMMA matrix by in situ polymerization, resulting in a bulk transparent polymeric nanocomposite. The magnetic behavior of the PMMA/Fe-oxide nanocomposites is investigated. The transparent PMMA/Fe-oxide nanocomposite has potentially interesting magneto-optic applications without compromising the advantages of a lightweight, noncorrosive polymeric material with very high transparency even for bulk samples.
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| 19. |
- Li, Shanghua, et al.
(author)
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The effect of ceria nanoparticles on the breakdown strength of transformer oil
- 2015
-
In: 2015 IEEE 11th International Conference on the Properties and Applications of Dielectric Materials (ICPADM). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781479989034 ; , s. 289-292
-
Conference paper (peer-reviewed)abstract
- Nanotechnologies have potential to be used in transformer industry in enhancing material properties which may lead to a compact design of transformer and reduced manufacturing cost. Effect of adding different nanoparticles such as titania, silica, nano-diamond, etc. has been studied in literatures. In this paper, nano-ceria particles have been successfully added into transformer mineral oil with different content. The suspension is very stable and no segmentation can be observed over several months. The ceria nanoparticles are commercially available, which have a quite narrow size distribution. UV-Vis, TGA and FT-IR are used to characterize the ceria nanofluids. The water content of the ceria nanofluids has been measured by Karl Fisher titration, which is important for the breakdown strength of transformer oil. AC voltage breakdown and lightning impulse voltage breakdown measurements have been performed on the ceria nanofluids. An enhancement of 15% on AC breakdown voltage has been observed on ceria nanofluids with some content compared to reference transformer oil. On the other hand, no clear difference on the lightning impulse breakdown voltage is observed between the ceria nanofluids and reference transformer oil.
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| 20. |
- Okoli, Chuka, et al.
(author)
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Characterization of Superparamagnetic Iron Oxide Nanoparticles and Its Application in Protein Purification
- 2011
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In: Journal of Nanoscience and Nanotechnology. - : American Scientific Publishers. - 1533-4880 .- 1533-4899. ; 11:11, s. 10201-10206
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Journal article (peer-reviewed)abstract
- The application of surface modified magnetic adsorbent particles in combination with magnetic separation techniques has received considerable awareness in recent years. There is a particular need in protein purification and analysis for specific, functional and generic methods of protein binding on solid supports. Nanoscale superparamagnetic iron oxide particles have been used to purify a natural coagulant protein extracted from Moringa oleiferaseeds. Spectrophotometric analysis of the coagulant protein was performed using synthetic clay solution as substrate. Protein binding with carboxyl and silica surface modified superparamagnetic iron oxide nanoparticles (SPION) were compared with the known carboxyl methyl cellulose (CMC) beads of ∼1 m. SPION modified with carboxyl surface showed higher binding capacity towards the coagulant protein compared to the CMC beads. The high surface area to volume ratio of the carboxyl-coated SPION resulted in high binding capacity and rapid adsorption kinetics of the crude protein extract. The purification and molecular weight of coagulant protein is analyzed by SDS-PAGE. This approach utilizes the most efficient, feasible and economical method of coagulant protein purification and it can also be applicable to other proteins that possess similar properties.
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| 21. |
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| 22. |
- Qin, Jian, et al.
(author)
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Injectable Superparamagnetic Ferrogels for Controlled Release of Hydrophobic Drugs
- 2009
-
In: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 21:13, s. 1354-1357
-
Journal article (peer-reviewed)abstract
- A ferrogel for magnetically controlled release of drugs is prepared by integration of superparamagnetic iron oxide nanoparticles and Pluronic F127 gels. The hydrophobic drug indomethacin is loaded in the ferrogel owing to the oil-in-water micellar structure. The characteristic solgel transition property renders the ferrogel an injectable drug carrier that will be, in principle, free from surgical implant procedure.
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| 23. |
- Sandin, Gustav A, 1983, et al.
(author)
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Environmental evaluation of a clear coating for wood: toxicological testing and life cycle assessment
- 2012
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In: PRA's 8th International Woodcoatings Congress (oral presentation and confereence proceeding paper).
