Nano Explorations: Fluorescent Janus droplet and its application in biosensing of Listeria Monocytogenes—Dec. 8

Tuesday, December 8 at 11 a.m. EST

Jie Li
Postdoctoral associate

Dynamic complex droplets afford versatile platforms for biosensing, and the biosensing methods based on droplets enable a combination of advantages including speed, cost-effectiveness, and portability. In this talk, Li will discuss a sensing method based on the agglutination of Janus emulsions for Listeria Monocytogenes, a gram-positive bacterium responsible for a potentially lethal foodborne bacterial illness.

The bio-recognition interface created between the Janus emulsions comprises an equal volume of hydrocarbon and fluorocarbon oils in Janus morphology. This is done by attaching antibodies to a functional surfactant polymer with a tetrazine/trans-cyclooctene (TCO) click reaction. The Listeria antibodies will be on the surface of the hydrocarbon hemisphere, since the surfactant will stay at the interface of hydrocarbon and water phase. Agglutinations of Janus droplets are formed when Listeria is added because of the strong binding between Listeria and the Listeria antibody located at the hydrocarbon surface of the emulsions.

By incorporating one emissive dye in the fluorocarbon phase and a blocking dye in the hydrocarbon phase of Janus droplets, Li can conduct a two-dye assay, which enables the rapid detection of trace Listeria in less than two hours via an emissive signal produced in response to Listeria binding. To clarify, the Janus structure is tilted from its equilibrium position as a result of the formation of agglutinations, and produces emission that would ordinarily be obscured by a blocking dye. Overall, this method not only provides rapid and inexpensive Listeria detection with high sensitivity, but also can be paired with antibodies or related recognition elements to create a new class of biosensors.

Attendees can join and participate in the series via Zoom. Meeting ID#: 860 986 455.

>>See the upcoming schedule and watch past talks.