Force measurements with optical tweezers inside living cells

J. Mas, A. Farre, J. Sancho-Parramon, E. Martin-Badosa, M. Montes-Usategui

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)
1 Downloads (Pure)

Abstract

The force exerted by optical tweezers can be measured by tracking the momentum changes of the trapping beam, a method which is more general and powerful than traditional calibration techniques as it is based on first principles, but which has not been brought to its full potential yet, probably due to practical difficulties when combined with high-NA optical traps, such as the necessity to capture a large fraction of the scattered light. We show that it is possible to measure forces on arbitrary biological objects inside cells without an in situ calibration, using this approach. The instrument can be calibrated by measuring three scaling parameters that are exclusively determined by the design of the system, thus obtaining a conversion factor from volts to piconewtons that is theoretically independent of the physical properties of the sample and its environment. We prove that this factor keeps valid inside cells as it shows good agreement with other calibration methods developed in recent years for viscoelastic media. Finally, we apply the method to measuring the stall forces of kinesin and dynein in living A549 cells.
Original languageEnglish
Title of host publicationOptical Trapping and Optical Micromanipulation XI
EditorsKishan Dholakia Gabriel C. Spalding
PublisherSPIE
Volume9164
ISBN (Print)9781628411911
DOIs
Publication statusPublished - 16 Sept 2014

Publication series

NameProceedings of SPIE
PublisherSPIE
Volume9164
ISSN (Print)0277-786X

Fingerprint

Dive into the research topics of 'Force measurements with optical tweezers inside living cells'. Together they form a unique fingerprint.

Cite this