ИСТИНА

Nowadays films and other products from bacterial cellulose (BC) are actively utilized in the medical industry due to a set of their unique properties, such as high moisture absorption capacity, mechanical strength, high porosity, good biocompatibility - these properties are especially important when used as wound and burn healing dressing materials and artificial skin1. However, BC does not possess antibacterial activity2, so there is a need to create composites based on it with antibacterial agents (such as biopolymer chitosan, or metal nanoparticles). We proposed a “green” method for formation of BC/chitosan films with new functionality in water saturated with CO2 under high pressure (several hundred atmospheres) taking into account that chitosan was proven to be soluble in such solutions before3. Such solvents are self-neutralizing at atmospheric pressure, and therefore much more biocompatible than traditional ones. IR spectroscopy and XPS showed the presence of chitosan on the surface of BC, as well as proved the hypothesized mechanism of composite formation due to hydrogen bonds between chitosan and BC. Scanning electron microscopy allowed to conclude that chitosan coats the BC fibers not only on the surface of the film, but also inside the matrix, increasing the effective diameter of the fibers. Moreover, by the method of labeled atoms, it was shown that the amount of chitosan in the BC film when applied from carbonic acid solutions under high CO2 pressure is 3 times greater than when applied from acetic acid by traditional method. For the first time we proposed to obtain composites from bacterial cellulose, chitosan and metal nanoparticles by the “green” metal-vapor synthesis method (without the use of reducing agents harmful to medical applications). The surface of the obtained composite materials was characterized using a number of methods, including XPS and IR spectroscopy, which is important for subsequent biological studies. Acknowledgments The reported study was funded by RFBR according to the research project № 18-29-06049 mk. References 1. N. Petersen, P. Gatenholm, Applied microbiology and biotechnology 2011, 91(5), 1277. 2. T. Maneerung, S. Tokura, R. Rujiravanit, Carbohydrate polymers 2008, 72(1), 43. 3. M.A. Pigaleva, I.V. Portnov, A.A. Rudov, I.V. Blagodatskikh, T.E. Grigoriev, M.O. Gallyamov, I.I. Potemkin, Macromolecules 2014, 47(16), 5749.