3D Bioprinting of Micro-Porous Macro Encapsulation System for Pancreatic Islet Transplantation

Abstract

Type 1 Diabetes Mellitus (T1DM) is caused by an immune-mediated destruction of pancreatic islets. Islet transplantation is an alternative treatment for T1DM. After the transplantation, the islets produce insulin, regulating the level of glucose in the blood. However, after the implantation, islets die easily because of immune response. Encapsulation technique is considered as an emerging solution to solve this problem. There are two representative strategies: Macro- and micro-encapsulation. Macro-encapsulation contains large volume of islet in a single system. Thus, in this study, we suggest the 3D bioprinted micro-porous macro-encapsulation system. This system was fabricated using 3D bioprinting technology and widely used biocompatible material PCL. When one layer is printed, 50 µm pores were produced. By shifting the second layer at small distance and stacking, it was possible to fabricate porous membrane which has smaller pores. To avoid the thermal damage to the islets encapsulated in the bioink, we fabricated two parts (upper lid and lower bottom) separately. In addition, protrusions were made inside and outside of each parts to combine two parts. In the future, this system can be used for protecting endocrine cells from the immune system when combined with a microencapsulation system (endocrine cells in dECM bioink).