Does anyone have experience using invitrogen expi293F system? How different this system is in practical matters from the Freestyle 293F?
I am interested in knowing if anyone out there has been able to corroborate this '20X' increase in membrane protein expression they claim it can achieve or is it a lot of ballooning and marketing? not using control IgG but real world hard to express proteins....
Thank you
Hi David. I've used the 293F cells and was able to minimally get around 0.75mg of protein from 60 mLs of media. This was the first run through and I had some issues with the his tag purification given the expi293F media can interfere with nickel chromatography.
I've noticed that you had moved ahead with the 293F system and made freeze downs. I'm having trouble making freezedowns that survive. I'm currently doing 10% DMSO in FBS (gave best post thaw viability, around 96%). However, they never recover and slowly die. Do you have any suggestions or protocols for freeze down methods? Like the cells/mL number of the flask when you choose to centrifuge cells to make freezedowns? Perhaps I made the freezedowns when the cells were too dense (around 5E6 cells/mL)? Thanks.
Hi Brian, thanks for your answer. Which protein did you express? Was it a membrane protein? Thank you
About the freezings, I regulary cryo-freeze them and no problem. Do you use a Mr. Frosty? 10% DMSO in FBS should work no problem...let me know. Thanks
d.
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