BME Lecture Series: Scott Tsai

Abstract: Droplet microfluidics is ubiquitous in biotechnological applications, ranging from single cell analysis to drug discovery to polymerase chain reactions. Despite its many applications, classical water-in-oil droplet microfluidic systems require the use of a toxic continuous oil phase, and many applications involve the laborious washing of droplets to remove the toxic oil phase. My talk will focus on describing a new class of droplet microfluidics platforms, which generate water-in-water droplets. Such water-in-water droplets are possible using aqueous two-phase systems (ATPS), which are formed when two incompatible polymers, such as polyethylene glycol (PEG) and dextran (DEX), are mixed in water and phase-separate above a critical polymer concentration. I will describe using microfluidics to generate water-in-water microemulsions with a high degree of monodispersity, by both active perturbation and completely passive flow focusing methods, and demonstrate the utility of these water-in-water droplets in controlled encapsulation and release of microparticles and cells. Following this, I will talk about the Pickering stabilization and magnetic manipulation of the droplets. Finally, I will briefly describe the generation of water-in-water-in-water double emulsions, and the polymerization of ATPS droplets into "spiky" microparticles that have future applications in drug delivery.

Bio: Scott Tsai is an associate professor in the Department of Mechanical and Industrial Engineering at Ryerson University, and an affiliate scientist at the Li Ka Shing Knowledge Institute of St. Michael’s Hospital. He obtained his BASc degree (2007) in mechanical engineering from the University of Toronto, and his SM (2009) and Ph.D. (2012) degrees in engineering sciences from Harvard University, training with Dr. Howard A. Stone. After a brief NSERC postdoctoral fellowship at the University of Toronto, Tsai joined Ryerson University at the end of 2012. At Ryerson, he leads the Laboratory of Fields, Flows, and Interfaces (LoFFI), which is currently developing innovative microfluidic approaches to generate and use water-in-water droplets and microbubbles in a variety of biomedical applications. Tsai is a recipient of the United States’ Fulbright Visiting Research Chair Award (2018), Ontario’s Early Career Researcher Award (2016), Canadian Society for Mechanical Engineering’s I. W. Smith Award (2015), and Ryerson University’s Deans’ Teaching Award (2015).