-
Conference paper (other academic/artistic)abstract
- WoodLife is an on-going project under the EU Seventh Framework Programme aimed at developing a water-based clear coating for exterior wood products. Adding nanoparticles to a conventional coating could improve its UV-protecting properties, thus decreasing the need for maintenance of coated wood products. Wood products could thereby replace non-wood alternatives, which could result in lower environmental impacts.This paper describes an environmental evaluation carried out within the WoodLife project, in which we test whether the nanoparticles are toxic for the bacteria Vibrio fischeri, and use Life Cycle Assessment (LCA) to map the environmental consequences of applying the coating on a wood product. This goes beyond the scope of most environmental evaluations of nanotechnologies, which tend to include either an assessment of the possible toxicity of the nanomaterial or an LCA.The toxicological testing indicates low ecotoxicity of the nanoparticles, but further development of suitable testing methods is warranted to enable a full ecotoxicological evaluation. The LCA shows that a wooden window frame with the new coating can be environmentally superior to plastic and aluminium window frames. However, the potential in part depends on variables such as recycling rates and disposal practices, which are highly uncertain for future products with long service lives.
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| 24. |
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| 25. |
- Sommertune, Jens, et al.
(author)
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Polymer/iron oxide nanoparticle composites—A straight forward and scalable synthesis approach
- 2015
-
In: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 16:8, s. 19752-19768
-
Journal article (peer-reviewed)abstract
- Magnetic nanoparticle systems can be divided into single-core nanoparticles (with only one magnetic core per particle) and magnetic multi-core nanoparticles (with several magnetic cores per particle). Here, we report multi-core nanoparticle synthesis based on a controlled precipitation process within a well-defined oil in water emulsion to trap the superparamagnetic iron oxide nanoparticles (SPION) in a range of polymer matrices of choice, such as poly(styrene), poly(lactid acid), poly(methyl methacrylate), and poly(caprolactone). Multi-core particles were obtained within the Z-average size range of 130 to 340 nm. With the aim to combine the fast room temperature magnetic relaxation of small individual cores with high magnetization of the ensemble of SPIONs, we used small (<10 nm) core nanoparticles. The performed synthesis is highly flexible with respect to the choice of polymer and SPION loading and gives rise to multi-core particles with interesting magnetic properties and magnetic resonance imaging (MRI) contrast efficacy.
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| 26. |
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| 27. |
- Thaler, Marlene, et al.
(author)
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Visualization and Analysis of Superparamagnetic Iron Oxide Nanoparticles in the Inner Ear by Light Microscopy and Energy Filtered TEM
- 2011
-
In: Nanomedicine: Nanotechnology, Biology, and Medicine. - : Elsevier BV. - 1549-9634. ; 7:3, s. 360-369
-
Journal article (peer-reviewed)abstract
- Nanoparticles as potential carriers for local drug transfer are an alternative to systemic drug delivery into the inner ear. We report on the first in vitro tests of a new ferrogel consisting of superparamagnetic iron oxide nanoparticles (SPIONs) and a Pluronic (R) F127 (PF127) copolymer. Pluronic copolymers possess a unique viscosity-adjustable property that makes PF127 gels easy to handle compared to conventional cross-linked hydrogels. This ferrogel was successfully tested in cadaver human temporal bones as well as in organotypic explant cultures of mouse inner ears. SPIONs were identified by light microscopy and localized with different imaging modes in energy-filtered transmission electron microscopy. Our approach shows a promising possibility to use iron oxide nanoparticles, which are suitable for visualization and characterization at both the light- and electron-microscopic levels. From the Clinical Editor: The authors report the first in vitro tests of a new ferrogel consisting of superparamagnetic iron oxide nanoparticles (SPIONs) and a Pluronic (R) F127 (PF127) copolymer for drug delivery in the inner ear, demonstrasting a promising possibility to use iron oxide nanoparticles, which are suitable for visualization and characterization at both the light- and electron-microscopic levels.
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| 28. |
- Ye, Fei, et al.
(author)
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Synthesis of high aspect ratio gold nanorods and their effects on human antigen presenting dendritic cells
- 2011
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In: International Journal Of Nanotechnology. - 1475-7435. ; 8:8-9, s. 631-652
-
Journal article (peer-reviewed)abstract
- High aspect ratio (AR) gold nanorods (NRs) attract great interest for biomedical applications due to their novel physicochemical properties. Here, we report a facile method for preparation of high AR gold NRs through a seedless surfactant-mediated protocol with the additive of nitric acid. High-resolution transmission electron microscopy studies showed that the concentration of nitric acid has great effects on the crystal structures of the initially formed nuclei and consequently the growth of gold NRs. A mechanism based on the effect of nitrate ions on surfactant micelle elongation and Ostwald ripening process is proposed for the growth of high AR gold NRs. The biocompatibility of high AR NRs was evaluated on primary human monocyte derived dendritic cells (MDDCs), and compared with that of spherical gold nanoparticles (NPs) and low AR NRs. Low AR (similar to 4.5) gold NRs induced considerable cell death due to CTAB, while spherical gold NPs (7 nm) and high AR (similar to 21) gold NRs showed no or minor effects on viability and immune regulatory markers, which supports the further development of high AR gold NRs for medical applications.
