scholarly journals The Fine-Tuned Release of Antioxidant from Superparamagnetic Nanocarriers under the Combination of Stationary and Alternating Magnetic Fields

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1212
Author(s):  
Lucija Mandić ◽  
Anja Sadžak ◽  
Ina Erceg ◽  
Goran Baranović ◽  
Suzana Šegota
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Quantum Interference ◽  
Fine Tuning ◽  
Force Microscopy ◽  
Peg 4000 ◽  
Vis Spectroscopy ◽  
Poly Ethylene ◽  
Alternating Magnetic Fields

Superparamagnetic magnetite nanoparticles (MNPs) with excellent biocompatibility and negligible toxicity were prepared by solvothermal method and stabilized by widely used and biocompatible polymer poly(ethylene glycol) PEG-4000 Da. The unique properties of the synthesized MNPs enable them to host the unstable and water-insoluble quercetin as well as deliver and localize quercetin directly to the desired site. The chemical and physical properties were validated by X-ray powder diffraction (XRPD), field emission scanning electron microscopy (FE–SEM), atomic force microscopy (AFM), superconducting quantum interference device (SQUID) magnetometer, FTIR spectroscopy and dynamic light scattering (DLS). The kinetics of in vitro quercetin release from MNPs followed by UV/VIS spectroscopy was controlled by employing combined stationary and alternating magnetic fields. The obtained results have shown an increased response of quercetin from superparamagnetic MNPs under a lower stationary magnetic field and s higher frequency of alternating magnetic field. The achieved findings suggested that we designed promising targeted quercetin delivery with fine-tuning drug release from magnetic MNPs.

scholarly journals C60 Fullerene as an Effective Nanoplatform of Alkaloid Berberine Delivery into Leukemic Cells

Pharmaceutics ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 586 ◽  
Author(s):  
Anna Grebinyk ◽  
Svitlana Prylutska ◽  
Anatoliy Buchelnikov ◽  
Nina Tverdokhleb ◽  
Sergii Grebinyk ◽  
...  
Keyword(s):  
Native American ◽  
Water Solubility ◽  
Middle Eastern ◽  
Leukemic Cells ◽  
C60 Fullerene ◽  
Force Microscopy ◽  
Molar Ratios ◽  
Atomic Force ◽  
Vis Spectroscopy

A herbal alkaloid Berberine (Ber), used for centuries in Ayurvedic, Chinese, Middle-Eastern, and native American folk medicines, is nowadays proved to function as a safe anticancer agent. Yet, its poor water solubility, stability, and bioavailability hinder clinical application. In this study, we have explored a nanosized carbon nanoparticle—C60 fullerene (C60)—for optimized Ber delivery into leukemic cells. Water dispersions of noncovalent C60-Ber nanocomplexes in the 1:2, 1:1, and 2:1 molar ratios were prepared. UV–Vis spectroscopy, dynamic light scattering (DLS), and atomic force microscopy (AFM) evidenced a complexation of the Ber cation with the negatively charged C60 molecule. The computer simulation showed that π-stacking dominates in Ber and C60 binding in an aqueous solution. Complexation with C60 was found to promote Ber intracellular uptake. By increasing C60 concentration, the C60-Ber nanocomplexes exhibited higher antiproliferative potential towards CCRF-CEM cells, in accordance with the following order: free Ber < 1:2 < 1:1 < 2:1 (the most toxic). The activation of caspase 3/7 and accumulation in the sub-G1 phase of CCRF-CEM cells treated with C60-Ber nanocomplexes evidenced apoptosis induction. Thus, this study indicates that the fast and easy noncovalent complexation of alkaloid Ber with C60 improved its in vitro efficiency against cancer cells.

Room Temperature Sample Scanning SQUID Microscope for Imaging the Magnetic Fields of Geological Specimens

2013 ◽  
Vol 475-476 ◽  
pp. 3-6 ◽  
Author(s):  
Qing Meng Wang ◽  
Hua Feng Qin ◽  
Qing Song Liu ◽  
Tao Song
Keyword(s):  
Magnetic Field ◽  
Low Temperature ◽  
Magnetic Fields ◽  
Liquid Helium ◽  
Quantum Interference ◽  
Three Dimensional ◽  
Input Circuit ◽  
Pickup Coil ◽  
Weak Magnetic Fields ◽  
Scanning Squid

