p4b · gentle stirring for stem cells on microcarriers
Which stirrer keeps every carrier afloat with the least stress for the cells?
Stem cells on microcarriers need just enough stirring: every carrier off the floor, and as little stress on the cells as possible. We 3D-printed helical stirrers, tested each one in our MAKE reactor with a camera under the floor, and predicted the results with our simulation before every test.
Pick a stirrer
They differ in width, number of turns and blade width. The number under each one is the slowest speed at which no carrier stays on the floor.
Same job, 3 to 4 times more shear
Every stirrer here keeps the carriers just off the floor, each at its own slowest speed. What differs is how roughly it treats the cells while doing so. We measure that as the shear in the roughest 1 % of the liquid, from simulation. The camera cannot see it, and a formula from stirrer size misses it by about 20 %. Wide stirrers came out gentlest. Between close neighbours the order can still shift on a finer simulation grid.
A small change that only the simulation saw coming
We mounted stirrer No. 12 higher above the floor, by 10 and by 15 mm. How much faster does it now have to turn? We asked a formula and our simulation before the tests. The formula only knows stirrer size and turns, not where the stirrer sits.
Find the gentlest stirrer for your cells
Design. We simulate your stirrer and vessel options, including the shear at the right speed.
Test. The best candidates run on our MAKE reactor, automated and documented.
Decide. You get a stirrer and a speed you can rely on, with fewer prototypes.
Book a call with the team meet.p4b.io/team
Good to know
One 75 mm transparent vessel, 400 ml water, dyed Cytodex microcarriers, MAKE reactor with automatic floor-image analysis. CFD: M-Star, single phase. Ribbon drawings are schematic. Data as of 22 Oct 2026. Manfred Satzer, Peter Satzer, Lena Achleitner, p4b GmbH.