The gut–islets axis connects nutrient sensing in the intestine with insulin secretion from the pancreas and plays an essential role in glucose regulation. GLP-1 released by intestinal L cells can enhance β-cell insulin secretion, and bile acids have recently been shown to influence this process through receptors such as TGR5 and FXR. However, the interaction between gut-derived signals and islet responses is highly dynamic and difficult to reproduce with standard cell culture systems. Most in vitro models lack the three-dimensional structure and fluid environment needed to reflect physiological conditions. A platform that can better mimic gut–islets communication and allow controlled testing of metabolic regulators would therefore be valuable for studying glucose homeostasis and related diseases.