POSTEROVÁ SEKCE D

The extensive use of zinc oxide nanoparticles (ZnONPs) has increased their release into aquatic environments, highlighting the need for integrated approaches to nanotoxicity assessment that combine nanoparticle characterization with biological responses. Cyanobacteria are valuable model organisms because changes in photosynthetic pigments and primary metabolism provide sensitive indicators of cellular stress.
The effects of ZnONPs (≤50 nm, Sigma-Aldrich) on Limnospira platensis were evaluated. Prior to application, nanoparticle suspensions were ultrasonicated in deionized water for 20 min. Cultures were exposed to ZnONPs (40-100 mg L⁻¹) during the lag and exponential growth phases. Nanoparticle behavior was characterized by monitoring zinc ion release in a model medium over seven days and colloidal stability by zeta potential measurements.
Under highly alkaline cultivation conditions, ZnONPs exhibited extremely low zinc ion release while maintaining high colloidal stability, evidenced by a consistently negative zeta potential. Biological responses were assessed using biomass, total protein, phycocyanin, and malondialdehyde (MDA) as toxicity endpoints.
ZnONPs induced concentration-dependent responses. Biomass decreased by 20-58%, total protein by 18-29%, phycocyanin was almost completely depleted at the highest concentrations, and MDA increased markedly, indicating oxidative stress. Similar response patterns were observed in both growth phases, although their magnitude depended on the developmental stage.
The results demonstrate that phycocyanin is a highly sensitive biomarker of ZnONP-induced stress. Integrating nanoparticle physicochemical characterization with multiple physiological and oxidative stress biomarkers provides a more reliable assessment of nanoparticle toxicity than any single endpoint.
ACKNOWLEDGEMENTS: This research was supported by the project 26.80013.5107.01ARM (NARD, Moldova) / 26NARD-1A005 (Armenia).

By atomic force microscopy (AFM) it is possible to indirectly measure one of the markers of living cells’ condition - the rigidity of their outer membrane. To obtain the Young modules, which represent membrane rigidity, we need to analyse AFM data, which can be done using many commercial software packages. However, commercial software often does not support real batch data processing, and in almost every case, they act like a black box without any options to fully control the correction processes on the data. Therefore, we are developing a Python-based tool to analyse AFM data, which will be open-source. It provides all the necessary steps in data analysis, like baseline corrections, removing bad-measured points from the dataset and calculating Young modules (with both Sneddon and Hertz models). This gives us full control over all steps of the data analysis and gives us the ability to process the whole measured dataframe at once. We utilize this evolving tool to assess the cytotoxicity of nanoparticles in human cells. Analyzing membrane mechanical changes during nanoparticle uptake provides valuable insights into the role of the protein corona in nano-bio interactions.

Introduction. Zinc oxide nanoparticles (ZnO NPs) are widely used in science, medicine, and industry. Due to their selective toxicity and increasing industrial application, investigation of their toxic effects is essential because of the associated risks of environmental contamination and human exposure.
Objective. To evaluate the effects of ZnO nanoparticles, polysaccharide (PSS), and their combination on leukocyte and lymphocyte morphology and counts in rats under acute and chronic experimental conditions.
Materials and Methods. Forty-eight male Wistar rats (90-120 g) were randomly assigned to acute and chronic exposure groups. Each group comprised four subgroups (n = 6): control, PSS, ZnO NPs, and ZnO NPs + PSS. Test substances were administered orally as powders mixed with feed. Acute exposure consisted of a single dose of 2000 mg/kg followed by a 14-day observation period, whereas chronic exposure involved daily administration of 250 mg/kg for 14 days. Hematological evaluation included analysis of leukocyte and lymphocyte parameters.
Results. Exposure to ZnO NPs, PSS, and their combination induced significant changes in the leukocyte profile. Leukocytosis was observed in most animals, while marked leukocytosis in some groups indicated intoxication, acute inflammation, or extensive tissue damage. Increased lymphocyte percentages suggested enhanced immune activity. Relative lymphopenia was associated with elevated granulocyte levels, a hallmark of acute inflammatory responses. Increased absolute counts of monocytes and eosinophils indicated activation of phagocytic processes.
Conclusions. Acute cytotoxic effects were observed in the ZnO and PSS groups, whereas the ZnO NPs + PSS combination demonstrated a protective effect. Activation of phagocytosis was also detected.
Was founded 26NARD-1A005

