Preparation of Borrelia-Infected Mammalian Cells for Helium Ion Microscopy

Preparation of mammalian cells for a Borrelia burgdorferi infection can be cumbersome especially if investigating possible cell entry processes. The initial steps of infection or entry into cells by a pathogen often involve attachment to the cell surface and plasma membrane changes. To topologically investigate with great resolution and detail these interactions of the pathogen and the mammalian cell, helium ion microscopy (HIM) can be employed. Here we describe a protocol used to define a specific multiplicity of infection (MOI) of Borrelia burgdorferi on a human chondrosarcoma cell line (SW1353) so that fine detail structures on the mammalian cell can be observed and quantified by HIM.