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Journal ArticleDOI: 10.1016/J.JALLCOM.2020.157013

Magnetic, microstructural and photoactivated antibacterial features of nanostructured Co–Zn ferrites of different chemical and phase compositions

05 Mar 2021-Journal of Alloys and Compounds (Elsevier)-Vol. 856, pp 157013
Abstract: Ferrites have found extensive uses in electrical, chemical and mechanical engineering, but their potential as biomaterials remains largely unexplored. Here we report on the use of a flash method based on urea decomposition to synthesize four different compositions of cobalt and zinc ferrite, including monophasic CoFe2O4, ZnFe2O4 and Co0.5Zn0.5Fe2O4, and CoFe2O4/ZnFe2O4 nanocomposite. Zn-ferrite nanoparticles were approximately the same size as those of Co-ferrite, but were better dispersed, rougher, more crystalline and less pronouncedly faceted. The mixed, monophasic Co0.5Zn0.5Fe2O4 composition was morphologically most similar to single-phase Co-ferrite. In the biphasic mixture of CoFe2O4 and ZnFe2O4, smooth and polydisperse Co-ferrite grains were coated by finer, cuboid and monodisperse Zn-ferrite nanoparticles. The porosity and the roughness of this composition were the highest, and so was its coercivity owing to the shielding of the ferrimagnetic Co-ferrite grains by the paramagnetic Zn-ferrite nanoparticles. Expectedly, the highest saturation magnetization (66.3 emu/g) was detected in Co-ferrite and the lowest (2.8 emu/g) in Zn-ferrite. Co-ferrite also exhibited the highest magneto-crystalline anisotropy, remanence and hysteresis loop area, while the highest exchange bias and susceptibility were found in the mixed, Co0.5Zn0.5Fe2O4 composition. All four ferrite compositions were biocompatible with human fibroblasts, but they demonstrated different antibacterial activities against Gram-negative E. coli and Gram-positive S. aureus, with the biphasic mixture of CoFe2O4 and ZnFe2O4 being more effective than Co0.5Zn0.5Fe2O4, CoFe2O4 or ZnFe2O4. Further, all the compositions were more active against both bacterial species under visible light than in the dark, indicating the photocatalytic formation of electron-hole pairs and reactive oxygen species that exert a damaging effect on the bacterial cells as the prime mechanism of action.

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Topics: Zinc ferrite (55%), Ferrite (magnet) (54%), Nanocomposite (50%)
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6 results found


Open accessJournal ArticleDOI: 10.1016/J.JMRT.2021.06.097
Abstract: Biocomposites containing hydroxyapatite (HAP)/zirconia (ZrO2) were modified with different contents of copper ions using the co-precipitation technique. The phase identification is performed by X-ray diffraction (XRD) while scanning electron micrographs (FESEM) showed surface morphology and exhibited that the grain size has changed from 0.17 to 0.43 μm for the lowest and the highest additional Cu2+ ions. Moreover, the average roughness has increased from 56.4 nm to 163.8 nm, while the maximum height of the roughness (Rt) increased from 503.9 to 878.9 nm for the lowest and the highest Cu2+ additions. Furthermore, the microhardness has been investigated and exhibited a significant improvement of 2.1 ± 0.1 to 4.6 ± 0.3 GPa for 0.0Cu–HAP@ZrO2 and 0.8Cu–HAP@ZrO2, respectively. Moreover, the corrosion rate decreases from 0.078 to 0.070 mm/y for the lowest and the highest modified copper ions. The cell viability has enhanced from 0.2C–HAP@ZrO2 composites achieved 88.04 ± 4%, which is the highest cell proliferation percentage. However, 0.8Cu–HAP@ZrO2 hit the highest values in both bacterial microorganisms, reaching 5.9 ± 0.6, 5.1 ± 0.4 mm. These significant antibacterial performances almost doubled from 0.2 to 0.8 of copper contribution is based on surface modification and amount of released reactive species that make it a promising bio applicable material.

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Topics: Copper (54%)

1 Citations


Journal ArticleDOI: 10.1016/J.MOLSTRUC.2021.130562
N.M. Basfer1, S.F. Mansour2, M.K. Ahmed3, M.K. Ahmed4Institutions (4)
Abstract: Degradation of pollutants, including organic dyes via photocatalysis technique, has attracted great concern last decade. Thus, modified hydroxyapatite (HAP) with vanadate ions ( V O 4 3 − ) has been fabricated using the co-precipitation method at different vanadate contributions. The obtained compositions have been investigated upon their structure, morphology, and optical properties. The structural calculations indicated that a-axis increased from 9.483 to 9.562 A for the lowest and the highest additional vanadate ions. Moreover, the average roughness developed from 30.5 to 56.3 nm upon the vanadate insertion. Moreover, the direct bandgap decreased from 3.9 to 3.82 eV upon the additional vanadate ions, while the refractive index increased slightly from 1.86 to 1.87. Further, the removal of methylene blue through aqueous solutions has been examined and showed that the removal effectiveness increased from 89.3 to 97.2% after 120 min of irradiation using visible light. These modified HAP crystals could encourage their utilization for potential applications incusing water treatment, besides their usages for biomedical applications.

