How to perform an ultra-fast microfluidic medium switch with an Elveflow® OB1 and an Elveflow® MUX

SET-UP TIME : 10-15 MIN / DIFFICULTY : *****

Abstract  

This application note shows how to perform an ultra-fast microfluidic medium switch (drugs, samples, etc) in an hypothetical chemical or biological environment, performed with an Elveflow® OB1 and an Elveflow® MUX as shown in these pictures:

We propose another configuration (using only an Elveflow OB1) to perform a fast flow switch. Click here to see the Application Note.

We also recommend to see the following review comparing the two configurations (OB1 or OB1+MUX).

Set-Up Diagram

These pictures show the microfluidic setup that will be used to perform a ultra-fast medium switch in this application note.

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 tutorials.

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 an ultra-fast medium switch:

Make sure that all the cables and tubings 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 tutorials.

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

• Step 1 – Open the Elveflow® smart interface on the computer and select the MUX. (“MUXS1” in the example case).
• Step 2 – Open the three valves where the three mediums are connected and press “Apply” (D1, D2 and D3 in the example case).
• Step 3 – Select the OB1 (“OB1Mix01” in the example case) and set an initial desired pressure rate value in mbar for each one of the three different mediums (130 mbar in the example case) on the relevant channels (channels 1, 2 and 3 in the example).
• Step 4 – Increase or decrease the pressure rate on the different channels until finding the equilibrium on the three mediums (the three mediums will converge and pass through the main channel without mixing with a laminar flow) (See the picture on the gallery below)

These equilibrium pressure rates will ideally not be far from being the same or very similar on the three channels but it will depend on different factors, such as the different density of the mediums used, the different resistivity of the setup (the number and type of connectors, the length of tubing used, etc).

• Step 5 – Once the equilibrium pressure rates have been set, select back the MUX. Then press the button “sequential -> on” and configure the combination of valves that will be open or closed with the desired length (4 seconds on the example case).
• Step 6 – Repeat “Step 4” for the other mediums by clicking on the “+” button or by adding the step to a project.
• Step 7 – Press the “Apply” or “Play” button in each case to start performing the project.

Congratulations! You can now perform an ultra-fast medium switch using an Elveflow® OB1 and an Elveflow® MUX!