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Bioreactors
Our bearingless motor technology is being used for pumps and stirrers in bioreactors for a variety of biotechnology applications. For example, Levitronix recently developed a "Bubble Bed Reactor" in collaboration with the Institute of Process Engineering at the ETH Zurich to serve as an incubator for growing new tissues.

The function of a bioreactor is to support and nourish growing cells and to provide oxygenation. Recent studies have shown that standard bioreactors tend to destroy cells due to the bursting of bubbles in the foam region. Our "Bubble Bed Reactor" was developed to reduce the risk of cellular damage due to cavitation related to the bursting of bubbles based on the concept outlined below.

The "Bubble Bed Reactor" creates a fluidic flow loop that circulates in the opposite direction to emerging bubbles from an oxygen source. By adjusting the flow to approximate the speed of the emerging bubbles, the bubbles can be accumulated and suspended in a "conical downcomer." Therefore, the resultant bubble bed functions to keep the suspended oxygen in prolonged contact with the fluid to promote a greater concentration of dissolved oxygen. The high concentration of dissolved oxygen then becomes available for the growing tissue that is also suspended within the liquid medium.

Bearingless motors offer exciting new options in the field of biotechnology and medicine.

The benefits of this new system include:

No rotating seals No wear An absolute hermetic system Simple cleaning and sterilization (no narrow clearances or fissures) No cell damage by the drive Precise control of stirrer speed and torque Monitoring of cell density by bearingless drive Improved oxygen uptake

Figure 1: Bubble Bed Reactor with magnetically driven and levitated stirrer