Barium-cross-linked alginate-gelatine microcapsule as a potential platform for stem cell production and modular tissue formation

Influence of gelatine concentration and cross-linker ions of Ca2+ and Ba2+ was evaluated on characteristics of alginate hydrogels and proliferation behaviours of model adherent and suspendable stem cells of fibroblast and U937 embedded in alginate microcapsules. Increasing gelatine concentration to 2.5% increased extent of swelling to 15% and 25% for barium- and calcium-cross-linked hydrogels, respectively. Mechanical properties also decreased with increasing swelling of hydrogels. Both by increasing gelatine concentration and using barium ions increased considerably the proliferation of encapsulated model stem cells. Barium-cross-linked alginate-gelatine microcapsule tested for bone building block showed a 13.5 +/- 1.5-fold expansion for osteoblast cells after 21days with deposition of bone matrix. The haematopoietic stem cells cultured in the microcapsule after 7days also showed up to 2-fold increase without adding any growth factor. The study demonstrates that barium-cross-linked alginate-gelatine microcapsule has potential for use as a simple and efficient 3D platform for stem cell production and modular tissue formation.