scholarly journals The Effect of Polyol Composition on the Structural and Magnetic Properties of Magnetite Nanoparticles for Magnetic Particle Hyperthermia

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2663 ◽  
Author(s):  
Kotoulas ◽  
Dendrinou-Samara ◽  
Angelakeris ◽  
Kalogirou
Keyword(s):  
Magnetic Particle ◽  
Magnetic Hysteresis ◽  
Chemical Properties ◽  
Main Idea ◽  
Triethylene Glycol ◽  
Magnetic Core ◽  
Reducing Agent ◽  
Heating Efficiency ◽  
Crystallite Sizes ◽  
Magnetic Features

A study of the influence of polyols, with or without an additional reducing agent, on crystallites’ size and magnetic features in Fe3O4 nanoparticles and on their performance in magnetic particle hyperthermia is presented. Three different samples were synthesized by thermal decomposition of an iron precursor in the presence of NaBH4 in a polyol. So far, triethylene glycol (TrEG) and polyethylene glycol (PEG 1000 and PEG 8000) that exhibit different physical and chemical properties have been used in order to investigate the influence of the polyols on the composition and the size of the NPs. Additionally, the presence of a different reducing agent such as hydrazine, has been tested for comparison reasons in case of TrEG. Three more samples were prepared solvothermally by using the same polyols, which led to different crystallite sizes. The magnetic core of the nanoparticles was characterized, while the presence of the surfactant was studied qualitatively and quantitatively. Concerning the magnetic features, all samples present magnetic hysteresis including remanence and coercivity revealing that they are thermally blocked at room temperature. Finally, a study on the influence of the MNPs heating efficiency from their size and the field amplitude was accomplished. In our polyol process the main idea was to control the specific loss power (SLP) values by the nanoparticles’ size and consequently by the polyol itself.

scholarly journals Functionalization of Cellulose-Based Hydrogels with Bi-Functional Fusion Proteins Containing Carbohydrate-Binding Modules

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3175
Author(s):  
Mariana Barbosa ◽  
Hélvio Simões ◽  
Duarte Miguel F. Prazeres
Keyword(s):  
Fusion Proteins ◽  
Fluorescent Protein ◽  
Protein A ◽  
Chemical Properties ◽  
Main Idea ◽  
Bioactive Molecules ◽  
Scaffolding Protein ◽  
Carbohydrate Binding ◽  
Biological Interactions ◽  
Carbohydrate Binding Modules

Materials with novel and enhanced functionalities can be obtained by modifying cellulose with a range of biomolecules. This functionalization can deliver tailored cellulose-based materials with enhanced physical and chemical properties and control of biological interactions that match specific applications. One of the foundations for the success of such biomaterials is to efficiently control the capacity to combine relevant biomolecules into cellulose materials in such a way that the desired functionality is attained. In this context, our main goal was to develop bi-functional biomolecular constructs for the precise modification of cellulose hydrogels with bioactive molecules of interest. The main idea was to use biomolecular engineering techniques to generate and purify different recombinant fusions of carbohydrate binding modules (CBMs) with significant biological entities. Specifically, CBM-based fusions were designed to enable the bridging of proteins or oligonucleotides with cellulose hydrogels. The work focused on constructs that combine a family 3 CBM derived from the cellulosomal-scaffolding protein A from Clostridium thermocellum (CBM3) with the following: (i) an N-terminal green fluorescent protein (GFP) domain (GFP-CBM3); (ii) a double Z domain that recognizes IgG antibodies; and (iii) a C-terminal cysteine (CBM3C). The ability of the CBM fusions to bind and/or anchor their counterparts onto the surface of cellulose hydrogels was evaluated with pull-down assays. Capture of GFP-CBM3 by cellulose was first demonstrated qualitatively by fluorescence microscopy. The binding of the fusion proteins, the capture of antibodies (by ZZ-CBM3), and the grafting of an oligonucleotide (to CBM3C) were successfully demonstrated. The bioactive cellulose platform described here enables the precise anchoring of different biomolecules onto cellulose hydrogels and could contribute significatively to the development of advanced medical diagnostic sensors or specialized biomaterials, among others.

