Opto-Mechanical Manipulation of Stem Cells

Hu Zhang , Kuo-Kang Liu , Alica El Haj
Institute of Science and Technology in Medicine, Keele University, Stoke-on-Trent, ST4 7QB, UK

© 2009 Zhang et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Institute of Science and Technology in Medicine, Keele University, Stoke-on-Trent, ST4 7QB, UK; Tel: 44(0)-1782-554600; Fax: 44(0)-1782-717709;


Stem cells have a great potential for regeneration of injured or degenerated tissues or organs. In delivery of cell therapy, stem cells are normally subjected to different levels of shear stress which may have a great impact on their proliferation and differentiation after they reach the target site. Although the shear stress has been recognized as one of key factors, the study on how it affects single stem cell mechanobiologically is not available. This paper reports an application of optical tweezers for manipulating the human mesenchymal stem cells which are exposed to various levels of shear stress in flow chambers. Our preliminary results show different responses of stem cells (the tether formation, cell shrinkage, presence of cell surface nanoparticles, cell rotation before aligning the flow direction) under shear forces in different flow chambers. Also, a few interesting optical characteristics of stem cells have been noticed; for example, the variation of refractive index within the cell may lead to different behaviors when they are manipulated by optical tweezers.

Keywords: Mesenchymal Stem Cells, Optical Tweezers, Shear Stress, Manipulation, Single Cell, Variation.