Construction and calibration of an optical trap on a fluorescence optical microscope

Woei Ming Lee, Peter J. Reece, Robert F. Marchington, Nikolaus K. Metzger, Kishan Dholakia

Research output: Contribution to journalArticlepeer-review

94 Citations (Scopus)


The application of optical traps has come to the fore in the last three decades. They provide a powerful, sterile and noninvasive tool forthe manipulation of cells, single biological macromolecules, colloidal microparticles and nanoparticles. An optically trapped microsphere may act as a force transducer that is used to measure forces in the piconewton regime. By setting up a well-calibrated single-beam optical trap within a fluorescence microscope system, one can measure forces and collect fluorescence signals upon biological systems simultaneously. In this protocol, we aim to provide a clear exposition of the methodology of assembling and operating a single-beam gradient force trap (optical tweezers) on an inverted fluorescence microscope. A step-by-step guide is given for alignment and operation, with discussion of common pitfalls.

Original languageEnglish
Pages (from-to)3226-3238
Number of pages13
JournalNature Protocols
Issue number12
Publication statusPublished - 2007 Dec 13

Bibliographical note

Funding Information:
ACKNOWLEDGMENTS This work is supported by the UK Engineering and Physical Sciences Research Council. We acknowledge several useful discussions with Daniel Burnham.

All Science Journal Classification (ASJC) codes

  • General Biochemistry,Genetics and Molecular Biology


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