Physicists from the University of Jyväskylä (Finland) used helium microscopy to study the behavior of bacteriophages: they obtained images of various stages of phage infection of bacteria.

Helium microscopy uses a helium ion beam instead of a focused electron beam, as in an electron microscope. Helium allows for higher resolution, greater depth of field, and, importantly, the ability to examine non-conductive objects.

The subject of the study was the T4 bacteriophage, which infects E. coli. Its particles attach to the bacterial wall and inject their DNA into it. The bacterium then transforms into a bacteriophage factory: in about half an hour, phage proteins and phage DNA are synthesized, which then assemble into particles and, destroying the bacterium, are released. All the main stages of the process (a - attachment, b - contraction of the tail appendage, injection of DNA into the bacterium, c - release of new virions) were recorded using helium microscopy.

IJ Maasilta et al. / University of Jyvaskyla