The development of composites with embedded gold nanoparticles (Au NPs) and biopolymeric matrices, such as cellulose acetate (CA), has gained significant attention due to their unique synergistic properties, including enhanced mechanical, physical, and thermal characteristics. In this study, a composite material consisting of Au NPs embedded in a CA matrix was prepared and thoroughly characterized and its cytotoxicity evaluated for potential medical applications such as drug delivery, biosensing, and imaging. The composite was prepared using a newly developed in situ method, ensuring mostly uniform dispersion of Au NPs within the CA matrix. Various characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), dynamic mechanical analyses (DMA), thermogravimetric analysis (TGA), and cell viability assay were employed to evaluate the structural, mechanical, thermal and biocompatibility properties of the as-prepared composite. The obtained results indicate that even a miniscule content of Au NPs (<0.14 wt%) within the CA matrix can significantly change the properties of such composites. The produced materials are compact, flexible, strong, and exhibit low cytotoxicity, making them suitable for a wide range of potential applications.

As human exposure to non-ionizing electromagnetic (EM) radiation increases, concerns regarding its long-term health effects have prompted the search for effective shielding materials. Traditional shielding materials, while effective, often come with high production costs, complex processing requirements, or environmental concerns. Therefore, materials that are affordable, flexible, biocompatible, and easy to manufacture are in high demand for various applications, ranging from consumer electronics to medical devices, where both performance and safety are crucial. This paper investigates the potential of self-prepared silver cellulose-acetate composite as a shield against non-ionizing EM radiation. The composite’s effectiveness was tested at various silver-to-cellulose ratios (20, 40, 60, and 80

The incorporation of nanoarchitectonics into the development of nanozymes to achieve target-specific geometry, dense active sites, and cascade catalysis is highly demanded for developing ultrasensitive bioassays. The improved dispersion and uniform distribution of metal active sites onto a three-dimensional (3D) mesoporous carbon support (MC) with a high surface area can lead to enhanced substrate binding, mobility, and collision probability and therefore, increased peroxidase mimetic activity. Herein, we report the fabrication of welldispersed superparamagnetic iron oxide (IO) nanoparticles (NPs) on mesoporous carbon (IO-MC) support with high Fe3+ active sites, high surface area, and ordered mesoporous pore channels that show promising catalytic activity at room temperature. The as-prepared IO-MC shows good nanozyme activity at room temperature with highly favorable Michaelis-Menten constant, Km (0.242 mM) and fast reaction rate (0.193 x 10- 7 MS-1). Finally, we demonstrate the functionality and pre-eminence of IO-MC nanozyme for bioassay. As a proof-of-concept, we develop a superior glucose assay that provides a LOD (limit of detection) of 2 mu M in the spiked sample. These findings suggest that homogeneously dispersed iron oxide NPs on MC show promising potential as nextgeneration nanozyme for developing sensitive bioassays.

Magnetic cellulose (MC) is prepared by hydrolysis of iron precursors in an aqueous dispersion of cellulose nanofibers. A thin, flexible film was then prepared by removing the water and drying the sample in a hot press at 110 °C followed by the removal of the water. Structural analysis of MC was performed and correlated with the measurement of electromagnetic properties. The magnetic cellulose showed high magnetic saturation of 68 emu/g with characteristic superparamagnetic behaviour, and conductivity in a range of semiconductors, with an increase of direct current (DC) conductivity with increasing temperature. Modification of cellulose with Fe3O4 has a positive effect on the DC conductivity and lower limit that needs to be exceeded to achieve a stable and sustainable conductivity in the range of 5–20 × 10–9 (Ω cm)−1 @30 °C is 65 wt

Iron nanoparticles are used as a targeted drug delivery system. The nanocarrier itself can be genotoxic, trigger oxidative stress or cell death. Therefore, we developed an AC/DC magnetic syringe for injecting, stimulating drug release and safe removing of the nanocarrier. Alongside we optimized the method for nanoparticles’ drug release kinetics and testing cytotoxicity in vitro. • This paper presents detailed instructions for construction of AC/DC magnetic syringe device for stimulated drug release, injection and ejection of magnetic nanoparticles; nanoparticles preparation; adsorbing methylene blue on nanoparticles; determination of drug release kinetics from nanocarriers on the example of methylene blue • Gomori´s Prussian blue reaction for differentiated SH-SY5Y human neuroblastoma cell line; MTT viability assay optimized for differentiated SH-SY5Y human neuroblastoma cell line and antioxidant enzymes activities assay and lipid peroxidation methods are optimized for cell analyses cell cultivation for nanoparticles cytotoxicity testing in vitro. • Those protocols are the first step toward further testing the effect of nanoparticles in vivo, on brain tissue.

