To date, the search for creating stable ferrofluids with excellent properties for biomedical application is one of the challenging scientific and practical investigations. In this study, novel Fe 3 O 4 /Ag nanohybrid ferrofluids from iron sand were synthesized using a double-layer method. The Fe 3 O 4 /Ag nanocomposites exhibited stable crystallite sizes of 11.8 12.1 nm and 36.8-37.2 nm for Fe 3 O 4 and Ag, respectively. The lattice parameters of the spinel structure Fe 3 O 4 and face-centered cubic Ag were respectively 8.344 Å and 4.091 Å. With increasing Ag amount, the crystallite phase of Ag in the nanocomposites increased from 40.2% to 77.2%. The XPS results confirmed that Fe 3 O 4 /Ag nanocomposites were successfully prepared, where Fe 3 O 4 mixed well with Ag via strong ionic bonding. The FTIR results confirmed the presence of Fe 3 O 4 /Ag, oleic acid, and dimethyl sulfoxide as the filler, first layer, and second layer, respectively. The as-prepared ferrofluids exhibited superparamagnetic behavior, where the saturation magnetization decreased with increasing Ag content. The Fe 3 O 4 /Ag nanohybrid ferrofluids exhibited excellent antimicrobial performance against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Candida albicans. More importantly, the Fe 3 O 4 /Ag nanohybrid ferrofluids decreased the progression of liver fibrosisrelated inflammation and fibrogenic activity on hepatic stellate cells.

Manganese (Mn)-doped black iron oxide (Fe3O4) magnetic fluids in the system of MnxFe[Formula: see text]O4 were successfully synthesized from natural magnetite (iron sand) by using co-precipitation method at room temperature. The analyses of the small angle neutron scattering (SANS) data by applying a log-normal sphere with a mass fractal models for [Formula: see text] and [Formula: see text] and two log-normal spheres with a single mass fractal models for [Formula: see text], 0.75 and 1 revealed that the primary particles of the MnxFe[Formula: see text]O4 fluids tended to decrease from 3.8[Formula: see text]nm to 1.5[Formula: see text]nm along with the increasing fraction of Mn contents. The fractal dimension ([Formula: see text]) increased from about 1.2 to 2.7 as the Mn contents were increasing; which physically represents an aggregation of the MnxFe[Formula: see text]O4 particles in the fluids growing up from 1 to 3 dimensions to consolidate a more compact structure. The magnetization curves of the fluids exhibited an increasing saturation magnetization from [Formula: see text] to [Formula: see text], and a decreasing on [Formula: see text] and 0.75, with the maximum achievement of [Formula: see text]. These phenomena may probably be due to the combined effects, arising from cationic and dopant distributions, aggregation and its size, and also fractal dimension. Furthermore, the decrease of blocking temperature of the MnxFe[Formula: see text]O4 magnetic fluids could be associated with the reduced particle sizes, while the freezing temperature had its highest peak intensity when it collectively occurred with the blocking temperature at a similar point of about 270[Formula: see text]K.

In this study, we report the synthesis of the magnetite/silica nanocomposites and their structural and functional groups, magnetic properties, morphology, antimicrobial activity, and drug delivery performance. The X-ray diffraction characterization showed that magnetite formed a spinel phase and that silica formed an amorphous phase. The particle sizes of magnetite increased from 8.2 to 13.2 nm with increasing silica content, and the particles were observed to be superparamagnetic. The nanocomposites tended to agglomerate based on the scanning electron microscopy images. The antimicrobial activity of the magnetite/silica nanocomposites revealed that the increasing silica content increased the inhibition zones by 74%, 77%, and 143% in case of Gram-positive bacteria (B. subtilis), Gram-negative bacteria (E. coli), and fungus (C. albicans), respectively. Furthermore, doxorubicin was used as the model compound in the drug loading and release study, and drug loading was directly proportional to the silica content. Thus, the increasing silica content increased the drug loading owing to the increasing number of OHÀ bonds in silica, resulting in strong bonds with doxorubicin. Based on this study, the magnetite/silica nanocomposites could be applied as drug delivery vehicles.

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In the present study, the eco-friendly and economical methods have been developed by employing natural iron sand as a main precursor to create Fe3O4/ZnO nanocomposites (NCs). The formation of Fe3O4/ZnO NCs was confirmed using XRD, synchrotron-based SAXS, FTIR spectroscopy, and SEM. The XRD results revealed that the Fe3O4 and ZnO crystallised spinel cubic and hexagonal wurtzite structures. The SAXS results exposed the construction of fractal dimension with the values of 3.20–3.70, which indicated a compact structure in 3-dimensions. The SEM images showed that the morphology of the samples tended to agglomerate in nanometric size. The FTIR spectra proved the presence of the Fe–O and Zn–O bonds as the main components of the NCs. The UV–vis spectroscopy analysis revealed that the bandgap energy of the Fe3O4/ZnO NCs ranged from 2.244 to 3.533 eV. Furthermore, the Fe3O4/ZnO NCs demonstrated superparamagnetic behaviour with the blocking temperature below 212 K, and their saturation magnetisation increased with increasing Fe3O4 content. Interestingly, all samples demonstrated excellent inhibitory performance against C. albicans, which indicates that the Fe3O4/ZnO NCs synthesised by eco-friendly and economical methods from natural iron sand for the first time are novel candidates for use as high-performance antifungal agents.