Seed train or seed culture expansion process

The seed train or seed culture expansion process is a series of steps used to generate the sufficient amount of viable cells for large-scale production of vaccines, viral vectors, monoclonal antibodies and other biologics. The purpose of the seed train is to progressively grow and expand the initial small-scale cell culture to inoculate the large-scale bioreactor for higher capacity production.

Conventional equipment, ideal for lower expansion volumes, includes glass-spinner flasks and T-flasks for adherent cell lines, as well as shake flasks and small volume stirred tanks for suspension cell lines. As the need for larger cell expansions (N-3) and intensified processes grows, more advanced equipment has emerged. This includes layered vessels, perfusion mode bioreactor rocker bags, and wave/rocking motion bioreactors, offering enhanced efficiency and scalability.

Univercells Technologies has recently developed a way to harvest the cells from its intensified fixed-bed bioreactors to dislodge cells and re-seed them with high viability.

The scale-X™ cell collect module is a benchtop cell harvest system for fixed-bed to fixed-bed inoculation.

The module retrieves cells through a combination of enzymatic and mechanical action, providing high cell harvest yields (up to 2.1×109 cells/m²) with excellent viability (>90%). This enables cost-effective cell expansion in GMP-compliant conditions, while de-risking the seed train process in a low footprint.

The use of the scale-X carbo bioreactor and cell collect module in a seed train can replace the last  steps of the seed train process, which typically involve a significant amount of flatware when using traditional technologies. Figure 1 presents a comparison between the seed train using cell factories and hyperstack. The assumptions used in this comparison are detailed in Table 1. As shown in the assumption table, the scale-X bioreactor can be seeded at a lower cell density and harvested at a higher density. Consequently, the total split ratio in the scale-X system is ultimately larger than that in the flatware system. This significant difference in split ratios highlights the advantages of adopting the scale-X bioreactor for seed train generation when comparing these two alternatives.

The scenario with the scale-X cell collect module not only reduces an entire passage step in 40 layers cell factories, it also requires less equipment at the last passage at a fraction of the cost to achieve the inoculation density for the scale-X nitro bioreactor.

Figure 1. Example scenario using Cell Factories to seed scale-X nitro 600m2 bioreactor

See Univercells Technologies newly introduced cell expansion solution based on the scale-X bioreactor to simplify the workflow for your seed train needs – the scale-X cell collect module.

Would you like to learn more ?

Our experienced Univercells Technologies teams are ready to support you at

Subscribe to
our newsletter