High throughput encapsulation of murine fibroblasts in alginate using the JetCutter technology

The JetCutter technology originally developed for high-throughput encapsulation of particles and substances into small beads was applied in this study for the entrapment of mammalian cells in alginate beads. In contrast to other established techniques such as the air jet droplet generation or laminar jet break-up, the JetCutter is capable of working with highly viscous fluids necessary for the production of stable beads based on hydrogels. A 1.5% (w/v) sodium alginate solution containing 2.0 x 106 murine fibroblasts/ml was processed under good manufacturing practice (GMP) conditions to beads with a mean diameter of 320 microm. The production capacity of the JetCutter technology was 5200 beads/s or to approximately 330 ml bead suspension per h. Beads were coated with poly-L-lysine and with an additional alginate layer to produce hollow microcapsules containing living cells. The influence of this method of encapsulation on the cell viability and morphology was investigated by light microscopic techniques. Encapsulated cells showed unchanged rates of proliferation and preserved morphology. They were able to survive in culture for extended periods of time. In conclusion, the JetCutter technology seems to be well suitable for alginate bead encapsulation of living mammalian cells.