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| 29. |
- Ye, Fei, et al.
(author)
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Uniform mesoporous silica coated iron oxide nanoparticles as a highly efficient, nontoxic MRI T 2 contrast agent with tunable proton relaxivities
- 2012
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In: Contrast Media & Molecular Imaging. - : Wiley. - 1555-4309 .- 1555-4317. ; 7:5, s. 460-468
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Journal article (peer-reviewed)abstract
- Monodisperse mesoporous silica (mSiO 2) coated superparamagnetic iron oxide (Fe 3O 4@mSiO 2) nanoparticles (NPs) have been developed as a potential magnetic resonance imaging (MRI) T 2 contrast agent. To evaluate the effect of surface coating on MRI contrast efficiency, we examined the proton relaxivities of Fe 3O 4@mSiO 2 NPs with different coating thicknesses. It was found that the mSiO 2 coating has a significant impact on the efficiency of Fe 3O 4 NPs for MRI contrast enhancement. The efficiency increases with the thickness of mSiO 2 coating and is much higher than that of the commercial contrast agents. Nuclear magnetic resonance (NMR) relaxometry of Fe 3O 4@mSiO 2 further revealed that mSiO 2 coating is partially permeable to water molecules and therefore induces the decrease of longitudinal relaxivity, r 1. Biocompatibility evaluation of various sized (ca. 35-95 nm) Fe 3O 4@mSiO 2 NPs was tested on OC-k3 cells and the result showed that these particles have no negative impact on cell viability. The enhanced MRI efficiency of Fe 3O 4@mSiO 2 highlights these core-shell particles as highly efficient T 2 contrast agents with high biocompatibility.
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| 30. |
- Zhao, Yichen, et al.
(author)
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Relaxation is the key to longer life : suppressed degradation of P3HT films on conductive substrates
- 2014
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In: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 2:33, s. 13270-13276
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Journal article (peer-reviewed)abstract
- Here we show the dependence of the degree of degradation of poly-3-hexylthiophene (P3HT) films on the conductivity of the supporting substrate. P3HT is widely used for organic solar cells and electronic devices because it allows simple, low cost fabrication and has potential for the fabrication of flexible devices. However, P3HT is known to have a relatively low photostability, and investigating the photodegradation mechanism is an active research field. We find that P3HT films on conductive substrates show significantly retarded degradation and retain their chemical and morphological features when compared to similar films on glass substrates. This 'substrate effect' in retarding the degradation of P3HT films is evident even upon prolonged exposure to air for up to five months.
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| 31. |
- Zhou, Jing, et al.
(author)
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MRI manifestation of novel superparamagnetic iron oxide nanoparticles in the rat inner ear
- 2010
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In: Nanomedicine. - : Future Medicine Ltd. - 1743-5889 .- 1748-6963. ; 5:5, s. 739-754
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Journal article (peer-reviewed)abstract
- Aim: Superparamagnetic iron oxide nanoparticles hierarchically coated with oleic acid and Pluronic F127 copolymers (POA@SPION) have shown exceptional 12 contrast enhancement. The aim of the present work was to investigate the MRI manifestation of POA@SPION in the inner ear. Materials & methods: A total of 26 male Wister rats were selected for testing POA@SPION administered through intracochlear, intratympanic and intravenous routes. MRI was performed with a 4.7 T MR scanner. Results & conclusion: POA@SPION can be introduced into the perilymph space, after which it becomes widely distributed and can demonstrate the integrity of the perilymph-endolymph barrier. Positive highlighting of the endolymph compartment against the darkened perilymph was visualized for the first time. POA@SPION passed through the middle-inner ear barriers in only small amounts, but stayed in the perilymph for 3 days. They did not traverse the blood-perilymph barrier or blood-endolymph barrier. The inner ear distribution of POA@SPION was confirmed by histology. POA@SPION is a promising T2 negative contrast agent.
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