The νpIVOT: An integrated particle image velocimeter and optical tweezers instrument for microenvironment investigations

N. Nève, J. K. Lingwood, J. Zimmerman, S. S. Kohles, D. C. Tretheway

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


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 languageEnglish (US)
Article number095403
JournalMeasurement Science and Technology
Issue number9
StatePublished - Sep 1 2008
Externally publishedYes


  • Cell biomechanics
  • Laser-based techniques
  • Microfluidics
  • Optical tweezers
  • Particle hydrodynamics
  • μPIV

ASJC Scopus subject areas

  • Instrumentation
  • Engineering (miscellaneous)
  • Applied Mathematics


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