Filling the Media Reservoir

The media reservoir can be filled in advance of the experiment. The filled media reservoir can be placed in a warm room in order to equilibrate the media temperature.

The nominal capacity of the Sterivex filter is 2 liters but with “clean” media (little undissolved material) you can often add more, whereas with “dirty” media (lots of undissolved material) the filter will clog quickly.

  1. Spray the capped media fill connector with 70% ethanol. Uncap the fill connector and attach a Sterivex pressure filter.
  2. Attach the shorter side of the filtration pump line to the other end of the Sterivax pressure filter
  3. Insert the peristaltic pump tubing into the media pump
    1. Flip the cover latch up until you can pull the cover off of the pump
    2. Remove the tubing restraints from the cover and put one clip on the tubing
    3. Place the clip with tubing in the cover and thread the tubing around the cover. The pump should turn clockwise. If you’re facing the pump, media will move from the left side to the right side.
    4. Clip the tubing on the other side of the cover as well
    5. Slide the cover back onto the pump and flip the cover latch down
  4. Place the other end of the filtration pump line into the media
  5. Pump media through the Sterivex pressure filter into the reservoir

  6. Detach the filtration pump line and leave the Sterivex filter uncapped.

    We find that the uncapped Sterivex filter will dry out and maintain an aseptic barrier when left attached to the reservoir. You can also spray the media fill connector with 70% ethanol, remove the Sterivex filter, and recap the media fill connector with an autoclaved male Luer cap. We find that capping the inlet to the Sterivex filter allows microbial growth in the residual liquid trapped on the inlet side of the filter; while the filter will likely maintain an aseptic barrier under these conditions as well, we try to avoid this.

Replenishing the Media Reservoir

The reservoir can be refilled during operation by attaching a new filter aseptically and pumping in new media while the system is operating.

  1. Spray the media fill connector (with either a cap or a used filter attached) with 70% ethanol.
  2. Detach the media fill connector and attach the outlet of a new Sterivex filter.
  3. Pump media through the Sterivex filter as described above.

Changing Media Sources

The media pump line can be switched to a new media source in order to change media during operation. If multiple growth chambers are fed from a single media reservoir using a media delivery manifold, then the entire manifold can be switched as a single unit.

  1. Spray both the capped media delivery connector on the new reservoir and the connection between the media pump line and the old reservoir with 70% ethanol.
  2. Uncap the media delivery connector on the new reservoir.
  3. Detach the media pump line from the old reservoir and attach it to the media delivery connector on the new reservoir.