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This work is aimed at studying the drug delivery applications of iron oxide (Fe 3 O 4 ) nanoparticles with strontium (Sr) doping with varying molar ratios prepared by the co-precipitation route. The impact of increased strontium content on the particle size and magnetic properties was investigated. The impending of these nanoparticles for drug loading, drug release, and their respective cytotoxicity was also inspected.First, iron oxide nanoparticles were doped with various amounts of strontium, from 0.25, 0.50, and 0.75, to 1 mol using co-precipitation method. These synthesized nanoparticles were characterized by XRD, SEM, EDX, VSM, and FTIR for evaluating crystal structure, phase purity, morphology, composition, magnetic properties, and functional groups, respectively. Drug loading and drug release properties were determined using UV-vis spectroscopy, whereas MTT assay evaluated cytotoxicity. Colloidal stability was assessed using zeta potential in PBS solution.The findings confirmed the successful doping of iron oxide with strontium via XRD and EDX. SEM results confirmed spherical morphology for all and needle-like structure for 1 mol strontium doped sample. For VSM results, a single domain structure was established. It was also observed that the drug encapsulation efficiency increases with increased strontium content. Cytotoxicity results by MTT assay revealed increased cytotoxicity with increasing nanoparticle concentration, and ibuprofen-loaded nanoparticles showed higher cytotoxicity than un-loaded nanoparticles at the same concentration. Zeta potential results showed colloidal stability of iron oxide nanoparticles increased by the addition of strontium.This study provided predominantly comparison of the cytotoxicity of ibuprofen-loaded and non-loaded nanoparticles on Hep-2 cancer cells at similar concentrations for the first time for both Fe 3 O 4 particles and Sr-doped Fe 3 O 4 nanoparticles and enclosed the impact of increasing Sr doping content on Fe 3 O 4 nanoparticles., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The magnetic nanoparticle composite NiFe2O4 has traditionally been studied for high-frequency microwave absorption with marginal performance towards low-frequency radar bands (particularly L and S bands). Here, NiFe2O4 nanoparticles and nanohybrids using large-diameter graphene oxide (GO) sheets are prepared via solvothermal synthesis for low-frequency wide bandwidth shielding (L and S radar bands). The synthesized materials were characterized using XRD, SEM, FTIR and microwave magneto dielectric spectroscopy. The dimension of these solvothermally synthesized pristine particles and hybrids lies within 30-58 nm. Microwave magneto-dielectric spectroscopy was performed in the low-frequency region in the 1 MHz-3 GHz spectrum. The as-synthesized pristine nanoparticles and hybrids were found to be highly absorbing for microwaves throughout the L and S radar bands (< -10 dB from 1 MHz to 3 GHz). This excellent microwave absorbing property induced by graphene sheet coupling shows application of these materials with absorption bandwidth which is tailored such that these could be used for low frequency. Previously, these were used for high frequency absorptions (typically > 4 GHz) with limited selective bandwidth.

This work is aimed at studying the drug delivery applications of iron oxide (Fe3O4) nanoparticles with strontium (Sr) doping with varying molar ratios prepared by the co-precipitation route. The impact of increased strontium content on the particle size and magnetic properties was investigated. The impending of these nanoparticles for drug loading, drug release, and their respective cytotoxicity was also inspected. First, iron oxide nanoparticles were doped with various amounts of strontium, from 0.25, 0.50, and 0.75, to 1 mol using co-precipitation method. These synthesized nanoparticles were characterized by XRD, SEM, EDX, VSM, and FTIR for evaluating crystal structure, phase purity, morphology, composition, magnetic properties, and functional groups, respectively. Drug loading and drug release properties were determined using UV–vis spectroscopy, whereas MTT assay evaluated cytotoxicity. Colloidal stability was assessed using zeta potential in PBS solution. The findings confirmed the successful doping of iron oxide with strontium via XRD and EDX. SEM results confirmed spherical morphology for all and needle-like structure for 1 mol strontium doped sample. For VSM results, a single domain structure was established. It was also observed that the drug encapsulation efficiency increases with increased strontium content. Cytotoxicity results by MTT assay revealed increased cytotoxicity with increasing nanoparticle concentration, and ibuprofen-loaded nanoparticles showed higher cytotoxicity than un-loaded nanoparticles at the same concentration. Zeta potential results showed colloidal stability of iron oxide nanoparticles increased by the addition of strontium. This study provided predominantly comparison of the cytotoxicity of ibuprofen-loaded and non-loaded nanoparticles on Hep-2 cancer cells at similar concentrations for the first time for both Fe3O4 particles and Sr-doped Fe3O4 nanoparticles and enclosed the impact of increasing Sr doping content on Fe3O4 nanoparticles. [ABSTRACT FROM AUTHOR]