Background: Zinc oxide nanoparticles (ZnO NPs) are increasingly used in food applications, raising concerns about their effects on the gastrointestinal barrier. The small intestine is a primary site of contact with ingested nanoparticles and may be vulnerable to structural alterations.
Objective: To evaluate the morphofunctional response of the small intestine to oral exposure to ZnO NPs administered alone or with PSS in Wistar rats.
Materials and Methods: Forty-eight male rats (90-120 g) were divided into acute and subacute exposure cohorts. Each cohort included four groups (n = 6): control, PSS, ZnO NPs, and ZnO NPs + PSS. Test substances were mixed with powdered chow. Acute exposure consisted of a single dose of 2000 mg/kg followed by 14 days of observation, whereas subacute exposure involved daily administration of 250 mg/kg for 14 days. Small-intestinal samples were examined histologically and morphometrically. Villus architecture, epithelial integrity, enterocyte proliferation, goblet cells, lymphoid infiltration, and mast-cell activity were assessed.
Results: Preliminary observations indicate exposure-dependent changes in the intestinal mucosa, including reduced enterocyte height, focal epithelial desquamation, villus deformation or fusion, and impaired epithelial renewal. Increased lymphocytic infiltration and mast-cell activation suggested a local inflammatory and adaptive response. Changes appeared more pronounced after repeated exposure and in the ZnO NPs + PSS group.
Conclusions: Oral exposure to ZnO NPs may disturb intestinal epithelial homeostasis and activate local immune mechanisms. Final quantitative analysis will determine their magnitude and statistical significance.
ACKNOWLEDGEMENT: This research was supported by the Armenian-Moldovan bilateral research project No. 26NARD-1A005 on nanoparticle safety.

Polyvinylidene fluoride (PVDF) is a polymer belonging to the fluoropolymer family. It is characterized by high thermal and chemical resistance, piezoelectric properties, and good mechanical strength. PVDF is widely used as a filtration layer in respirators. This experiment investigated the effects of ultraviolet radiation (UV) on a PVDF membrane and the formation of particles released during the degradation process. The samples were exposed to UV radiation with a wevelength of 365 nm for a duration of one week in a specially designed photoreactor. Subsequently, the PVDF membrane was characterized using an ATR-FTIR method. Particles released during the degradation process were analyzed by DLS and SEM method coupled with EDS for elemental analysis.
ATR-FTIR analysis confirmed the presence of characteristic PVDF absorption bands, however, no clear evidence of material degradation was observed after one week of UV exposure. In contrast, SEM analysis revealed the presence of released particles with irregular morphology, which were likely the result of fragmentation of the PVDF membrane. Subsequent TEM analysis confirmed the SEM findings. DLS analysis showed the highest abundance of particles with an average hydrodynamic diameter of 91 nm. The results suggest that improper disposal of PVDF membrane waste may lead to the release of membrane fragments into the environment, potentially causing adverse environmental impacts.

The rapid development of technology and industry has resulted in an increasing presence of nanoparticles in the environment. While they may pose potential ecological risks, they are also widely applied in medicine as drug delivery systems and in agriculture as innovative nanofertilizers. In recent years, particular attention has been given to the use of nanomaterials to enhance plant nutrient use efficiency. Iron is an essential microelement required for proper plant growth and development, playing a crucial role in processes such as photosynthesis and cellular respiration.
The aim of this study was to investigate whether iron oxide nanoparticles (in form of α- and γ-Fe₂O₃), differing in size and morphology, exhibit differences in bioavailability and interactions with plant cells. We analyzed the impact of nanoparticle type and concentration on root growth, root anatomical traits, intracellular localization of nanoparticles performed by transmission electron microscopy and concentration of nanoparticles within roots and leaves, and the content of other microelements in plant tissues by ICP-MS measurements. The zeta potential and tendency to aggregation of α- and γ-Fe₂O₃ nanoparticles in water and MS plant culture medium were also investigated. The experiments were conducted using the model plant Arabidopsis thaliana in a hydroponic culture.
The results contribute to a better understanding of the relationship between the physicochemical properties of α- and γ-iron oxide nanoparticles and their biological effects on plants. This knowledge is essential for environmental risk assessment and for evaluating the potential application of iron nanoparticles as advanced nanofertilizers.