Automating Microfluidics: Reconfigurable Virtual Channels for Cell and Droplet Transport

The emerging field of digital microfluidics promises to solve many shortcomings of traditional continuous-flow fluidics. This technology has a few incarnations, including EWOD (eletrowetting on dielectric) and DEP (dielectrophoresis) chips. Both consist of large arrays of electrical pixels which move droplets and cells. They actuate fluids actively, have error feedback, are programmable, perform operations in parallel, and do not rely on external pumps. For these reasons we foresee the increased use of digital microfluidics in the near future. We also foresee a gradual shift away from purpose-built microfluidic devices, towards multi-purpose platforms with specific applications encoded in software. To this extent we present here a new paradigm of encoding and automating microfluidic operations using video files. We use this technology to create several configurations of virtual microfluidic channels and to play film clips using living cells on a DEP chip.Engineering and Applied SciencesPhysic

Drag Reduction And Heating

Paper presented at 2018 Canadian Society of Mechanical Engineers International Congress, 27-30 May 2018.An external force is required to maintain the relative movement of horizontal plates. It is shown that this force is reduced when the plates are subject to a spatially distributed heating. The largest reduction occurs for heating wavelengths of the order of distance between the plates with its magnitude increasing proportionally to the second power of the relevant Rayleigh number. It is shown that a sufficiently strong heating eliminates the need for the driving force altogether. The effect is active only in small Reynolds number flows