Plasma for artificial skin
SIBFU biotechnologists are improving membranes for the treatment of burns and trophic wounds
Russian and German researchers studied the effect of low-temperature argon-ammonia plasma treatment on films made of biodegradable polymer poly-3–hydroxybutyrate used in tissue engineering, and found out how the resulting chemical changes and the new surface relief affect fibroblasts - connective tissue cells. The results of the work are published in the authoritative journal European Polymer Journal (Surmenev et al., Low-temperature argon and ammonium plasma treatment of poly-3-hydroxybutyrate films: Surface topography and chemistry changes affect fibroblast cells in vitro).
Cell replacement therapy is a highly sought–after and promising area of regenerative medicine. In order to replace the lost or damaged (for example, as a result of a burn) tissues of the human body, special structures carrying cultured cells are currently used. For example, dermal equivalents are used to restore the skin, including human skin cells – fibroblasts and keratinocytes. Such an artificial analogue of real skin consists of two layers – dermal and epidermal. The dermal layer is based on a three–dimensional matrix - most often collagen or fibrin, carrying fibroblasts, and the epidermal layer is formed on the surface of the dermal due to the growth of keratinocytes, which make up 90% of the cells of the upper layer of human skin. Poly-3-hydroxybutyrate and its copolymers obtained by biotechnological means are considered suitable for the construction of cell matrices, among others. These are biocompatible and biodegradable polymers produced with the help of special bacteria.
"For the cells to grow and function properly, they need to get a foothold on some surface. Therefore, they are cultivated on special frames made of biocompatible materials, and then, together with these frames, they are transferred to the victim's body. But when the cells take root in the patient's body and form a new tissue, the substrate should "go away" – preferably slowly dissolve, without poisoning the body and without causing immune rejection. Therefore, we use a safe, biocompatible and biodegradable biosynthetic polymer to create matrices," said one of the authors of the study, associate professor of the Basic Department of Biotechnology. Anatoly Boyandin.
When choosing a cell frame, it is necessary to take into account the properties of its surface: hydrophilicity or hydrophobicity, roughness, charge. The cell culture interacts best with moderately hydrophilic surfaces that love and "attract" water and biological fluids, as well as ensure good cell reproduction and attachment. At the same time, the surface of poly-3-hydroxybutyrate is quite hydrophobic.
"We needed to increase the hydrophilicity of polyhydroxybutyrate membranes. To do this, they were treated with plasma obtained from pure ammonia and pure argon, as well as from a mixture of these gases in different proportions (with 20%, 30%, 40%, 50% and 70% ammonia). In all cases, the surface of the films has changed significantly, acquired roughness and became hydrophilic. During the experiment, we found out that, although ammonia plasma increased the hydrophilicity of the polymer surface more strongly, argon plasma treatment had the greatest positive effect on growth and metabolic processes in fibroblasts of laboratory mice. The fact is that extreme degrees of hydrophilicity can also negatively affect the attachment of cells; it was during argon plasma treatment that the change in the polymer surface was optimal for the tasks set. We believe that the developed technology for improving the polymer surface can be used in the future to create biomedical products, such as scaffolds for tissue engineering, cardiovascular stents, periodontal membranes, and so on," the scientist concluded.
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