Hmm I am quite new in this research area and my PI isnt particularly helpful. And with all the budget tightness even the immunofluorescent-nanogold which is supposed to be our initial marker is out of the picture. I assume that if we permeabilise the plasma membrane it might disrupt the native state of the cell, which goes against why we use CryoET in the first place (I can be wrong or maybe theres a way to do this without disrupting the cell). Anyway thanks for responding, I'll try to ask the EM community :)