Abstract
Monodisperse microscale drops formed with microfluidic devices are useful for encapsulating cells, microgel particles, or even additional drops. These techniques are thus useful for applications ranging from high-throughput biology to monodisperse particle and capsule synthesis, which require encapsulation of such objects. However, it is challenging to efficiently encapsulate the objects in all drops; often, the objects are encapsulated inefficiently, resulting in many improperly filled, unusable drops. Here, we describe a phenomenon that allows very efficient encapsulation. We use the inflow of the object to plug the drop maker nozzle; the continued injection of the outer phase pinches off a drop, thereby encapsulating the object; this yields precisely one object encapsulated per drop.
Highlights
We introduce the objects into a drop maker device having a nozzle that is long and narrow; when the object is in the nozzle, and in the optimal position for encapsulation, it creates a temporary plugging that causes the pressure to rise in the continuous phase upstream; this induces droplet pinch off
In this regime when drop formation is not triggered, the diameter of the double emulsions is approximately constant, because the size at which the outer drops form is determined by the flow conditions in the second nozzle, which are unchanged by actuating the valves, as shown in Fig. 3d, left
To further confirm this scenario, we extend our measurements over a wider range of TQm; we accomplish this using both microgel particles and small drops to trigger drop formation
Summary
Microfluidic devices can form monodisperse drops with controlled properties and dimensions.[1,2,3,4] They can load objects in the drops, including cells, microgel particles, and even additional drops.[5,6,7,8] These techniques are attractive for applications in high-throughput biology: using drops as tiny “test tubes,” cells, beads, and other reagents can be encapsulated to perform large numbers of reactions at high rates, for ultra-efficient directed evolution, and genetic sequencing applications[9,10,11,12,13]. The inner drop plugs the nozzle, causing the pressure to rise in the continuous phase upstream, which is restricted to flow through gutters at the corners of the channel and thin lubricating layers on its faces
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
