Search

The applications of magnetic nanoparticles (MNPs) as biocatalysts in different biomedical areas have been evolved very recently. One of the main challenges in this field is to design affective MNPs surfaces with catalytically active atomic centres, while producing minimal toxicological side effects on the hosting cell or tissues. MNPs of vanadium spinel ferrite (VFe 2 O 4 ) are a promising material for mimicking the action of natural enzymes in degrading harmful substrates due to the presence of active V 5+ centres. However, the toxicity of this material has not been yet studied in detail enough to grant biomedical safety. In this work, we have extensively measured the structural, compositional, and magnetic properties of a series of V x Fe 3-x O 4 spinel ferrite MNPs to assess the surface composition and oxidation state of V atoms, and also performed systematic and extensive in vitro cytotoxicity and genotoxicity testing required to assess their safety in potential clinical applications. We could establish the presence of V 5+ at the particle surface even in water-based colloidal samples at pH 7, as well as different amounts of V 2+ and V 3+ substitution at the A and B sites of the spinel structure. All samples showed large heating efficiency with Specific Loss Power values up to 400 W/g (H 0  = 30 kA/m; f = 700 kHz). Samples analysed for safety in human hepatocellular carcinoma (HepG2) cell line with up to 24h of exposure showed that these MNPs did not induce major genomic abnormalities such as micronuclei, nuclear buds, or nucleoplasmic bridges (MNIs, NBUDs, and NPBs), nor did they cause DNA double-strand breaks (DSBs) or aneugenic effects-types of damage considered most harmful to cellular genetic material. The present study is an essential step towards the use of these type of nanomaterials in any biomedical or clinical application., Competing Interests: Declaration of competing interest The authors declare that they do not have any affiliations that would lead to conflicts of interest. There were no financial or non-financial forms of assistance provided by third parties specifically for the conduct of the research presented in this manuscript. The authors have had no financial interests or relationships within the past three years that are related to the subject matter of the manuscript, including advisory roles, consulting, equity ownership, or receipt of non-financial support. None of the co-authors hold any patents or copyrights relevant to the work in this manuscript. There are no additional activities or relationships that the authors need to disclose, which could be perceived as influencing the research or its interpretation., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

In this work, a new approach to construct self-assembled hybrid systems based on natural PSII-enriched thylakoid membranes (PSII BBY) is demonstrated. Superfine m-WO 3 NPs (≈1-2 nm) are introduced into PSII BBY. Transmission electron microscopy (TEM) measurements showed that even the highest concentrations of NPs used did not degrade the PSII BBY membranes. Using atomic force microscopy (AFM), it is shown that the organization of PSII BBY depends strongly on the concentration of NPs applied. This proved that the superfine NPs can easily penetrate the thylakoid membrane and interact with its components. These changes are also related to the modified energy transfer between the external light-harvesting antennas and the PSII reaction center, shown by absorption and fluorescence experiments. The biohybrid system shows stability at pH 6.5, the native operating environment of PSII, so a high rate of O 2 evolution is expected. In addition, the light-induced water-splitting process can be further stimulated by the direct interaction of superfine WO 3 NPs with the donor and acceptor sides of PSII. The water-splitting activity and stability of this colloidal system are under investigation. RESEARCH HIGHLIGHTS: The phenomenon of the self-organization of a biohybrid system composed of thylakoid membranes enriched in photosystem II and superfine WO 3 nanoparticles is studied using AFM and TEM. A strong dependence of the organization of PSII complexes within PSII BBY membranes on the concentration of NPs applied is observed. This observation turns out to be crucial to understand the complexity of the mechanism of the action of WO 3 NPs on modifications of energy transfer from external antenna complexes to the PSII reaction center., (© 2023 Wiley Periodicals LLC.)

We developed a fast, single-step sonochemical strategy for the green manufacturing of magnetite (Fe 3 O 4 ) magnetic nanoparticles (MNPs), using iron sulfate (FeSO 4 ) as the sole source of iron and sodium hydroxide (Na(OH)) as the reducing agent in an aqueous medium. The designed methodology reduces the environmental impact of toxic chemical compounds and minimizes the infrastructure requirements and reaction times down to minutes. The Na(OH) concentration has been varied to optimize the final size and magnetic properties of the MNPs and to minimize the amount of corrosive byproducts of the reaction. The change in the starting FeSO 4 concentration (from 5.4 to 43.1 mM) changed the particle sizes from (20 ± 3) to (58 ± 8) nm. These magnetite MNPs are promising for biomedical applications due to their negative surface charge, good heating properties (≈324 ± 2 W/g), and low cytotoxic effects. These results indicate the potential of this controlled, easy, and rapid ultrasonic irradiation method to prepare nanomaterials with enhanced properties and good potential for use as magnetic hyperthermia agents., Competing Interests: The authors declare no competing financial interest.