FreeStyle™ 293 Expression Medium, 20 L - FAQs

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7 product FAQs found

我能将FreeStyle 293表达培养基或FreeStyle CHO表达培养基直接上样至镍柱中，以用于His标签蛋白的纯化操作吗？

在使用FreeStyle 293表达培养基时，我们推荐稍早一些收获细胞，以减少宿主细胞蛋白所造成的非特异性结合，之后对培养上清液进行0.2 或0.1 µM的膜过滤，再上样至镍柱。另一方面，FreeStyle CHO表达培养基中含有的EDTA将会对镍柱起到洗脱的作用。因此在上样之前，应对这一培养基进行透析或缓冲体系交换，也可通过向上清液加入1-3 mg/L NiSO4或NiCl来螯合EDTA。另外可使用铁盐或钴盐。

培养于FreeStyle 293表达培养基中的FreeStyle 293-F细胞能使用ExpiFectamine293试剂和增强剂进行转染吗？如果可以，转染效率会比使用FreeStyle Max试剂更高吗？

您可使用ExpiFectamine293试剂来转染FreeStyle 293表达培养基中培养的FreeStyle 293-F细胞；不过，增强剂只会对蛋白表达提供少许的促进作用，因为这一产品是针对更高密度培养设计的，而FreeStyle 293表达培养基并不适用。 

Can I load the FreeStyle 293 Expression Medium or FreeStyle CHO Expression Medium directly onto a nickel column for His-tagged protein purification?

With FreeStyle 293 Expression Medium, we would recommend harvesting the cells a little earlier to reduce any nonspecific binding by host cell proteins and then filtering the culture supernatant through a 0.2 or 0.1 µM membrane before loading onto the column. On the other hand, FreeStyle CHO Expression Medium contains EDTA that will strip the nickel column. The medium can be subjected to dialysis or buffer exchange prior to loading on the column, or the EDTA can be chelated by adding 1-3 mg/L NiSO4 or NiCl to the supernatant. Iron or cobalt salts can also be used.

Can FreeStyle 293-F cells grown in FreeStyle 293 expression medium be transfected with ExpiFectamine293 Reagent along with enhancers? Is so, will the transfection efficiency be higher than that with FreeStyle Max Reagent?

You should be able to use the ExpiFectamine293 Reagent for transfection of Freestyle 293-F cells grown in FreeStyle 293 Expression Medium; however, the enhancers will provide only a little boost in expression as they are designed to work with higher density cultures that FreeStyle 293 Expression Medium cannot support.

Find additional tips, troubleshooting help, and resources within our Transfection Support Center.

Is it necessary to grow FreeStyle 293-F cells in 8% CO2 when using the FreeStyle 293 Expression Medium? If 8% CO2 cannot be arranged, can I supplement the media with an additional reagent?

Our recommendation of 8% CO2 for the optimal growth of Freestyle 293 cells in Freestyle 293 Expression Medium is based on the bicarbonate content in the media and growth conditions of the cells observed by R&D. That said, you may use lower concentrations of CO2 if necessary (5% is common) to grow these cells. You may observe slightly slower growth kinetics or lower cell concentrations, but functionally the entire system will still work.

Does FreeStyle 293 Expression Medium contain any components that would interfere with concentrating secreted proteins from HEK 293 cells via ammonium sulfate precipitation?

Yes, the FreeStyle 293 Expression Medium contains Pluronic F-68 and lipids that would interfere with ammonium sulfate precipitation. Dialysis or tangential flow filtration can be used to remove lipids and Pluronic F-68 from the medium. Then you can concentrate the medium with ammonium sulfate.

Find additional tips, troubleshooting help, and resources within our Cell Culture Support Center.

What is the difference between FreeStyle 293 Expression Medium and FreeStyle F17 Expression Medium?

FreeStyle F17 Expression Medium was designed from a different base formulation than FreeStyle 293 Expression Medium. FreeStyle F17 medium shows equal or better performance than the FreeStye 293 medium for certain cell lines and proteins. It is capable of supporting the growth of 293 and CHO cells and offers a wider variety and selection of transient cell culture media options.

Find additional tips, troubleshooting help, and resources within our Cell Culture Support Center.