This study investigated the concentration-dependent effects of zinc oxide nanoparticles (ZnO NPs, 30–70 nm) on the freshwater microalga Lobosphaera sp. under different salinity conditions (0–4 g L⁻¹ NaCl). ZnO NPs demonstrated dual effects: low concentration (0.75 mg L⁻¹) enhanced growth and alleviated salt stress, while higher concentrations (7.5–75 mg L⁻¹) caused significant growth inhibition (up to 52%) and induced oxidative stress. Salinity did not significantly affect NPs aggregation patterns, and neither salinity nor aggregation degree influenced toxicity outcomes. NPs concentration plays a dominant role of toxicological effects. Dose-dependent increases in catalase activity and ROS-positive cells confirmed NPs-induced oxidative stress. Crucially, zinc bioaccumulation correlated with NPs concentration but dissociated from dissolved Zn²⁺ release, demonstrating particle-driven toxicity. Our findings challenge the ion-release paradigm and highlight the potential of low-dose ZnO nanoparticles as effective stress-protectors in algal biotechnology, offering new strategies for enhancing microalgal resilience under environmental stress.

Copper (II) oxide nanoparticles (CuO NPs) attract much attention as a promising antimicrobial agent. We studied the antibacterial properties of three types of CuO NPs against Escherichia coli bacteria: flake-shaped particles with a diameter of 50–200 nm and a thickness of 10–20 nm (CuO-CD synthesized by chemical deposition), spherical particles with a size of 20–90 nm (CuO-EE obtained by electrical explosion), and rod-shaped particles with a length of 100–200 nm and a diameter of 30 × 70 nm (CuO-CS commercial sample). We tested how the shape, size, and concentration of the NPs, and composition of the dispersion medium affected the properties of the CuO NPs. We prepared dispersions based on distilled water, a 0.9% NaCl solution, and the LB broth by Lennox and used Triton X-100 and sodium dodecyl sulfate (SDS) as stabilizers. The concentration of NPs was 1–100 mg L⁻¹. We showed that the dispersion medium composition and stabilizer type had the greatest influence on the antibacterial effects of CuO NPs. We observed the maximum antibacterial effect for all CuO NP types dispersed in water without a stabilizer, as well as in LB broth with the SDS stabilizer. The maximum inhibition of culture growth was observed under the influence of CuO-EE (by 30%) and in the LB broth with the SDS stabilizer (by 1.3–1.8 times depending on the type of particles). In the saline solution, the antibacterial effects were minimal; in some cases, the CuO NPs even promoted bacterial culture growth. SDS increased the antibacterial effects of NPs in broth and saline but decreased them in water. Finally, among the particle types, CuO-CS turned out to be the most bactericidal, which is probably due to their rod-shaped morphology and small diameter. At the same time, the concentration and aggregation effects of CuO NPs in the colloidal systems we studied did not have a linear action on their antibacterial properties. These results can be used in the development of antibacterial coatings and preparations based on CuO NPs to achieve their maximum efficiency, taking into account the expected conditions of their use.

The effect of blast-furnace sludge containing trace elements (iron, zinc, silicon) on the microalgae Chlorella fusca, Chlorella vulgaris, and Scenedesmus rubescens under the conditions of a newly developed photobioreactor is investigated. It is shown that the addition of sludge in concentrations of 0.1–1 g/L stimulates culture growth. The maximum number of C. fusca and C. vulgaris cells is observed at 1 g/L of sludge in the medium, and in S. rubescens, at 0.1 g/L. At the same time, the viability of C. vulgaris decreases by 17%, and S. rubescens, by 23% at the maximum sludge concentration. C. fusca proves to be the most tolerant to its effects. It is worth noting that an increase in the total protein content is noted for C. fusca and S. rubescens, which makes this approach promising for the production of feed additives. The results obtained, taking into account the need to assess environmental safety, can be applied in the development of biotechnologies for the disposal of industrial waste.

This paper presents the results of a study on the physicochemical characteristics of the binding between single-layer graphene nanosheets (GNs) and typical enzymes of the antioxidant system of the fish Danio rerio. The enzymes chosen as target proteins were superoxide dismutase 1 (SOD1), glutathione peroxidase 8 (Gpx8) and catalase (Cat). Virtual molecular structures of the target enzyme and GN were modeled and optimized. Two GN sizes were studied: 25 × 25 and 35 × 35 Å. Using UniProt DB and PrankWeb, annotated binding amino acid residues were compared with amino acid residues associated with GN obtained from the prediction results. For all proteins except Gpx8, the topology of amino acid residues potentially involved in binding to nanosheets was precisely localized. The number of amino acid residues involved in the formation of the molecular cavity ranged from 13 to 30. Molecular interactions between enzymes, proteins and GN were predicted using the rigid molecular docking method using AutoDock software. The study showed the formation of more stable GN-enzyme complexes for 25 × 25 Å GN with fairly low binding energies. The Gibbs free energy values for each combination of GN-enzyme complexes range from –10.1 to ‒15.9 kcal/mol. The article discusses the potential biological effects of the studied carbon-based GNs on the antioxidant system of fish D. rerio. The presented approach seems promising for studying and predicting the cytotoxicity of pollutants based on graphene nanoparticles.

Due to the increasing use of nanomaterials in agriculture, the effects of copper(II) oxide nanoparticles (CuO NPs) on plants are of considerable interest. This study analyzes the effect of CuO NPs synthesized by chemical precipitation and electrical explosion of a wire, as well as a commercial CuO NP sample, all stabilized with the antimicrobial polymer polyhexamethylene biguanide hydrochloride (PHMB), on spring wheat (Triticum aestivum L.) seedlings. X-ray diffraction analysis and scanning electron microscopy have revealed significant differences among the samples in phase purity, particle size, and morphology (rod-shaped, spherical, and flake-like particles). Rod-shaped nanoparticles from the commercial sample exhibited the highest colloidal stability in aqueous dispersions. Bioassays have shown that all CuO NP dispersions enhanced seed germination and biomass accumulation, particularly in roots, while seedling length was reduced. The strongest stimulatory effect, including increased chlorophyll content and catalase activity, has been recorded for the commercial CuO NP sample at a concentration of 100 mg/kg. Copper accumulated predominantly in the above-ground parts of the plants. Overall, the results indicate that nanostructured CuO–PHMB complexes may represent an effective approach for improving the growth of spring wheat. However, long-term studies are needed to assess their ecological safety.

The paper presents the results of studying the intermolecular interactions of enzymes of the Danio rerio antioxidant system (superoxide dismutase 1, glutathione peroxidase 8, and catalase) and Cds and ZnS nanoparticles. The virtual molecular structures of target enzymes and metal sulfide nanoparticles were modeled and optimized. For all proteins except glutathione peroxidase 8, the topology of amino acid residues potentially involved in binding to nanotubes was precisely localized. The number of amino acid residues involved in the formation of the molecular cavity ranged from 13 to 30. According to the results of the study, it was found that the formation of nanoparticle-enzyme complexes with average binding energy values from –3.43 to –8.24 kcal/mol is possible. All nanoparticles were characterized by the formation of electrostatic bonds in the ligand-binding sites of proteins, which in general should lead to the same scenario in the form of inhibition of protein function. The presented approach is promising for studying the eco- and cytotoxicity of such pollutants as nanoparticles of cadmium and zinc sulfides.