Type 1 diabetes (T1D) is an autoimmune disease where the patientsâ insulin-producing pancreatic islet cells are mistakenly destroyed by their own immune system. Delivery of immunoprotected donor islets or more ideally stem cell-derived insulin producing cells has been considered as a promising, superior alternative to the standard, imperfect and tedious insulin therapy. However, it remains challenging to develop a cell delivery device that is long-term functional and has none or minimal safety concerns especially when stem cell-derived cells are used. In this talk, I will discuss our recent efforts to develop different types of cell delivery devices with a particular focus on nanofiber-based ones that have the potential to overcome both the functionality and safety challenges.