Hello guys,
I've always centrifuged my HEK293Ts using 15 or 50 mL centrifuge tubes. For these, 300G for 3 min at RT (during standard passaging) gives me great results.
However, now we are willing to use a larger tube size, precisely 500 mL centrifuge tubes.
I was wondering if this modification might require an adaptation of the centrifugation parameters, supposedly the G-force. We will be using the same centrifuge, so the radius of the motor won't change.
Many thanks
since you are using the same rotor, the key variable here is the distance traveled in the new tube compared to the old (depth of medium).
I agree with Ellen the only parameter that would change is the time to sediment (pellet) of the cells because the distance they have to traverse changes when you change the tube/volume of media. However, since you are using xg to quantify the force the tubes experience and not RPM which would vary with rotor size, you only have to take into consideration the time component. Meaning you just have to add more time to your spindown protocol to compensate for the extra distance (assuming larger tubes=using more media). Additionally, you might have to consider the heat generated during centrifugation due to drag (larger tubes+longer spining=more drag=more heat). If you increase the time of centrifugation more heat will be generated, this is however an ignorable variable if your centrifuge is refrigerated. You will have to determine empirically how much more time you need but I would say it is safe to start at doubling your time. If you can, when you spin down your cells next time, collect the supernatant and spin it down again to see if you are leaving cells behind and would need to add more time to your spin down to increase recovery.
Yes, centrifugation parameters, especially the G-force, can be affected by changes in the tube size. A larger tube will require a higher G-force to achieve the same level of sedimentation as a smaller tube. The centrifugation speed and duration may also need to be adjusted. It is recommended to perform a trial run with the 500 mL tubes and adjust the parameters as necessary to achieve optimal results. Additionally, the weight of the tubes and the volume of the cell suspension should also be considered when determining the appropriate centrifugation conditions.
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