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Topics: Vanadate (59%), Vanadium (53%)

1 Citations


Journal ArticleDOI: 10.1007/S00339-021-05037-Z
Rania Ramadan1, Mai M. El-MasryInstitutions (1)
01 Nov 2021-Applied Physics A
Abstract: In the present work, nanocomposites of CeO2/ZnO and CeO2/SiO2 were prepared to be used as adsorbing materials for the Cr (VI) heavy metal from water. According to the non-toxic and low-cost properties of zinc oxide and silica, they have been prepared as a nanocomposite with anti-oxidant cerium oxide. The prepared CeO2/SiO2 nanocomposite showed larger removal efficiency for Cr (VI) from aqueous solution of (55%) at optimum conditions of pH = 7 after 100 min. The adsorption kinetics for Cr (VI) on surface of CeO2/Zno and CeO2/SiO2 were well fitted with pseudo-second-order kinetic model. The adsorption mechanism follows monolayer Langmuir isotherm model. The prepared samples were investigated and characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-spectroscopy, field emission scanning electron microscopy (FESEM) and N2 adsorption–desorption isotherm (BET) isotherm. The efficiency of the prepared samples for removing of Cr (VI) from aqueous solution was investigated in different experimental conditions (different PH and contact time).

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Journal ArticleDOI: 10.1007/S10854-021-06913-3
El. Abouzir1, Mohammed Belaiche1, M. Elansary1, C. Ahmani Ferdi1  +1 moreInstitutions (2)
Abstract: Co0.7Zn0.3Fe2−xGdxO4 (x = 0.02) ferrite nanoparticles with average size of 32 nm is synthesized by the co-precipitation method for the first time. X-ray diffraction spectra revealed the formation of single-phase spinel with a high crystallinity. Fourier transform infra-red spectra confirmed the formation of spinel matrix crystallographic sites and Scanning Electron Microscopy images confirmed the formation of agglomerated spherical particles with nanometric sizes. The analysis of the magnetic properties indicates that the coercivity (Hc) and Curie temperature (Tc) values increase while the saturation magnetization (Ms) value decreases upon doping with Gd. These results can be seen as a significant improvement of the magnetic properties compared to the undoped material, which could be beneficial for nanotechnology applications. The material is also studied from a theoretical perspective using first-principles calculations. The used PBE-HF method based on the GGA method with the implication of the onsite-exact-exchange proved to be very accurate in describing the system, giving rise to a semi-conducting behavior for the inverse spinel CoFe2O4 and a metallic electronic structure for Gd-doped Co0.7Zn0.3Fe2O4.

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Topics: Spinel (56%), Coercivity (55%), Curie temperature (54%)

Open accessJournal ArticleDOI: 10.1007/S11664-021-09285-W
J. Gajendiran, S. Gokul Raj, G. Ramesh Kumar1, S. Gnanam2  +2 moreInstitutions (3)
Abstract: In this work, BiFeO3 and BiFeO3-CoFe2O4 bioceramic compounds were investigated and their photoluminescence (PL) characteristics and antimicrobial activity were compared in detail. The crystallite size, crystalline strain, and optical band gap of the compounds were estimated using the Williamson-Hall (W-H) plot, which was derived from powder x-ray diffraction patterns. The W-H plot revealed that the crystallite size increased and the crystalline strain value decreased for the BiFeO3-CoFe2O4 when compared to pure BiFeO3. The formation of a binary phase structure was confirmed by the Raman spectrum of the synthesized composite material. In the PL analysis, weak PL visible emission bands were observed for both the pure and composite samples, indicating that fewer oxygen vacancy defects occurred. The antimicrobial activity of pure BiFeO3 and BiFeO3-CoFe2O4 was investigated in detail, and the results are discussed.

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Topics: Crystallite (52%), Photoluminescence (51%)

References
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111 results found


Journal ArticleDOI: 10.1016/0378-4274(95)03532-X
01 Dec 1995-Toxicology Letters
Abstract: Iron and hydrogen peroxide are capable of oxidizing a wide range of substrates and causing biological damage. The reaction, referred to as the Fenton reaction, is complex and capable of generating both hydroxyl radicals and higher oxidation states of the iron. The mechanism and how it is affected by different chelators, and the interpretation of results obtained in biological systems, are discussed.

