What is the amplitude of the shaker?
The amplitude of the shaker refers to the diameter of the tray when it is circular. Sometimes we call the "oscillating diameter" or "track diameter" symbol: ?. As a standard, Infors offers shakers with amplitudes of 3mm, 25mm and 50mm
What is oxygen transfer efficiency (OTR)?
Oxygen transfer efficiency refers to the efficiency with which oxygen is introduced into the liquid from the atmosphere. The higher the OTR value, the higher the oxygen transfer efficiency.
Effects of amplitude and speed <br> Both of these factors affect the mixing of the medium in the flask. The better the mixing effect, the better the oxygen transfer rate (OTR). Following these guidelines, you can choose the most appropriate amplitude and speed.
In general, the choice of 25mm amplitude can be applied to all cultures as a universal amplitude.
Because of this, most shakers have an amplitude of 25 mm. In some applications, if there are special restrictions on oxygen delivery/cell growth, some special amplitudes may be chosen.
Bacterial, yeast and fungal culture:
The oxygen transfer efficiency in the shake flask is much lower than in the bioreactor. Oxygen delivery in most cases may be a limiting factor in shake flask culture. The amplitude is related to the size of the conical flask: large bottles use large amplitudes.
Recommendation: 25mm amplitude for tapered flasks from 25ml to 2L
50mm amplitude for tapered flasks from 2 to 5 liters
Cell culture:
However, mammalian cell culture requires relatively low oxygen and low power input.
* For 250mL shake flasks, sufficient oxygen delivery is provided over a wide range of amplitude and vibration speeds (20-60mm amplitude; 100-300rpm).
* If a larger diameter flask (Fernbach flask) is recommended to use 50 mm amplitude
* For disposable culture bags, a 50mm amplitude is recommended.
Microplates and deep well plates:
There are two different ways to achieve maximum oxygen transfer for microplates and deep well plates!
* Use 50mm amplitude, the speed is not lower than 250rpm
* Use 3mm amplitude, speed is 800-1000rpm
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Please note the following points <br> In many cases, even if a reasonable amplitude is selected, it may not increase the amount of biological cultivation, because the increase in the amount of culture will be affected by many factors. For example: If one or two of the ten factors are not ideal, then no matter how good the other factors are, the growth of the cultivation volume is limited, or it can be said that if the limiting factor of the culture amount is only oxygen transmission, the amplitude is correct. The choice will result in an obvious increase in the incubator. For example, if the carbon source is a limiting factor, no matter how good the oxygen transfer effect is, it will not reach the ideal culture amount.
Amplitude and speed <br> Both amplitude and speed affect oxygen transfer. If the cell culture is very low (such as 100 rpm), the difference in amplitude has little effect on oxygen delivery. To achieve the highest oxygen transfer effect, first increase the speed as much as possible, and the tray will properly balance the speed. Not all cultures are able to grow well under high-speed shocks, and some cultures that are sensitive to shear forces can cause culture death.
Other influencing factors <br> Other factors also have an effect on oxygen delivery:
* Liquid loading: The volume of the Erlenmeyer flask is not more than one third of the total volume. If the maximum oxygen transfer is to be achieved, the liquid volume must not exceed 10%. Never put the liquid volume up to 50%.
* Spoiler: Spoiler is effective in increasing oxygen delivery in all types of culture. Some manufacturers recommend the use of "super high yield" culture bottles. The spoiler of this bottle will increase the liquid friction and the shaker may not reach the maximum set speed.
The relationship between amplitude and speed <br> The centrifugal force in the shake flask can be calculated by the following formula: FC=rpm2 × There is a linear relationship between the amplitude centrifugal force and the amplitude: if the amplitude is 25mm to 50mm (the same speed), the centrifugal force is increased by 2 times. There is a square relationship between centrifugal force and speed: if the speed is increased by 2 times (the amplitude is the same), the centrifugal force is increased by 4 times. If the speed is increased by 3 times, the centrifugal force is increased by 9 times!
If the amplitude is 25 mm, the culture is carried out at a given speed. If you want to use the amplitude of 50mm to achieve the same centrifugal force, the speed should be calculated by the square root of 1/2, so you should use 70% of the speed to achieve the same culture conditions.
Please note that the above is only a theoretical method of calculating the centrifugal force. There are other influencing factors in real-world applications. This calculation method can get an approximation for operational reference.
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