Continuing our previous research work on a drug delivery system based on combined AC/DC magnetic fields, we have developed a prototype AC/DC magnetic syringe device for stimulation of drug release from drug carriers, with the options of injecting/removing drug carriers. The porous Fe3O4 carrier, in a dose-dependent manner, causes acute oxidative damage and reduces the viability of differentiated SH-SY5Y human neuroblastoma cells, indicating the necessity for its removal once it reaches the therapeutic concentration at the target tissue. The working mechanism of the device consists of three simple steps. First, direct injection of the drug adsorbed on the surface of a carrier via a needle inserted into the targeted area. The second step is stimulation of drug release using a combination of AC magnetic field (a coil magnetised needle with AC current) and permanent magnets (DC magnetic lens outside of the body), and the third step is removal of the drug carriers from the injected area after the completion of drug release by magnetising the tip of the needle with DC current. Removing the drug carriers allows us to avoid possible acute and long term side effects of the drug carriers in the patient's body, as well as any potential response of the body to the drug carriers.

The anisotropy of the critical current density, the n-factor and the irreversibility field of mono-core in-situ MgB2 tapes have been studied at various magnetic field orientations and temperatures. Undoped as well as silicon carbide (SiC) and malic acid (C4H6O5) added tapes were studied. The anisotropy is noticeably influenced by the additives due to different carbon contents and fabrication processes. The malic acid added tape exhibits almost isotropic behavior compared to SiC doped MgB2 tapes due to the homogeneous carbon substitution through the chemical solution route, which paves the way to design MgB2 tapes to be applied for industrial magnet application.

In this study, we analyze the properties of boron isotope (B)-rich powders from three different sources, that is, American, Cambridge, and Pavezyum, to fabricate the bulk MgB superconductors and evaluate their superconducting properties. While B-rich powder is an essential precursor to fabricate MgB superconductors for fusion magnet applications, the properties of the B powder turned out to be critical to determine the quality of the final superconducting product. Therefore, appropriate control of processing conditions is needed to comply with the requirements of the nuclear fusion application. Analysis of the B isotope ratio by accelerator mass spectroscopy and neutron transmission revealed that all three types of powder are enriched with B to better than 99 at % quality. In addition, Pavezyum's B shows the lowest crystallinity and smallest crystalline domain size as evidenced by the high-resolution X-ray diffractometer and scanning electron microscopy. The chemical states of the boron isotope investigated with near edge X-ray absorption fine structure spectroscopy and X-ray photoemission spectroscopy also reveals that Pavezyum boron has amorphous structure. MgB bulks and multi-filamentary (12-filament) wires have been manufactured, sintered at different temperatures and characterized via the transport critical current density. The wire with Pavezyum B shows three times higher current carrying capacity at a particular magnetic field compared to the wire using Cambridge B and hence, Pavezyum B boron has the potential for manufacturing fusion grade MgB based magnets. The results of this study demonstrated that Boron powders with higher purity, smaller grain size and lower crystallinity are critical for improving the superconducting and electronic properties of MgB samples fabricated from the powder. Thus, the low-neutron-activation MgB is possibly an affordable and technically viable candidate to replace NbTi superconductors in the low field poloidal field and correction coils for the next-generation fusion reactors.

The effect of cold high pressure densification (CHPD) on anisotropy of the critical current density (Jc) in « in situ » single core binary and alloyed MgB2 tapes has been determined as a function of temperatures at 4.2 K, 20 K and 25 K as well as at applied magnetic fields up to 19 T. The study includes binary and C4H6O5 (malic acid) doped MgB2 tapes before and after CHPD. It is remarkable that the CHPD process not only improved the Jc values, in particular at the higher magnetic fields, but also decreased the anisotropy ratio, Γ = Jc///Jc┴. In binary MgB2 tapes, the anisotropy factor Γ increases with higher aspect ratios, even after applying CHPD. In malic acid (C4H6O5) doped tapes, however, the application of CHPD leads only to small enhancements of Γ, even for higher aspect ratios. This is attributed to the higher carbon content in the MgB2 filaments, which in turn is a consequence of the reduced chemical reaction path in the densified filaments. At all applied field values, it was found that CHPD processed C4H6O5 doped tapes exhibit an almost isotropic behavior. This constitutes an advantage in view of industrial magnet applications using wires with square or slightly rectangular configuration.

