Asymmetrical flow field-flow fractionation (AF4) is a separation method based on hydrodynamic size of the sample components. It can separate a broad size range of components (~103 to 109 Da; particle diameter from ~1 nm to ~1 μm), but is especially well suited for high molecular weight samples such as virus-sized particles and extracellular vesicles. Separation takes place in an open channel where the flows control sample elution. Separation does not involve stationary phase, allowing gentle separation and good recoveries. The method is compatible with a wide variety of buffers. Coupling to various analytical detectors enables rapid assays on the molecular weight and size and their distribution, degradation, and aggregation of the sample components giving information on the sample quality. In addition to being an advanced analytical method, AF4 can be used in a semipreparative mode for purification. Here, we summarize archaeal virus production methods and virus purification by AF4 and provide examples on the steps that need optimization for obtaining good separation with the focus on halophilic archaeal viruses. Importantly, AF4 method is suitable for a variety of viruses and extracellular vesicles regardless of their host organism.
Eskelin, K., Oksanen, H.M. (2022). Archaeal Viruses: Production of Virus Particles and Vesicle-like Viruses and Purification Using Asymmetrical Flow Field-Flow Fractionation. In: Ferreira-Cerca, S. (eds) Archaea. Methods in Molecular Biology, vol 2522. Humana, New York, NY. https://doi.org/10.1007/978-1-0716-2445-6_31