In brief, I want to sample media from a bioreactor on a daily basis, over a long period of time. The idea is to have an aspiration tube extending into the media, connected to a length of silicone tubing, and then to a Swaglok check valve: (https://www.swagelok.com/downloads/webcatalogs/en/MS-01-176.pdf)
(This brand/style check valve appeals to me since I can dry-heat sterilize the silicone tubing while its connected to the check valve.)
The upstream side of the check valve can be attached to the silicone tubing via a barbed adapter. When not in use, the check valve can soak in 70% (if not 90%) alcohol. When needed, the downstream side of the check valve can be connected to a vacuum collection device. It IS acceptable if the media be mixed with alcohol or any other disinfecting fluid. All that is necessary is that the bioreactor not be contaminated.
A disadvantage to this approach is that the tube will be a "dead" area in which there is no flow. Whatever traces of bacteria might be in the bioreactor could (it seems) proliferate in such an area, and be re-introduced. This can be minimized by attempting to remove all media that is aspirated into the aspiration tube, but there will be some minimal back-wash.
The second problem relates to contanimant ingress through the check valve. Soaking in alcohol is better than nothing, but not perfect either.
Does this seem like reasonable approach? Are there any suggestions for better procedures? Thanks.
Kessel: One needs to trade convenience with potential contamination in a long run. We simply take sample from the vent opening using a pipette to take samples.
Dear Kessel,
We usually do the sampling as Ke-Wei Zhao described.
You can also check out the DasGip fermenter's sampling tube, it is pretty good to achieve aseptic sampling:
https://online-shop.eppendorf.us/US-en/Bioprocess-44559/Bioprocess-Systems-60767/DASGIP-Parallel-Bioreactor-Systems-PF-133597.html
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