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Experimental fluorescence device for dielectrophoretic sorting of droplets in microfluidic chips
Ježek, Jan ; Pilát, Zdeněk ; Šmatlo, Filip ; Zemánek, Pavel
At present, many chemical and biological disciplines use different forms of spectroscopy for their observations. One of the most common methods is fluorescence spectroscopy. During the last seven years, microfluidic techniques began developing rapidly, using channels in which two immiscible liquids create droplets with diameters from units to tens to hundreds of micrometers. These droplets serve as liquid microcontainers containing the analysed sample and the necessary reagents. Using special microfluidic techniques, it is possible to fuse droplets with different contents (controlled triggering of chemical reactions), to change the concentration of reactants in the droplet with high speed (concentration gradients), or sort the droplets by content (creation of new cell strains).\n\n
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Compact device for fluorescence measurement by optical fiber in microfluidic chip
Ježek, Jan ; Pilát, Zdeněk ; Zemánek, Pavel
In our paper we present a device that combines fluorescence spectroscopy with fiber optics. The device allows high speed detection (in the order of kHz) of the fluorescence signal, which is coming from the sample by an inserted optical fiber, e.g. from a micro-droplet flow in a microfluidic chip, from the liquid flowing in the transparent capillary, etc. The device uses a laser diode at a wavelength suitable for excitation of fluorescence, excitation and emission filters, optics for focusing the laser radiation into the optical fiber, and a highly sensitive fast photodiode for detection of fluorescence.
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Opticaly trapped tunable droplet microlaser
Ježek, Jan ; Pilát, Zdeněk ; Brzobohatý, Oto ; Jonáš, Alexandr ; Aas, M. ; Kiraz, A. ; Zemánek, Pavel
We introduce tunable optofluidic microlasers based on optically stretched, dye-doped emulsion droplets confined in a dual-beam optical trap. Droplets were created in microfuidic chips. Optically trapped microdroplets of oil emulsified in water and stained with fluorescent dye act as an active ultrahigh-Q optical resonant cavities hosting whispering gallery modes (WGMs). All-optical tuning of the laser emission wavelength was achieved by a controlled deformation of the droplet shape using light-induced forces generated by dual-beam optical trap.
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