Biomedical engineering is a fast developing discipline of science which combines the achievements of engineering and life sciences towards restoration and fabrication of complex physiological systems. Hence, the major challenge for biofabrication is mimicking natural extracellular matrix. Thus, bioink based on porcine, pancreatic ECM with semi-synthetic additives was develop. An extensive survey on obtained material was performed in both in vitro and in vivo tests. Petals of bioink with porcine islets was 3D printed and glucose stimulation tests was carried to verify the islets functionality. Insulin secretion assay showed that the bioink served appropriate conditions for islets which secreted significantly more insulin while compared to 2D islets culture. The cytotoxicity test of fabricated bioink on model L929 cell line was run and according to ISO 10993-5, the bioink appeared to be non-cytotoxic. Hence, in vivo experiments on murine model were performed. Animals with transplanted 3D constructs were examined for following parameters: AST, ALT, KC, IL-6 and TNF-α. Experiment took 12 months, and no disturbances of tested parameters were observed. Finally, mechanical properties of 3D printed constructs and their ultrastructure analysis were investigated. We conclude that newly developed bioink is appropriate for extrusion bioprinting and we proved to be non-cytotoxic. Furthermore, it constitutes a favorable conditions for the process of neovascularization which was noticed after 8 weeks after transplantation to animal model.