Magnetite (Fe₃O₄) nanoparticles have found numerous applications due to the ease of fabrication, favourable combination of physical and chemical properties, as well as environmental and biological safety. At the same time, their functional applications in memristive devices remain underexplored, especially with regard to nanocrystalline phases that can be obtained by various means of solution chemistry. In this study, we examine the physical properties, morphology, and biocompatibility of magnetite nanoparticles obtained by hydrolytic and non-hydrolytic synthesis routes. For this purpose, we have revisited two solution chemistry methods for obtaining magnetite nanoparticles in water and lower alcohols. Notably, magnetite nanoparticles obtainedviathe hydrolytic route have demonstrated an appreciably high value of the resistive switching ratioR_OFF/R_ON∼ 10³which is comparable to the highest values ever reported for iron oxide memristors. The advantageous suitability of the hydrolytically synthesized magnetite nanoparticles for resistive switching applications is rationalized by their higher purity and crystallinity, as well as by the plausible activity of residual water molecules and hydroxy groups on facilitating the topotactic redox reaction associated with the resistive switching phenomenon.

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Here we report the methodology for nanocomposite fabrication based on the inkjet printing technique. Doped TiO₂ nanoparticles with Sc contents up to 10 wt.% were synthesized and adapted towards a facile fabrication of microscale structures and thin film printing. Implementation of the state-of-the-art low-temperature synthesis allowed to us successfully incorporate high concentrations of Sc³⁺ ions into the TiO₂ lattice and improve the light absorption characteristics of the resulting materials. Without affecting the anatase structure substantially, Sc doping gave rise to an intensified absorbance capacity and provided the means for the efficient fabrication of Sc-TiO₂ microarchitectures via the inkjet printing technique. The changes in the spectral and structural characteristics of the Sc-TiO₂ composites were observed by Energy Dispersive X-Ray spectroscopy (EDX), X-ray diffraction (XRD), and UV-vis methods. The rheological parameters of the colloidal suspension based on the synthesized Sc-TiO₂ nanoparticles were adapted for inkjet printing in terms of the optimal viscosity, morphology, and surface tension. The developed individual ink characteristics allowed us to produce a close coherence between the enhanced optical properties of the Sc-TiO₂ prepared the sol-gel method and the inkjet-printed films. The introduced methodology features the possibility to inkjet-print doped and pure TiO₂ robust films for potential large-scale fabrication.

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A highly selective adsorbent for multivalent cationic species based on a sitinakite-type titanosilicate was prepared from a leucoxene ore enrichment waste. The synthesized material was used as for the selective removal of alkali-earth strontium (II) and barium (II) cations as well as for the cationic species based on the natural isotopes of uranium, radium, and thorium from aqueous solutions. The influence of such parameters as the pH, the initial concentration of the ions, the presence of other electrolytes on the sorption parameters was investigated. The sorption capacity of the synthesized material at ambient conditions is 80 and 110 mg/g for Sr²⁺ and Ba²⁺, respectively, and it rises with increasing temperature. Furthermore, the material shows a high selectivity towards radionuclides of radium, uranium, and thorium. By using the current titanosilicate materials, the extracting degree of over 99% could be achieved when extracting these species from their respective standard aqueous solutions. The origin of the high adsorption selectivity for cationic complexes of thorium and uranium is rationalized based on periodic density functional theory calculations. The obtained results indicate that the described materials could be promising and inexpensive sorbents for the selective extraction of radioactive isotopes and particularly those of Sr, Ba and U, Th, Ra.

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Stability is the key property of functional materials. In this work we investigate computationally the degradative potential of a model Mn-BTC (BTC = benzene-1,3,5-tricarboxylate) metal–organic framework (MOF) building block in aqueous solutions under oxidative conditions. Model density functional theory calculations have shown that the direct hydrolysis of the Mn-containing moieties is more difficult than their decomposition via oxidation-induced paths. While the interaction with H2O2 species is of non-covalent nature and requires O–O-bond breaking to initiate Mn-center oxidation, open-shell O2 species readily oxidize radical Mn-centers and form bonds of σ-, π-, or δ-symmetry with the metal. The oxidative transformations of di-Mn paddle-wheel carboxylate structure-forming units are accompanied with substantial distortions of the coordination polyhedra that, together with the increased Lewis acidity of the oxidized metal centers, facilitates the hydrolysis leading to the degradation of the structure at a larger scale. Whereas such a mechanism is expected to hamper the catalytic applications of such Mn-MOFs, the associated structural response to oxidizing and radical species can create a basis for the construction of Mn-MOF-based drug delivery systems with increased bio-compatibility.@en

We describe the synthesis and properties of a new composite material based on heparin and MIL-101(Fe) metal-organic framework. The intrinsic instability of MIL-101(Fe) towards hydrolysis enables binding of heparin molecules to the framework structure as is evidenced by DFT calculations and adsorption experiments. The de novo formed heparin-MOF composites showed good biocompatibility in in vitro and demonstrated pronounced anticoagulant activity. The specific interaction between the bioactive molecule and the carrier is critical for the selective degradation of the complex in the body fluids and for the enhanced activity. Hep-MIL-101(Fe) composite could serve as a drug-releasing depot for nanofabrication and to introduce anticoagulant activity to medical devices and biocoatings. Addition of Hep-MIL-101(Fe) to a sol-gel derived thrombolytic matrix allowed the combination of anticoagulant and thrombolytic activities in a single hybrid nanomaterial that could be applied as a bioactive nanocoating for PTFE vein implants.

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Metal-organic frameworks comprise a class of crystalline porous coordination polymers with unique chemical and physical properties. On the one hand, due to high specific surface area, biocompatibility and stability in biological media, framework materials are ideal candidates for the development of new dosage forms, in particular, for drug delivery systems. On the other hand, the modular structure of frameworks provides an opportunity for computational screening and predictive calculations. This opens new prospects for the design of modern functional materials. The computational screening and simulation of adsorption ± desorption processes play a key role in the development of drug delivery systems, as they provide data that are difficult to obtain solely from experiments. These data can greatly assist in the development of drug delivery systems. The first part of the review gives a brief overview of the metal-organic frameworks which have already proved to be potential drug carriers as well as frameworks which are currently being extensively studied and gain attention in this area. The second part addresses the concept of rational design and computer-aided design of such systems. The bibliography includes 216 references.

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