DropBase:droplet electrosorting 3
Overview
Description
Microfluidic chip device for fluorescence-activated droplet sorting (FADS) of ≈ 3 pL-sized droplets (offline-incubation). Blue: silanised area for emulsion handling, depth: 21.5–23 μm. Red: signal electrode (-). Black: ground electrode (+).
Reference
D. Schnettler Fernández, O. J. Klein, T. S. Kaminski, P.-Y. Colin, F. Hollfelder. Ultrahigh-throughput directed evolution of a metal-free α/β-hydrolase with a Cys-His-Asp triad into an efficient phosphotriesterase. unpublished
Submitted by: David Schnettler Fernández
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Usage Notes
Please enter any comments that other users may find useful below this note (such as flow rates that worked well for particular oil/aqueous phases). When providing usage notes please provide as much detail as useful. We would request that you 'sign' any comments with your initials.
Optics and electronics of the microfluidic on-chip sorting device were set-up as previously described ([1], [2]). After incubation at room temperature, 3 pL droplets were reinjected from the collection tubing into the sorting device at a rate of 10–25 μL/h. To enable precise sorting of single droplets, the distance between the droplets was increased by injection of spacing oil (Novec HFE-7500, 3M, USA) into the device at a flow rate of 100–300 μL/h. The asymmetric Y- shaped junction in the device ensures that all droplets automatically flow into the waste channel, unless deviated by an electrical pulse into the sorting channel. A 488-nm laser was focused 100 μm upstream of the sorting junction through a 40× microscope objective (UPlanFLN, Olympus, Japan) for fluorophore excitation and the emitted fluorescent light was collected and amplified using photomultiplier tubes (PMM02, Thorlabs, USA). Whenever the fluorescence peak reached a user-defined threshold, an electric field was applied by the two electrodes on the sorting device, attracting the highly fluorescent droplet towards the narrower sorting channel. Droplets were sorted into a collection tube pre-filled with 100 μL nuclease-free water. DSF
