AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Development and Evaluation of MEMS Air-Microfluidic Particle Focusing Systems
OMID MAHDAVIPOUR, Dorsa Fahimi, Apoorva Jain, Igor Paprotny, University of Illinois at Chicago
Abstract Number: 428 Working Group: Instrumentation and Methods
Abstract All of the current aerosol detection, sorting and counting methods will be greatly improved if the particles suspended in the airstream can be focused into a narrow stream. Focusing particles can improve the functionality (e.g. sensitivity) of established detection methods. Also many undesirable effects due to contact between particles and outer walls of a channel (e.g. wall losses) can be avoided by confining the aerosol stream in the center of a channel.
Air-microfluidics is the field of developing microfluidic devices that use air, as oppose to liquid, as the working fluid. In this work, we present a microfabricated three dimensional (3D) air-microfluidic particle focusing systems. In the hydrodynamic version of this system, horizontal focusing is achieve by squeezing the main flow using clean sheath flow from the sides of the microchannels. To extend the focusing to the vertical direction, grooved structures on top and bottom of microchannels are utilized. A novel fabrication technique has been used which is compatible with fabrication process of MEMS PM mass sensors, making it easier to integrate these two components into a small air-microfluidic footprint. Several different designs are investigated and discussed. The performance of this system is evaluated using a unique opto-gravimetric system developed at UIC. Polystyrene latex spheres (PSLs) of different sizes are collected on membrane filters attached to the outlet of the system. Epi-fluorescent microscopy techniques are then used to image and investigate the distribution of the particles on the filter. Experimental results confirm the efficacy of this method for focusing particles in microchannels.