PARENT SESSION
1:30 PM to 3:30 PM
Saturday, April 20, 2002
Poster Session 1 Noninvasive Treatment Monitoring and Treatment Planning
Room: Nevada 1-2
(MP01-12) Dynamics of cell culture media temperature inside flasks kept in laboratory incubators.
Moros, Eduardo*,1, Xu, Mai1, Straube, William1, Roti Roti, Joseph1, 1 Washington University in St. Louis, St. Louis, MO
ABSTRACT-
The temperature history of culture media may have subtle and important effects on the biological response of cells to physical agents such as drugs, hyperthermia, ionizing and non-ionizing (e.g., radiofrequency, ultrasound) radiations. In this study, we measured the temperature changes inside T-25 flasks filled with 5 ml of culture media as they were brought into two different incubators set to 37.0 and 41.1°C. These incubators were water-jacketed, kept at 5% CO2 and humidified by a water reservoir located at the bottom. We also characterized the impact on steady state media temperature as the incubator doors were opened for 30 s, 60 s and > 10 min. These times simulate what happens during normal operation as an incubator is opened for a relatively quick (30 - 60 s) or long placement/removal (>10 min) of items. Finally, we investigated the use of heat capacitors (T-150 flasks completely filled with water) on temperature dynamics. For the 37°C incubator, the 30 and 60 s open-door conditions caused average drops of 0.35 and 0.95°C, respectively. Recovery times (to within 0.1°C of the steady state value) were 2 to 3 hrs long. For the 41.1°C incubator, the 30 and 60 s open-door conditions caused average drops of 0.5 and 0.7°C, respectively. Recovery times were 1.5 to 2.5 hrs long. Long open-door conditions (> 10 min) caused temperature drops > 5°C and required 2 and 4 hrs of recovery time for the 37 and 41.1°C incubators, respectively. As expected, temperature drops for flasks positioned on top of heat capacitors were smaller but the recovery times were much longer. The use of heat capacitors may be advantageous in certain situations, particularly for short open-door conditions. In general, temperature changes take up to 30 min after the door has been closed. This is due to the re-humidification of the air inside the incubator after a sudden loss of humidity (and thus heat). We believe that it is important for investigators to consider temperature dynamics in the design of experimental protocols.
KEYWORDS: temperature, stability, incubator, cell