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Topics: Hydrogen peroxide (61%), Hydroxyl radical (57%), Oxidizing agent (55%) ... read more

867 Citations


Open accessJournal Article
Abstract: The size of a cation is important in determining its site preference. In oxide spinels containing 2 (super +) and 3+) ions (2-3 spinels) there is a tendency for the larger ion to prefer the tetrahedral site; the reverse holds for 2-4 spinels. A set of cation radii optimized to best fit spinel lattice parameters is presented.--Modified journal abstract.

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Topics: Lattice energy (53%)

559 Citations


Open accessJournal ArticleDOI: 10.1021/JP0732763
Changwa Yao1, Qiaoshi Zeng1, Gerardo F. Goya1, Teobaldo E. Torres1  +6 moreInstitutions (1)
Abstract: Ferromagnetic zinc ferrite nanocrystals at ambient temperature were synthesized via the thermal decomposition of metal−surfactant complexes. Characterization measurements including transmission electron microscopy and X-ray diffraction were performed for as-synthesized ZnFe2O4 particles. The sample has a relatively narrow size distribution with an average particle size of 9.8 ± 0.2 nm and standard deviation of 30%. The as-synthesized zinc ferrite nanocrystals are superparamagnetic at room temperature with a blocking temperature TB = 68 ± 2 K and a saturation magnetization MS = 65.4 emu·g-1 at T = 10 K, which are caused by the change in the inversion degree of the spinel structure. A coercive field of HC = 102 ± 5 Oe in the blocked state indicates small particle anisotropy, although evidence of surface spin canting was inferred from magnetization data in the as-synthesized ZnFe2O4 nanocrystals. Our results demonstrate that magnetic properties of magnetic particles can be largely modified by just changing p...

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Topics: Zinc ferrite (58%), Magnetization (58%), Superparamagnetism (57%) ... read more

268 Citations


Journal ArticleDOI: 10.1016/J.CIS.2017.07.033
Abstract: Zinc oxide (ZnO), as a material with attractive properties, has attracted great interest worldwide, particularly owing to the implementation of the synthesis of nano-sized particles. High luminescent efficiency, a wide band gap (3.36eV), and a large exciton binding energy (60meV) has triggered intense research on the production of nanoparticles using different synthesis methods and on their future applications. ZnO nanomaterials can be used in industry as nano-optical and nano-electrical devices, in food packaging and in medicine as antimicrobial and antitumor agents. The increasing focus on nano zinc oxide resulted in the invention and development of methods of nanoparticles synthesis. Recently, various approaches including physical, chemical and biological ("green chemistry") have been used to prepare ZnO nanocomposites with different morphologies. The obtained nanoparticles can be characterized with a broad range of analytical methods including dynamic light scattering (DLS), electron microscopy (TEM, SEM), UV-VIS spectroscopy, X-ray diffraction (XRD) or inductively coupled plasma with mass spectrometry (ICP-MS). With these it is possible to obtain information concerning the size, shape and optical properties of nanoparticles. ZnO NPs exhibit attractive antimicrobial properties against bacteria (Gram-positive and Gram-negative) and fungi. Zinc oxide nanocomposites show also selective toxicity toward normal and cancerous cells, which is explained by reactive oxygen formation (ROS). Yet despite the potentially interesting antitumor activity of ZnO nanoparticles, it has been proven that they can be also cytotoxic and genotoxic for multiple types of human cells (i.e. neuronal or epithelial cells). This paper reviews the methods of synthesizing zinc oxide nanocomposites as well as their characteristics, antimicrobial activity and cytotoxicity against normal and tumor cells.

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Topics: Nanoparticle (53%), Nanomaterials (52%), Zinc (52%)

224 Citations


Journal ArticleDOI: 10.2174/1568026615666150414142209
Abstract: Silver nanoparticles (AgNPs) exhibit a consistent amount of flexible properties which endorse them for a larger spectrum of applications in biomedicine and related fields. Over the years, silver nanoparticles have been subjected to numerous in vitro and in vivo tests to provide information about their toxic behavior towards living tissues and organisms. Researchers showed that AgNPs have high antimicrobial efficacy against many bacteria species including Escherichia coli, Neisseria gonorrhea, Chlamydia trachomatis and also viruses. Due to their novel properties, the incorporation of silver nanoparticles into different materials like textile fibers and wound dressings can extend their utility on the biomedical field while inhibiting infections and biofilm development. Among the noble metal nanoparticles, AgNPs present a series of features like simple synthesis routes, adequate and tunable morphology, and high surface to volume ratio, intracellular delivery system, a large plasmon field area recommending them as ideal biosensors, catalysts or photo-controlled delivery systems. In bioengineering, silver nanoparticles are considered potentially ideal gene delivery systems for tissue regeneration. The remote triggered detection and release of bioactive compounds of silver nanoparticles has proved their relevance also in forensic sciences. The authors report an up to date review related to the toxicity of AgNPs and their applications in antimicrobial activity and biosensors for gene therapy.

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Topics: Silver nanoparticle (62%)

160 Citations