Scalable transient gene expression in adherent mammalian cells using polyethylenimine

Transient gene expression (TGE) has become a powerful tool over the last decade, as time to market is a key factor in biopharmaceutical industry. TGE is used to produce small amounts of recombinant protein for functional and structural studies. To broaden the applicability of the method, the scale-up of TGE has been in scope of the scientific community over the last decade. Culture volumes of up to 100 l have been transfected, but there are still bottlenecks regarding the compatibility of the transfection method and media composition as well as media exchange or dilution required after transfection. Cell immobilization on microcarriers is a scalable option to circumvent cell concentration by centrifugation and subsequent dilution or perfusion. Furthermore microcarrier-based cultivation offers a simple solution for medium exchange which allows to maintain cultures during a production period of several weeks.