Characterization of CuSbSe2 crystallites synthesized using a hot injection method

RSC Advances ◽  
2016 ◽  
Vol 6 (101) ◽  
pp. 99297-99305 ◽  
Author(s):  
Hsing-I. Hsiang ◽  
Chang-Ting Yang ◽  
Jui-Huan Tu
Keyword(s):  
Single Phase ◽  
Triethylene Glycol ◽  
Reducing Agent ◽  
Injection Method ◽  
Hot Injection ◽  
Low Toxic

In this study, a novel and facile hot injection method for the synthesis of single phase CuSbSe2 crystallites was developed by using low toxic triethylene glycol as both the solvent and reducing agent and triethylenetetramine as co-reducing agent.

scholarly journals Comparison of gas dehydration methods based on energy consumption

2016 ◽  
Vol 20 (2) ◽  
pp. 253-258
Author(s):  
B.S. Kinigoma ◽  
G.O. Ani
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
High Pressures ◽  
Energy Requirement ◽  
Chemical Properties ◽  
Triethylene Glycol ◽  
Design Engineers ◽  
Natural Gas Dehydration ◽  
Physical And Chemical ◽  
Low Pressures

This study compares three conventional methods of natural gas (Associated Natural Gas) dehydration to carry out the dehydration process and suitability of use on the basis of energy requirement. These methods are Triethylene Glycol (TEG) absorption, solid desiccant adsorption and condensation. Analyses performed were based on dehydration of Natural Gas saturated with 103Nm3/h water content at a temperature range of -10O C to 30oC, and gas pressure variation between 7MPa and 20MPa. This analysis and study showed that energy required for all three processes decreases with increase in pressure, but condensation dehydration requires the least energy at high pressures. Results obtained shows that, both at high pressures and low pressures, TEG dehydration is most suitable and in cases where very low Tdew is required, solid desiccant adsorption is preferable. In conclusion, the findings in this paper will aid natural gas process design engineers to decide on what method to use base  on energy consumption and on the physical and chemical properties of the final products.Keywords: Dehydration, Absorption, Desiccant, Condensation, Triethylene Glycol (TEG)

scholarly journals Micromixer Synthesis Platform for a Tuneable Production of Magnetic Single-Core Iron Oxide Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1845
Author(s):  
Abdulkader Baki ◽  
Norbert Löwa ◽  
Amani Remmo ◽  
Frank Wiekhorst ◽  
Regina Bleul
Keyword(s):  
Iron Oxide ◽  
Magnetic Nanoparticles ◽  
Iron Oxide Nanoparticles ◽  
Magnetic Particle ◽  
Biomedical Application ◽  
Ac Susceptibility ◽  
Chemical Properties ◽  
Oxide Nanoparticles ◽  
Aqueous Synthesis ◽  
Characterization Methods

Micromixer technology is a novel approach to manufacture magnetic single-core iron oxide nanoparticles that offer huge potential for biomedical applications. This platform allows a continuous, scalable, and highly controllable synthesis of magnetic nanoparticles with biocompatible educts via aqueous synthesis route. Since each biomedical application requires specific physical and chemical properties, a comprehensive understanding of the synthesis mechanisms is not only mandatory to control the size and shape of desired nanoparticle systems but, above all, to obtain the envisaged magnetic particle characteristics. The accurate process control of the micromixer technology can be maintained by adjusting two parameters: the synthesis temperature and the residence time. To this end, we performed a systematic variation of these two control parameters synthesizing magnetic nanoparticle systems, which were analyzed afterward by structural (transmission electron microscopy and differential sedimentation centrifugation) and, especially, magnetic characterization methods (magnetic particle spectroscopy and AC susceptibility). Furthermore, we investigated the reproducibility of the microtechnological nanoparticle manufacturing process compared to batch preparation. Our characterization demonstrated the high magnetic quality of single-core iron oxide nanoparticles with core diameters in the range of 20 nm to 40 nm synthesized by micromixer technology. Moreover, we demonstrated the high capability of a newly developed benchtop magnetic particle spectroscopy device that directly monitored the magnetic properties of the magnetic nanoparticles with the highest sensitivity and millisecond temporal resolution during continuous micromixer synthesis.

