| In Ion Mobility Spectrometry, charged species (ions) are injected into an enclosed drift chamber that has an electric field applied along its axis. Under the influence of the electric field, the ions are transported through the chamber towards a detector. The ion’s mobility along the drift chamber is a function of the ion electric charge, mass, and size. Therefore, different ions will be transported at different velocities and each individual ion type will have its own signature mobility. The identity of the ions can be determined by measuring the signature mobility and comparing the results to an established database. The mobility is expressed as a function of (a) the electric field and drift length (the known parameters) and (b) the drift time (the measured parameter), where drift time is the duration between ion injection and response at the detector. This work examines a gating strategy and counter electrode configuration for a ‘planar-type’ device that can be used to further the development of miniaturized Ion Mobility Spectrometers. |  |
| The goal is to use an immunosensor designed to function with common particle–based fluorescence immunoassays. The chemifluorescent reaction product creates a change of fluid composition. As a result, the electrical and dielectric properties of the fluid change. When implemented on a digital microfluidic (DMF) device, the fluorescence reaction will hence be picked up by a change in the capacitance across the parallel electrodes. This research develops an integrated digital microfluidic system capable of executing biochemical protocols. The system performs liquid control and handling, as well as incorporates sensors for electrochemical detection. |  |
Selected Publications
(2015) Modelling the capacitance of multi-layer conductor-facing interdigitated electrode structures, Sensors and Actuators, B: Chemical 213, doi:10.1016/j.snb.2015.02.088
(2015) Characterization of coplanar electrode structures for microfluidic-based impedance spectroscopy, Sensors and Actuators, B: Chemical 218, doi:10.1016/j.snb.2015.04.106
(2012) Characterizing the surface quality and droplet interface shape for microarray plates, Langmuir 28(26), doi:10.1021/la302091t
(2012) Automated detection of particle concentration and chemical reactions in EWOD devices, Sensors and Actuators, B: Chemical 164(1), doi:10.1016/j.snb.2012.01.027
(2011) Mechanical filtration of particles in electrowetting on dielectric devices, Journal of Microelectromechanical Systems 20(4), doi:10.1109/JMEMS.2011.2159101
(2010) An empirically validated analytical model of droplet dynamics in electrowetting on dielectric devices, Langmuir 26(24), doi:10.1021/la103702t
(2010) An empirically validated model of the pressure within a droplet confined between plates at equilibrium for low Bond numbers, Experiments in Fluids 48(5), doi:10.1007/s00348-009-0773-8
(2010) Using capacitance measurements in EWOD devices to identify fluid composition and control droplet mixing, Sensors and Actuators, B: Chemical 145(1), doi:10.1016/j.snb.2009.12.019
(2012) Electrospray from a droplet, Experimental Thermal and Fluid Science 37, doi:10.1016/j.expthermflusci.2011.10.002
(2011) An overview of electrospray applications in MEMS and microfluidic systems, Journal of Microelectromechanical Systems 20(6), doi:10.1109/JMEMS.2011.2168810
(2009) On the pulsed and transitional behavior of an electrified fluid interface, Journal of Fluids Engineering, Transactions of the ASME 131(9), doi:10.1115/1.3203203
(2008) Application of an equilibrium model for an electrified fluid interface - Electrospray using a PDMS microfluidic device, Journal of Microelectromechanical Systems 17(6), doi:10.1109/JMEMS.2008.2006822
(2008) Plane model of fluid interface rupture in an electric field, Physics of Fluids 20(4), doi:10.1063/1.2891311
(2013) A drop-on-demand-based electrostatically actuated microdispenser, Journal of Microelectromechanical Systems 22(1), doi:10.1109/JMEMS.2012.2221681
(2013) Electrowetting on dielectric (EWOD)-based thermo-responsive microvalve for interfacing droplet flow with continuous flow, Journal of Microelectromechanical Systems 22(3), doi:10.1109/JMEMS.2012.2228846
(2012) Characterizing the surface quality and droplet interface shape for microarray plates, Langmuir 28(26), doi:10.1021/la302091t
(2010) A piezoactuated droplet-dispensing microfluidic chip, Journal of Microelectromechanical Systems 19(1), doi:10.1109/JMEMS.2009.2036866