Overview

The OT-2's default height at which pipettes will aspirate and dispense is 1 millimeter above the bottom of a well. This article covers how to adjust the height at which pipettes aspirate and dispense in python protocols and in Protocol Designer.

Adjusting Aspirate/Dispense Height in Python

In order to adjust the aspirate/dispense height in a python protocol, you'll need to add a .top() or .bottom() command to the destination location of the pipette's aspirate or dispense command.

Code example

A default dispense or transfer command would look like this:

p10.transfer(
    5,
    source_plate.wells('A1'),
    destination_plate.wells('A1'),
    new_tip = 'always'
    )

If you want to make this transfer to 3 millimeters above the bottom of destination_plate , your code would look like this:

p10.transfer(
    5,
    source_plate.wells('A1'),
    destination_plate.wells('A1').bottom(3),
    new_tip = 'always'
    )

Another example of a change to a transfer location would be to 2 millimeters below the top of a container. Your code would look like this:

p10.transfer(
    5,
    source_plate.wells('A1'),
    destination_plate.wells('A1').top(-2),
    new_tip = 'always'
    )

For both offsets from bottom and top, you can pass any integer value, positive and negative. Positive is above bottom or top, and negative is below bottom or top.

In order to make this change for a destination of a dispense or transfer command that is a list of wells, you would need to make a list variable using code like this:

destination_wells = [well.bottom(3) for well in plate.wells()]

This code will create a list of all wells in the container plate . Using this list, you can pass it into any dispense or transfer command like this:

p10.transfer(
    5,
    source_plate.wells('A1'),
    destination_wells,
    new_tip = 'always'
    )

Adjusting Aspirate/Dispense Height in Protocol Designer

In Protocol Designer, you make the adjustment to aspirate or dispense height when defining a transfer or mix step. When you are in the window where you define a transfer or mix step, click the gear icon next to the Aspirate or Dispense heading to expand your options:

Once you've clicked the gear, you will notice that there are a number of advanced options available for you to adjust. To adjust the aspirate/dispense height, click the field under "Tip Position."


This will open a separate window in which you can either raise or lower the height in increments of 1mm by clicking the "+" and "-" buttons, or manually enter a height in the text field.

Click "Done" to save the adjustment to the aspirate/dispense height.

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