For virus development and production, it is important to know the virus concentration at different stages of the process, to optimize the clone used as well as the production yields. For example, instances such as clone screening, multiplicity of infection (MOI) optimization and adaptations of cell culture methods are instances when virus concentration, or virus titre as it is also commonly called, is of interest.

Dynamic light scattering (DLS) is often used in virus development, in a screening function to separate good and stable samples from those with contaminants or aggregates. With the new multi-angle DLS (MADLS) based particle concentration measurement in the Zetasizer Ultra, it is now possible to get both size and size distribution as well as particle concentration per population, within a few minutes.

In this application note, Allergan are kindly sharing data from their evaluation of the Zetasizer Ultra, examples of three adeno-associated virus (AAV) samples are shown. The concentration results are compared to results from capsid ELISA based virus titre assays.