In this study, cellulose nanofibers are used as a template to synthesise magnetic nanoparticles with a uniform size distribution. Magnetic nanoparticles are grafted on the surface of nanofibers via in situ hydrolysis of metal precursors at room temperature. Effects of different concentrations of nanofibers on the morphology, the crystallite size of magnetic nanoparticles, and the thermal and magnetic properties of the membrane produced from the cellulose nanofibers decorated with magnetic nanoparticles are examined. The sizes of magnetic nanoparticles produced in this study are below 20 nm, and the crystallite size of the nanoparticles is in the range of 96-130 angstrom. The flexible magnetic membranes containing a high concentration of magnetic nanoparticles (83-60 wt%) showed superparamagnetic behaviour with very high magnetic properties (67.4-38.5 emu g(-1)). The magnetic membrane was then used as an environmentally friendly, low-cost catalyst in a sulphate radical-based advanced oxidation process. The membranes successfully activated peroxymonosulphate (PMS) to remove Rhodamine B (RhB), a common hydrophilic organic dye applied in industry. 94.9 % of the Rhodamine B was degraded in 300 min at room temperature, indicating that the magnetic nanocellulose membrane is highly effective for catalyzing PMS to remove RhB.

An important criterion in the evaluation of drug delivery systems based on nanoparticles is the drug release kinetics. From numerous published works, it is obvious that the fraction of the released drug as a function of time shows qualitatively the same behaviour, even when the release is assisted by an external force. In this study a series of experiments has been performed on a system that can be considered as the simplest drug delivery system. It consists only of uncoated/unprotected superparamagnetic magnetite nanoparticles in the form of mesoporous aggregates and adsorbed flavonols (quercetin, myricetin, or myricitrin). The simultaneous utilization of external permanent and oscillating magnetic fields remarkably accelerated the flavonol release. There is no a specific pulling force that eventually causes the rupture of the bonds between the molecules and the particle surface, i.e. the detachment of an individual molecule is thermally activated. The adsorption of molecules onto nanoparticles follows almost without delay quick changes in the field-induced motion of the nanoparticles, and they are subject to more frequent collisions with the surrounding solvent molecules. The barrier fluctuations occur due to the magnetic field dependence of the nanoparticle phonon spectra, to which the adsorbed flavonol molecule vibrations are strongly coupled. The phonon frequencies and phonon damping of a ferromagnetic nanoparticle are actually affected by the magnetic field through the spin-phonon coupling. The rate of release (spontaneous or forced) is invariably a first-order process, which can be considered a basic property of a broad class of drug nanodelivery systems.

To develop powerful wind turbine generators using superconducting technology, high-performance superconducting racetrack coils are essential. Herein, we report an evaluation of a multifilamentary magnesium diboride (MgB2) conductor-based racetrack coil cooled and impregnated simultaneously by solid nitrogen (SN2). The coil was wound on a copper former with 13 mm winding width, an inner diameter of 124 mm at the curvature, and 130 mm length of the straight section. An in situ processed S-glass-insulated 36-filament MgB2 wire was wound on the former in two layers with 19.5 turns, and heat treated via the wind and react method without any epoxy resin. The coil was evaluated for critical temperature and transport critical current in the SN2 environment at different temperatures up to 31.3 K in self-field. The coil was able to carry 200 A transport current at 28.8 K in self-field. During coil charging and operation, SN2 effectively acted as an impregnation material. The test results demonstrate the viability to use MgB2 racetrack coil potentially with SN2 impregnation in advanced rotating machine applications.

Magnesium diboride (MgB2) is a superconductor characterized by interesting properties like rather high superconducting transition temperature T-c = 39 K, long coherence length and low anisotropy. In addition, it has a very simple crystal structure and low density. Those properties make the MgB2 an ideal candidate for a wide range of applications.To improve the electromagnetic properties of MgB2, magnetic nickel-cobalt-boron (NiCoB) nanoparticles (mean grain size 17 +/- 3 nm) were added to Mg and B precursor powders and sintered at 650 degrees C, i.e. the temperature of MgB2 superconductor formation. The nearly spherical NiCoB nanoparticles, as-prepared by the chemical reduction of metallic salts, were amorphous according to previous study. The resulting MgB2 sample, formed after the sintering at 650 degrees C, was subjected to detailed microstructural analysis which included the application of various experimental methods: XRD, FE-SEM, EDS, elemental mapping, TEM and SAED. The methods confirmed the formation of new crystal CoNi phase (due to heat treatment at 650 degrees C), consisting of spherical nanoparticles (similar to 6 nm) with tendency to spherical agglomerates formation. Those nanosized magnetic particles (characterized by the single domain magnetic structure and blocking temperature TB below room temperature), located at MgB2 grain boundaries, could serve as effective magnetic pinning centers in MgB2, thus improving its electromagnetic properties.

