Atomic force microscopy observation and characterization of single virions and virus-like particles by nano-indentation

Structure and function of viruses are intimately related, and one of the goals in virology is to elucidate the mechanisms behind this relation. A variety of research endeavours is focused on studying these mechanisms and a relatively new technique in this field is Atomic Force Microscopy (AFM). Using AFM virions and virus-like particles can be imaged and manipulated at the single particle level. Here we review recent AFM nano indentations studies unveiling for instance the mechanics of capsid genome interactions, morphological changes that drive viral maturation, capsid stabilizing factors and viral uncoating. We show that in an increasing amount of literature a clear link between mechanics and infectivity is observed, which not only provides us with new fundamental insights into virology, but also provides ways to improve virus-like particles for applications in nanomedicine and nanotechnology.