I’m running into an issue with my Echo 650 where DMSO is spilling when transferring from a 384 PP source plate to a 384 LDV destination plate. I’m transferring 9000 nL (2.5 nL droplets) per well, which is under the rated max volume for the LDV plate (~12 µL).
The thing is, I don’t see this problem when transferring directly from PP to a standard 384 assay plate at comparable volumes. It only happens when the LDV plate is the destination.
I’m using the LDV as an intermediate plate for serial dilutions — the low dead volume makes it ideal so I’m not wasting compound. But I can’t get the volume in there cleanly via acoustic transfer.
A few details:
Echo 650
Source: 384 PP, 100% DMSO
Destination: 384 LDV
Transfer volume: 9000 nL per well
Fluid class: DMSO
My suspicion is that the practical max destination volume for DMSO in the narrow LDV wells is lower than the rated spec due to DMSO’s lower surface tension, but I haven’t been able to find documentation on this.
Has anyone run into this? Is there a known max destination volume for DMSO specifically in LDV plates? Or is something else going on here?
Any suggestions for getting ~9 µL of DMSO into an LDV plate (acoustically or otherwise) would also be appreciated. Thanks!
9uL will be a super slow dispense via the Echo. What’s that take? Like 60mins per plate?
Such a large volume will be much more easily achieved with a disposable tip liquid handler. Bravo would be my choice, but Beckman, Tecan, Hamilton, anything really is going to be better than an Echo for this purpose. The downside is that you will need to use up disposable tips, unless you do it with a fixed tip Tecan 8 channels at a time.
For reference the highest volume we’d ever dispense on an Echo was 1uL. You could have better luck with doing this dispense in smaller increments on the Echo. I’m not positive that an Echo will be lowering the transducer to follow the source liquid level as it dispenses. With 9uL the liquid level is going to have a marked change and the transducer will need refocusing on the meniscus. To test that theory you could do nine 1uL dispenses and see if the DMSO is still seeping out of the destination plate.
Thank you so much. And yes it is about 10 minutes per plate. I am new to this, and the nine 1uL dispenses is a good test and I will try it today. We are also working on getting a Bravo up and running.
I think the Bravo is your ideal solution if you already have one. Even if it’s just a 96ST head you can still work with 384-well plates. And the Bravos will easily hit the small wells of a 384LDV plate. We used to use Bravos to dispense into 1536-well plates (with a bit of trouble).
Don’t forget to survey the destination plate between the transfers, to get the most diagnostic info. (Skip first couple of transfers, as thickness of the liquid column will not be sufficient for reliable results). Also, pay attention that the environment in which you are operating the plates is as dry as possible.
My suggestion for such a large volume is to use a Thermo Multidrop Combi nl reagent dispenser. It is very reliable and accurate and no need for disposable tips. Also, if your Echo is part of a Tempo platform, the integration of the Combi nl is rather straightforward and the device does not take up much space.
We have a few setups like this and to date we are very happy with the performance. Note that we only transfer DMSO with the Combi nl and usually for backfilling or to prepare the Fix plates. It saves a lot of time on the platform.