In recent years, 3D bioprinting has proven to be a promising method for tissue reconstruction for in vitro drug studies and regenerative medicine. The reconstruction of such artificial tissue requires suitable materials that meet the requirements of both the printing technology and the tissue to be reconstructed. Chemically functionalized biopolymers are well suited for these applications as covalently crosslinked hydrogels. The focus of my project is the functionalization of gelatin with photoreactive groups and the synthesis of suitable crosslinkers. By covalent cross-linking with visible light biocompatible hydrogels are obtained. These materials are chemically, physically and biologically characterized and used in various 3D printing technologies such as extrusion printing, direct laser writing and inkjet printing.