Raydrop, Double Emulsion Device

Check out our webinar to learn more about the RayDrop double emulsion device!

Most commercial microfluidic droplet generators rely on the planar flow-focusing configuration implemented in polymer or glass chips. The planar geometry, however, suffers from many limitations and drawbacks, such as the need of specific coatings or the use of dedicated surfactants, depending on the fluids in play. On the contrary, and thanks to their axisymmetric geometry, glass capillary-based droplet generators are a priori not fluid-dependent. Nevertheless, they have never reached the market because their assembly requires art-dependent and not scalable fabrication techniques. Here we present a new device, called Raydrop, based on the alignment of two capillaries immersed in a pressurized chamber containing the continuous phase. The dispersed phase exits one of the capillaries through a 3D-printed nozzle, placed in front of the extraction capillary for collecting the droplets. This non-embedded implementation of an axisymmetric flow-focusing is referred to co-flow-focusing.

In the context of a growing demand of controlled droplets in many areas, discover the Raydrop that emerges as a very robust and versatile solution easily implementable in laboratories with little experience and facilities in microfluidics.

What you will learn:

Introduction to droplet-based microfluidics
Current method & technologies present on the market droplet & emulsion production
Understand the advantages & challenges of droplet-based microfluidics
Discover a new method for droplet and emulsion production

Most commercially available and lab-made droplet generators are based on a flow-focusing technology implemented in rectangular microchannels fabricated by lithography and made of polydimethylsiloxane (PDMS), polymers or glass. However, this planar configuration has many limitations due to the contact between the walls of the microchannels and both phases at the junction, requiring laborious and often ephemeral wettability treatments of these walls. On the contrary, due to their axisymmetric configuration, glass capillary systems do not have this drawback since the dispersed phase is never in contact with the walls of the outer capillary.

Therefore, The RayDrop double emulsion device relies on the alignment of two glass capillaries inside a pressurized chamber. A 3D-printed micro-nozzle is additionally connected at the tip of the injection capillary, enforcing the dripping of small droplets. This non-embedded design presents both the characteristics of a co-flow (axisymmetric geometry) and a flow-focusing (dramatic local accelerations of the continuous phase), and is thereby called non-embedded co-flow-focusing.