I need to transfer variable volume which could range from 0.5ml to 15ml using 5ml channel but I don’t see smart step for 5ml channel. Does that mean I’ve to add many if/else to figure out the loop for transferring more than tip capacity volume? For 1ml channels, smart step figures out if the volume is more than 1ml and it will do multiple asp/disp by itself.
Hi Rishi,
Unfortunately, there is no equivalent 5mL smart step like there is for the 1mL channels. We can work on an example method for how to best accomplish what you need though! We’ll post it when ready!
-Eric
@Rishi - See below for a download link containing a demo method that shows some simple implementations of pipetting high dynamic volume ranges.
Demo method - high dynamic volume range processing
When you import, a helper SMT library will also import alongside the method called ‘HighVolumeHelper.smt’. I wrote this to contain a couple functions that will process an array of volumes (ranging from relatively small, to much greater than what a 5mL tip could transfer in a single aspiration/dispense).
Depending on the situation (reagent aliquot vs sample transfer) this function will modify the volume array and corresponding sequences to account for volumes that exceed the capacity of the liquid class. Essentially, positions/volumes that exceed the maximum supported volume will be replicated an appropriate amount of times, with transfer volumes modified accordingly to achieve the required total volume for the well/container.
Note that the function does not optimize the sequence for optimal transfer efficiency (to account for positions in the same y coordinate or random access limitations that 5mL channels can sometimes cause), but I programmed a couple different transfer options. One shows the simplest possible code, perming a reagent aliquot of varying volumes to an unoptimized sequence. The other (which is disabled in the linked demo method) shows an optimized approach using the popular STAR Channel Tools library of the STAR Tools Suite, which optimizes each transfer for best efficiency, as well as channel access.
Let me know if you have any questions.
-Nick
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Hi Eric,
Thanks for your response and willingness to generate an example method. I am almost done with writing this method with a way around but would love to see your way.
Best,
Rishi
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Hi Nick,
Thank you so much for sharing an example method. I looked through the method and also went through the high volume helper library. This is very helpful. I’ll try this out and let you know if I’ve any questions.
So far, the way I have achieved it is by going through the array of transfer volumes, 4 at a time (as 4x 5ml channels with 4ml filtered tip capacity on STAR) and if any one of the 4 volumes are above 4ml and less than 8ml then divided all 4 volumes by 2. Then I put the loop variable that would go 1 time if all 4 volumes are less than 4ml, 2 times if between 4ml and 8ml and so on. However, this would divide the small volumes unnecessarily into multiple transfers. In your method, you have added extra transfer steps only for the out of range samples. I also like that you divided the volume from array with the max supported transfer volume from liquid class to get the required number of transfers instead of using multiple if/else. Thanks again for your help. This will be a good library to use in such instances.
Cheers,
Rishi
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