scholarly journals Engineering Core-Shell Structures of Magnetic Ferrite Nanoparticles for High Hyperthermia Performance

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 991 ◽  
Author(s):  
Mohamed S. A. Darwish ◽  
Hohyeon Kim ◽  
Hwangjae Lee ◽  
Chiseon Ryu ◽  
Jae Young Lee ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Cobalt Ferrite ◽  
Magnetic Core ◽  
Ferrite Nanoparticles ◽  
Shell Structures ◽  
Precipitation Process ◽  
Core Shell ◽  
Heating Efficiency

Magnetic ferrite nanoparticles (MFNs) with high heating efficiency are highly desirable for hyperthermia applications. As conventional MFNs usually show low heating efficiency with a lower specific loss power (SLP), extensive efforts to enhance the SLP of MFNs have been made by varying the particle compositions, sizes, and structures. In this study, we attempted to increase the SLP values by creating core-shell structures of MFNs. Accordingly, first we synthesized three different types of core ferrite nanoparticle of magnetite (mag), cobalt ferrite (cf) and zinc cobalt ferrite (zcf). Secondly, we synthesized eight bi-magnetic core-shell structured MFNs; Fe3O4@CoFe2O4 (mag@cf1, mag@cf2), CoFe2O4@Fe3O4 (cf@mag1, cf@mag2), Fe3O4@ZnCoFe2O4 (mag@zcf1, mag@zcf2), and ZnCoFe2O4@Fe3O4 (zcf@mag1, zcf@mag2), using a modified controlled co-precipitation process. SLP values of the prepared core-shell MFNs were investigated with respect to their compositions and core/shell dimensions while varying the applied magnetic field strength. Hyperthermia properties of the prepared core-shell MFNs were further compared to commercial magnetic nanoparticles under the safe limits of magnetic field parameters (<5 × 109 A/(m·s)). As a result, the highest SLP value (379.2 W/gmetal) was obtained for mag@zcf1, with a magnetic field strength of 50 kA/m and frequency of 97 kHz. On the other hand, the lowest SLP value (1.7 W/gmetal) was obtained for cf@mag1, with a magnetic field strength of 40 kA/m and frequency of 97 kHz. We also found that magnetic properties and thickness of the shell play critical roles in heating efficiency and hyperthermia performance. In conclusion, we successfully enhanced the SLP of MFNs by engineering their compositions and dimensions.

scholarly journals Dynamic magnetic characterization and magnetic particle imaging enhancement of magnetic-gold core–shell nanoparticles

Nanoscale ◽  
2019 ◽  
Vol 11 (13) ◽  
pp. 6489-6496 ◽  
Author(s):  
Asahi Tomitaka ◽  
Satoshi Ota ◽  
Kizuku Nishimoto ◽  
Hamed Arami ◽  
Yasushi Takemura ◽  
...  
Keyword(s):  
Magnetic Particle ◽  
Magnetic Core ◽  
Gold Coating ◽  
Shell Nanoparticles ◽  
Gold Core ◽  
Magnetic Particle Imaging ◽  
Particle Imaging ◽  
Core Shell Nanoparticles ◽  
Imaging Performance ◽  
Core Nanoparticles

The gold coating on magnetic core nanoparticles enhanced magnetic particle imaging performance due to an alteration in dynamic magnetic responses.

Usability evaluation of 3-D visualisations augmented by cartoons for teaching solids and crystal structures in chemical engineering

2018 ◽  
Vol 5 (4) ◽  
pp. 83-89
Author(s):  
Konstadina Dalacosta ◽  
Evangelia. A. Pavlatou
Keyword(s):  
Crystal Structures ◽  
Undergraduate Students ◽  
Conceptual Understanding ◽  
Chemical Engineering ◽  
Chemical Properties ◽  
Main Idea ◽  
Zinc Sulphide ◽  
Freedom Of Movement ◽  
Physical Chemical ◽  
Digital Material