A microscope to image weak magnetic fields using a low-temperature superconducting quantum interference device (SQUID) had developed with a liquid helium consumption rate of ~0.5L/hour. The gradient pickup coil is made by a low-temperature superconducting niobium wire with a diameter of 66 μm, which is coupled to the input circuit of the SQUID and is then enwound on the sapphire bobbin. Both of the pickup coil and the SQUID sensor are installed in a red copper cold finger, which is thermally anchored to the liquid helium evaporation platform in the vacuum space of the cryostat. To reduce the distance between the pickup coil and sample, a 100 μm thick sapphire window is nestled up to the bottom of the cryostat. A three-dimensional scanning stage platform with a 50 cm Teflon sample rack under the sapphire window had the precision of 10 μm. To test the fidelity of the new facility, the distribution of the magnetic field of basalt slice specimens was determined. Results show that the spatial resolution of the newly-designed facility is 500 μm with a gradient magnetic field sensitivity of 380fT. This opens new opportunities in examining the distribution of magnetic assemblages in samples, which bear great geological and geophysical information.

scholarly journals The loss of energy in metal plates of finite thickness, due to eddy currents produced by alternating magnetic fields

1926 ◽  
Vol 111 (759) ◽  
pp. 604-614 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Eddy Currents ◽  
Finite Thickness ◽  
Metal Plate ◽  
The Self ◽  
Alternating Magnetic Field ◽  
Metal Plates ◽  
Alternating Magnetic Fields

The induction of eddy currents in metal plates which are subjected to alternating magnetic fields has been discussed by Clerk-Maxwell, J. J. Thomson and many others. When an alternating magnetic field is produced normal to the surface of a metal plate, eddy currents are induced at the surface of the plate, which gradually penetrate its interior, the current dying away as it penetrates more deeply into the metal. The diffusion of the currents into the plate depends upon the self-induction and resistance of the paths along which they flow, and can be calculated by the same kind of formula as is used for determining the conduction of heat through a metal slab.

scholarly journals The Covalent Tethering of Poly(ethylene glycol) to Nylon 6 Surface via N,N′-Disuccinimidyl Carbonate Conjugation: A New Approach in the Fight against Pathogenic Bacteria

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2181
Author(s):  
Sumita Swar ◽  
Veronika Máková ◽  
Ivan Stibor
Keyword(s):  
Photoelectron Spectroscopy ◽  
Pathogenic Bacteria ◽  
Polymer Surface ◽  
Nylon 6 ◽  
Secondary Amines ◽  
Surface Immobilization ◽  
Water Contact ◽  
Force Microscopy ◽  
Poly Ethylene

Different forms of unmodified and modified Poly(ethylene glycols) (PEGs) are widely used as antifouling and antibacterial agents for biomedical industries and Nylon 6 is one of the polymers used for biomedical textiles. Our recent study focused on an efficient approach to PEG immobilization on a reduced Nylon 6 surface via N,N′–disuccinimidyl carbonate (DSC) conjugation. The conversion of amide functional groups to secondary amines on the Nylon 6 polymer surface was achieved by the reducing agent borane-tetrahydrofuran (BH3–THF) complex, before binding the PEG. Various techniques, including water contact angle and free surface energy measurements, atomic force microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy, were used to confirm the desired surface immobilization. Our findings indicated that PEG may be efficiently tethered to the Nylon 6 surface via DSC, having an enormous future potential for antifouling biomedical materials. The bacterial adhesion performances against S. aureus and P. aeruginosa were examined. In vitro cytocompatibility was successfully tested on pure, reduced, and PEG immobilized samples.

scholarly journals Theranostic Nanoplatforms of Thiolated Reduced Graphene Oxide Nanosheets and Gold Nanoparticles

2020 ◽  
Vol 10 (16) ◽  
pp. 5529 ◽  
Author(s):  
Pascal Tomasella ◽  
Vanessa Sanfilippo ◽  
Carmela Bonaccorso ◽  
Lorena Maria Cucci ◽  
Giuseppe Consiglio ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Density Functional ◽  
Metal Salt ◽  
Colorimetric Assay ◽  
Neuroblastoma Cells ◽  
Human Neuroblastoma ◽  
Force Microscopy ◽  
Vis Spectroscopy

