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bioRxiv · 10.1101/2024.03.01.583031

FACS-Sortable Picoreactors for Ultra High-throughput Screening of Catalysts in Biphasic Environments

Thompson, S.·Zhang, Y.·Yang, Z.·Nichols, L. A.·Fordyce, P. M.
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Abstract

Biphasic environments can enable successful chemical reactions where any single solvent results in poor substrate solubility or poor catalyst reactivity. For screening biphasic reactions at high-throughput, a platform based on microfluidic double emulsions could use widely available FACS (Fluorescence Activated Cell Sorting) machines to screen millions of picoliter reactors in a few hours. However, encapsulating biphasic reactions within double emulsions to form FACS-sortable droplet picoreactors requires optimized solvent phases and surfactants to produce triple emulsion droplets that are stable over multi-hour assays and compatible with desired reaction conditions. This work demonstrates such FACS-sortable triple emulsion picoreactors with a fluorocarbon shell and biphasic octanol-in-water core. First, surfactants were screened to stabilize octanol-in-water emulsions for the picoreactor core. With these optimized conditions, stable triple emulsion picoreactors were produced (>70% of droplets survived to 24 hours), and the ability to produce protein in the biphasic core was demonstrated via cell-free protein synthesis. Finally, triple emulsion picoreactors were sorted based on fluorescence using commercial FACS sorters at >100 Hz with 75-80% of droplets recovered. These triple emulsion picoreactors have potential for future screening bead-encoded catalyst libraries, including enzymes such as lipases for biofuel production.

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Thompson, S., Zhang, Y., Yang, Z., Nichols, L. A., Fordyce, P. M.. 2024-03-05. FACS-Sortable Picoreactors for Ultra High-throughput Screening of Catalysts in Biphasic Environments. https://doi.org/10.1101/2024.03.01.583031

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