Temperature regulation during centrifugal elutriation and its effect on cell separation.

Centrifugal elutriation appears to be a promising method for cell separation. The quality of the separation may be limited by the control of temperature within the separation chamber, which affects the fluid viscosity and rotor speed. The factors affecting the temperature regulations have been re-examined. At flow rates between 10 and 40 mL/min the temperature within the chamber was primarily dependent on the temperature of the fluid flowing into the rotor. Increases in the temperature of the fluid while it flowed through the rotor were observed and were greater at higher rotor speeds and lower flow rates. This heating, caused by friction at the rotating seal, could raise the fluid temperature within the chamber by as much as 6 degrees C. Fluctuations in the temperature of the centrifuge produced temperature variations of only 0.3 degrees C in the fluid in the elutriation chamber. Small increases in the rate of elutriation of cells, concomitant with centrifuge cooling and speed fluctuations, were detected by optical density measurements. However, neither the modal volume nor coefficient of variation of the collected cells were affected.