2019, Tiganova, I. G., Makarova, E. A., Philipova, N. I., Romanishkin, I. D., Akhlyustina, E. V., Meerovich, G. A., Loschenov, V. B., Ахлюстина, Екатерина Витальевна, Меерович, Геннадий Александрович, Лощенов, Виктор Борисович

© 2019 Published under licence by IOP Publishing Ltd. Polycationic derivatives of synthetic bacteriochlorin with absorption in the near infrared range are promising for the creation of photosensitizers (PS) for antimicrobial photodynamic therapy. In the present work, the photophysical and antibacterial properties of PS based on tetracationic derivatives of synthetic bacteriochlorins: hydrophilic 3-Py 4 BC(EtBr) 4 Br4 in aqueous solution and amphiphilic 3-Py 4 BCHP 4 Br 4 in the dispersion of Kolliphor ELP were studied. Analysis of absorption and fluorescence in a wide range of concentrations has demonstrated low aggregation of the PS over the entire range. A high efficiency of photodynamic inactivation of Gram-positive Staphylococcus aureus and Gramnegative Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii bacteria was observed.

2020, Savelieva, T. A., Kuryanova, M. N., Akhlyustina, E. V., Linkov, K. G., Meerovich, G. A., Loschenov, V. B., Савельева, Татьяна Александровна, Ахлюстина, Екатерина Витальевна, Меерович, Геннадий Александрович, Лощенов, Виктор Борисович

During intraoperative fluorescence navigation to remove various neoplasms and during pharmacokinetic studies of photosensitizers in laboratory animals, in many cases, the ratio of photosensitizer accumulation in the tumor and normal tissue can reach > 10-fold, which inevitably changes their optical properties. At the same time, the tumor formation process causes various metabolic and structural changes at cellular and tissue levels, which lead to changes in optical properties. A hardware-software complex for the spectral-fluorescence studies of the content of fluorochromes in biological tissues with significantly different optical properties was developed, and it was tested on optical phantoms with various concentrations of photosensitizers, absorbers, and scatterers. To correct the influence of optical properties on the photosensitizer concentration analysis by fluorescence spectroscopy, we propose the spectrum-processing algorithm, which combines empirical and theory-based approaches.

2023, Pominova, D. V., Ryabova, A. V., Markova, I. V., Akhlyustina, E. V., Skobeltsin, A. S., Поминова, Дарья Вячеславовна, Рябова, Анастасия Владимировна, Ахлюстина, Екатерина Витальевна, Скобельцин, Алексей Сергеевич

A spectroscopic study of the photophysical properties of methylene blue (MB) in aqueous solutions was carried out. Absorption and fluorescence spectra as well as fluorescence lifetime were recorded. The concentration dependence of the intensity and shape of the spectra allowed establishing the ranges of MB concentrations for in vitro and in vivo studies at which aggregation is not observed (up to 0.01 mM, which corresponds to 3.2 mg/kg). Studies of photodegradation in biological media showed that photobleaching of more than 80% in plasma and culture media is observed already at a dose of 5 J/cm2 , while in water at this concentration and dose photobleaching is not yet observed, and at a dose of 50 J/cm2 photobleaching of MB is about 30%. It was found that in media containing proteins and having an alkaline pH, photobleaching occurs significantly faster than in neutral aqueous media. The ionic strength of the solution has no effect on the photobleaching rate. Such photobleaching is caused by the photodegradation of MB rather than the transition to the leucoform.The efficiency of singlet oxygen generation and photodynamic activity were evaluated in vitro. In the investigated range of MB concentrations, the efficiency of singlet oxygen generation is rather low, because positively charged MB binds to negatively charged cell membranes, which leads to a change in the type of photodynamic reaction. The emergence of other reactive oxygen species (ROS), different from singlet oxygen, in cells has been demonstrated. The generation of ROS and the low quantum yield of singlet oxygen generation indicate the tendency of MB to provide the type I photosensitization mechanism (electron transfer with the formation of semi-reduced and semi-oxidized MB+ radicals) rather than to the type II mechanism (energy transfer to oxygen with the formation of singlet oxygen) in biological media and in vivo.

