Channel Tool Optimization for 3 Sequences

Hi all,

I must come back once again cause there is a specific problem I’ve been stuck on for the past couple of days. I’ve been using the STAR channel tool library to optimize my sequences (one aspirate sequence and one dispense sequence) for the span-8 channels and it works wonders, especially when dealing with left/right sorting.

However, things get messy when I want to optimize 3 sequences (one aspirate sequence and two dispense sequences). In my protocol, I am aspirating from one sequence (100 uL) and then dispensing into two different sequences (50 uL each) using the same tip.

I could get into the nitty-gritty details of attempts I made to try to resolve this but I don’t want to make the post any longer. I could also split the pipetting step into two individual aspirating/dispensing steps but that would double the tip count and increase the runtime.

TLTR: Is there a way to optimize three sequences (one aspirate sequence and two different dispense sequences) for the span channel? Or, is it even possible to do so?

Any help appreciated as always,


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Hi @Nat ,

The STAR Channel Tools library was written with standard pipetting in mind which is where the 2 sequences comes in to play as typical pipetting references an aspirate and a dispense. If your source and target locations aren’t specific, meaning the contents of channel 1 can go anywhere to the target plate / tube you could use three calls of Channel Access 1 sequence at the beginning of your loop.

If the sequences are specific and require channel 1 to dispense to specific wells then you would need a custom sorting library that has 3 sequences in mind to maintain the order or to hardcode the sequences so that you are pipetting efficiently without sorting.

Could you give a little more detail on the process you are trying to write for? For example Tube to plate with replicate dispense, something like that to help paint a picture.

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Hi @BrandonBare_Hamilton

Thank you for the explanation as I figured that was the limitation of the library but I wanted to be sure. Each sequence is specific and below is a simple diagram of my protocol where the purple box is the aspiration sequence and the red and blue are the first and second dispensation sequence respectively. This protocol is basically preparing one sample in two different conditions so it is key for the dispensing sequence to be sort like below.

Can it be sorted vertically rather than horizontally?

Either way, I’d probably use a loop twice with channel patterns of 10101010 for first loop and 01010101 for second loop and only increment the aspirate sequence on the second loop. Then dispense in an optimised way (probably better vertically optimised but up to you). Then you only have two sequences.

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