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Acoustic sorting of microfluidic droplets at kHz rates using optical absorbance.

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Sparrow, Raymond W 
Gantz, Maximilian 


Droplet microfluidics allows one to address the ever-increasing demand to screen large libraries of biological samples. Absorbance spectroscopy complements the golden standard of fluorescence detection by label free target identification and providing more quantifiable data. However, this is limited by speed and sensitivity. In this paper we increase the speed of sorting by including acoustofluidics, achieving sorting rates of target droplets of 1 kHz. We improved the device design for detection of absorbance using fibre-based interrogation of samples with integrated lenses in the microfluidic PDMS device for focusing and collimation of light. This optical improvement reduces the scattering and refraction artefacts, improving the signal quality and sensitivity. The novel design allows us to overcome limitations based on dielectrophoresis sorting, such as droplet size dependency, material and dielectric properties of samples. Our acoustic activated absorbance sorter removes the need for offset dyes or matching oils and sorts about a magnitude faster than current absorbance sorters.


Acknowledgements: This work is part of a project that has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 813786 (EVOdrops). This work reflects only the author's view, and the Research Executive Agency is not responsible for any use that may be made of the information it contains. It was supported by a studentship from the BBSRC Doctoral Training Account, (E. J. M., BB/M011194/1), a Trinity College/Benn W Levy SBS DTP PhD Studentship (M. G.) and an H2020 ERC Advanced Investigator Award (F. H., 695669).


Microfluidics, Acoustics, Spectrum Analysis, Oils, Coloring Agents, Microfluidic Analytical Techniques

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Lab Chip

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Royal Society of Chemistry (RSC)
Biotechnology and Biological Sciences Research Council (BB/M011194/1)
European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (813786)