Keywords: methylene blue

Effect of amphiphilic polymers on the photodynamic activity of methylene blue and rose bengal in vitro experiments

https://doi.org/10.58224/2619-0575-2025-8-4-5
Abstract
Objectives: To study the effect of amphiphilic polymers on the dark and photoinduced toxicity of dyes with photosensitizing properties – methylene blue (MB) and rose bengal (RB) – in in vitro experiments.
Methods. In vitro experiments were carried out on human lung carcinoma A549 cells and on cultures of gram-negative (Pseudomonas aeruginosa) and gram-positive (Staphylococcus aureus) bacterial cells using a phototherapeutic LED with a wavelength of λ = 530 nm (for the RB) or λ = 660 nm (for the MB).
Results. Amphiphilic polymers (Pluronic F-108 and poly-N-vinylpyrrolidone) were shown to enhance the dark and photoinduced toxicity of dyes. MB was also shown to exhibit greater activity (compared to RB) in photodynamic inactivation of Gram-negative bacteria, while RB (compared to MB) was shown to exhibit greater activity in the inactivation of Gram-positive bacteria.
Conclusions. MB in combination with amphiphilic polymers is a potential drug of choice for both photodynamic therapy (PDT) of cancer and antibacterial PDT of Gram-negative bacteria. At the same time, RB-based systems hold promise for the development of antibacterial PDT of Gram-positive bacteria.
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Sorption characteristics of bacterial cellulose obtained from the symbiotic culture of Medusomyces gisevii

https://doi.org/10.58224/2619-0575-2025-8-4-9
Abstract
The structural and sorption characteristics of bacterial cellulose (BC) synthesized by the symbiotic culture of Kombucha Medusomyces gisevii in nutrient media with different carbon sources (3% sucrose, 6% sucrose, 6% molasses) were studied. It was found that the maximum specific yield of BC biomass was observed when using 6% molasses (11.807 g/g), while the highest content of pure cellulose was recorded in a medium with 6% sucrose (3.81%). Scanning electron microscopy and gas adsorption analysis showed that lyophilized BC samples have a developed macroporous structure. The sorption capacity of the materials with respect to the cationic dye methylene blue was studied. It was found that lyophilized BC possesses a significantly higher sorption capacity (22.809 mg/g) compared to the native film dried by convection (11.689 mg/g). The potential of using bacterial cellulose as a basis for sorption materials and functional carriers is demonstrated.
Objectives: study of the influence of cultivation conditions and drying methods on the structural, morphological and adsorption characteristics of bacterial cellulose.
Methods. Nutrient media with varying carbon sources were used for cultivation. Sample structure was examined using a Nova NanoSem 450 scanning electron microscope (FEI Company, USA) and a TriStar II 3020 gas adsorption analyzer (Micromeritics, USA). Sorption capacity was determined using a Nabi spectrophotometer (MicroDigital Co., Republic of Korea) based on the absorption of methylene blue from an aqueous solution.
Results. Optimal cultivation conditions for maximum biomass yield and cellulose content were determined. It was found that freeze-drying produces a material with a high specific surface area and a developed porous structure, resulting in increased sorption activity.
Conclusions. Bacterial cellulose, especially its lyophilized form, demonstrates high potential as an effective and biocompatible sorbent, as well as a promising carrier of active substances and medicinal preparations.
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ADSORPTION OF 4-NITROPHENOL AND DYES ON SILVER-DOPED TiO2, TiO2-ZrO2, ZrO2 XEROGELS UNDER UV IRRADIATION

Abstract
Nanoscale and composite materials containing titanium and zirconium oxides are of the greatest theoretical and practical interest. Their advantages are low cost, availability of production, the choice of source components and matrices of different nature. This work is an immersion in the subject of research at the Peoples' Friendship University of Russia. The research topic is extremely relevant, because silver appears only once in the list of previously used modifiers, and it is possible to study this issue. The production of TiO2 and ZrO2 nanopowders with dopants using gel technology is a simple and well-studied method for the synthesis of photocatalysts, but the effect of powder irradiation on adsorption has not been studied much, especially for irradiation of dry material with its subsequent introduction into an adsorption solution. It is of interest to study the effect on the adsorption of para-nitrophenol (the state of the molecule - anion or molecule), depending on the pH of the environment, on synthesized xerogels of titanium dioxide and zirconium. It is also necessary to conduct a study to understand the effect of silver on the adsorption of various types of dyes. Model dyes of the cationic type (methylene blue) and anionic type (methylorange) can be used to determine the charged surface centers of materials based on TiO2 and ZrO2 that do not contain or contain a dopant component.
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