In the current work cobalt, magnesium and lithium dopant substitution is performed in series of SrFe(12-2x)(Co,Mg,Li)xO19 (for x = 0.0, 0.15, 0.25, 0.5) using sol–gel method. The prepared samples were calcined at 950 °C for 4h. The synthesized samples were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). LCR meter was used for performing dielectric measurements. The formation of hexagonal SrFe(12-2x)(Co,Mg,Li)xO19 was confirmed using XRD. Debye Scherer was used to determining the crystallite size in the range of 37–57 nm. The band positions were studied using FTIR. The real part of the dielectric constant enhanced to 77.8 at 250 Hz for x = 0.5. The value of dielectric loss for cobalt, magnesium, and lithium-doped strontium hexaferrite nanoparticles has increased from 2.21 to 54.0 at 250 Hz. AC conductivity values also showed an increase as the concentration increased in strontium hexaferrite. AC conductivity results explain that electron hopping governs the conduction process. The electrical properties and conductivity rise with the increasing concentration of dopant. The enhanced dielectric properties and increased conductivity of the prepared nanoparticles make it applicable in supercapacitors and charge storage devices. [ABSTRACT FROM AUTHOR]

For achieving a higher supercapacitor performance, electrode material with high surface area and conductivity such as graphene, graphene nanoplatelets (GNP), and carbon nanotubes along with Transition Metal oxides (TMO) can be used. Herein, the composite of graphene nanoplatelets with ternary metal oxide of manganese, nickel, and cobalt (MNC) is synthesized through a facile cost-effective hydrothermal process and its compositional, morphological, and electrochemical properties are investigated. As-synthesized MNC-GNP composite showed excellent electrochemical properties owing to the high porosity offered by graphene nanoplatelets and synergistic effects produced by individual components of the composite. For comparative studies, ternary oxide MNC was prepared by the same hydrothermal route. The cubic structure of the MNC-GNP composite is confirmed by X-ray diffraction (XRD). Scanning Electron Microscope (SEM) showed distinct hierarchical dendritic structures which showed an increase in density by the addition of graphene nanoplatelets. Electrochemical testing revealed that MNC-GNP exhibited an enhanced specific capacity of 605 mAh g-1 which is higher compared to MNC which exhibited 243 mAh g-1 at a current density of 2 mV s-1. GCD also depicted an increased charge-discharge time in the case of MNC-GNP as compared to its counterpart. MNC-GNP has also shown charge stability up to 99.5 % of capacity retention up to 1000 cycles. Hence, synthesized composite shows to be an effective electrode material for supercapacitors owing to enhanced electrochemical properties. [ABSTRACT FROM AUTHOR]

• Zr4+-Y3+ substituted hexaferrite nanoparticles were successfully synthesized using sol-gel citrate precursor method. • Structural, magnetic and electromagnetic attenuation properties were investigated in detail. • Optimum reflection loss of -32. 27 dB at 6.43 GHz was observed for the composition of Ba 0.5 Sr 0.5 Fe 11.61 Zr 0.35 Y 0.03 O 19. Novel compositions of Ba 0.5 Sr 0.5 Fe 12-1.1x Zr x Y 0.1x O 19 (0.0≤x≤0.5) nanoparticles were synthesized using sol-gel citrate precursor method. X-ray diffraction confirmed the formation of magneto-plumbite hexagonal phase with average crystallite size of 55-70 nm. The fourier transformed infrared spectroscopy revealed the presence of metal cations vibrational modes in 460-600 cm−1 range. The Zr-Y contents influenced magnetic behavior and shielding properties with maximum total shielding effectiveness of -31 dB in K band, and -21 dB in X-band, observed for x=0.35. The microwave absorption studies revealed optimum reflection losses with maximum value of -32 dB at 6.4 GHz frequency for x=0.35. The obtained values validate the candidacy of Zr-Y substituted Ba-Sr hexaferrite nanoparticles for uninterrupted airborne surveillance, radar absorption and high frequency shielding applications. [Display omitted] [ABSTRACT FROM AUTHOR]

