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Proceedings Paper

Force and membrane compliance measurements using laser interferometry and optical trapping
Author(s): Luke P. Ghislain; Watt W. Webb
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Paper Abstract

The development of the single beam gradient force optical trap has improved the experimental capabilities available to cell biologists for noninvasive micromanipulation and mechanical measurement on living cells. Laser traps can be used not only to optically manipulate particles including bacteria, yeast cells, and intracellular organelles ranging in size from 25 nm to 25 micrometers with fine control of position (10 nm) but also to measure small (0.1 pN) forces in biological systems. For a given particle, trapping forces are linearly related to the laser power so that a relatively simple way of measuring force is to trap a particle at high power and gradually reduce it until the particle just escapes from the trap. The `escape' power, which is usually calibrated against the viscous drag of the aqueous medium at varying laser power levels, is a measure of the force.

Paper Details

Date Published: 3 September 1993
PDF: 2 pages
Proc. SPIE 1889, Holography, Interferometry, and Optical Pattern Recognition in Biomedicine III, (3 September 1993); doi: 10.1117/12.155726
Show Author Affiliations
Luke P. Ghislain, Cornell Univ. (United States)
Watt W. Webb, Cornell Univ. (United States)

Published in SPIE Proceedings Vol. 1889:
Holography, Interferometry, and Optical Pattern Recognition in Biomedicine III
Halina Podbielska, Editor(s)

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