Prep cannot shake with a lid on the heater/shaker unit

Hamilton (Microlab Prep)
1

It seems that the Prep cannot shake with a lid on (while it knows that it has one on the plate).

We have an application where we need to shake mammalian cells in a 24 well deepwell but we need a lid on. The software does not allow us to do this. I didn’t realize this until very recently. We have a strict volume requirement and cannot lower the volume below 2.5 mLs in a 10 mL deepwell.

Development story goes like this…

  1. I attempted mixing with the 1 mL tips, it was far too slow, risking damage to the cells. I won’t go into further details about that.

  2. Next was mixing with the heater/shaker. This mixes well but needs to be at a sufficient speed to get thorough mxing. I found when performing cross-contamination testing, with cells generating fluorescent proteins, that cross-contamination occurs at a rate that is too high for our process.

  3. Same shaking but we added a lid to the plate, which we put on and take off manually, (open Prep in a BSC). No contamination. I had submitted for plate definitions to have lids that fit well for our plate type. Once I had those definitions, I realized that the robot errors out when trying to shake with a lid on.

Has anyone found a way to get around this? I was told that not shaking with a lid is a necessary feature. I strongly disagree with this as it results in cross-contamination and in the 6 months of using a lid I had no issues with it on the shaker.

If we could resolve this issue, we intend to expand our usage of the instrument for the application. Unfotunately, this is a deal breaker. I don’t remember this limitation on our Star line. I believe that I have used plate lids on the shaker. I also believe that it can be pipetted to and from on the shaker which also seems to be unavailable on the Prepbut is less of a concern right now.

2

Hi @Madclem1, thanks for laying this out so clearly, and for sharing the data from your contamination checks.

You’re correct: in the current Prep software, the system blocks shaker operations when a plate is defined or tracked as lidded. This constraint is a functional guardrail rather than a statement that shaking with lids is inherently ‘wrong’ for every workflow. It exists because lid fit, retention, and off-axis clearance vary significantly across different plate/lid combinations and shake orbits. The software currently takes a conservative approach to prevent unexpected lid movement or collisions during unattended runs.

That said, your point is well taken. For cell culture workflows, shaking without a lid can introduce real risks, and your data clearly shows how lidded shaking resolves the cross-contamination issue in your process.

Regarding a timeline: our next software release is already in late-stage QA, so we won’t be able to include this change in the immediate cycle, but we are assessing it for a subsequent update. I have already reached out to our product support team to pull the details on your specific plate+lid combo so we can use it for testing. If you’re willing, please DM me with your exact heater/shaker parameters (speeds and durations) so we can ensure those are factored into our evaluation.

In the meantime, we understand why you’ve moved to manual lid handling in the BSC as a workaround, and we’re committed to helping you get to a more automated, robust solution.