Growing Cells on Beads
3.5.15.
There are two types of beads suitable for BI cellular assays: Cytodex ® and Cytopore ® beads (Amersham Pharmacia Biotech, Uppsala, Sweden). While Cytodex beads are elastic and fragile, and suitable for fluorescence spectroscopy, Cytopore beads are robust and have a much larger surface available for cell growth since they are porous. Growing adherent cells on either type of beads is done by the same procedure. Cells grown in a medium in a flask are trypsinized to release them from the flask surface, washed in fresh medium, and used to inoculate a 10 mL culture tube containing 20 mg dry weight of carrier beads. The beads are prepared according to the manufacturer’s instructions. Briefly, 20 mg of dry beads were hydrated overnight in 1 mL of Hank’s balanced salt solution (HBSS). The beads were sterilized by autoclaving at 121°C for 30 min. An aliquot of beads corresponding to 20 mg dry weight was equilibrated with cell culture medium by washing several times. The bead medium slurry was warmed to 37°C prior to inoculation with the cells. After inoculation, the cells and beads were gently stirred and settled several times in a 15 mL Falcon tube.
The images below show (from left to right): 1) rotating bead container that serves as cell-bead reservoir attached to LOV module. 2) Chinese Hamster Ovary cells grown on Cytodex Beads. 3) Cytopore beads with transfected hepocytes attached by the procedure described above. Since Cytopore beads are porous, the cell density is much higher than on Cytodex beads that provide only the outer surface for cellular attachment.
