Biological Stirrer FAQs

Q: Can the culture vessels used with the MCS system be autoclaved?

A: Yes, the glass culture vessels and stirring rods can be autoclaved at 121°C, 15psi for 30 minutes.

Q: What is the recommended washing procedure for the culture vessels?

A: The flasks can be washed in the same way as standard laboratory glassware. Do not use strong alkalis or aggressive abrasive action as this may damage the siliconised coating of the vessels. After washing, the flasks should be rinsed with deionised water to remove any traces of the washing chemicals before autoclaving.

Q: How often is it necessary to re-siliconise the stirrer vessels?

A: All the vessels are supplied pre-siliconised. We recommend that they are re-siliconised every 5-10 uses to retain the water repellancy. Standard solutions for siliconising glassware can be used, such as Sigmacote® from Sigma Aldrich. The bottles and stirrers should be cleaned, dried and then the siliconising agent added, swirled to ensure complete coverage of the surfaces and then allowed to air dry. Follow the manufacturer's instructions for the product used. After treatment the glassware will require rinsing a few times with deionised water before autoclaving.

Q: Will the stirrers generate heat and increase the temperature in the incubator?

A: Negligible heat is generated by the stirring action due to the non-slip magnetic drive between the rotating magnets in the base and the embedded magnets in each stirring rod. The continuous running of the motor produces no measurable increase in temperature which could affect the cells/media.

Q: Is it possible to buy the culture flask's magnetic stirrer rod separately?

A: Yes, the magnetic stirrer rods can be purchased separately. The part codes for each vessel size are shown in the table below.

Q: Can we use Techne culture vessels with other magnetic stirrers if the vessel is of suitable size with the stirrer?
Vessel Size Part Code of Stirrer
125ml 6007989
250ml 6007635
500ml 6007619
1 litre 6007620
3 litre 6100290
5 litre 6100289

A: It is not possible to use the culture flasks with other stirrers. The MCS system has a maximum speed setting of 80rpm, whereas the lowest setting of many general purpose magnetic stirrers is ~100rpm. Most cells are cultured at a speed of 15-25rpm so this would not be possible with a standard stirrer. Also the action of the biological stirrer is very specific and very smooth with the slow start/stop function to prevent damage to the cells and this is not available on standard magnetic stirrers.

Q: Are the caps on the flasks vented?

A: No, the flask caps are not vented. It would be possible to partly unscrew the caps on the side arms if required. Since the working volume of the flask is only about half the actual flask capacity, there is usually enough oxygen in the flask for the culture. The flasks are generally used for mammalian and insect cell culture and not for rapidly dividing cells such as bacteria where there is a high demand for oxygen and a high CO₂ output. Therefore the air space in the flask is usually sufficient between media changes.

Q: How does the flask size correlate with the volume?

A: The vessel size refers to the working volume. Therefore a 500ml vessel has a nominal working volume of 500ml, although the actual fill capacity is 1000ml. This allows for a large air space above the culture to provide enough oxygen for growth between media changes. Likewise with the MCS stirrer systems, the vessel size refers to the nominal working volume of the vessel.

Q: What is the material composition of the cell culture Vessels?

A: The bottles themselves are made of 3.3 expansion borosilicate glass. This is a low expansion glass i.e. it does not easily crack when heated. The caps, both the main and side are made from polypropylene. The seals and flexible joints are made from silicone. The adapter for the main cap is made from PTFE (Teflon).

Q: Can I stir all different flask sizes on my MCS platform?

A: No. Each of the MCS platforms may be used with two or more sizes of culture vessel, except the MCS-104XL which is set for 5 litre vessels only. The position of the unit magnet(s) must be adjusted for the particular vessel being used to give the optimum stirring action. Instructions are given in the user manual.

The MCS-101L units have their magnets set for 5 litre vessels when they leave Techne but can also be adjusted for 3 litre culture vessels. MCS-102L, MCS-104L and MCS-104S units have their magnets set for 500ml vessels when they leave Techne. 500ml is the maximum size that can be used with the MCS-104S but the MCS-102L and MCS-104L can also use up to 1 litre vessels.