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Riordon J.,University of Ottawa | Nash M.,University of Ottawa | Jing W.,University of Ottawa | Godin M.,University of Ottawa | Godin M.,Ottawa Carleton Institute for Biomedical Engineering
Biomicrofluidics | Year: 2014

We demonstrate a microfluidic device capable of tracking the volume of individual cells by integrating an on-chip volume sensor with pressure-activated cell trapping capabilities. The device creates a dynamic trap by operating in feedback; a cell is periodically redirected back and forth through a microfluidic volume sensor (Coulter principle). Sieve valves are positioned on both ends of the sensing channel, creating a physical barrier which enables media to be quickly exchanged while keeping a cell firmly in place. The volume of individual Saccharomyces cerevisiae cells was tracked over entire growth cycles, and the ability to quickly exchange media was demonstrated. © 2014 AIP Publishing LLC.


Tahvildari R.,University of Ottawa | Beamish E.,University of Ottawa | Tabard-Cossa V.,University of Ottawa | Godin M.,University of Ottawa | Godin M.,Ottawa Carleton Institute for Biomedical Engineering
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2015

Nanopore arrays are fabricated by controlled dielectric breakdown (CBD) in solid-state membranes integrated within polydimethylsiloxane (PDMS) microfluidic devices. This technique enables the scalable production of independently addressable nanopores. By confining the electric field within the microfluidic architecture, nanopore fabrication is precisely localized and electrical noise is significantly reduced. Both DNA and protein molecules are detected to validate the performance of this sensing platform. © 2015 The Royal Society of Chemistry.


Riordon J.,University of Ottawa | Nash M.,University of Ottawa | Calderini M.,University of Ottawa | Godin M.,University of Ottawa | Godin M.,Ottawa Carleton Institute for Biomedical Engineering
Microelectronic Engineering | Year: 2014

We demonstrate a microfluidic device that integrates high-sensitivity volume sensing with active pressure-driven flow sorting. Label-free size-based sorting of microparticles and cells is achieved using hydrodynamic flow focusing combined with a resistive pulse sensor with tunable sensitivity that utilizes the Coulter principle. Measurements are performed in real time, and pressure-driven flows are automatically adjusted in feedback to direct microparticles into one of multiple outlet sorting channels at 97.3% efficiency and with a resolution of ∼3 μm3. In a subsequent test, cells were sorted by volume from a single culture of Saccharomyces cerevisiae (yeast) at 100% efficiency. Next, we demonstrate the device's ability to size a population of cells at high-throughput and identify features of interest prior to sorting. Subpopulations of arrested G1 and M-phase cells were successfully resolved from a single yeast culture. This integrated on-chip sizing and sorting method is ideal for sorting small numbers of particles/cells at very high resolution. © 2014 Elsevier B.V. All rights reserved.


Flaxman T.E.,University of Ottawa | Smith A.J.J.,University of Ottawa | Benoit D.L.,University of Ottawa | Benoit D.L.,Ottawa Carleton Institute for Biomedical Engineering
Journal of Orthopaedic Research | Year: 2014

Sex-related differences in neuromuscular activation have been previously identified and are thought to be an underlying contributor to the ACL injury mechanism. During dynamic tasks evaluating the role of muscle action as it relates to joint stability is difficult since individual muscle contributions to force generation are confounded by biomechanical factors of movement. The purpose of this study was to examine sex-related differences in knee muscle action during a weight-bearing isometric exercise and identify the stabilising role of these muscles. Healthy young adults stood with their dominant leg in a boot fixed to a force platform. A force matching protocol required participants to modulate normalised ground reaction forces in various combinations of anterior-posterior, medial-lateral loads while maintaining a constant joint position. Normalised electromyographic data of eight muscles crossing the knee joint were displayed in polar plots. Patterns were quantified with an orientation analysis and mean activation magnitudes were computed. Females demonstrated symmetrical activation patterns with significantly greater activation in the rectus femoris (p = 0.037), lateral gastrocnemius (p = 0.012), and tensor fascia lata (p = 0.005) compared to males. High between-subject reliability (ICC = 0.772-0.977) was observed across groups suggesting we have identified fundamental sex-related differences in knee joint stabilisation strategies. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:310-317, 2014. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

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