Imaging techniques for studying virus–cell interactions: a review of current methods and challenges

Knowledge of virus-host cell interactions is central to the formulation of antiviral therapies and vaccines. Because of their nanoscale size and dynamic nature, viruses are inherently difficult objects to investigate. Virus characterization, such as imaging viral structures, intracellular viral trafficking, and infection molecular mechanisms, has relied heavily on sophisticated imaging approaches. Classical light microscopy imaging, such as fluorescence and super-resolution microscopy, provides information on viral entry, replication, and protein localization within living cells. Electron microscopy (EM) techniques, such as Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and Cryo-Electron Microscopy (Cryo-EM), provide high-resolution structural information on the viruses and their replication compartments. Advances in correlative imaging techniques, which include light and electron microscopy, have improved our ability to study virus-induced cellular changes in three dimensions. But in comparison to the earlier developments, it remains challenging in virus imaging: a compromise between resolution and sample preparation, restrictions in labeling methods, the challenge in imaging rapid virus-host interactions, and biosafety limitations for highly pathogenic viruses. Solutions to these types of issues will be provided with the newer techniques such as AI-powered imaging analysis, nanotechnology-based imaging probes, and cryo-electron tomography. This review covers the present imaging methods in virology, their utilities and limitations, as well as future prospects, with an emphasis on microscopy to discern the interaction of viruses with cells electron microscopy.