Friedrich's instructions are to shake off the biofilms every 3 or 4 weeks, leaving a small amount on the surface from which a new biofilm can grow. As mentioned in the previous blog, other scientific accounts of growing TB biofilms seem to stop at 5 weeks. We initially started 8 flasks to grow H37rv biofilms and at 4 weeks growth we tried the 'shaking off' with 5 of the flasks leaving three flasks unshaken.
We were pleased to find that even with quite vigorous shaking that while most of the biofilm swirled around in the liquid and then dropped to the bottom of the flask, some returned to the surface. And three weeks later we were even more pleased to find that the biofilm had regrown in those which had been shaken and we were able to shake them off again.
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| Close ups of the biofilms in flask 3 |
I would love to know more about the changes that are happening in the biofilm but there are no resources in the lab for me to test these easily and we are not yet at a stage where the lab is willing to commit significant other resources to this work.
