Low-shear gas transfer (O_2 supply/CO_2 removal) techniques are required for culturing shear-sensitive organisms such as animal and insect cells, where the conventional agitation and/or air sparging cause metabolic changes and cell death. Since the difficulty results from the scanty oxygen solubility in aqueous media, it may be addressed by addition of "pseudo-erythrocytes", i.e. oxygen-carrying particles analogous to the erythrocytes in blood. We developed relatively stable perfluorocarbon (PFC) emulsions (< 0.2 umm) and applied them to different low-shear bioreactors; rotating culture tubes, surface-aerated vessels, and column bioreactors (1-3). The oxygen transfer enhancement effect was modeled and experimentally demonstrated with the higher cell concentrations obtained. The emulsions, however, suffered from the potential negative effects of the surfactants used and the gradual increase in droplet size due to intrinsic emulsion instability.
展开▼
