The influence of selenium (Se) nanoparticles in the form of rods (SeNrs) and spheres (SeSps), synthesized by laser ablation, on the structural and functional properties of human blood erythrocytes and neutrophils was studied for anticancer activity in vitro. SeNrs and SeSps do not have cytotoxicity towards neutrophils and do not cause hemolysis. The elastic modulus and resistance of erythrocytes to HOCl-induced hemolysis increased after binding of Se nanoparticles to the plasma membrane. The interaction of Se nanoparticles with neutrophils is accompanied by their actin-dependent macropinocytosis, triggering intracellular signaling processes leading to the assembly and activation of NADPH oxidase. Comparative analysis of the effects of SeNrs and SeSps on cells showed that they have similar effects. This may be due to the fact that SeNrs interact with the cell surface with their end faces, and, therefore, have the same initial contact with the plasma membrane as SeSps. However, SeSps and SeNrs showed chronic cytotoxicity after 48 h incubation, indicating the need to find ways to reduce their toxicity further. Further use of Se nanoparticles in anisotropic form in biomedical research for the development of therapeutic agents seems promising.

A study was carried out on the spectralluminescent properties of fl uorescein after its reaction with various reactive oxygen and halogen species ( O_2^∙-, H2O2, HOCl, HOBr, HOSCN, N-chloramine, taurine N-chloramine, and taurine N-bromamine) as well as in the myeloperoxidase (MPO)–H2O2–Cl–/Br–/SCN– system. Reaction with only HOBr or with the MPO–H2O2–Br system turns fluorescein into a compound with an absorption maximum at 518 nm. The fluorescence maximum is recorded at 540 nm when excited at 520 nm, corresponding to eosin Y (brominated fluorescein). Conditions with phosphatebuffered saline (PBS) at pH 7.4 containing 137 mM NaCl, 5 mM fluorescein, 15–30 mM NaBr, and 25–50 mM H2O2 were found to be optimal for detecting HOBr in solution. A qualitative method for determining the brominating activity of MPO in vitro has been proposed. This method was used to study the effect of physiological and synthetic inhibitors as well as reactive oxygen and halogen species scavengers on the brominating activity of MPO. Our results indicate that fluorescein holds promise for use in a fluorescent method for detecting the brominating activity of mammalian hemecontaining peroxidases.

In this paper, the effect of Nd:YAG laser radiation on the properties of the BSA protein is investigated. A solution with a protein concentration of 5 mg/ml was irradiated for 30 minutes. After a 5-minute and 30-minute exposure, absorption spectra were taken, the particle size in the solution was determined by dynamic light scattering (DLS), the refractive index was determined, and fluorescent maps were taken. Raman spectroscopy of proteins was also performed. The results showed that after irradiation, the absorption of the protein solution decreases in the spectral range corresponding to amino acid residues. In DLS experiments, it was shown that the peak corresponding to protein molecules decreases, and the peaks corresponding to large aggregates (>100 nm) grow. Raman spectroscopy has shown that there is a decrease in intensity at a wavelength of 1570 cm -1 . There were no significant changes in the refractive indices and the shape of the fluorescent maps. The data suggest that partial denaturation of proteins took place.

The effect of a surgical laser on the physicochemical properties of bovine serum albumin molecules has been investigated. After exposure to laser radiation, the optical density of the protein solution increased, the fluorescence intensity decreased, a significant decrease in the intensity of the α-helix band was observed in the Raman spectrum, and the refractive index of solution did not change significantly. At the same time, the viscosity of the albumin solution increased and pseudoplasticity decreased. Massive damage to the polypeptide chain of the protein was not detected, while intensive aggregation was found. Thus, the processes of partial denaturation and aggregation prevailed in the albumin solution under the action of surgical laser radiation; aromatic amino-acid residues were damaged insignificantly and there was no fragmentation of albumin molecules.

The influence of various mechanical influences (transfusion, stirring, vibration, shaking, etc.) and magnetic installations (used in the application of spin chemistry methods) on colloidal solutions of protein and water, which are often used in pharmaceutical production, was studied. It has been shown that when mechanical influences are applied, physical and chemical properties of water and aqueous colloids of the IgG protein are changed. Magnetic fields do not have a significant effect on water; however, variation in a number of physical and chemical characteristics is observed in protein colloids. Moreover, the effect after exposure to magnetic fields with a frequency of 8 Hz is higher compared to the effect after exposure to magnetic fields with a frequency of 50 Hz. This effect persists even at extremely low concentrations of IgG protein molecules. The measurement system proposed in this work makes it possible to monitor the state of protein molecules in a non-invasive mode. In the future, optical and potentiometric methods built into flow systems can be used at all stages of the production of protein pharmaceuticals.

Hypochlorous acid (HOCl) derived from hydrogen peroxide and chloride anion by myeloperoxidase (MPO) plays a significant role in physiological and pathological processes. Herein we report a phenoxazine-based fluorescent probe Celestine Blue B (CB) that is applicable for HOCl detection in living cells and for assaying the chlorinating activity of MPO. A remarkable selectivity and sensitivity (limit of detection is 32 nM), along with a rapid "turn-on" response of CB to HOCl was demonstrated. Furthermore, the probe was able to detect endogenous HOCl and reactive halogenated species by fluorescence spectroscopy, confocal microscopy, and flow cytometry techniques. Hence, CB is a promising tool for investigating the role of HOCl in health and disease and for screening the drugs capable of regulating MPO activity.

