Abstract
A novel instrument to manipulate and characterize the mechanical environment in and around microscale objects in a fluidic environment has been developed by integrating two laser-based techniques: micron-resolution particle image velocimetry (νPIV) and optical tweezers (OT). This instrument, the νPIVOT, enables a new realm of microscale studies, yet still maintains the individual capabilities of each optical technique. This was demonstrated with individual measurements of optical trap stiffness (∼70 pN νm-1 for a 20 νm polystyrene sphere and a linear relationship between trap stiffness and laser power) and fluid velocities within 436 nm of a microchannel wall. The integrated device was validated by comparing computational flow predictions to the measured velocity profile around a trapped particle in either a uniform flow or an imposed, gravity-driven microchannel flow (R2 = 0.988, RMS error = 13.04 νm s-1). Interaction between both techniques is shown to be negligible for 15 νm to 35 νm diameter trapped particles subjected to fluid velocities from 50 νm s-1 to 500 νm s-1 even at the highest laser power (1.45 W). The integrated techniques will provide a unique perspective toward understanding microscale phenomena including single-cell biomechanics, non-Newtonian fluid mechanics and single particle or particle-particle hydrodynamics.
Original language | English (US) |
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Article number | 095403 |
Journal | Measurement Science and Technology |
Volume | 19 |
Issue number | 9 |
DOIs | |
State | Published - Sep 1 2008 |
Externally published | Yes |
Keywords
- Cell biomechanics
- Laser-based techniques
- Microfluidics
- Optical tweezers
- Particle hydrodynamics
- μPIV
ASJC Scopus subject areas
- Instrumentation
- Engineering (miscellaneous)
- Applied Mathematics