Death rate in a small air-lift loop reactor of vero cells grown on solid microcarriers and in macroporous microcarriers

Scale up aspects of sparged insect-cell bioreactors

CONCLUSION

In this chapter we have attempted to evaluate the most important parameters which can be useful for the pur-pose of design and scale up. Insect cells and animal cells in general can be grown well in large vessels. However, none of the theories and parameters discussed in this chapter have been validated on a larger scale than laboratory and small pilot reactors. Selection of the most suitable design and scale-up method there-fore needs in particular studies in larger vessels. The Kolmogorov theory and the killing-volume model are in this respect the most promising approaches for the optimal design of large-scale animal-cell bioreactors.

A fibrous-bed bioreactor for continuous production of developmental endothelial locus-1 by osteosarcoma cells

Genetically engineered human osteosarcoma cells containing developmental endothelial locus-1 (del-1) gene were studied for production of Del-1, a protein that has the properties of an extracellular matrix protein and can regulate vascular morphogenesis and remodeling. Del-1 has been studied as a potential anti-angiogenesis drug targeting solid tumors. In this study, osteosarcoma cells were cultured in a fibrous-bed bioreactor (FBB) to continuously produce Del-1. The FBB was constructed by packing a polyester fibrous matrix into a 1.5-l spinner flask. The effects of media composition, including the serum content in the medium, and dilution rate on cell growth, metabolism, and Del-1 production were studied. A gradual reduction of serum content from 10% (v/v) to 0.5% (v/v) caused no loss in Del-1 production. However, the production of Del-1 decreased significantly in a serum-free medium, suggesting some nutrients present in the serum were important to culture viability and Del-1 production. The continuous FBB culture was stable for long-term production of Del-1, with a higher Del-1 titer than that normally obtained in T-flask cultures and overall productivity similar to the total production from 300 25-cm(2) T-flasks. Reducing geneticin in the medium from 250 microg ml(-1) to zero at later culturing stages had no significant effect on Del-1 production. The FBB was operated for a period of more than 4 months without any notable degeneration, and reached a final cell density of 3 x 10(8) cells ml(-1) of packing volume with >90% cell viability. The good reactor performance can be attributed to the three-dimensional environment provided by the fibrous matrix that allows for efficient mass transfer and cell immobilization and growth. Scanning electron microscopic and confocal scanning laser microscopic studies of the cell-matrix showed that cells formed large aggregates in the fibrous matrix and cell density was relatively uniform in the matrix.