Abstract
The magnetic tweezer is a simple and stable single-molecule manipulation instrument. However, the standard probe-tracking methods have typically failed to reach the high resolution (∼0.3 nm) needed to measure motor protein stepping. In this paper we present a novel illumination geometry, based on an inverted microscope with Hg lamp illumination, that aims to push the resolution of magnetic tweezers to their ultimate thermal limits. Using a metal-coated coverslip and motorized magnets, we convert a standard inverted microscope into a high-resolution magnetic tweezers instrument. Our novel optical geometry reduces the restrictions on magnet design inherent to transmission-based illumination, and does not require fiber-optic coupling. We introduce a high-speed CMOS camera as the optical detector, and demonstrate how an improvement in temporal resolution directly impacts the spatial resolution.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Otto O, Czerwinski F, Gornall JL, Stober G, Oddershede LB, Seidel R, Keyser UF (2010) Real-time particle tracking at 10,000fps using optical fiber illumination. Opt Express 18(22):22722–22733
Prahl S (2012) Mie scattering calculation. http://omlc.ogi.edu/calc/. Accessed 29 Feb 2012
Lansdorp BM, Saleh OA (2012) Power spectrum and allan variance methods for calibrating single-molecule video-tracking instruments. Rev Sci Instrum 83(2):025115
Kim K, Saleh OA (2009) A high-resolution magnetic tweezer for single-molecule measurements. Nucleic Acids Res 37(20):e136
Schäffer E, Nørrelykke SF, Howard J (2007) Surface forces and drag coefficients of microspheres near a plane surface measured with optical tweezers. Langmuir 23(7):3654–3665
Bouchiat C, Wang MD, Allemand JF, Strick T, Block SM, Croquette V (1999) Estimating the persistence length of a worm-like chain molecule from force-extension measurements. Biophys J 76(1):409–413
Acknowledgements
We gratefully acknowledge S. Pennathur and T. Wynne for lending us their hs-CMOS camera, A. Weinberg for manufacturing parts, and F. Freitas for reviewing this manuscript. B.L. acknowledges support from an NSERC PGS-D fellowship.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2013 The Society for Experimental Mechanics
About this paper
Cite this paper
Lansdorp, B.M., Saleh, O.A. (2013). High Speed Magnetic Tweezers at 10,000fps with Reflected Hg-Lamp Illumination. In: Shaw, G., Prorok, B., Starman, L. (eds) MEMS and Nanotechnology, Volume 6. Conference Proceedings of the Society for Experimental Mechanics Series. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-4436-7_13
Download citation
DOI: https://doi.org/10.1007/978-1-4614-4436-7_13
Published:
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4614-4435-0
Online ISBN: 978-1-4614-4436-7
eBook Packages: EngineeringEngineering (R0)