Oneview 4k camera

The morphology of the N-CNSs was observed under TEM (FEI Tecnai G 220 S-Twin, Hillsboro, OR, USA). One drop of suspension was deposited on a carbon-coated copper grid loaded with 5 µL of the N-CNSs suspended in Milli-Q water, and it was allowed to dry for contrast enhancement with 1.5% uranyl acetate. Images were acquired using a Gatan OneView 4K camera mounted on a Jem-2100Plus (Jeol, Tokyo, Japan) operating at 200 kV. Samples were analyzed with ImageJ software (NIH).

All electron micrographs were taken with a JEM-2100 Plus Transmission Electron Microscope (JEOL) operating at 80 kV equipped with a OneView 4 K camera (Gatan). For CLEM, cells of interest were identified using the obtained fluorescent and brightfield image. Reconstruction was done using ICY and ec-CLEM plugin.
For electron tomography, Ultrathin sections of 200 nm were cut using an ultramicrotome (Leica, UC7) and incubated with 10 nm protein A gold (CMC, Utrecht) diluted 1:25 in ddH20. Sections were stained with 2% Uranyl acetate for 20 min and Reynolds lead citrate solution for 3 min. Images and Tilt series for 1.108 nm thickness were acquired from −65° to 65° with 1° increment on a JEM-2100 Plus Transmission Electron Microscope (JEOL) operating at 200 kV equipped with a OneView 4 K 32 bit (Gatan) using SerialEM (Mastronarde, 2005). Reconstruction was done using Imod and Imaris. Specific information regarding sample processing for electron microscopy can be found in the Supplementary information file.