2.6.7. Transmission electron microscopy (TEM)
Samples were stored at 4°C up to grid preparation. Briefly, 4 μL of a sample at 134 μg/mL was applied to a previously discharged carbon film on 300 mesh copper grids (CF300-CU-TH, Electron Microscopy Sciences, USA) for 1-2 min, gently dried with filter paper and stained for 2-5 s with 15 mg/mL uranyl formate (22450, Electron Microscopy Sciences, USA). Negatively stained samples were imaged on a Hitachi HT-7800 microscope operated at 80 kV.