Mechanical enhanced hydrogel fiber encapsulating cells for long-term transplantation

This paper describes a core-shell hydrogel microfiber consisted of alginate and tetra-arm poly(ethylene glycol) (tetra-PEG) encapsulating rat insulinoma cells using a microfluidic process with a coaxial device and rapid gelation induced by diffusion of two different cross-linkers of barium ion and dithiothreitol (DTT) in the laminar flow. Microfluidic techniques are able to encapsulate the cells in 3D configuration such as beads and fibers. For the medical treatment, an excellent method was reported that the retrievable graft of rat primary islet cell fiber for the treatment of diabetic mice. However, the microfiber constructed of alginate hydrogel becomes weak of the strength, this issue is important for long-term transplantation. We here took an approach to improve the material, and developed composite hydrogel microfibers encapsulating cells with high mechanical strength. Using the double-network hydrogel consisted of barium-alginate and tetra-PEG as microfibers shell, the microfibers were able to encapsulate cells and maintained their shape without broken for 14 days intraperitoneal transplantation.