How to perform a controlled drug switch with an Elveflow® MUX?

Abstract

This application note shows how to easily perform a controlled drug switch on a hypothetical chemical or biological environment (drug screening or cell culture) using an Elveflow® MUX as shown in these pictures:

For drug switch in perfusion chambers or one inlet microfluidic chips, discover our dedicated Perfusion Pack.

Setup Diagram

This picture shows the microfluidic setup to perform a controlled drug switch :

As often as possible avoid using soft tubing (like Tygon) which involves compliance and then increases the response time of the system.
If you’re not familiar with microfluidic tubings, you may read our dedicated reviews.

The following diagram illustrates the complete chain of elements involved in this application note. You will need to assemble all these parts to set up your experiment:

Protocol

Using the Elveflow® smart interface to perform a controlled drug switch:

Be sure that all the cables and tubing are well connected to your Elveflow devices (USB cable, 24V DC, etc).

Perform leakage tests and remove any air bubbles before starting your experiment to ensure a good flow regulation.
Knowing what fitting is best suited for your needs is a first step towards success. If you’re not familiar with microfluidic fittings, you may read our specific reviews.

In order to monitor the pressure to perform an ultrafast medium switch, it is necessary to follow the next steps:

• Step 1 – Open the Elveflow® smart interface on the computer by connecting the MUX and the OB1.
• Step 2 – Select the OB1 (“OB1MixO1” on the example case) and set an initial desired pressure value in mbar for each drug and control medium. On the example case we have set:

Channel 1 (orange drug): 100 mbar (70% of the channel)

Channel 2 (control medium): 100 mbar (100% of the channel)

Channel 3 (green drug): 90 mbar (30% of the channel)

It is possible to save this configuration for later use by clicking on the “save config” menu option.
It is possible to change the channel name by directly editing the channel name display at the left side of the window.

• Step 3 – In order to add this instrument configuration to the scheduler , click on the “Add step to project” button.
• Step 4 – Click on the “See instrument” button and select the MUX (“MUX-P-00” in the example case), click the “advanced” button and double click on one group to open its configuration panel.
• Step 5 – On the “Selected valves” tab, select the three valves which will be involved in the experiment.
• Step 6 – Go to the “On state” tab and click on the “Use multi step” button in order to program the sequence that will be repeated.
• Step 7 – On the first step of the MUX sequence, select the valves that control drugs injection (valve A1 and A3 in the example case. On the second step of the MUX sequence, select the valve that control the control medium injection (valve A2 in the example case). Finally, set a duration time for each step (5 seconds in the example case).
• Step 8 – In order to add this instrument configuration to the scheduler , click on the “Add step to project” button.
• Step 9 – On the project window, click on the “Add step to project” button and select the action “Wait” in order to set a time length to perform the instrument configurations listed above (10 seconds in the example case).
• Step 10 – Back on the OB1 main window set the next desired pressure values in mbar for each drug and control medium. On the example case we have set:

Channel 1 (orange drug): 90 mbar (30% of the channel)

Channel 2 (control medium): 100 mbar (100% of the channel)

Channel 3 (green drug): 100 mbar (70% of the channel)

• Step 11 – In order to add these parameters to the scheduler, click on the “Add step to scheduler” button.
• Step 12 – Repeat steps from 4 to 9.
• Step 13 – Once the complete sequence is configured, we are going to configure a loop in order to repeat it a desired number of times from 1 to infinite. On the project window, click the “add step to project” button and choose the “Go to” action.
• Step 14 – Select the step where the loop will begin (step 1 in the example case) and the number of times the loop is going to be repeated (5 times in the example case).
• Step 15 – Finally, press the “Start” button to perform the scheduled sequence and its repetitions.

If needed, it is possible to see a graph display by clicking on the “open graph display” button. Set the desired maximum and minimum shown parameters on the display window for pressure and flow rate and press the play icon to launch the pressure and flow rate profiles display. Select the channels you want to display by ticking the corresponding boxes on the channel display selection block.

The screenshots corresponding to some of these steps are in the following gallery:

Congratulations! You’ve achieved a controlled drug switch using an Elveflow® OB1 and an Elveflow® MUX!