Engineering considerations on the use of liquid/liquid two-phase systems as a cell culture platform

BACKGROUND: Application of perfluorocarbon based liquid/liquid two-phase systems for cell culture expansion has been investigated at small scale for more than 30 years and it has been established that such systems are able to support the survival of a variety of cell lines. Application of drops in liquid/liquid dispersions as temporary microcarriers is an exciting prospect as it enables adherent cells to be grown in stirred bioreactors, without the need to use enzymatic dissociation methods to harvest the cells. RESULTS: Two aspects of scaling up of perfluorocarbon/cell culture medium dispersions were investigated: (i) the effect of processing conditions on drop size/interfacial area; and (ii) the kinetics of separation of a stagnant dispersion. The processing conditions to produce the stable ‘liquid microcarriers’ with average drop size between 150 and 220 µm have been established. Separation of dispersion into two continuous systems requires complete removal of proteins from the perfluorocarbon/cell culture medium interface. CONCLUSIONS: The correlation relating average drop size to the energy input and physical properties of both phases was developed and the method of separation of stable perfluorocarbon/cell culture medium dispersion was established. As the perfluorocarbon does not deteriorate during cell expansion and subsequent separation followed by sterilization, it could be re-used, making application of such systems at large scale very attractive and economical.