Hydrogel-based co-culture and application of two types of islet cells.

This study aimed to develop a hydrogel-based co-culture system for pancreatic α- and β-cells to mimic native islet composition and achieve bidirectional blood glucose regulation. Monodisperse sodium alginate microsphere encapsulating α-TC6 and β-TC6 cells in a 2:8 ratio were fabricated using a microfluidic electrostatic spray platform. Key processing parameters (voltage, collection distance, flow rate, and alginate concentration) were optimized to precisely control microsphere diameter, yielding highly uniform spheres with excellent monodispersity. The alginate hydrogel exhibited favorable swelling properties and viscoelasticity, providing a supportive 3D microenvironment. In vitro, the microspheres demonstrated high biocompatibility, with cell viability exceeding 95% after 72 hours of co-culture. Encapsulation did not impair cellular function, as evidenced by unhindered insulin and glucagon secretion compared to unencapsulated controls, in streptozotocin-induced diabetic C57BL/6 mice, transplantation of these cell-laden microspheres into the subcutaneous brown fat significantly improved glucose homeostasis. Treated mice showed markedly better glucose tolerance during intraperitoneal glucose tolerance tests and maintained lower fasting blood glucose levels compared to sham-operated and unencapsulated cell transplantation groups. Furthermore, the treatment alleviated diabetes-associated weight loss, with the microsphere group showing a significant weight increase post-transplantation. Histological analysis confirmed the biocompatibility of the implants, with no significant pathological changes in major organs. In conclusion, this sodium alginate microsphere system effectively co-cultures functional islet cells, provides immunoisolation, and restores bidirectional glucose regulation in a diabetic mouse model, offering a promising strategy for pancreatic islet modeling and cell- based diabetes therapy.