The best Jc performance (8×104A·cm−2 at 10T, 4.2K) has been obtained in our work among all the in-situ powder-in-tube (PIT) MgB2 wires reported so far by tailoring their boron and magnesium precursors, as well as employing appropriate high pressure during the manufacturing process. Moreover, the second stage densification using the special HIP has been applied to commercial long-length wire. Our work suggests that the economical starting precursors and the combination of cold and hot densification techniques could represent a promising alternative for industrial and economical production of practical MgB2 wires with excellent Jc.

Porous structures made up of Fe3O4 nanoparticles were used to adsorb methyl blue in water. Controlled release of the methyl blue to water was then achieved by application of a magnetic field. Application of a pure DC field did not result in any release. Application of a pure AC field caused released of the methyl blue. However, a combination of both DC and AC fields resulted in much faster release. The mechanism by which this operated is believed to result from viscous friction. Nanoparticles are strongly aligned in the DC field and oscillate under the influence of the AC field. This study demonstrates a concept for controlled drug delivery, where pharmaceutical molecules, similar to methyl blue, would be adsorbed onto porous Fe3O4 structure and the released at a target by application of appropriately localised magnetic fields.

Event Abstract Back to Event Magnetically triggered smart liposomes Md Shahriar Hossain1*, Boris Martinac2*, Jung Ho Kim1*, M Azam Ali3*, Mislav Mustapic1*, Yoshitaka Nakayama2* and Joseph Horvat1* 1 Institute for Superconducting and Electronic Materials, University of Wollongong, Science and Engineering, Australia 2 Victor Chang Cardiac Research Institute, Mechano Biology Laboratory, Australia 3 University of Otago, Department of Applied Science, New Zealand Introduction: The magnetic properties of superparamagnetic nanoparticles have been the subject of research for many years. Within the last decade there has been a rapidly growing interest for magnetic nanoparticles motivated by numerous existing and expected applications in biomedicine, like separation of magnetically tagged cells, targeted drug or radionuclide transport into the cells or tissues, contrast improvement in diagnostic MRI and magnetic hyperthermia (local destruction of tumour tissues by inductive heating), amongst many others. The use of magnetic nanoparticles as a drug delivering system is still defined by its biocompatibility and selective targeting to the desired cell or tissue under the guidance of external magnetic field. Advances in current technologies and the development of magnetic nanoparticles as drug delivery systems to deliver drugs to tumor hypoxic zones have fast-tracked in the past decade and led to the development of various magnetic nano-formulations such as liposomes, metallic/nonmetallic, and polymeric nanoparticles. In this study, we have developed superparamagnetic CoFe2O4 nanoparticles for binding to MscL. We show their lack of toxicity on a human cell culture. In addition, we demonstrate the activation of MscL by magnetic field in the presence of the superparamagnetic nanoparticles using patch fluorometry[1]. Materials and Methods: We developed superparamagnetic nanoparticles for activation of the MscL nanovalves by magnetic field. Synthesised CoFe2O4 nanoparticles with the radius less than 10 nm were labelled by SH groups for attachment to MscL. Liposomes made of azolectin (Sigma) were produced using the dehydration/rehydration method as reported previously (Delcour et al. 1989; Häse et al. 1995). Activation of MscL by magnetic field with the nanoparticles attached was examined by the patch clamp technique showing that the number of activated channels under ramp pressure increased upon application of the magnetic field. In addition, we have not observed any cytotoxicity of the nanoparticles in human cultured cells. Nano particles were also characterized by XRD, TEM, FTIR and MPMS. Results and Discussion: By recording the channel activity in patch clamp experiments we found that the number of activated channels increased upon application of the magnetic field in the presence of the nanoparticles, which was not the case in the absence of the magnetic field [Figure 1]. The nanoparticles coated with SH groups on their surface can bind to the cysteine residue of each subunit of the M42C MscL channel mutant by forming a disulphide bond, as previously shown in several EPR and FRET spectroscopic studies. Conclusion: In summary, our study indicates that superparamagnetic nanoparticles of average size of less than 6 nm coated with SH groups are highly suitable as components of a trigger mechanism for opening MscL nanovalves. Due to their very large open pore and property of being modulated by mechanical stimuli MscL channels present an ideal candidate for use as nanovalves in liposomal drug delivery. Consequently, a combination of MscL channels and the magnetic nanoparticles generated for this study holds promise for use in the development of “smart liposomes”, a new generation of liposomal drug delivery system. References:[1] Y. Nakayama…M. S. A. Hossain…B. Martinac et al., “Magnetic nanoparticles for smart liposomes" European. Biophysics Journal, in-press (DOI: 10.1007/s00249-015-1059-0) Keywords: Drug delivery, biomaterial, microstructure, material design Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Liposomes in anti-cancer therapies Citation: Hossain M, Martinac B, Kim J, Ali M, Mustapic M, Nakayama Y and Horvat J (2016). Magnetically triggered smart liposomes. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.01581 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. * Correspondence: Dr. Md Shahriar Hossain, Institute for Superconducting and Electronic Materials, University of Wollongong, Science and Engineering, North Wollongong, Australia, Email1 Dr. Boris Martinac, Victor Chang Cardiac Research Institute, Mechano Biology Laboratory, Darlinghurst, Australia, Email2 Dr. Jung Ho Kim, Institute for Superconducting and Electronic Materials, University of Wollongong, Science and Engineering, North Wollongong, Australia, Email3 Dr. M Azam Ali, University of Otago, Department of Applied Science, Dunedin, New Zealand, Email4 Dr. Mislav Mustapic, Institute for Superconducting and Electronic Materials, University of Wollongong, Science and Engineering, North Wollongong, Australia, Email5 Dr. Yoshitaka Nakayama, Victor Chang Cardiac Research Institute, Mechano Biology Laboratory, Darlinghurst, Australia, Email6 Dr. Joseph Horvat, Institute for Superconducting and Electronic Materials, University of Wollongong, Science and Engineering, North Wollongong, Australia, Email7 Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Md Shahriar Hossain Boris Martinac Jung Ho Kim M Azam Ali Mislav Mustapic Yoshitaka Nakayama Joseph Horvat Google Md Shahriar Hossain Boris Martinac Jung Ho Kim M Azam Ali Mislav Mustapic Yoshitaka Nakayama Joseph Horvat Google Scholar Md Shahriar Hossain Boris Martinac Jung Ho Kim M Azam Ali Mislav Mustapic Yoshitaka Nakayama Joseph Horvat PubMed Md Shahriar Hossain Boris Martinac Jung Ho Kim M Azam Ali Mislav Mustapic Yoshitaka Nakayama Joseph Horvat Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Mobile phone subscriptions continue to increase across the world, with the electromagnetic fields (EMF) emitted by these devices, as well as by related technologies such as Wi-Fi and smart meters, now ubiquitous. This increase in use and consequent exposure to mobile communication (MC)-related EMF has led to concern about possible health effects that could arise from this exposure. Although much research has been conducted since the introduction of these technologies, uncertainty about the impact on health remains. The Australian Centre for Electromagnetic Bioeffects Research (ACEBR) is a National Health and Medical Research Council Centre of Research Excellence that is undertaking research addressing the most important aspects of the MC-EMF health debate, with a strong focus on mechanisms, neurodegenerative diseases, cancer, and exposure dosimetry. This research takes as its starting point the current scientific status quo, but also addresses the adequacy of the evidence for the status quo. Risk communication research complements the above, and aims to ensure that whatever is found, it is communicated effectively and appropriately. This paper provides a summary of this ACEBR research (both completed and ongoing), and discusses the rationale for conducting it in light of the prevailing science.

