Bioprinting of human primary and iPSC-derived islets with retained and comparable functionality

Currently, type 1 diabetes (T1D) can be treated through implantation of allogenic islets, which replenish the beta cell population, however this method requires an extensive post-implantation immunosuppressant regimen. Personalized cellular therapy can address this through implantation of an autologous cell population, induced pluripotent stem cells (iPSCs). Cellular therapy, however, requires an encapsulation device for implantation, and so to achieve this uniformly with cells in a clinical setting, bioprinting is a useful option. Bioprinting is dependent on having a bioink that is printable, retains structural fidelity after printing, and is supportive of cell type and function. While bioprinting of pancreatic islets has been demonstrated previously, success in maintaining islet function post-printing has been varied. The objective of this study is to investigate the feasibility of printing functional islets by determining the appropriate combination of bioink, printing parameters, and cell configuration. Here, we detail the successful bioprinting of both primary human islets and iPSC-derived islets embedded in an alginate/methylcellulose bioink, with functionality sustained within the construct for both cell lineages. Sc-RNAseq analysis also revealed that printing did not adversely affect the genetic expression and metabolic functionality of the iPSC-derived islets. Importantly, the iPSC-derived islets displayed comparable functionality to the primary islets, indicating the potential to act as a cell source alternative for T1D implantation.