AF4-MALS Enables Separation and Sizing of a Virus Mixture

Postnova Analytics has published an applications report that presents data from a collaboration with the Analytical Development group at Biogen Inc. on separation of a virus mixture using Asymmetrical Flow Field-Flow Fractionation (AF4) and measurement of their radius of gyration (Rg).


Pharmaceutical and biotech companies are increasingly using viruses as gene therapy delivery vehicles due to their versatility and safety. Viruses can be loaded with DNA or RNA and delivered to a specific location in the body to treat or cure a disease. However, one of the biggest challenges for manufacturing a homogeneous virus sample is the presence of viral aggregates, which negatively affect transduction efficiency, biodistribution, and immunogenicity. Due to their relatively large size, often over 50 nm in diameter, virus aggregates are challenging to separate and characterize by traditional column-based chromatography techniques such as Size Exclusion Chromatography (SEC).

The application report details how, in order separate multi-modal virus samples by size, a Postnova AF2000 AF4 system was used, coupled to a Postnova 21-angle Multiple Angle Light Scattering (MALS) detector for measuring the Rg.

The data presented demonstrates that AF4-MALS is a powerful tool for the separation of virus particles. This powerful technique is shown to separate viruses and aggregates from a few nm up to >100 nm. This means that AF4-MALS can easily separate and size multi-modal virus samples, including the larger Ad5 virus and its aggregates with high resolution and precision.

Modular in design, the AF2000 FFF system incorporates the combined experience, expertise and technological advances from Postnova Analytics' nearly two decades of leadership in FFF. Incorporating a range of FFF modules in a single integrated system to provide universal separation, the AF2000 offers more flexibility, better performance and more robust results than any system before. The AF2000 FFF system is available with a wide range of add-on modules, extra options and special FFF detectors, such as Refractive Index (RI), Multi Angle Light Scattering (MALS) and Dynamic Light Scattering (DLS). All Postnova FFF modules and detectors have been especially developed for FFF and are perfectly optimised not only for the use with the AF2000 but also for easy interfacing with high-end detection technologies from other suppliers that may already be at use in your laboratory. 

For a copy of the application report please visit To discuss how AF4 systems can separate and characterise your virus, virus-like particles and vaccine components please contact Postnova Analytics Inc. on +1-801-521-2004 or This email address is being protected from spambots. You need JavaScript enabled to view it..