This question is part of the following Ask The Expert session:
There are several transfection methods to produce AAVs. You may have come across more frequently polymer-based transfection reagents such as PEI, lipid-based and Calcium phosphate. What makes PEI and in general polymer-based transfection reagents more suitable to produce AAVs compared to lipid and calcium-based is the productivity and cost-effectiveness. There are several PEI that are commercially available, but only one PEI that is optimized for viral vector production: PEIpro®. Compared to calcium phosphate, PEI-based transfection can decrease down by 10 times DNA amount and can be used to transfect cells grown in the presence of or in the absence of serum. It brings versatility and scalability by being the go-to transfection reagent compatible with most production platforms, adherent or suspension for small to large scale production capacities. Compared to lipid-based transfection reagent, PEI-based transfection is designed for large scale production: it is cost-effective by substantially bringing down the cost per production batch and is compatible with most production medium and complexation media to adapt to each manufacturer’s process. Last but not least, the availability of the transfection reagent at higher quality grade, ideally GMP Pharma grade, to move on to producing clinical batches is necessary, and must be taken into account in the choice of a reagent as early as possible to guarantee efficient transition from PD to manufacturing.