Wound Dressings Made of Biodegradable Natural Polymers Polyhydroxyalkanoates (PHAs): Production and Properties

Рост количества производственных и бытовых травм и ожогов диктует необходимость поиска и разработки материалов и средств для восстановления повреждений кожных покровов. В статье представлены результаты исследования экспериментальных раневых покрытий, сконструированных из разрушаемых природных полиэфиров полигидроксиалканоатов (ПГА) методом электростатического формования. Исследования на лабораторных животных с модельными ожогами кожных покровов показали, что разработанные мембраны из ПГА обеспечивают регенерацию кожи через 7 суток, что сопоставимо с контролем, в котором применяли принятую в клинической практике коллагеновую повязку. Разработанные нетканые мембраны могут быть использованы в качестве эквивалента коллагеновой повязки при лечении ожоговых ран II степениIncreasing number of industrial and household injuries and burns lead to the necessity of research and development of new materials and resources for damaged skin regeneration. In this study results of experimental investigation of wound dressing made of natural degradable polyesters polyhydroxyalkanoates (PHAs) using electrospinning are presented. Studies on laboratory animals with model skin burns showed that the developed PHA membranes provide regeneration of the skin after 7 days and it is comparable with the control collagen dressings used in clinical practice. Developed nonwoven membranes may be used as the equivalent of collagen dressings in the treatment of II degree burn

Wound Dressings Made of Biodegradable Natural Polymers Polyhydroxyalkanoates (PHAs): Production and Properties

Рост количества производственных и бытовых травм и ожогов диктует необходимость поиска и разработки материалов и средств для восстановления повреждений кожных покровов. В статье представлены результаты исследования экспериментальных раневых покрытий, сконструированных из разрушаемых природных полиэфиров полигидроксиалканоатов (ПГА) методом электростатического формования. Исследования на лабораторных животных с модельными ожогами кожных покровов показали, что разработанные мембраны из ПГА обеспечивают регенерацию кожи через 7 суток, что сопоставимо с контролем, в котором применяли принятую в клинической практике коллагеновую повязку. Разработанные нетканые мембраны могут быть использованы в качестве эквивалента коллагеновой повязки при лечении ожоговых ран II степениIncreasing number of industrial and household injuries and burns lead to the necessity of research and development of new materials and resources for damaged skin regeneration. In this study results of experimental investigation of wound dressing made of natural degradable polyesters polyhydroxyalkanoates (PHAs) using electrospinning are presented. Studies on laboratory animals with model skin burns showed that the developed PHA membranes provide regeneration of the skin after 7 days and it is comparable with the control collagen dressings used in clinical practice. Developed nonwoven membranes may be used as the equivalent of collagen dressings in the treatment of II degree burn

Modification of Arabinogalactan Isolated from Larix sibirica Ledeb. into Sulfated Derivatives with the Controlled Molecular Weights

The process of sulfation of arabinogalactan—a natural polysaccharide from Larix sibirica Ledeb.—with sulfamic acid in 1,4-dioxane using different activators has been studied for the first time. The dynamics of the molecular weight of sulfated arabinogalactan upon variation in the temperature and time of sulfation of arabinogalactan with sulfamic acid in 1,4-dioxane has been investigated. It has been found that, as the sulfation time increases from 10 to 90 min, the molecular weights of the reaction products grow due to the introduction of sulfate groups without significant destruction of the initial polymer and sulfation products. Sulfation at 95 °C for 20 min yields the products with a higher molecular weight than in the case of sulfation at 85 °C, which is related to an increase in the sulfation rate; however, during the further process occurring under these conditions, sulfation is accompanied by the destruction and the molecular weight of the sulfated polymer decreases. The numerical optimization of arabinogalactan sulfation process has been performed. It has been shown that the optimal parameters for obtaining a product with a high sulfur content are a sulfamic acid amount of 20 mmol per 1 g of arabinogalactan, a process temperature of 85 °C, and a process time of 2.5 h

Impact of pathogen reduction methods on immunological properties of the COVID-19 convalescent plasma

Background and objectives: COVID-19 convalescent plasma is an experimental treatment against SARS-CoV-2. The aim of this study is to assess the impact of different pathogen reduction methods on the levels and virus neutralizing activity of the specific antibodies against SARS-CoV2 in convalescent plasma. Materials and methods: A total of 140 plasma doses collected by plasmapheresis from COVID-19 convalescent donors were subjected to pathogen reduction by three methods: methylene blue (M)/visible light, riboflavin (R)/UVB and amotosalen (A)/UVA. To conduct a paired comparison, individual plasma doses were divided into 2 samples that were subjected to one of these methods. The titres of SARS-CoV2 neutralizing antibodies (NtAbs) and levels of specific immunoglobulins to RBD, S- and N-proteins of SARS-CoV-2 were measured before and after pathogen reduction. Results: The methods reduced NtAbs titres differently: among units with the initial titre 80 or above, 81% of units remained unchanged and 19% decreased by one step after methylene blue; 60% were unchanged and 40% decreased by one step after amotosalen; after riboflavin 43% were unchanged and 50% (7%, respectively) had a one-step (two-step, respectively) decrease. Paired two-sample comparisons (M vs. A, M vs. R and A vs. R) revealed that the largest statistically significant decrease in quantity and activity of the specific antibodies resulted from the riboflavin treatment. Conclusion: Pathogen reduction with methylene blue or with amotosalen provides the greater likelihood of preserving the immunological properties of the COVID-19 convalescent plasma compared to riboflavin