Degree Name

Master of Philosophy


Intelligent Polymer Research Institute


Type I diabetes is an autoimmune disease affecting millions of people in the world. It occurs when the pancreas cannot produce insulin, resulting in episodes of hyperglycaemia that can lead to heart attacks, renal failure, or death. The main cause is the auto destruction of beta cells that produce insulin, located in the pancreatic islets (or islets of Langerhans). Current treatments include insulin injections that decrease the blood glucose level. However, it can sometimes generate hypoglycaemia or insulin resistance on the patients. Bioprinting allows controlled engineering of pancreatic islets with hydrogel scaffolds and transplanting them into the patients. Nevertheless, immunotolerance of the grafted constructs has yet to be achieved. Currently, the islets are implanted together with immunosuppressors to avoid the rejection, but these affect the functionality of the beta cells. Co-transplanting regulatory T cells (Tregs) that regulate the autoimmune response could be the solution to immune rejection. Thus, co-axial extrusion printing is a promising approach, as it allows printing two types of bioinks. Pancreatic islets can be printed in the core of the structure and Tregs in the shell, protecting the islets. This project was mainly focused on the development of the bioink for the shell. The ink consists of a hydrogel that promotes cell growth and allows bioprinting (2% alginate/7.5% gelatin methacrylolyl (GelMA)/3.5% gelatin), and growth factors for Treg functionality (IL-2). The growth factors were encapsulated in GelMA microspheres for a sustained release inside the ink. The release rate of IL-2 was studied, as well as the ink properties and printability.

FoR codes (2008)

090301 Biomaterials, 090408 Rheology, 030306 Synthesis of Materials, 030301 Chemical Characterisation of Materials



Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.