Introduction: Tissue engineering is currently on advanced stage of development which gives a possibilities for novel strategy of personal treatment of type 1 diabetes.

Aim: In the following study, a bioink based on ECM derived from decellularization of porcine pancreas was applied for 3D bioprinting.

Materials and Methods: The SCID (n=60) and BALB (n=20) mice were used as a model for in vivo study. Porcine islets mixed with bioink were printed on extrusion printer and transplanted on studied animals. Effectiveness of transplanted petals with regard of their insulin secretion was evaluated based on glucose and c-peptide concentration in blood samples of studied animals. Thus, animals were divided into three groups: mice with transplanted islet-laden petals, mice with transplanted islets into kidney capsule and untreated mice. Examination of studied parameters took place at four time points during the experiment, at the beginning and on day 7th , 14th and 28th day of experiment.

Results: Group with transplanted petals from day 7th expressed lower mean fasting glucose concentration while compared with untreated group (129 mg/dl, 119 mg/dl, 118 mg/dl vs. 140 mg/dl, 139 mg/dl, 140 mg/dl respectively in 7th, 14th and 28th day post-transplantation; p<0.001). Post-surgery transverse section of petals revealed that connective tissue of studied animals surrounded and stabilized transplanted petals. Fibroblasts infiltration over time resulted in the process of new blood vessels formation within the petals. Hence, presented in the study bioink provides a favorable conditions for islets functionality. The bioprinted construct was stable over time. Furthermore, no pathological conditions of studied animals were observed which indicates that bioprinted petals were biocompatible.

Conclusion: Bionic flake transplantation lowered glucose levels significantly.