2024, Kogan, E., Meerovich, G., Karshieva, S., Akhlyustina, E., Loschenov, V., Меерович, Геннадий Александрович, Ахлюстина, Екатерина Витальевна, Лощенов, Виктор Борисович

PDT using PSs based on polycationic derivatives of synthetic bacteriochlorin against Lewis lung carcinoma provides effective inhibition of tumor growth with an increase in the lifespan and survival of mice in the group. PDT with polycationic photosensitizers destroys CSCs and tumor neovascularization, and activates the desmoplastic reaction. These results open up new opportunities for increasing the effectiveness of treatment and reducing the incidence of relapses and metastases after PDT.

2019, Linkov, K. G., Meerovich, G. A., Akhlyustina, E. V., Savelieva, T. A., Loschenov, V. B., Меерович, Геннадий Александрович, Ахлюстина, Екатерина Витальевна, Савельева, Татьяна Александровна, Лощенов, Виктор Борисович

© 2019 Russian Photodynamic Association. All Rights Reserved. Currently, the most promising method for the study of pharmacokinetics of drugs with fluorescent properties is the spectral-fluorescent method. In this article, we propose an algorithm for expanding the dynamic range of the spectrum analyzer by automatically monitoring the maximum spectral density in the recorded fluorescence spectrum and automatically controlled changes in the accumulation time depending on this value, followed by compensation of the output signal with regard to this change, as well as hardware circuit solutions that allow this algorithm. Testing of LESA-01-"Biospeс" spectrum analyzer, upgraded using the proposed approach, was carried out on photosensitizer dispersions based on tetra-3-phenylthiophthalocyanine hydroxyaluminium of various concentrations (from 0.01 mg/l to 50 mg/l), approximately corresponding to the concentrations realized in the process of studying pharmacokinetics in calibration samples and tissues of experimental animals. The proposed solutions that implement the algorithm for recording fluorescence spectra with automatic change of accumulation time depending on the signal level, ensured a significant expansion of the dynamic range of the spectrum analyzer (up to 3.5 orders of magnitude) and improved accuracy in pharmacokinetic studies.

2020, Tiganova, I. G., Makarova, E. A., Tolordava, E. R., Zhizhimova, Yu. S., Meerovich, G. A., Akhlyustina, E. V., Loschenov, V. B., Меерович, Геннадий Александрович, Ахлюстина, Екатерина Витальевна, Лощенов, Виктор Борисович

© Published under licence by IOP Publishing Ltd.Antibacterial photodynamic therapy is a promising method of treating local infected foci, especially surgical and burn wounds, trophic and diabetic ulcers. This work explores the photophysical and antibacterial properties of novel phthalocyanine- and synthetic-bacteriochlorin-based octacationic photosensitizers (PS). The results of the study confirm their low degree of aggregation at high concentrations, as well as high efficiency of photodynamic treatment of Gram-negative bacterial biofilms.

2023, Kononenko, V. V., Arutyunyan, N. R., Ashikkalieva, K. K., Zavedeev, E. V., Akhlyustina, E. V., Ахлюстина, Екатерина Витальевна

Laser synthesis of polyyne molecules C2nH2 (n andgt; 2) in liquid hydrocarbons is a complex process in which intense pulsed radiation decomposes the initial carbon-containing substance (the hydrocarbon solvent itself or the solid carbon particles in a suspension). Notwithstanding the fact that the mechanism of pulsed laser ablation in liquids (PLAL) is widely accepted, the effect of the laser parameters on laser-driven polyyne formation is still not understood in detail. Here, we report a study of the polyyne yield as a function of the laser field intensity and exposure dose. Several carbon-containing liquids, including pure n-hexane, pure ethanol, and graphite powder suspended in ethanol, were treated with tightly focused picosecond IR radiation (wavelength of 1064 nm, pulse duration of 10 ps). The synthesis rate was characterized by UV-vis optical absorption spectroscopy. The yields of the polyynes were found to vary in exact accordance with the value of the absorbed laser energy, following specific nonlinear or linear laws. The influence of the laser intensity on the partial concentration of polyynes in the solution was analyzed.