Cells of two molecular genetic types of breast cancer—hormone-dependent breast cancer (ZR-75 cell line) and triple-negative breast cancer (BT-20 cell line)—were studied using atomic force microscopy and an optical nanomotion detection method. Using the Peak Force QNM and Force Volume AFM modes, we revealed the unique patterns of the dependence of Young’s modulus on the indentation depth for two cancer cell lines that correlate with the features of the spatial organization of the actin cytoskeleton. Within a 200–300 nm layer just under the cell membrane, BT-20 cells are stiffer than ZR-75 cells, whereas in deeper cell regions, Young’s modulus of ZR-75 cells exceeds that of BT-20 cells. Two cancer cell lines also displayed a difference in cell nanomotion dynamics upon exposure to cytochalasin D, a potent actin polymerization inhibitor. The drug strongly modified the nanomotion pattern of BT-20 cells, whereas it had almost no effect on the ZR-75 cells. We are confident that nanomotion monitoring and measurement of the stiffness of cancer cells at various indentation depths deserve further studies to obtain effective predictive parameters for use in clinical practice.

Background: Fungal infections can pose great threat to sight. Immediate treatment is usually required; antifungal agents are widely accepted and are effective in most cases. The present experimental study aims to investigate the probable effects of intravitreal injection of antifungal agents on the structure and mechanical properties of the surface of peripheral blood erythrocytes. Methods: Nine albino New Zealand white rabbits, aged five months old, were chosen for the experiment. Solutions of micafungin, voriconazole, or balanced salt solution (BSS) were injected into the midvitreous. Animals were divided into two experimental groups and one control group. Blood sampling from an intravenous (IV) line was performed after 10 days from the last IV injection. An atomic force microscope (AFM) was used to study the structural and mechanical properties of cell surfaces. Results: The analysis results showed that the parameters of the cytoskeleton’s spatial organization changed insignificantly with the antifungal drug treatment. Conclusions: Our findings suggest that locally administered antifungal drugs can cause significant changes to the structure and frictional properties of the erythrocyte surface. These effects occur in the long-term period after administration of the drugs and represent a potential possibility for violation of blood supply to tissues, and the further development of negative side effects.

Objective.To reveal changes in the structural and nanomechanical properties of the erythrocyte surface caused by the action of X-ray radiation in vitro on the whole blood of rats on a high-cholesterol diet using the method of atomic-force microscopy.Materials and methods.The blood of male Wistar rats being on a high-cholesterol diet for two months was exposed to X-ray radiation (320 kV) at doses of 1 and 100 Gy. The structural, elastic and adhesive properties of the surface of isolated and glutaraldehyde-fxed erythrocytes at the nanoscale were studied using the atomic- force microscope BioScope Resolve in PeakForce QNM mode in air.Results.The study has identifed an increase in the stiffness of the erythrocyte surface at a dose of 1 Gy and its decrease to almost control values at a dose of 100 Gy, which was accompanied by an increase in the size of the average cell of the erythrocyte membrane skeleton. At the same time, no signifcant changes in the morphology, adhesive properties and roughness of the relief of erythrocytes have been found.Conclusion.The obtained data indicate that X-ray radiation (1–100 Gy) induces the dose-depending reorganization of the structure and changes in the stiffness of the erythrocyte surface layer at the nanoscale without changing the cell morphology for rats on a high-cholesterol diet.

Objective. To establish histological changes in lung tissue and the interrelationship of these changes with the properties of nanoscale blood particles in laboratory animals caused by local irradiation of their upper torso with X-rays.Materials and methods. Local irradiation of Wistar rats was carried out using a X-RAD 320 Biological Irradiator (Precision X-Ray, USA) in doses of 0.1, 1, and 15 Gy. After a 3-week post-irradiation period, the activity of catalase and superoxide dismutase, sizes and zeta-potential of nanoparticles were measured in blood; a histological analysis of the lungs was carried out for rats non-irradiated and irradiated by various X-rays doses.Results. A semi-quantitative assessment of the pulmonary fibrosis progression showed an increase in the fibrosis grade depending on the irradiation dose (rs = 0.5531, p˂0.0001). In the blood of irradiated animals, the size and zeta potential of nanoscale particles increased significantly after irradiation of rats with a dose of 0.1 Gy (p < 0.05). The activities of superoxide dismutase and catalase in the irradiated rat’s blood changed non-monotonically depending on the dose.Conclusion. In the experimental animal model, significant changes in the body state were found after irradiation with a low dose (0.1 Gy) at different hierarchical levels. The changes are more pronounced in the blood antioxidant system and the system of nanoparticles of blood, less — at the level of composition and structure of the organ (lung). Further study of radiation and induced changes of blood nanoparticles is advisable not only to deepen the understanding of mechanisms of development of post-radiation pathological conditions but also to evaluate the efficacy of new radioprotective drugs in an experiment with a view to their subsequent introduction into clinical practice.

The mechanical properties of cells, determined mainly by the properties and structure of the cytoskeleton, are heterogeneous at the micro- and nanoscale. The spatial distribution of mechanical parameters such as elastic modulus and adhesion force over the surface of fibroblasts characterizes their mechanical phenotype. By mapping mechanical properties using the Force Volume mode of atomic force microscopy and using statistical analysis methods (modeling parameter distributions with a two-component Gaussian mixture and clustering data), patterns of changes in the spatial distribution of the mechanical properties of the fibroblast surface of primary cultures isolated from the lungs of non-irradiated and irradiated 14-month-old Wistar rats and a 3-week post-radiation period were established. After irradiation, the proportion of surface areas with increased elastic properties and reduced adhesive properties corresponding to the plasmalemma areas above the structures of stress fibers changes. The findings indicate that irradiation at both low (0.1 Gy) and high (1 and 15 Gy) doses induces alterations in the mechanical phenotype of fibroblasts during the early late post-radiation period. These characteristic modifications in fibroblast mechanics may represent early biomarkers of radiation-induced complications, such as radiation fibrosis.

Objective. By the means of atomic force microscopy to determine the changes in the parameters of the structural and mechanical properties of peripheral blood lymphocytes induced by the irradiation of whole blood by X-rays and identifying the possibility of assessing a state and radiation-induced lymphocyte death programs by analyzing a set of such parameters.Materials and methods. Whole blood of rats and humans was irradiated with X-rays (1–100 Gy) in vitro. Lymphocytes were isolated from the blood after a day of storage, placed on glass slides, fixed with glutaraldehyde and dried. The study of structural and mechanical properties was carried out with the help of atomic force microscope Bruker Bioscope Resolve in Peak Force QNM mode in air. For the sets of AFM parameters, which included elastic modulus, adhesion force, cell surface roughness and cell sizes, a k-mean clustering of data was carried out for the studied experimental groups.Results. The X-ray irradiation of the blood caused changes in the structural and mechanical properties of lymphocytes measured by AFM at the nanoscale. Clustering analysis of the sets of AFM parameters revealed clusters with similar structure in each experimental group (humans, 6and 16-month rats). The studied four clusters were associated with cell states and cell death programs: non-activated cells, activated cells with increased stiffness, apoptotic cells with reduced stiffness, and cells dying via programs other than apoptotic ones with increased stiffness. Each cluster (cell type) with a specific set of AFM parameters was represented differently in the blood lymphocyte population, depending on the dose of X-rays.Conclusion. The set of ACM parameters of lymphocytes including elastic modulus, adhesion force, roughness, and cell sizes, can be helpful for automatically determining the state and death program of lymphocytes after the local irradiation of humans with the involvement of peripheral blood (for example, after radio-therapeutic causes).