The effects of graphene oxide (GO) addition on the dispersion of nano-silver (Ag) in an MgB2 matrix were studied using bulk samples prepared through a diffusion process. The influence of the dispersion of Ag and Ag/GO particles on the critical current density (JC) of MgB2 was also investigated. GO has emerged as an excellent dopant which can significantly improve both lowand highfield performance of MgB2 due to its capability to improve inter-grain connectivity (GO), and interand intra-grain pinning (GO and AgMg). The addition of nano-size Ag particles also results in improvement of vortex pinning, and at the same time, it offers the advantage of preventing the loss of Mg during the sintering process. It is found that dispersion of nano-silver in the presence of GO results in significant improvements to the critical current density in MgB2, particularly at high magnetic fields, due to improved inter-grain connectivity and flux pinning. The use of the GO net as a platform for doping MgB2 in our case with Ag, yielded a 10 times better critical current density (JC) than standard Ag doping at 9 T and 5 K. Even without sophisticated processes, we obtained JC result of 10 A/cm at 9 T and 5 K, which is one of the best ever achieved.

The unavailability of high quality precursor is encouraging researchers to seek effective ways to fabricate magnesium diboride (MgB2) wire. Herein, cost-effective amorphous boron powder produced through a diborane (B2H6) gas process is investigated for the possibility of further industrial application. A thin carbon layer to encapsulate the boron particles is simultaneously deposited by pyrolysis of hydrocarbon. We found that the carbon-encapsulated amorphous boron has a high upper critical field due to impurity scattering, and thereby, enhanced high-field critical current density. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.