Protein Source Station

The Protein Source Station is an area in the NT8 software where you interact with your protein solutions, such as adding an aspirate and dispense task to the Protein Tray Station. As a very low dead volume machine, the NT8 requires proper setup of reagents to ensure optimal performance.

Protein Source Station

An inactive protein source is indicated by a grey Protein Source Station in the Device View. You must set up your protein source in NT8 before performing any experiments involving either the high volume (HV) or low volume (LV) protein block. Read below to better understand the difference between HV and LV protein blocks.

Inactive Protein Source

Low Volume (LV) Protein Block	High Volume (HV) Protein Block
Can hold up to 3 μL of protein sample, 300 nL of which is dead sample.	Can hold up to 13 μL of protein sample, 500 nL of which is dead volume.
Can be filled using an LCP head (if present).	The volume can be calculated by NT8 either manually or automatically.
Always calculates protein volume automatically.	Provides continuous update of the remaining protein volume in the protein tray during an aspiration task (if you set the volume manually).
An active low volume protein block is indicated by the words Low Volume appearing at the top of the Protein Source Station icon, as shown below. Active Low Volume Protein Block	An active high volume protein block is indicated by the words High Volume appearing at the top of the Protein Source Station icon, as shown below. Active High Volume Protein Block

See the sections below for more information on automatic and manual protein volume calculation.

Enabling Automatic Protein Volume Calculation

NT8 always enables the Automatic Protein Volume Calculation when you use an LV protein block because the LV protein block is typically used for one-time task runs before it needs to be filled again. With Automatic Protein Volume Calculation enabled, the software will automatically calculate the required volume of sample to be aspirated from the protein tray, compensating for any dead volume. Meanwhile, the HV protein block allows you to choose whether the volume calculation is manual or automatic. The latter function is enabled by default. If it is disabled in your software, follow the tutorial below to enable this function.

Note

It is recommended to use the automatic volume calculation feature, and pipette the specified volume into the protein block for use in your experiment.

To enable the protein volume calculation for high volume protein block:

1. Right-click the protein source image and select Set Protein Volume. The Protein Volume Setup panel appears:

   Note

   If you are using a High Volume protein block, right click the protein source image and select Set High Volume Protein Tray. Your hardware may be equipped with automatic sensors to distinguish between protein blocks.

   

   The Protein Volume Setup Panel

2. Check the Auto check boxes, then click OK. Please note that the maximum volume of the low and high volume protein trays are 3 µL per well and 13 µL per well, respectively.

Warning

Use a 2, 10 or 20 µL pipette to dispense the calculated volume of solution into each well of the specified column. This should be done as the last step before initiating a dispense, to minimize the risk of evaporation while preparing the experiment. It is important to practice proper reverse pipetting technique to eliminate bubbles when loading the protein tray. See Reverse the Pipetting Technique topic below for more information. Alternatively, you could use the aliquoting feature of a suitable electronic pipette.

Note

Due to larger dead volume, a warning message will appear if you assign a High Volume protein block to an aspiration task with a volume lower than 3 μL (3000 nL). Hover over the Warning sign displayed next to the Aspirate action column in the task list to view the notification and its recommendation.

(HV Protein Block) Setting the Protein Volume Manually

If you manually set the volume of protein in your HV protein block, NT8 will provide a continuous update of your remaining protein volume in the Protein Source Station icon as the protein is aspirated from the protein tray. At the end of the task run, the NT8 software will also show the remaining volume that hasn’t been aspirated yet. You can use the remaining volume for another experiment.

Note

It is strongly recommended to use the automatic volume calculation feature in NT8, and fill the specified volume into the protein block for use in your experiment.

To set the protein volume manually:

1. Right-click the protein source image and select Set Protein Volume. The Protein Volume Setup dialog appears:

   Note

   If you are using a High Volume protein block, right click the protein source image and select Set High Volume Protein Tray. Your hardware may be equipped with automatic sensors to distinguish between protein blocks.

   

   Defining the Protein Volume Manually

2. Uncheck the Auto check boxes and type the desired protein volume in Volume fields for each column. Please note that if the Auto check boxes are left checked, the NT8 will automatically calculate the protein volume required for any aspiration tasks assigned to the protein tray instead of your specified volume.

   Note

   Due to larger dead volume, a warning message will appear if you assign a High Volume protein block to an aspiration task with a volume lower than 3 μL (3000 nL). Hover over the Warning sign displayed next to the Aspirate action column in the task list to view the notification and its recommendation.

3. Fill in the volume available in each reservoir of a particular column using reverse pipetting.

   Warning

   Ensure that the volume set on the NT8 Control Software matches the actual volume in each reservoir of the protein source. Reservoir volume must be the same for each reservoir in a column.

