Microfluidics application note
Published on 27 August 2019
Introduction to flow focusing in microfluidics
Video: Hydrodynamic focusing inside a microfluidic device
Microfluidicists use Hydrodynamic flow focusing in microfluidics as a powerful tool, that can be used for numerous applications, such as microfluidic mixing, separations, sensors, cell analysis, flow cytometry, diffusion-controlled chemical reactions and microfabrication. Hydrodynamic flow 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 microfluidics setup used to easily perform precise flow focusing, and we will see how to take advantage of OB1 MK3+ flow controller’s performance to create a perfectly focused stream.
Application of flow focusing in microfluidics
- microfluidic mixing
- separations
- sensors
- cell analysis
- flow cytometry
- diffusion-controlled chemical reactions
- microfabrication
List of components
Hydrodynamic flow focusing setup diagram
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PROTOCOL & RESULTS
Narrow precise and stable microfluidic flow focusing using Elveflow OB1 Pressure Controller
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 to the middle channel to obtain a very narrow stream. Note that the stream obtained can be really thin and remains stable in time.
Ramps to the middle outlet
Complex flow focusing using Elveflow OB1 Pressure Controller
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.
Oscillating middle stream
Flow focusing inside a microfluidic device using the Elveflow OB1 Pressure Controller
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.
Electrocardiogram
Microfluidic blood flow behavior with hydrodynamic focusing using Elveflow OB1 Pressure Microfluidic
It is also possible to load custom pressure patterns. In the following example, an electrocardiogram pattern is applied to the middle stream and mimics the blood flow circulation.
RELATED TUTORIALS AND REVIEWS
Interested in droplet generation? Check out our dedicated application note!
Microfluidics knowledge
Do you want tips on how to best set up your microfluidic experiment? Do you need inspiration or a different angle to take on your specific problem? Well, we probably have an application note just for you, feel free to check them out!
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