Facts
In comparison to a Levitronix^® pump, a 4-Piston Diaphragm Pump consists of multiple valves that restrict fluid motion to the desired direction. Valve interaction can lead to shear stress, which can result in a reduced cell viability.

Test conditions
Two Levitronix^® and one 4-Piston Diaphragm pumps’ shear stress generation were compared by observing their effect on respective cell viabilities. A fixed volume of CHO cells was pumped in three identical closed loop configurations. The flow rate of each pump was set to 3.4 lpm and backpressures of 0.03, 0.3, and 0.6 bar, respectively. The cell viability was measured at selected times and compared.

Results
Both Levitronix^® pump systems revealed a significantly lower cell stress effect on CHO cells than compared to the 4-Piston Diaphragm Pump. Even at high speeds, the cell death rate was about 30% lower in the Levitronix^® pumps than in the 4-Piston Diaphragm Pump.

Cell viability for all three pumps at 3.4 lpm and 0.03 bar