For more information contact:
Colly Mitchell, Parker H. Petit Institute for Bioengineering and Bioscience
Contact Colly Mitchell colly.mitchell@ibb.gatech.edu
404-894-5982
McDevitt Research Highlighted in Nature Materials
Atlanta (August 1, 2008) — "Materials in a Cellular World"
Biological factors are not the only influence on stem-cell behaviour — the physics and chemistry of the environment play a part too. The interaction of materials science and stem-cell science brings with it a wealth of opportunities for future therapies.
John A. Hunt is in the Division of Clinical Engineering, School of Clinical Sciences, University of Liverpool, Daulby Street, Liverpool L69 3GA, UK. e-mail: huntja@liv.ac.uk
It is well established that materials can be implanted into the body to provide medical therapies; historically these so-called biomaterials have replaced or augmented a lost or deteriorated function of the body. However, implanted materials impact and upset the homeostasis of the body and, in particular, are known to affect cellular physiology and function. The determination and control of cell–material interactions are therefore critical to ensure that the material and host live together and function correctly.
Stem cells, which are present in the extracellular matrix (ECM) of normal tissues, are predisposed to changes in their environment. In response to these stimuli, they can differentiate down tissue and organ-specific pathways for repair and, dare it be said, regeneration. Their response to biological stimuli has been well studied over recent years and these physiological triggers clearly influence cell behaviour, however, the impact of the environment, and the materials that the cells come in contact with, are less understood. This stem-cell–materials interaction is a veritable Pandora's Box that has been recently opened, and a session was dedicated to this topic at the World Biomaterials Congress in Amsterdam in May 2008.
Todd McDevitt (Georgia Institute of Technology) reported how controlling the physical parameters of the fluidics of suspensions of cell cultures can reproducibly control the homogeneity of embryonic stem cells during the formation of embryoid bodies (Fig. 1). The rotary speed of orbital shakers was precisely controlled to deliver different flow conditions to suspension cultures during the development of embryoid bodies6. Changing the speed of rotation by as little as 25 r.p.m. to 55 r.p.m. was significant enough to increase the yield and homogeneity of the cells in the embryoid bodies. In addition, rotation speed was shown to control the potential of embryonic stem cells to differentiate down tissue-specific pathways, particularly neural and epidermal. The shear stress on the cells in the rotary fluidic system has a direct effect on their gene expression, and hence their differentiation. However, the cell-signaling pathways that are involved in the variation of gene expression are yet to be elucidated. The rotary results show that by precisely controlling the physical parameters of the cells' environment, it is possible to deliver significant triggers to embryonic stem cells in a cell-culture suspension bioreactor.
For full article, view: http://www.nature.com/search/executeSearch?sp-q-9=NMAT&sp-q=mcdevitt&sp-c=10&sp-x-9=cat&sp-s=0&sp-a=sp1001702d&sp-sfvl-field=subject%7Cujournal&sp-x-1=ujournal&sp-p-1=phrase&sp-p=all
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