ibidi Pump System
6.10
Medium Exchange
A medium exchange is necessary when the nutrients in the medium are used up by the cells (pH) or
if evaporation exceeds a certain level (e.g., 5%). When a medium exchange is necessary will depend
on your setup.
When changing the medium, never let the tubing dry out! Otherwise air bubbles may form in the
tubing.
There are two options to exchange medium: First you can exchange only the medium in the reser-
voirs, which is typically done for endothelial cells which need a certain proportion of pre-conditioned
medium. Second, if you wish to perform a complete exchange, you must push out the used medium
from the tubing with fresh medium.
In principal, to perform a medium exchange you need to follow these steps (values in brackets apply
to the 2 ml reservoirs):
1. Stop the pump when the medium is equilibrated at 5 ml (1 ml).
2. Disconnect the Fluidic Unit (air pressure tubing and electric cable) and move it to a sterile flow
hood.
3. Perform the medium exchange (see the two options below).
4. Transfer the Fluidic Unit back to the incubator, reconnect it and start the program again.
6.10.1
Medium exchange with left-over conditioned medium (option 1):
1. Carefully remove the medium in the reservoirs with a pipette. Make sure that you do not
remove any medium from the tubing! Otherwise air bubbles will be introduced.
2. Refill both reservoirs to the 5 ml (1 ml) mark.
used medium
fresh medium
laminar flow hood
Figure 37: Medium exchange with a left-over of used medium in the tubing.
6.10.2
Complete medium exchange (option 2):
1. Carefully remove the medium in the reservoirs with a pipette. Make sure that you do not
remove any medium from the tubing!
2. Fill one reservoir to the 5 ml (1 ml) mark with fresh medium and await until the medium
equilibrates at
∼
2.5 ml (0.5 ml).
3. Remove the used medium from the reservoir.
Instruction Manual
49
Version 2.6 (May 12, 2022)
