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Accurate position tracking of optically trapped live cells

McAlinden, Niall; Glass, David G.; Millington, Owain R.; Wright, Amanda J.

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Niall McAlinden

David G. Glass

Owain R. Millington

Amanda J. Wright


Optical trapping is a powerful tool in Life Science research and is becoming common place in many microscopy laboratories and facilities. There is a growing need to directly trap the cells of interest rather than introduce beads to the sample that can affect the fundamental biological functions of the sample and impact on the very properties the user wishes to observe and measure. However, instabilities while tracking large inhomogeneous objects, such as cells, can make tracking position, calibrating trap strength and making reliable measurements challenging. These instabilities often manifest themselves as cell roll or re-orientation and can occur as a result of viscous drag forces and thermal convection, as well as spontaneously due to Brownian forces. In this paper we discuss and mathematically model the cause of this roll and present several experimental approaches for tackling these issues, including using a novel beam profile consisting of three closely spaced traps and tracking a trapped object by analysing fluorescence images. The approaches presented here trap T cells which form part of the adaptive immune response system, but in principle can be applied to a wide range of samples where the size and inhomogeneous nature of the trapped object can hinder particle tracking experiments.

Journal Article Type Article
Acceptance Date Dec 20, 2013
Online Publication Date Mar 3, 2014
Publication Date Apr 3, 2014
Deposit Date Apr 17, 2014
Publicly Available Date Apr 17, 2014
Journal Biomedical Optics Express
Electronic ISSN 2156-7085
Publisher Optical Society of America
Peer Reviewed Peer Reviewed
Volume 5
Issue 4
Public URL
Publisher URL http://www.
Additional Information This paper was published in Biomedical Optics Express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.


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