State of the art treatment in regenerative medicine includes regeneration of damaged tissue by cell tissue engineering. In order to form a new tissue, cells need an appropriate substrate to which they can be attached and on which they can differentiate and proliferate. Such substrates are called scaffolds. Since the size and shape of the defect is different from patient to patient, the optimal scaffold should also be individual for each patient. 3D printing enables to precisely control the architecture and microstructure of the scaffold as well as scaffold can be designed for each individual. The materials used for 3D printing, called bioinks, have to be biocompatible and biodegradable. Fibroin, a protein derived from silk, is one of such biomaterials. The aim of the diploma was to study the rheological properties of bioinks with different composition of silk fibroin, gellan gum and Ca2+ ions and to determine the most suitable composition for three-dimensional printing. The proportion of gellan gum in bioink must be as low as possible, and the bioink must have viscoelastic properties that enable printing in a temperature range that does not cause protein denaturation. In the diploma thesis, the rheological and mechanical properties of hydrogel scaffolds of various compositions were measured. The results showed that fibroin can be used as a bioink material when combined with gellan gum. The most suitable bioink composition for the three-dimensional printing is 50 % fibroin, 50 % gellan gum and 0.04 ml solution of CaCl2 at a concentration of 300 mM, since it gels at lower temperatures with a narrow interval and forms a solid gel at room temperature.
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