Application Note How to perform hydrodynamic focusing inside a microfluidic device

Video: Hydrodynamic focusing inside a microfluidic device

With the OB1 Mk3 microfluidic flow control system

Hydrodynamic focusing is a powerful tool for microfluidicists that can be used for numerous applications, such as microfluidic mixing, separations, sensors, cell analysis, flow cytometry, diffusion-controlled chemical reactions and microfabrication. Hydrodynamic focusing occurs when fluids with different velocities are injected side by side. The most common way to perform hydrodynamic focusing is to use a 3 inlets microfluidic chips, where the core flow containing the sample of interest is sheathed by an inert fluid.

In this application note, we will detail the fluidic setup used to easily perform precise flow focusing, and we will see how to take advantage of the performances of the OB1 Mk3 flow controller to create a perfectly focused stream.

List of components


This following diagram and pictures show the microfluidic setup used for this application note.

microfluidic flow focussing

You will find some pictures of the fluidic setup in the following gallery:

Hydrodynamic flow focusing Microfluidic Setup 2

Hydrodynamic flow focusing Microfluidic Pressure controller

Hydrodynamic flow focusing Microfluidic Setup


The Elveflow® Smart Interface is a user-friendly software that will allow you to easily perform different experiments of flow focusing. The aim of the hydrodynamic focusing is to position the elements of interest (fluid, cells, particles) at a precise spot, and thus the flow control has to be reactive and stable. We are going to see how we can obtain unique and accurate flow focusing thanks to the OB1 Mk3 Elveflow flow controller.

In this first video, we are gradually decreasing the pressure applied on the middle channel to obtain a very narrow stream. Note that the stream obtained can be really thin and remains stable in time.

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It is also possible to create complex flow focusing by applying pressure patterns, such as ramps to the middle outlet of the pressure controller. The focusing can thus be quickly adjusted  from a large stream to a very narrow stream positioned precisely in the microfluidic channel.

Microfluidic flow focusing complex pressure pattern

By applying ramps with a 180° shift to the two border streams, you can easily create an oscillating middle stream. The middle stream stay really stable with the same width and can be extremely thin.

It is also possible to load custom pressure patterns. In the following example, an electrocardiogram pattern is applied on the middle stream and mimics the blood flow circulation.

Microfluidic flow focusing custom pressure pattern ECG

Interested in droplet generation? Check out our dedicated application note!


We  provide the only microfluidic flow control system using Piezo technology that enables a blazing fast flow change in your microdevice.

Piezo electric microfluidics flow control