Visualization of Giant Virus Infection in Amoeba Using Helium Ion Microscopy

Begin with a multi-well plate containing amoeba cells infected with giant viruses at different stages of infection.

Some infected cells lysed and released viruses along with virus-filled vesicles.

These cells adhere to a poly-L-lysine–coated silicon chip.

Add a fixative to preserve the cellular structure, then wash the cells.

Stain with osmium tetroxide, which binds to the cell membrane and enhances contrast by increasing electron density.

Wash to remove excess stain, then add tannic acid, which reacts with osmium and further improves membrane visibility.

Next, treat the cells with increasing concentrations of ethanol to gradually dehydrate them.

Image the sample using helium ion microscopy for nanometer-scale resolution.

Observe the invaginations of the cell membrane near attached viruses, which likely indicate viral entry into the amoeba cells through endocytosis.

Visualize clusters of viruses and virus-filled vesicles near lysed cells, indicating viral release.