Impact of the Membrane Structure of the Stationary Phase on Steric Exclusion Chromatography (SXC) of Lentiviral Vectors.

For steric exclusion chromatography (SXC), hydrophilic stationary phases are used to capture the target molecule in the presence of polyethylene glycol. The influence of the structure and pore size of the stationary phase on the process requirements are not yet well understood. To better understand the SXC process, membranes with different pore sizes that served as a stationary phase were compared for the purification of lentiviral vectors (LVs). A design of experiments (DoE) was performed to assess the combined impact of PEG concentration and membrane pore size on the purification performance. A visualization experiment showed that the LVs were captured on the first membrane layer for a pore size up to 2.2 µm, and for a pore size larger than 2.2 µm, LVs were also partly found on the second and third membrane layers. Moreover, we could observe that increasing membrane pore size requires a higher PEG concentration to achieve comparable LV recoveries. Using five membrane layers as a stationary phase was sufficient to achieve good performance, supporting the visualized capture results. In conclusion, we could show that each stationary phase has its optimal PEG buffer compositions for SXC, depending on the membrane structure and pore size.