Sequence Set-Up for Dispense Aliquoting

Hamilton (Venus)
1

Hi all,

I am brainstorming a new method involving sampling from 50 mL tubes and dispensing either two or four replicates of each sample into wells of a 24-deep well plate. The idea is a user would input a worklist of the 50 mL tube IDs and desired volume of each tube to be aliquoted per replicate (all replicates for one sample would be identical), and the system would use a standardized dispense sequence so replicates are vertically adjacent (see below for a quite colorful example):

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What I am struggling to wrap my head around is how to set up the dispense sequence such that either pattern is followed and I don’t end up with e.g. channel 2 containing sample 2 ending up in B1 because channel 2 incremented the sequence by 1.

I was thinking I could set up separate sequences for each replicate dispense (e.g. for a 2 replicate workflow, replicate one sequence would use wells A1, C1, A2, C2, A3, C3 and so on of each destination plate; replicate two sequence would use B1, D1, B2, D2, B3, D3, and so on…) and then just use two dispense steps in the method, one pointing at each sequence.

Is there a better way to do this? Can I specify channel 1 should dispense twice before channel 2 begins its dispense and so on? Are there any aliquoting libraries that would blow my mind?

Thanks!

2

The most direct fix would be to duplicate wells in the aspirate sequence.

Sequence   Well
1           A1
2           A1
3           B1
4           B1
...

It would be a pain to set this up per number of replicates. Seems like you could also loop and manually sequence count in some way, but it would take some testing.

3

I’m doing something very similar and finding that the PowerSteps Replicate step is pretty slick for this type of dispensing. Have you looked into the various replicate configurations that this step offers?

4

This would work, but at the expense of needing to utilize multiple tips per sample, which is bit of a trade-off here.

I may give the idea of defining two separate sequences and using one for dispense 1, and the other for dispense 2 with automatic sequence counting a try. A little ugly considering I’ll need to do a similar strategy for 4 repeats (4 sequences/4 dispenses), but logically it seems straightforward, at least.

5

I’ve actually never used Powersteps. This seems like a good excuse to explore them more. Thanks for reminding me that those exist.

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