ИСТИНА

Nowadays, the general vector of polymer science development is pointed at respecting the environment, at refusing to use potentially allergenic substances in the biomedical field, at meeting the requirements of extra purity in catalysis applications, and at imparting new functional properties to composites. In this regard, studies in biocompatible solvents that do not require subsequent neutralization, such as water saturated with CO2 under high pressure (solution of carbonic acid), as well as in pure supercritical (SC) CO2, that can impart new properties with advantages to substances modified in such media, look promising. The developments of our team in this area include the dissolution of cationic polymers (including chitosan) in carbonic acid under high CO2 pressure without the use of traditional acids and the creation of sponges (with/or without cross-linking agents such as genipin, or metal nanoparticles), composites with other polymers (for example, with bacterial cellulose), as well as complexes with metal nanoparticles (Ag, Au, Pt and Cu) based on these solutions. These composites can be in the form of hydrogels, dry sponges, films and capsules. Further development of these new materials can be achieved through supercritical impregnation of drugs into them. Moreover, we have shown that after treatment in SC CO2, or in a solution of carbonic acid under high pressure CO2, the size of drug crystallites can be significantly reduced, which can improve their bioavailability. Thus, following the paradigm of using media containing CO2 under high pressure as the main "green" solvents we have created many different materials with improved mechanical properties, increased surface functionality, antimicrobial properties, reusable catalyst properties, as well as materials suitable for transdermal delivery of hormones (for example, -estradiol). Acknowledgments This work was supported by the Russian Science Foundation (grant no. 20-73-10180).