Microfluidic droplet generation

Microfluidic droplet generation is a technique to create highly reproducible droplets in a very controlled manner. The basis of this technique lies in bringing together of two immiscible liquids that together form the droplet. Microfluidic droplet generation allows great control of the droplet size, and is also suitable for handling very small volumes of liquid.

The chip: the heart of the process

The most basic system for microfluidic droplet generation consists of a pump that is connected via tubing to the droplet generator chip. The latter forms the heart of the system, because here the actual droplet formation takes place. At Micronit, you can choose from a topconnect or a sideconnect system, where the first has great ease of use and the second is famous for its small footprint. The droplet generator chips are also available for both systems.

Key features of droplet generator chips:

• Chips available for a range of droplet sizes up to 140µm in diameter
• Chemically inert materials
• Large viewing area of the channels

The borosilicate glass chips come in a standard polypropylene (PP) fluidic slide. They can be supplied with or without a coating.

Geometries

Droplet generation takes place by combining two immiscible liquid flows into a droplet. These flows are called the continuous phase (forming the external part of the droplet) and the dispersed phase (forming the internal part of the droplet).

The two most common chip designs used for microfluidic droplet generation are the T-junction and the focused flow design. The simplest of these two is the T-junction. In this design, the dispersed phase is introduced into the continuous phase via a 90 degree angle to form the droplet. In the focused flow design, the continuous phase is guided towards the dispersed phase in two separate flows, and envelops it at the intersection.

 

 

 

Micronit offers chips with both of these geometries.

Surface wetting properties

Wetting properties of the chip surface are crucial for the formation of the wanted droplets. Micronit’s droplet generators are made of borosilicate glass, and therefore naturally hydrophilic. This makes them suitable for generating organic droplets in an aqueous phase (oil-in-water droplets). For projects that need aqueous droplets in an organic phase (water-in-oil droplets), we offer droplet generators with a hydrophobic coating.

Scaling up: parallel droplet generation

Once you have a proof of principle on a single droplet generator and want to ramp up the production of the droplets, you can switch to the our parallel droplet generator. This eight-nozzle droplet generator increases the production rate by eight times, while it can easily be connected to your existing system. A simple way to scale up your experiment!

Droplet generation setup

In addition to the various single or parallel droplet generators, Micronit also offers a complete droplet generation setup. The only thing that needs to be added is a pumping system. You can get either choose a top connect or a side connect system. The setups consist of a chip holder, a connection kit and other tools for a quick start of your project. In the ordering process, you can add your chips of choice. Micronit does not supply pumps, but we can advise you on a number of types with which we have good experiences.

Our setups offer an easy way to perform the complex process of droplet generation. We wish you a lot of fun experimenting and we’ll be glad to help you with advice and assistance if needed!