Development of double-layered alginate-chitosan hydrogels for human stem cell microencapsulation

Abstract

Microencapsulation is a promising technology for stem cell therapy and tissue regeneration. Our previous work proposed the application of microencapsulation technology for improving allogeneic hematopoietic stem cell transplantation. In this current work, we developed a feasible method for encapsulating human umbilical cord blood-derived hematopoietic stem cells. The cells were initially entrapped in ionic cross-linked alginate beads based on a conventional method. It was noticed that alginate beads were easily dissolved in phosphate-buffered saline with Ca2+/Mg2+, suggesting a poor stability of alginate beads. Therefore, a double-layered microcapsule was developed by coating the alginate gel with glutaraldehyde cross-linked chitosan. Measurement of relative swelling ratio showed that the double-layered gel could expand 1.49-fold in a rich culture medium. A homogenous cell distribution could be visualized in solid core alginate microcapsule by a DNA staining. Altogether, this study presented a feasible method to fabricate a double-layered alginate-chitosan microcapsule for human stem cells.