Integrated, Continuous Emulsion Creamer

• Published in: Analytical chemistry (Washington) 2017-12, Vol.89 (24), p.13227-13234
• Main Authors: Cochrane, Wesley G, Hackler, Amber L, Cavett, Valerie J, Price, Alexander K, Paegel, Brian M
• Format: Article
• Language: English
• Subjects: Assaying; Automation; Chemistry; Coding; Deoxyribonucleic acid; Dispersion; DNA; Drainage channels; Droplets; Drug discovery; Enzymatic activity; Enzymes; Incubation; Incubators; Instrumentation; Kinases; Microfluidics; Miniaturization; Oil; Phosphodiesterase; Processors; Robotics; Screening
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/acs.analchem.7b03070

Automated and reproducible sample handling is a key requirement for high-throughput compound screening and currently demands heavy reliance on expensive robotics in screening centers. Integrated droplet microfluidic screening processors are poised to replace robotic automation by miniaturizing biochemical reactions to the droplet scale. These processors must generate, incubate, and sort droplets for continuous droplet screening, passively handling millions of droplets with complete uniformity, especially during the key step of sample incubation. Here, we disclose an integrated microfluidic emulsion creamer that packs (“creams”) assay droplets by draining away excess oil through microfabricated drain channels. The drained oil coflows with creamed emulsion and then reintroduces the oil to disperse the droplets at the circuit terminus for analysis. Creamed emulsion assay incubation time dispersion was 1.7%, 3-fold less than other reported incubators. The integrated, continuous emulsion creamer (ICEcreamer) was used to miniaturize and optimize measurements of various enzymatic activities (phosphodiesterase, kinase, bacterial translation) under multiple- and single-turnover conditions. Combining the ICEcreamer with current integrated microfluidic DNA-encoded library bead processors eliminates potentially cumbersome instrumentation engineering challenges and is compatible with assays of diverse target class activities commonly investigated in drug discovery.