In chemical engineering, undergraduate students often have to face the highly demanding process of understanding concepts from the microscopic level (e.g., ionic crystals such as zinc sulphide or covalent lattice crystals diamond, graphite, graphene etc.) and then explain with certain physical–chemical properties their macroscopic behaviour. Therefore, the main idea was to construct a specifically designed educational material that focusses on the benefits of viewing visualisations to enhance students’ conceptual understanding of solids and crystal structures augmented by cartoons, and evaluate its usability. The interactive ‘cartoons’ agents were developed from scratch, giving them freedom of movement and realism at the same time. A research was conducted in the School of Chemical Engineering in Greece (National Technical University of Athens), evaluated the usability of the digital material and the contribution of the 3-D visualisations and the cartoons agents in the understanding of such high-cognitive load concepts.Keywords: Cartoons, 3-D visualisations, crystal structures, chemical engineering.

scholarly journals Magnetic Properties of NiZn Ferrite Nanofibers Prepared by Electrospinning

2019 ◽  
Vol 9 (20) ◽  
pp. 4297 ◽  
Author(s):  
Na ◽  
Kim ◽  
Song ◽  
Choi
Keyword(s):  
Magnetic Properties ◽  
Electromagnetic Interference ◽  
Polymer Concentration ◽  
Chemical Properties ◽  
Size Control ◽  
Precursor Solution ◽  
X Ray Diffraction ◽  
Crystallite Sizes ◽  
20 Nm ◽  
Physical And Chemical

When the size of a material is decreased to the nanoscale, the effects of forces that are not influential on a macroscopic scale become increasingly important and the electronic structure is improved. The material then exhibits significantly different physical and chemical properties than in the bulk state. The smaller the size of the material, the more exposure it receives to the nano effects, and the physical properties can be changed via size control. In this study, Ni0.5Zn0.5Fe2O4 ferrite nanofibers were prepared by electrospinning, and the sizes of the prepared samples were controlled to ensure different average diameters by controlling the polymer concentration of the precursor solution. Field emission scanning electron microscope images showed that the samples had average diameters of 224 to 265 nm. The single crystal phase of Ni0.5Zn0.5Fe2O4 and the different crystallite sizes of 13 to 20 nm were confirmed by X-ray diffraction analysis. The magnetization behavior of the samples was measured using a vibrating sample magnetometer and the result confirmed that the samples had different magnetic properties, according to the diameter and crystallite size of the nanofibers. This study suggests that control of magnetic properties and excellent electrical conductivity in a one-dimensional nanostructure can be positively applied to improve the performance of a filler for the electromagnetic-interference shielding film.

scholarly journals Mechanochemical synthesis of carbon-stabilized Cu/C, Co/C and Ni/C nanocomposites with prolonged resistance to oxidation

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mariia Galaburda ◽  
Evgeniya Kovalska ◽  
Benjamin T. Hogan ◽  
Anna Baldycheva ◽  
Andrii Nikolenko ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Carbon Shell ◽  
Surface Oxide Layer ◽  
Step Method ◽  
Carbon Nanocomposites ◽  
Crystallite Sizes ◽  
The Stability ◽  
Oxidation In Air ◽  
Polymer Fillers ◽  
20 Nm

AbstractMetal-carbon nanocomposites possess attractive physical-chemical properties compared to their macroscopic counterparts. They are important and unique nanosystems with applications including in the future development of nanomaterial enabled sensors, polymer fillers for electromagnetic radiation shields, and catalysts for various chemical reactions. However, synthesis of these nanocomposites typically employs toxic solvents and hazardous precursors, leading to environmental and health concerns. Together with the complexity of the synthetic processes involved, it is clear that a new synthesis route is required. Herein, Cu/C, Ni/C and Co/C nanocomposites were synthesized using a two-step method including mechanochemical treatment of polyethylene glycol and acetates of copper, nickel and cobalt, followed by pyrolysis of the mixtures in an argon flow at 700 °C. Morphological and structural analysis of the synthesized nanocomposites show their core-shell nature with average crystallite sizes of 50 (Cu/C), 18 (Co/C) and 20 nm (Ni/C) respectively. The carbon shell originates from disordered sp2 carbon (5.2–17.2 wt.%) with a low graphitization degree. The stability and prolonged resistance of composites to oxidation in air arise from the complete embedding of the metal core into the carbon shell together with the presence of surface oxide layer of metal nanoparticles. This approach demonstrates an environmentally friendly method of mechanochemistry for controllable synthesis of metal-carbon nanocomposites.

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