Fig. 2.

Fixed-bed reactor system for stem cell expansion. The bioreactor consists of a glass cylinder filled with glass spheres as bed. Oxygen measurements are performed on-line with optical sensors (IPO2) at the in- and the outlet of the reactor. The cells are transferred into the reactor from an inoculum vessel. The following cultivation runs automatically with a perfusion of the reactor with preconditioned medium. Medium exchange is done if necessary whereby the exchanged medium is collected in the waste vessel. For the cell harvest, the reactor is automatically washed with PBS, followed by incubation with enzyme solution for cell detachment. The detachment is stopped by addition of medium and detached cells are collected in the collecting vessel.