In this study, graphene oxide (GO) and reduced-thiolated GO (rGOSH) were used as 2D substrate to fabricate nanocomposites with nanoparticles of gold nanospheres (AuNS) or nanorods (AuNR), via in situ reduction of the metal salt precursor and seed-mediated growth processes. The plasmonic sensing capability of the gold-decorated nanosheets were scrutinized by UV-visible (UV-VIS) spectroscopy. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analyses (TGA), and atomic force microscopy (AFM) were performed in order to prove the actual reduction that occurred concomitantly with the thiolation of GO, the increase in the hydrophobic character as well as the size, and preferential gathering of the gold nanoparticles onto the nanosheet substrates, respectively. Moreover, the theoretical electronic and infrared absorption (UV-VIS and IR) spectra were calculated within a time-dependent approach of density functional theory (DFT). Eventually, in vitro cellular experiments on human neuroblastoma cells (SH-SY5Y line) were carried out in order to evaluate the nanotoxicity of the nanocomposites by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium reduction (MTT) colorimetric assay. Results pointed out the promising potential of these hybrids as plasmonic theranostic platforms with different hydrophilic or hydrophobic features as well as cytotoxic effects against cancer cells.

Torsion constraints from cosmological magnetic field and QCD domain walls

2014 ◽  
Vol 29 (33) ◽  
pp. 1450171 ◽  
Author(s):  
L. C. Garcia de Andrade
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Domain Walls ◽  
Solar Physics ◽  
Mean Field ◽  
Fine Tuning ◽  
Standard Model Extension ◽  
Fermionic Sector ◽  
Dynamo Mechanism ◽  
Analogous Expression

Earlier Kostelecky [Phys. Rev. D 69, 105009 (2004)] has investigated the role of gravitational sector in Riemann–Cartan (RC) spacetime with torsion, in Lorentz and CPT violating (LV) Standard Model extension (SME). In his paper use of quantum electrodynamic (QED) extension in RC spacetime is made. More recently L. C. Garcia de Andrade [Phys. Lett. B 468, 28 (2011)] obtained magnetic field galactic dynamo seeds in the bosonic sector with massless photons, which proved to decay faster than necessary [Phys. Lett. B 711, 143 (2012)] to be able to seed galactic dynamos. In this paper it is shown that by using the fermionic sector of Kostelecky–Lagrangian and torsion written as a chiral current, one obtains torsion and magnetic fields explicitly from a Heisenberg–Ivanenko form of Dirac equation whose solution allows us to express torsion in terms of LV coefficients and magnetic field in terms of fermionic matter fields. When minimal coupling between electromagnetic and torsion fields is used it is shown that the fermionic sector of QED with torsion leads to resonantly amplify magnetic fields which mimics an α2-dynamo mechanism. Fine-tuning of torsion is shown to result in the dynamo reversal, a phenomenon so important in solar physics and geophysics. Of course this is only an analogy since torsion is very weak in solar and geophysics contexts. An analogous expression for the α-effect of mean-field dynamos is also obtained where the α-effect is mimic by torsion. Similar resonant amplification mechanisms connected to early universe have been considered by Finelli and Gruppuso.

Flow Control Using Alternating Magnetic Fields During Crystal Growth From a Melt

2012 ◽  
Author(s):  
Yue Huang ◽  
Kenneth E. Davis ◽  
Brent C. Houchens
Keyword(s):  
Magnetic Field ◽  
Crystal Growth ◽  
Magnetic Fields ◽  
Flow Control ◽  
Body Force ◽  
Stokes Equations ◽  
Magnetic Reynolds Number ◽  
Rotating Magnetic Field ◽  
Bandgap Energy ◽  
Alternating Magnetic Fields

Flow control during bulk melt crystal growth is desirable for producing ternary alloy semiconductors with tunable lattice parameters and bandgap energy, providing custom materials for specific electro-optical applications. Segregation between constituent elements in the melt, be it through preferential rejection at the growth front or density variations, limits the growth rate and the uniformity in the crystal. External alternating magnetic fields are employed to stir the electrically conducting melt. While mixing is desired, turbulent flow is generally not. Precise control is required to maintain a laminar melt flow while providing sufficient mixing. Stirring via a rotating magnetic field (RMF) and a three-coil traveling magnetic field (TMF) is modeled and compared for a cylindrical melt confined in an ampule. The RMF imposes a body force in the azimuthal direction while the TMF induces primarily radial and axial body forces. The magnetic fields are effectively decoupled from the flow fields due to the small magnetic Reynolds number. Therefore, the magnetic fields are first determined using a finite element solver. The flows are then solved by a spectral element model of the Navier-Stokes equations including an electromagnetic body force term.

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