Fig. 2.

Effects of MIN6 cell-packing density in PEG hydrogels on glucose responsive insulin secretion. MIN6 cells were dispersed into single cells and encapsulated at different cell densities as indicated. Cell-laden hydrogels were maintained in RPMI-1640 medium containing 10% FBS for 10 days before insulin secretion was tested in Krebs–Ringer buffer solution (KRB). The amount of insulin secreted from samples incubated in 25 mM glucose KRB was normalized to the amount of insulin secreted from the respective samples incubated in 2 mM glucose KRB and expressed as an insulin secretion index (Mean ± SEM, n = 4). All values of the insulin secretion index were significantly different from 1 (p < 0.05), with & indicating lower and * indicating higher than 1.