Opto-Mechanical Manipulation of Stem Cells

Abstract

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 prolif- eration and differentiation after they reach the target site. Although the shear stress has been recognized as one of key fac- tors, 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 re- fractive index within the cell may lead to different behaviors when they are manipulated by optical tweezers.