Mix (Bravo, Vertical Pipetting Station)

Description

The Mix (Bravo) () and Mix (Vertical Pipetting Station) () tasks aspirate and dispense liquid multiple times to mix it. The task allows you to specify different well-bottom distances for the aspirate and dispense actions.

 

Task is available for...	Task is available in...
Bravo Platform	Main Protocol, Bravo Subprocess
Vertical Pipetting Station	Main Protocol, Vertical Pipetting Station Subprocess

Task parameters

Note: The task parameters for Mix (Bravo) and Mix (Vertical Pipetting Station) are identical.

After adding the Mix task at the desired point in the protocol, set the following parameters in the Task Parameters area:

 

 

 

 

Parameter	Description
Location, plate	The labware involved in the Mix task.
Location, location	The location at which the Mix task occurs. <auto-select> automatically places the labware at the first-available or appropriate location for the task. If accessories are installed on the deck or shelf, the software uses the accessory configuration information in Bravo Diagnostics or Vertical Pipetting Station Diagnostics to determine the correct location for the task.
Volume (0–200 µL)	The volume of liquid to be mixed in each well.
Pre-aspirate volume (0–200 µL)	The volume of air to be drawn before the pipette tips enter the liquid.
Blowout volume (0–200 µL)	Specifies the volume of air to dispense after the main volume has been dispensed while the tips are still in the wells. Typically, the blowout volume is the same as the pre-aspirate volume.
Liquid class	The pipetting speed and accuracy. IMPORTANT To ensure consistent pipetting, always select a liquid class for liquid-handling tasks.
Mix cycles ((0–100)	Specifies how many times to repeat the aspirate-and-dispense cycle.
Dynamic tip extension (0–20 mm/µL)	The rate at which the pipette head moves during the Aspirate task. The software calculates the distance over which the tips will move without crashing. Use dynamic tip extension to prevent spills as the pipette tips displace the liquid. To move the tips: • At the same rate as the volume change. Calculate dynamic tip extension (DTE) as follows: DTE = (well depth)/(well vol) = 1/A, where A is the cross-sectional area of a well with straight walls • Faster than the volume change. DTE > 1/A • Slower than the volume change. DTE < 1/A The starting and ending positions can be calculated as follows: (Vaspirated * DTE) + Distancewell bottom Note: Instead of a negative aspirated volume, the software automatically moves downward toward the well bottom with each aspirate action.
Well selection	The wells at which the Dispense task occurs. Click the field, and then click the button to select the wells in the Well Selection dialog box. Use this parameter only if the pipette head has fewer tips than the number of wells in the microplate, or if you are in single-row or single-column mode.
Pipette technique	The pipette location offset you want to use for the Dispense task. The list of pipette techniques are defined in the Pipette Technique Editor.
Aspirate distance (0–100 mm)	The distance between the end of the pipette tips and the well botttoms during the aspirate action. IMPORTANT The labware definition must be accurate and the teachpoint must be precise in order for the system to position the tips at the correct distance from the well bottom.
Dispense at different distance	The option to dispense at a pipette tip height that is different than the aspirate distance. Select the check box to enter a value for the dispense distance.
Dispense distance (0–100 mm)	The distance between the end of the pipette tips and the well bottoms during the dispense action.
Perform tip touch	The option to touch the pipette tip on one or more sides of the well.
Which sides to use for tip touch	The side or sides of the well to use during tip touch: North, South, East, West, North/South, West/East, West/East/South/North.
Tip touch retract distance (–20 to 50 mm)	The vertical distance for the pipette tips to rise before touching the sides of the wells.
Tip touch horizontal offset (–5 to 5 mm)	The horizontal distance the tips move. The value is based on the well diameter specified by the labware definition. For example, if you set a value of: • 0, the tips move a horizontal distance equal to the well radius • > 0, the tips attempt to move past the well radius, which results in a more forceful tip touch • < 0, the tips move a distance less than the radius of the well, resulting in a lighter tip touch

Quadrant pattern well selection

 

 

A quadrant is an evenly spaced array of locations that are accessible by the tips on a pipette head. The following table lists the types of pipette heads and the number of accessible quadrants in various microplates.

