You probably could request that Thermo make you a custom SILAC compatible version of the Expi293 media, although I imagaine it'll be even more excessively expensive than Expi293 media already is (I know all too well how much of a cost it is). If you want all the advanatges of the Expi system (growth to high density etc), that's likely all that you can really do.

Dear Shannon Bareesel

if i'm right for SILAC you need 15N uniform labelled protein sample. I'm right?

If yes, i have done some prelininary trials of production of 15N labelling protein with Expi293 using the Bioexpress6000 media (https://shop.isotope.com/productdetails.aspx?itemno=CGM-6000-N).

The purified sample was analized by 15N HSQC spectra and the spectra was not so bad which is indicative of 15N labelling. However we did not estimated the % of labelling,

You can find those preliminary data at the end (minute 8) of the following video: Uniform 15N, 13C and 2H protein labeling using E.coli and more avaialble on my blog (ProteoCool) at the following link:

https://www.blogger.com/video.g?token=AD6v5dwMieb--rE6-qY-WfM4fv8o-2PbxqaWuGxZ7_U3QB5tB113BQ1lEjHxpZhRMLWIWkeHmZV_LcuaESWuqDtZe1L3JI62cDvZaMQyL6BLVQxIRJtuE7IPw8SYCQHKWSV4_CCL0cs

i hope it could be usefull to you

good luck

Manuele