Olga A. Gruznova

In the present research, a new type of biomimetic material loaded with chlorophyll derivatives (CpDs) for photodynamic therapy based on poly(3-hydroxybutyrate) (PHB) was fabricated by the electrospinning method. Such matrices showed great potential for the advanced delivery of photodynamic therapeutic reagents to targeted regions and options for prolonged local application. The key morphological characteristics of fibrous materials were investigated. It was found that incorporation of CpDs leads to a change in the average fiber diameter from 3.5 µm to 2.1 µm, increasing porosity from 80% to 90% and accompanied by an over 3-fold increased proportion of open pores. Moreover, the CpD application facilitated fine hydrophilicity tuning, allowing an increase of this parameter up to 10% under different conditions, neutralizing the hydrophobic nature of the matrix polymer and photosensitizer. Moreover, changes in physical properties, supramolecular structure, photosensitizing effect, and singlet oxygen generation were investigated. The data obtained show that the proposed materials are great examples of convenient and reliable carriers for advanced PDT. The results obtained demonstrate high antimicrobial activity in the presence of irradiation as well as noticeable efficacy against carcinoma, both light and dark.

The aim of the study is to comparatively analyze the reparative properties of chlorophyll (Chl), the active ingredient in nettle extract, and hemin in free and polymeric forms, using an experimental incised wound model. The experiment was designed to study wound regeneration by secondary intention. The study was conducted on white, nonlinear mice matched for similar weight, age, and gender and quarantined for 7 days. Wound area was analyzed, and the regeneration process was monitored. Therapy began on the first postoperative day. 200 μl of the preparations were applied daily. The animals' general condition, motor activity, and wound surface condition were assessed by phases of progression (inflammation, regeneration, and epithelialization) using the planimetric method proposed by J.I. Kundin. Polymeric forms of Chl and hemin induced high-quality tissue reparation, shortening the regeneration time. A high degree of reparation was observed in the 1st and 3rd experimental groups, with normotrophic healing. A moderate degree of healing was observed in the 2nd and 4th groups. On the 7th day, the 1st group showed the most intense reduction in wound surface area of all experimental groups – 47 %. In the 2nd experimental group, wound area decreased by 43.6 %, with wounds without eschar formation and low granulation. In the third experimental group of mice, an increase in wound surface area by 14 % (within the error limit) was observed. In the fourth experimental group, a significant decrease in wound surface area was 6.6 %. By day 21, the wound surface of mice in both experimental groups had completely epithelialized. Polymeric forms of Chl and hemin demonstrated high regenerative activity in this experiment. The obtained data suggest their potential use in the treatment of farm animals.

This work is devoted to the electrospinning of biocompatible fibrous matrixes for microbial wound therapy. The problem of treating staphylococcal-infected wounds remains urgent. In this study, we propose a new approach to the use of the chlorophyll (Chl) and poly-3-hydroxybutyrate (PHB) composite system in the treatment of infected wounds. The structure and properties of the electrospun polymer matrix based on PHB modified with various concentrations of Chl was investigated by SEM, confocal microscopy, DSC, EPR. The release rate, fluorescence, and antimicrobial activity of Chl incorporated into PHB were studied. The high efficiency of the developed materials was shown with the participation of laboratory animals.

The work presents the results of a study on a new disinfectant known as “Aseptobrom” for use in veterinary medicine. It contains didecyldimethylammonium bromide and alcohols as active substances. The laboratory trials showed that the disinfectant had significant antimicrobial activity against Escherichia coli (strain 1257), Staphylococcus aureus (strain 209-P) and Mycobacterium (strain terrae). As a result, it was found that S. aureus was more sensitive than E. coli. When rough, moisture-absorbing surfaces were contaminated with E. coli, disinfection was achieved with a 1% solution (3-hour exposure, disinfectant consumption rate – 0.5 L/m²). In case of contamination with staphylococcus, a 0.4% solution was used. Other specified parameters were not changed. To destroy Mycobacterium, a concentration of 6.0% was required with an exposure of 24 h. Moreover, the disinfectant was applied twice with an interval of 60 min. The consumption rate of the preparation for each irrigation was 0.5 L/m². A study of the corrosion properties of the preparation showed that, in comparison with sodium hydroxide, it has a slight corrosive effect on metal surfaces, in particular on stainless steel and iron test plates.

This work is devoted to the creation of biocompatible fibrous materials with a high antimicrobial effect based on poly-3-hydroxybutyrate (PHB) and chlorophyll (Chl). The data obtained show the possibility of obtaining fibrous materials from PHB and Chl by electrospinning methods. The obtained electrospun matrices were investigated by the SEM, DSC and FTIR methods. Various key properties of the matrices were evaluated, including hydrophilicity and mechanical strength, as well as photodynamic and light-dependent antimicrobial effects against the conditionally pathogenic microorganism Staphylococcus aureus. The results demonstrate a significant improvement in electrospinning properties for a concentration of 0.5% Chl and a reduction in fiber formation defects, as well as an increase in the strength of nonwovens. It was found that the antimicrobial potential of Chl-PHB (with concentrations of Chl of 1.25 and 1.5%) is higher than that of Chl in free form. It was also determined that irradiation increases the inhibitory effect of Chl, both in free form and in the form of a complex with a polymer.

The incorporating method of Fe^IIICl-tetraphenylporphyrin (FeClTPP) into the poly-N-vinylpyrrolidone (PVP) polymeric matrix is presented. A number of FeClTPP-PVP films with FeClTPP content varying by an order of magnitude were obtained and deposited on the inner surfaces of glass vessels. These vessels were used to simulate the surfaces of objects of veterinary and sanitary control that require periodic antibacterial treatment (disinfection). The antibacterial activity of indicated concentrations of FeClTPP-PVP against antibiotic-resistant gram-negative and gram-positive microorganisms - Escherichia coli (E. coli, strain 1257) and Staphylococcus aureus (S. aureus, strain 209 P) was demonstrated. As these microorganisms are also representatives of the most frequently encountered contaminants, we have studied the prepared bacterial suspensions from daily cultures of E. coli and S. aureus in dilutions from 10⁸ to 10⁴ CFU/mL. After that, the artificial contamination of the inner surfaces of the test objects was carried out. Antibacterial activity was determined by the degree of inhibition and was recorded visually and spectrophotometrically. The inhibitory effect on the growth of E. coli and S. aureus was directly proportional to the concentration of FeClTPP-PVP and inversely proportional to the degree of microorganism’s dilution. The greatest effect (about 87% reduction in bacterial growth) was achieved by the influence of FeClTPP-PVP maximum concentration.

В работе описан метод получения порфирин-полимерной системы – гемин-поли(3-гидроксибутират) (гемин-ПГБ) и ее ингибирующее действие на рост грамотрицательных и грамположительных микроорганизмов – Escherichia coli и Staphylococcus aureus, которые являются частой причиной раневых инфекций. Оценка антимикробной активности проводилась путем измерения зоны задержки роста бактерий после их суточного инкубирования. Было показано, что эффективность гемин-ПГБ находилась в прямой зависимости от процентного содержания в полимере гемина. Так, существенное ингибирующее действие на E. coli и S. aureus оказывал ПГБ с 5% гемина (мас.%). Полученная порфирин-полимерная система может быть рекомендована для использования в качестве антисептического материала при обработке ран.