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.
Bibliographical noteFunding 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
- Biochemistry, Genetics and Molecular Biology(all)