Seed Train Expansion Planner

Configure your production bioreactor and cell line parameters. The planner automatically generates the optimal seed train from cryovial to production scale.

PRODUCTION

Target Bioreactor

Total Vessel Volume (L)
Working Volume Fraction (%) ?
Target Inoculation Density (x106 cells/mL)
Total Cells Needed (calculated)
CELL LINE

Growth Parameters

Cell Line Preset
Doubling Time (hours)
Max Passage Density (x106/mL)
Seeding Density (x106/mL)
Start Date (Vial Thaw)
Media Cost ($/L, optional)
Seed Train Summary
Seed Train Vessel Progression
Detailed Expansion Plan
Timeline View — Days per Expansion Stage
Media & Cost Summary

How to plan a cell culture seed train

A seed train (or cell expansion train) is the sequential series of passages required to expand cells from a frozen cryovial to sufficient quantity for inoculating a production bioreactor. Proper seed train planning is critical for upstream bioprocess development, ensuring adequate cell numbers at each stage while minimizing passage count and total timeline.

The key parameters are cell doubling time (how fast cells divide), seeding density (cells/mL at inoculation of each stage), and maximum passage density (cells/mL at harvest). Working backwards from the production vessel, you determine how many cells are needed, then select appropriate vessels at each preceding step that can provide those cells.

Standard vessel progression typically follows: cryovial, T-flask (T-25, T-75, T-175), shake flask (125 mL to 2L), spinner flask or wave bag for intermediate volumes, then stirred-tank bioreactors for large-scale expansion. The working volume fraction varies by vessel type: T-flasks have fixed volumes, shake flasks use ~20% of nominal volume, and bioreactors typically operate at 70% of total volume.

Related Articles

Doubling Time Reference
Published doubling times for 50+ cell lines

Frequently Asked Questions

What is a seed train in cell culture?

A seed train is the sequential expansion of cells from a small frozen vial through progressively larger vessels until you have enough cells to inoculate your production bioreactor. Each step involves seeding cells at a low density, growing them to a target density, then transferring to a larger vessel.

How do I calculate the number of seed train steps?

Work backwards from your production bioreactor. Calculate the total cells needed at inoculation (working volume x target inoculation density). Then determine how many cells you can harvest from each progressively smaller vessel, stepping down until you reach cryovial scale. Each step is constrained by the vessel working volume and the maximum cell density achievable.

What is the typical inoculation density for CHO cells?

CHO cells are typically seeded at 0.3-0.5 x 10^6 cells/mL. They can grow to a maximum passage density of 8-10 x 10^6 cells/mL with a doubling time of 20-24 hours.

How long does a typical seed train take?

A mammalian cell seed train typically takes 14-28 days from vial thaw to production bioreactor inoculation, depending on the number of expansion steps, cell doubling time, and target production scale.

What vessels are used in a seed train?

Seed trains typically progress through: cryovials (1-2 mL), T-flasks (T-25, T-75, T-175), shake flasks (125 mL to 2L), spinner flasks (250 mL to 3L), wave/rocking bioreactors (2-50L), and stirred-tank bioreactors (2L to 10,000L+).

Why is working volume different from total vessel volume?

Working volume is the actual liquid volume used in a vessel. For bioreactors it is typically 70% of total volume to allow headspace for aeration, foam, and mixing. For shake flasks it is usually 20% of nominal volume for adequate gas exchange. T-flasks have fixed working volumes based on their growth surface area.