High-speed micro-PIV measurements of transient flow in microfluidic devices

Abstract

This paper reports a new technique of micro-resolution particle image velocimetry (PIV). To investigate transient phenomena in a microfluidic device, a high-speed micro-PIV technique was developed by combining a high-speed camera and a continuous wave (CW) laser. The technique was applied to a micro counter-current flow, consisting of water and butyl acetate. The velocity fields of water in the micro counter-current flow were visualized for a time resolution of 500 µs and a spatial resolution of 2.2 × 2.2 µm 2 . Using the micro-PIV technique, the vortex-like motions of fluorescent particles around the water-butyl acetate interface were captured clearly.

Hydrodynamic property of the cytoplasm is sufficient to mediate cytoplasmic streaming in the Caenorhabiditis elegans embryo

“…To acquire the velocity distributions of the flows with high spatial resolution, we conducted particle image velocimetry (PIV) analysis (11,15,24,25). We used VIT-2 ∷ GFP (26) to visualize the yolk granules, conventional probes for cytoplasmic streaming (Fig.…”

“…PIV was conducted with a highly accurate subpixel analysis using the gradient method (24,44). Details of the procedure are described in SI Materials and Methods.…”

Two rotating cilia in the node cavity are sufficient to break left–right symmetry in the mouse embryo

“…To study the dynamics of nodal flow, we measured its velocity distribution by particle image velocimetry (PIV) 8,13 (Supplementary Movie 1). Time-lapse observations were performed during L-R axis determination with the use of a whole-embryo culture system 8 .…”

Confocal micro-PIV measurements of three-dimensional profiles of cell suspension flow in a square microchannel

“…In this way, when using a confocal micro-PIV system it is crucial not only determine the lateral and axial image resolution but also the optical slice thickness. Note that for the case of the conventional micro-PIV system the out-of-plane is usually associated to the depth of field (Meinhart et al 2000, Nguyen and Wereley 2002, Shinohara et al 2004) whereas in the confocal micro-PIV is related to the optical slice thickness.…”

“…This combination, known as micro-PIV, have greatly increased the resolution of the conventional PIV and as a result the micro-PIV technique have started to be widely used to investigate the flow behaviour in micro-fluidic devices. (Meinhart et al 1999, Koutsiaris et al 1999, Sugi et al 2002, klank et al 2002, Devasenathipathy et al 2003, Chiu et al2003, Shinohara et al 2004). However, by using conventional microscopes the entire flow field is illuminated and consequently the out-of-focus emitted light can result in high levels of background noise which contribute to degrading the measured velocity fields (Meinhart et al 1999, Meinhart et al 2000, Nguyen and Wereley 2002.…”