Imaging aquatic animal cells and associated pathogens by atomic force microscopy in air

Atomic force microscopy (AFM) is a sophisticated imaging tool with nanoscale resolution that is widely used in structural biology, cell biology, and material science, among other fields. However, to date it has rarely been applied to the study of aquatic animals, especially on one of the main cultured species, shrimp. One reason for this is that no shrimp cell line established until now, primary cell is fragile and difficult to be studied under AFM. In this study, we used AFM to image three different types of biological material from shrimp (Litopenaeus vannamei) in air, including hemocytes and two associated pathogens. Without obvious deformations when the cells were imaged in air and in the case for the haemocytes and the cells were fixed as well. The result suggests hydrophobic glass coverslips are a suitable substrate for adhesion of these samples. The method described here can be applied to the preparation of other fragile biological samples from aquatic animals for high-resolution analyses of host–pathogen interactions and other basic physiological processes.