Supragel-mediated Efficient Generation of Pancreatic Progenitor Clusters and Functional Glucose-responsive Islet-like Clusters

Although several synthetic hydrogels with defined stiffness have been developed to facilitate the proliferation and maintenance of human pluripotent stem cells (hPSCs), the influence of biochemical cues in lineage-specific differentiation and functional cluster formation has been rarely reported. Here, we present the application of Supragel, a supramolecular hydrogel formed by synthesized biotinylated peptides, for islet-like cluster differentiation. We observed that Supragel, with a peptide concentration of 5 mg/mL promoted spontaneous hPSCs formation into uniform clusters, which is mainly attributable to a supporting stiffness of ∼1.5 kPa as provided by the Supragel matrix. Supragel was also found to interact with the hPSCs and facilitate endodermal and subsequent insulin-secreting cell differentiation, partially through its components: the sequences of RGD and YIGSR that interacts with cell membrane molecules of integrin receptor. Compared to Matrigel and suspension culturing conditions, more efficient differentiation of the hPSCs was also observed at the stages 3 and 4, as well as the final stage toward generation of insulin-secreting cells. This could be explained by 1) suitable average size of the hPSCs clusters cultured on Supragel; 2) appropriate level of cell adhesive sites provided by Supragel during differentiation. It is worth noting that the Supragel culture system was more tolerance in terms of the initial seeding densities and less demanding, since a standard static cell culture condition was sufficient for the entire differentiation process. Our observations demonstrate a positive role of Supragel for hPSCs differentiation into islet-like cells, with additional potential in facilitating germ layer differentiation.