Steven graduated from Saint Louis University in 2014 with a B.S. in Biochemistry. As an undergraduate, he worked under R. Scott Martin on microfluidic devices interfacing capillary electrophoresis with electrochemical detection for neurotransmitter analysis. In 2014, he joined Ryan C. Bailey’s research group at the University of Illinois at Urbana-Champaign and moved to the University of Michigan at Ann Arbor in late summer 2016. Current projects include engineering microfluidic devices for high throughput manipulation of water-in-oil droplet reactor libraries as a tool for chemical biology. When not in lab, Steve enjoys woodworking, board games, and watching hockey.
The K-Channel: A Tool For Biochemistry In Picoliter Droplets
Droplet microfluidic systems rapidly generate libraries of miniaturized reactions. By compartmentalizing small sample volumes (100 pL) in immiscible oil, reducing sample loss and contamination, droplets provide an ideal platform for precise handling of small biochemical samples. While this approach can manipulate thousands of unique, individually addressable reactors, sophisticated in-droplet chemistries are typically limited by combinations of specialized architectures, and necessary steps like injecting reagents or sampling from droplets require optimizing these complex combinations, a time-, resource-, and expertise-intensive process. We have developed the “K-channel,” a modular platform for droplet manipulation. At the intersection of a continuous cross-channel flow with the water-in-oil droplet-containing main channel, the device robustly and reproducibly performs a range of droplet processing modes. K-channel operations alter droplets using: reagent injection, fluid extraction, droplet splitting, and droplet respacing. Droplet operations are selected by applied conditions like pressure, electric field, and magnetic field, so the geometry need not be changed. As a combinatorial module, serial K-channel structures enable sample washing in droplets (200 droplets per second) by retaining functionalized magnetic beads in droplets (98% retention) during droplet splitting (1:1 daughter droplet ratio) and injection (100% volume added). Other applications for the K-channel include characterizing fluid flow through on-chip droplet reactors to ensure uniform reaction time. We envision that the K-channel can provide a simple, modular platform for biochemical analysis in droplets.