Fig. 1
From: Droplet microfluidic screening to engineer angiotensin-converting enzyme 2 (ACE2) catalytic activity
An ultra-high-throughput ACE2 screening platform. (a) An overview of our microfluidic screening system. Yeast displaying ACE2 variants are encapsulated in droplets with the Ang-II substrate and an amino acid detection kit. The droplets are incubated offline, reinjected onto a sorting chip, analyzed for fluorescence signal, and active ACE2 variants are sorted and collected for downstream analysis. (b) Ang-II cleavage by ACE2 releases free phenylalanine, which is detected using a commercial amino acid detection kit [15]. (c) Our ACE2 assay can reliably detect Ang-II cleavage by ACE2-displaying yeast. Error bars represent one standard deviation for triplicate measurements. (d) A mock sorting experiment where negative and positive control ACE2 yeast are combined at a 10:1 ratio, put through the full microfluidic screening pipline, and the pre/post-sort populations are analyzed for ACE2 activity. The microfluidic system can enrich active ACE2 fivefold. Error bars represent one standard deviation for triplicate measurements