4. Click OK.

Reverse Pipetting Technique

Reverse pipetting technique is used to dispense a measured quantity of liquid by means of an air displacement pipette. In traditional pipetting, one would aspirate the required amount of sample by pushing the pipette’s plunger to the first stop and then releasing it. The dispense then would require pushing out the entire sample and a small amount of air by pushing the plunger past the first stop and to the second one. In contrast, reverse pipetting involves pushing the plunger to the second stop, thus overaspirating, and dispensing the required amount by pushing the plunger to the first stop. This technique is particularly useful to eliminate bubbles when loading the protein tray.

Prerequisite:

• You are using an air-displacement pipette.

To fill the protein tray in reverse pipetting technique:

1. OPTIONAL: Take the Protein Source out of the Protein Source Station.

2. Attach the Tip to the Pipette, and set the volume as needed.

3. Press down the plunger to the second stop (purging position).

4. Immerse the tip to the protein solution liquid and slowly release the plunger to draw up the liquid to the tip.

5. Dispense the liquid into the Protein Source wells by pressing down the plunger to the first stop. Please note that this approach will leave a small volume of the liquid inside the tip, which is normal.

6. Repeat the steps 3-6 until all protein wells are filled with the required volume.

   Note

   After you have filled all the protein wells, if desired, you can recover the overaspirated volume from the pipette tip by pressing down the plunger to the second stop.

Creating a Dispense Task for the Protein Tray

When you use low volume protein block, you can tell the NT8 to fill the protein tray using LCP heads (if present), which always provide a highly precise dispense. Follow this tutorial to add a dispense task for your protein tray.

1. Right-click the Protein Source Station icon and select Aspirate/Dispense.

   OR

   Double-click the Protein Source Station icon.

2. Under Select Operation, select Dispense, as shown in the image below. The LCP Syringe option in the Select Head option is selected automatically.

   

   Creating a Dispense Task for the Protein Tray

3. Under Column, select which columns in the protein tray you want to dispense the protein sample into.

4. Next to Z-Offset, choose the distance from the tray you want the tip of the syringe to dispense from. The default value is 0.1 mm.

5. Click Add to save the changes.

   OR

   Select Add More if you want to add more Dispense commands and set up additional dispense volumes.

Protein Source Station Right-Click Menu Option

Option	Description
Aspirate/Dispense	Launches the Task Details window. The Aspirate/Dispense option is enabled only if you have already added the Pick Tip command to the Task List, (see The Tip Caddy Stations). Dispense Protein Option in Task Details Aspirate Protein Option in Task Details Select Operation Provides Aspirate and Dispense options. Select Aspirate if you want the NT8 to aspirate protein from the protein source. Select Dispense if you want to dispense protein sample into the protein source. When you use an LV protein block, NT8 allows you to dispense protein sample into the protein tray using an LCP head, which can provide a highly precise dispense. Select Head If you choose Aspirate task, the Low Volume Tips head is automatically selected. If you choose Dispense task, the LCP Syringe head is selected. Select Source/Select Target Column Lets you to select the protein source column number. The NT8 will perform the action on the selected column. Please note that if you are using an HV protein block, the protein column numbers will be disabled if you haven’t set the protein volume (see Setting the Protein Volume). Liquid Class Lets you select the protein liquid class. Set Parameters Volume Set the protein volume in nL to be aspirated or dispensed by typing a new value into the corresponding field, or clicking the up and down-arrows to increase or decrease the volume. Mixing Cycle Set the number of times you want the sample to be mixed. Mixing Volume Set the volume in nL to be mixed. Pre-Dispense Set the additional volume in nL to be aspirated after aspirating the targeted volume. Z-Offset Determines the clearance between the tips and the plate surface or between the LCP syringe and the protein tray surface for a dispense task. Use Smart Aspirate Selecting this option allows the NT8 to automatically calculate the z-offset at which the tips will stop before aspirating. If you want the tips to aspirate protein sample from the same height for all columns, deselect the Use Smart Aspirate option. Warning The aspirate custom height option is for advanced users or FORMULATRIX support only! Add Adds the specified settings to the Task List and closes the Task Details window. Add More Adds the task to the task list and waits for you to add another aspirate or dispense command. Close Exists the Task Details window. Note The blue indicator will highlight based on the number of tips attached to the NT8 head. For example, if you are going to aspirate using all of the 8 tips to dispense to 96-well plate, the blue indicator will highlight all tips, while only 4 tips will be highlighted for 24-well plate dispensing.
Set Protein Volume	For HV tips only. See Setting HV Protein Volume Manually.
Set High Volume Protein tray/Set Low Volume Protein Tray	Lets you to select the specific protein tray type to be used in your experiment. The NT8 supports the use of both a low volume protein tray and high volume protein tray.

Related Topics

• Hardware Overview

• Liquid Class Guidelines

• The Tip Caddy Stations