Preparation of water-insoluble silk fibroin films, study of their structure and properties

Silk fibroin is one of the promising natural polymers that already being used in medicine to forming of suture materials. The possibility of forming scaffolds in the form of films, sponges or gels for cell cultivation and transplantation will significantly expand the scope of application of this material in tissue engineering. The conditions for obtaining silk fibroin insoluble in water in the form of films were worked out. The structural transition on the surface of the films to a coarsely fragmented state after treatment of the films with methanol was demonstrated using optical microscopy. Using FTIR spectroscopy, the conformational transition of silk fibroin from the disordered structure of the untreated film to the $\beta$-folded structure was confirmed. Using the method of differential scanning calorimetry, the glass transition temperature of the native film was determined as 216$^{\circ}$C. The study of the mechanical properties of silk fibroin films in a liquid medium showed that their strength decreases and their elasticity increases by almost 15 times compared to tests of the same films in a dry state.