Bacterial cellulose (BC) is currently one of the most popular environmentally friendly materials with unique structural and physicochemical properties for obtaining various functional materials for a wide range of applications. In this regard, the literature reporting on bacterial nanocellulose has increased exponentially in the past decade. Currently, extensive investigations aim at promoting the manufacturing of BC-based nanocomposites with other components such as nanoparticles, polymers, and biomolecules, and that will enable to develop of a wide range of materials with advanced and novel functionalities. However, the commercial production of such materials is limited by the high cost and low yield of BC, and the lack of highly efficient industrial production technologies as well. Therefore, the present review aimed at studying the current literature data in the field of highly efficient BC production for the purpose of its further usage to obtain polymer nanocomposites. The review highlights the progress in synthesizing BC-based nanocomposites and their applications in biomedical fields, such as wound healing, drug delivery, tissue engineering. Bacterial nanocellulose-based biosensors and adsorbents were introduced herein.
Using a wide range of different physical and chemical methods, it was found that the oxidative stress caused by addition of hydrogen peroxide to the incubation medium has a significant effect on the conformation of haematoporphyrin, influencing the oxygen-binding properties of haemoglobin in red blood cells. Morphofunctional characteristics of red blood cells change; in particular, we have observed the transformation of erythrocytes, their transition into echinocytes. In erythrocytes, in response to increased lipid peroxidation (LPO) antioxidant enzymes become active. The use of natural antioxidants (-carotene and resveratrol) works towards reducting the level of oxidative processes. Resveratrol has the greatest antioxidant effect.
It has been shown that the intensification of oxidative processes is observed when somatic nerves of rats are damaged. Accumulation of malondialdehyde occurs, and the phase properties of the lipid bilayer change, especially in the distal part of the nerve. Under the same conditions, there are multidirectional changes in the activity of antioxidant enzymes, superoxide dismutase (SOD) activity decreases, and catalase (CAT) activity increases. Under the action of resveratrol, there is a decrease in the number of TBA-active products in both areas of the damaged nerve. Alongside resveratrol action, SOD and CAT activity tends to return towards the control values. Similar patterns are observed in the action of resveratrol on the phase states of lipids with the damage to somatic nerves. By summarizing the data obtained, it can be claimed that when the nerve is damaged, profound changes occur both in the lipid component and in the antioxidant system. Resveratrol has a stabilizing effect on the studied parameters, and a longer period of time is required for their complete recovery.
It has been shown that in the somatic nerve’s lipids, both during excitation and transection, changes occur with the composition of individual phospholipids and in phospholipids fatty acids, which changes the phase state of the myelin and nerve fiber axolemma lipid bilayer. A main contribution in the nerve degenerative processes is dependent on the composition phospholipid’s fatty acid changes during the activation of both Ca2+-dependent and Ca2+-independent phospholipase A2 forms. At the same time, we studded changes in phosphoinisitol (PI) and diacylglycerol (DAG), which depend on the phosphoinositide cycle function during nerve excitation and degeneration processes. It was found that myelin lipids and nerve fiber axolemmas are involved not only in the functioning of the peripheral nerves, but also the pathological processes underlying deep functional and structural disorders. The effect of resveratrol on regeneration processes in the damaged rat sciatic nerve has also been investigated.
The levels of neurotrophic factors and the protein composition of somatic nerve membranes were studied during injury and survival of nerves in rats exposed to the action of clobetasol. It was shown that the drug administered intramuscularly induced a more pronounced increase in the level of neurotrophic growth factors and structural proteins responsible for recovery processes than the drug released from a hydrogel derived from microbial polysaccharides; it also stabilized the content of the total protein fraction in the damaged somatic nerves. Proteins of the injured neural conductor degraded less in animals receiving intramuscular injections of clobetasol, probably because the drug administered by injection had better availability than the drug administered from hydrogel composite (slow drug release). In addition, an increase in the amounts of DNA and some protein fractions indicated that clobetasol contributed the activation of genes associated with remyelination. We suppose that clobetasol can stimulate synthesis of neurotrophic growth factors, thereby triggering the phosphatidylinositol-3-kinase and mitogen-activated protein kinase signaling pathways that regulate the processes of cytoskeletal reorganization and axonal growth, as well as enhance the synthesis of structural and axonal proteins necessary to restore the functional activity of the injured nerve fibers.
In the course of the studies, it was shown that the use of clobetasol is accompanied by an increase in the content of nerve growth factor and total protein, as well as the restoration of the conductivity of nerve fibers, which indicates its participation in the launch of regenerative signaling pathways responsible for the activation of protein synthesis and the restoration of the functional activity of injured somatic nerves.