A system of kinetic equations describing the changes in the concentration of reactive oxygen species (ROS) in aqueous solutions of proteins was obtained from the analysis of chemical reactions involving singlet oxygen. Applying the condition of the stationarity of the intermediate products to the system, we determined the functional dependence of the hydrogen peroxide concentration on the protein concentration under the action of thermal and laser radiation. An approximate analytical solution to the nonlinear system of differential equations that define the ROS concentration dynamics was found. For aqueous solutions of bovine serum albumin (BSA) and bovine gamma globulin (BGG), the orders and rate constants of the reactions describing the ROS conversions were determined by minimizing the sum of squared deviations of the functions found by solving both the static and dynamic problems from experimentally measured dependences. When solving the optimization problem, the Levenberg–Marquardt algorithm was used.

Hypochlorous acid (HOCl) plays an important role in the immune system not only protecting the organism from pathogens, but also, due to its high reactivity, provoking the development and complication of many diseases. Therefore, the development of highly sensitive and selective HOCl biosensors, including fluorescent probes, to better understand the roles of HOCl in living systems, is of great importance. Nevertheless, there are many difficulties associated with HOCl registration in biological probes (chemo- and photostability, cytotoxicity, fluorescence and absorption characteristics, selectivity, sensitivity, etc.). Thus, the development of new chemosensors has been relevant for many years. In this review, we describe classification of small-molecule probes for HOCl detection in biological systems, as well as summarize the results of the development of chemosensors, their photophysical properties, and biological applications. Particular attention is paid to the achievements in this area over the years 2016–2021. A number of problems related to the design and application of small-molecule probes are formulated. Due to the absence of a "gold standard" among the HOCl chemosensors, which is associated with the commercial unavailability or complex methods of synthesis of new sensors as well, some recommendations are given regarding the field of the chemosensor application. Trends in the development of fluorescent chemosensors for HOCl visualization in living cells are outlined.

Влияние антимикробных пептидов медицинской пиявки Hirudo medicinalis на клетки крови человека / И. В. Горуко, Д. В. Григорьева, А. Д. Живолковская, В. Е Реут., А. В. Соколов, Е. Н. Графская, О. М. Панасенко, В. Н. Лазарев // Физико-химическая биология как основа современной медицины : тез. докл. Междунар. науч. конф., посвящ. 75-летию со дня рождения проф. Е. В. Барковского, Минск, 21 мая 2021 г. / под ред. В. В. Хрусталёва, А. Д. Тагановича, Т. А. Хрусталёвой. – Минск, 2021. – С. 76-77.

The interaction of the oxazine dye gallocyanine with reactive oxygen ( $$^{\centerdot }{\text{O}}_{2}^{ - },$$ Н2О2) and halogen (HOCl) species has been studied by spectrophotometry, mass spectrometry, and spectrofluorimetry. It has been shown that gallocyanine reacts with HOCl and $$^{\centerdot }{\text{O}}_{2}^{ - }$$ (but not with Н2О2) to form fluorescent products. It has been found using the inhibition assay that, both in the xanthine/xanthine oxidase system and in activated human blood neutrophils, the main contribution to the conversion of gallocyanine to a fluorophore comes from its reaction with $$^{\centerdot }{\text{O}}_{2}^{ - }{\text{.}}$$ The results obtained suggest that gallocyanine can act as a fluorogenic chemosensor and be used for estimating the activation of neutrophils and the NADPH-dependent production of superoxide anion radical by neutrophils and other blood cells, as well as for testing antioxidant drugs designed with the aim to correct diseases associated with oxidative stress.

Методами спектрофотометрии, масс-спектрометрии и спектрофлуориметрии исследовано взаимодействие красителя оксазинового ряда галлоцианина с активными формами кислорода и галогенов (HOCl).Показано, что галлоцианин реагирует с HOCl и (но не с Н 2 О 2 ) с образованием флуоресцирующих продуктов.С использованием ингибиторного анализа установлено, что как в системе ксантин/ксантиноксидаза, так и в присутствии активированных нейтрофилов крови человека основной вклад в превращение галлоцианина во флуорофор вносит его реакция с Полученные результаты позволяют заключить, что галлоцианин может выполнять роль флуорогенного хемосенсора и использоваться для оценки активации нейтрофилов, NADPH-зависимой продукции супероксидного анион-радикала нейтрофилами и другими клетками крови, а также для тестирования антиоксидантных препаратов,

We investigated the effect of drugs (dapsone, paracetamol, and isoniazid) on the production of reactive oxygen and halogen species by neutrophils. The standard fluorescent method using scopoletin as well as recently developed fluorescent methods using oxazine dyes, celestine blue B, and gallocyanine were employed for this purpose. Celestine blue B reacts selectively with hypochlorous acid, while gallocyanine reacts mainly with the superoxide radical-anion, which reveals the regulatory effect of anti-inflammatory drugs on neutrophil NADPH-oxidase and myeloperoxidase responsible for the production of reactive oxygen and halogen species, respectively. These results indicate that gallocyanine and celestine blue B hold promise as chemosensors for studying the effect of drugs used in anti-inflammatory therapy for the neutrophil respiratory burst.

We investigated the influence of drugs (dapsone, paracetamol and isoniazid) on the reactive oxygen and halogen species production by neutrophils. The standard fluorescent method based on scopoletin, as well as the recently developed fluorescent methods based on oxazine dyes, celestine blue B and gallocyanine, were used for this purpose. Celestine blue B selectively reacts with hypochlorous acid, and gallocyanine reacts mainly with the superoxide radical anion, which permits to reveal the regulatory effect of anti-inflammatory drugs on the neutrophil NADPH-oxidase and myeloperoxidase activity, responsible for the reactive oxygen and halogen species production, respectively. The obtained results indicate that gallocyanine and celestine blue B dyes are promising chemosensors to study the effect of drugs used in anti-inflammatory therapy on the neutrophils respiratory burst. Keywords: paracetamol, dapsone, isoniazid, neutrophil activation, oxidative stress, reactive oxygen species, reactive halogen species.