A simple, sensitive, selective and real time detection protocol was developed for Pb 2+ ions in water using liquid crystals (LCs). In this method, NiFe 2 O 4 nanoparticles were synthesized using chemical co-precipitation method. Crystallite size, morphological, functional groups and magnetization studies were confirmed using X-ray diffraction, Scanning Electron Microscopy, and Fourier transform infrared spectroscopy techniques, respectively. The nanoparticles were mono dispersed with average particle size of 20 ± 2 nm. The surfactant stabilized magnetic nanoparticles were incubated in liquid crystal based sensor system for the detection of Pb +2 ions. The bright to dark transition of LC was observed through optical microscope. When this system was further immersed with a solution containing Pb 2+ ions, it caused homeotropic to planar orientation of LC. This interaction is attributed to the presence of abundant hydroxyl groups in such as M-OH, Fe-OH on the surface of spinel ferrites nanoparticles. These groups interact with metal ions at aqueous interface, causing disruption in LCs orientation giving bright texture. This sensor showed higher selectivity towards Pb 2+ ions. The detection limit was estimated to be 100 ppb. The cheap and effective protocol reported here should make promising development of LC based sensor for lead ion detection. [ABSTRACT FROM AUTHOR]

A series of Al3+ substituted NiAl x Fe 2-x O 4 (0.0 = x ≤ 0.5) nanoparticles was synthesized using the chemical co-precipitation route. The effect of Al3+ ions doping was investigated in terms of structural, degradation, magnetic and electrical properties of the nanoparticles (NPs). The XRD patterns confirmed the formation of the spinel cubic phase. FT-IR spectra revealedtwo consistent absorption bands indicating the intrinsic stretching vibrations of O2- Fe3+ around 591-615 cm−1 and 416-428 cm−1 bond lengths for tetrahedral and octahedral sites respectively. The magnetic properties decrease as the concentration of Al3+ increases. The decrease of magnetic parameters can be explained by the difference between magnetic moments of Al3+ and Fe3+ cations. Maxwell-Wagner model of space charge polarization was utilized to explain the dielectric properties with frequency. The increasing dielectric losses indicated the suitability of synthesized NPs for microwave absorption, telecommunication, electronics and other high frequency applications. The dependence of dielectric properties on grains and grain boundaries was further investigated via impedance spectroscopy and complex electric modulus. The study of photo-degradation efficiency of NPs was performed using organic methylene blue dye. The results showed satisfactory degradation with maximum degradation efficiency of 84.45% for NPs with composition NiAl 0·5 Fe 1·5 O 4. • Al3+ substituted Ni ferrite NPs were successfully synthesized. • Octahedral and Tetrahedral site vibrations were confirmed via FT-IR spectroscopy. • AC conductivity and dissipation factor showed significant reduction. • NPs showed satisfactory degradation of methylene blue dye with 84%. [ABSTRACT FROM AUTHOR]

Abstract: Strontium hexaferrite nanoparticles with nominal composition SrZr x Cd x Fe12−2x O19 (for x =0.0–0.6) with step increment of 0.2 have been synthesized by the chemical co-precipitation technique. XRD, hysteresis loops measurements and LCR meter were employed to evaluate the structure, magnetic and dielectric properties of SrZr x Cd x Fe12−2x O19 nanomaterials. The XRD analysis confirms the single phase and various parameters such as lattice constants (a and c), cell volume and crystallite size have also been calculated from the XRD data. The crystallite size is found in the range of 28–39nm. The magnetic properties such as saturation magnetization, remanence and coercivity are calculated from the hysteresis loops. Values of saturation magnetization are found to increase up to the substitution level of x =0.0–0.2 while that of remanence and coercivity decrease continuously with increase in Zr–Cd concentration. The dielectric properties as a function of frequency under normal conditions were also measured in the frequency range of 500Hz to 1MHz. The dielectric constants and tangent of dielectric loss factor remained within the range of 3347–30 and 11–0.24, respectively. The decrease in coercivity while increase in saturation magnetization confirms that the synthesized materials are suitable for applications in high-density recording media. [Copyright &y& Elsevier]

Abstract: Spinel nickel ferrite with nominal composition NiFe2−x Sb x O4 (where x =0.0, 0.2, 0.4, 0.6, 0.8 and 1) has been synthesized by the reverse microemulsion method. The samples synthesized were characterized by XRD, FTIR, TGA/DTGA, SEM, AFM, Mossbauer Spectroscopy and DC electrical resistivity measurements. The XRD analysis confirmed the formation of single spinel phase and the crystallite size was found to be in the range of 8–38nm. The particle size of the synthesized samples was also confirmed by the AFM and SEM which was found in the range of 5–45nm and 10–45nm, respectively and this size is small enough for obtaining the suitable signal-to-noise ratio in high density recording media. The Mossbauer spectra of samples showed two well-resolved Zeeman patterns corresponding to A and B sites and also observed a doublet at higher substitution. The DC electrical resistivity showed an interesting behavior with temperature and observed a metal-to-semiconductor transition temperature (T M–S) which suggests that the material can be applied for switching applications. The resistivity increases with the increase in Sb-content and it suggests that the material can be fruitfully used for applications in microwave devices. [Copyright &y& Elsevier]