 

Pipette head channels/pin tool pins	Microplate	Number of quadrants
96	96-well 384-well 1536-well	1 4 16
384	384-well 1536-well	1 4
1536 (pin tool only)	1536-well	1

The following diagram demonstrates the concept of quadrants. The diagram shows a portion of a 384-well microplate and highlights the four quadrants (Q1, Q2, Q3, and Q4) that are accessible by the A1 tip of a 96-channel pipette head. Notice that the green color highlights all of the quadrant 1 (Q1) wells across the microplate.

 

 

 

 

 

Instead of a column- or row-wise pattern, you can select a quadrant pattern during well selection.

The quadrant pattern option is available only if:

•	The number of channels in the pipette head (or pins in a pin tool) is fewer than the number of wells in the microplate. For example, you can use a 96-channel pipette head to dispense liquid into a 384-well microplate or 1536-well microplate.

•	All the channels are selected in the Set Head Mode task when using a pipette head. (The Set Head Mode task is not an option when using a pin tool).

•	The liquid-handling task is inside a loop.

IMPORTANT If you select a quadrant pattern, specifications in the Well Selection dialog box will override task.Wellselection values assigned in the Advanced Settings area.

To select a quadrant pattern:

1	In the Task Parameters area, click the Well selection parameter box, and then click the Browse button. The Well Selection dialog box opens. By default, the Normal well selection option is selected. This option is used for column- and row-wise liquid-handling patterns.

 

2	Select Quadrant pattern in a loop. The contents of the dialog box change. Notice the following:

•	Red numbers (1 through 4) appear on wells A1, A2, B1, and B2. The numbers indicate the pipetting sequence: 1 is the starting well, and 4 is the last well. In the following example, the sequence is A1, A2, B1, B2.

•	Green wells indicate the starting well in the pipetting sequence.

•	Pattern buttons at the bottom of the dialog box indicate the movement of the pipette channels. The movement description is provided in the text box above the buttons.

Note: The last two patterns are unavailable if a group contains 16 wells. For example, the last two patterns are not available if you have a 96-well pipette head and a 1536-well microplate.

 

3	Select the starting well. The well becomes green and is labeled 1.

In the following example, the third quadrant (B1 well) is selected.

 

4	Click a pattern button to specify the pipette channel movement. After you click a pattern, the red numbers in the graphic are updated to show the sequence.

In the following example, the second pattern is selected (right-to-left, then top-to-bottom). The third quadrant (B1) is the starting well. The resulting movement is:

Quadrant 3 (B1)

Quadrant 2 (A2)

Quadrant 1 (A1)

Quadrant 4 (B2)

 

5	When you are finished, click OK to save the changes and return to the VWorks window.

 

 

Example: Mix the contents in the destination microplate on the Bravo Platform

Goal

Aspirate contents from a source microplate (Source 1), dispense into a destination microplate, and then mix the contents in the destination microplate. Use the default Mix parameters.

Implementation

The Bravo deck is physically set up as follows:

•	The destination microplates are at Bravo deck location 1.

•	The source microplate is at deck location 2.

•	The tipbox is at deck location 9.

In the protocol, the following are added:

•	Process for the destination microplate

•	Configured labware for the source microplate

•	Configured labware for the tipbox

In the Destination plate process, a Bravo subprocess is added. Within the subprocess, a Mix task is added after the Aspirate and Dispense tasks as shown in the following example.

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In the Mix Task Parameters area, Destination is selected, because the goal is to mix the contents in the destination microplate.

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Related information

 

For information about...	See...
Adding devices	• Adding devices • Device user guide
Adding tasks in a protocol	Adding and deleting tasks
Aspirate task	Aspirate (Bravo, Vertical Pipetting Station)
Dispense task	Dispense (Bravo, Vertical Pipetting Station)
Set Head mode task	Set Head Mode (Bravo)
Tips On task	Tips On (Bravo, Vertical Pipetting Station)
Tips Off task	Tips Off (Bravo, Vertical Pipetting Station)
Pipette technique	Specifying pipetting techniques
Microplate-handling tasks	Setting parameters for microplate-handling tasks
Microplate-storage tasks	Setting parameters for microplate storage tasks
Scheduling tasks	Setting parameters for scheduling tasks
I/O-handling tasks	Setting parameters for I/O-handling tasks