Artyom S Minin

Carbon-encapsulated nickel nanoparticles (Ni@C) are of considerable interest for catalysis, biotechnology, and hybrid nanostructures. However, the distribution of carbon between the metallic core and the surrounding shell remains difficult to assess. In this work, we apply 13C NMR spectroscopy to directly probe carbon localization in Ni@C nanocomposites, complemented by reference measurements on hollow carbon shells. Two distinct 13C NMR signals are resolved. One line, centered at zero shift, is assigned to glass-like carbon in the shell. The second line, shifted to higher frequency, exhibits a strong temperature dependence and is attributed to carbon atoms dissolved in the ferromagnetic nickel core. The absence of splitting indicates that these carbon atoms occupy crystallographically equivalent positions, most likely octahedral interstitial sites. After annealing at 1273 K, the shifted line disappears while the magnetization increases markedly, confirming carbon migration from the core to the shell. Magnetization measurements reveal a distribution of Curie temperatures among different nanoparticle fractions, reflecting the inhomogeneous distribution of carbon interstitials within the nickel lattice. These results provide direct experimental evidence for a carbon solid solution within the nickel core and demonstrate the capability of 13C NMR to determine carbon localization in core-shell nanocomposites.

The study of 2,2′-bipyridine-like ligands for the creation of sensors for zinc(II) ions was carried out, including for use in biological systems, for which the range of available sensors is currently limited. New derivatives of quinazolin-4(3H)-one and 1,3,4-oxadiazole containing a tripicolylamine moiety were synthesized. Photophysical properties of both these 2,2′-bipyridine-like ligands and their complexes with zinc(II) ions were studied. 2-Substituted quinazolin-4(3H)-one showed itself as a typical PET sensor for zinc cations; a significant increase in the luminescence of an acetonitrile solution was observed upon the addition of zinc(II) perchlorate (from Vero culture cells, including those artificially enriched with zinc, was studied. The possibility of using 2-pyridyl-substituted quinazolin-4(3H)-ones as sensors for zinc(II) ions has been demonstrated; however, further research in this area is required for their effective application in biological environments.

We developed highly fluorescent photocages based on a 2-aryl-1,2,3-thiazol-4-yl-1,2,3-thiazole core. Extensive experimental and theoretical studies demonstrated their excellent properties compared to published light-based masking systems.

Cell migration, shape maintenance, and intracellular signaling are closely linked to dynamic changes in cell morphology and the cytoskeleton. These processes involve the reorganization of the cytoskeleton within the cytoplasm, affecting all its key components: intermediate filaments, microtubules, and microfilaments. A promising strategy for remotely controlling cellular functions is the use of magnetic nanoparticles, which can influence cellular physiology. This approach, known as magnetogenetics, has been applied in various areas of cell and molecular biology. Applying a magnetic field allows for the non-invasive modulation of biochemical processes, cell migration, and morphological changes in cells containing magnetic nanoparticles. In our study, magnetic nanoparticles were conjugated with antibodies targeting cytoskeletal components, enabling the magnetically induced manipulation and deformation of the cell cytoskeleton. Our research introduces a novel approach to manipulating specific cytoskeletal components and altering cell polarity with spatial precision in vitro using magnetic nanoparticles associated with the cytoskeleton.

We have designed novel push–pull systems based on CF₃-substituted pyridines and pyrimidines. The photophysical properties of these new fluorophores have been examined using both absorption and emission spectral analyses in acetonitrile solutions and solid states. All fluorophores proved to exhibit moderate absolute quantum yields of up to 0.33 in solutions and up to 0.12 in solid states, depending on their specific structures. Most fluorophores have demonstrated significant aggregation-induced emission behavior, making them suitable as robust and low-toxicity bioimaging agents for bioimaging studies. Comparison with known dyes and studies on various cell cultures demonstrated the selectivity of the obtained push–pull systems for visualizing lipid droplets.

Interactions with the extracellular environment and biological responses are based on biochemical pathways. Cytoskeletal reorganization is a dynamic process accompanied by filament polymerization and depolymerization, that allows the cell to effectively perceive and respond to external mechanical stimuli by altering their biomechanical properties. The contribution of mechanical deformations of individual cytoskeletal elements to changes in intracellular signaling has not been covered in the existing literature. In our article, we investigated changes in gene expression after regulated cytoskeletal deformation using a constant magnetic field and magnetic nanoparticles associated with antibodies to cytoskeletal proteins (vimentin, beta-actin and acetylated tubulin). For the first time, we have identified and described the biological pathways involved in the regulation of mechanical deformations of cytoskeletal elements.

Magnetogenetics is a promising field of biology devoted to the manipulation of biological objects by magnetic fields, where magnetic nanoparticles usually act as actuators. However, studying the response of biological objects is hampered by the fact that microscopes are usually made of ferromagnetic materials, making it difficult to work with them in powerful magnetic fields. This article focuses on building a DIY 3d printed microscope based on the ESPressoscope platform, integrated into a gradient magnetic system of permanent magnets. The article reveals the design, choice of materials and, using the example of cellular spheroids saturated with magnetic nanoparticles, demonstrates the application of MagnEspScope for the observation of magnetophoresis of biological objects.

Lanthanide complexes with organic ligands exhibit unique photophysical properties, including long-lived emission lifetimes, large Stokes shifts, and sharp emission bands, making them highly attractive for bioanalytical and biomedical applications. Incorporating these complexes into nanoparticles can further enhance signal intensity and assay sensitivity in both in vitro and in vivo settings. Here, we report the first successful use of the desolvation method to synthesize bovine serum albumin (BSA) nanoparticles loaded with europium complexes. This simple approach involved the dropwise addition of an ethanolic solution of europium complex precursors into an aqueous BSA solution, followed by thermal cross-linking to generate disulfide bonds. We systematically optimized synthesis parameters—including pH, precursor concentration, and addition rate—to produce nanoparticles with high brightness and low polydispersity. Under optimized conditions, the resulting nanoparticles exhibited a uniform size of 150–160 nm (PDI<0.15) as determined by dynamic light scattering and electron microscopy. Each nanoparticle encapsulated approximately 350 europium complexes, achieving quantum yields of 0.77–1.18% with excitation/emission maxima at 360/615 nm. The synthesis yield was ~80%, and the nanoparticles demonstrated excellent size stability across physiological pH conditions and after three months of storage. However, luminescence intensity decreased over time and under certain buffer conditions. Cytotoxicity studies using Vero cells showed cell viability above 80% at nanoparticle concentrations up to 1 mg/mL. The key challenges to be addressed are the improvement of synthesis reproducibility and the stability of luminescent properties.