HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 293/2/C597    most recent 00562.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Puig-de-Morales-Marinkovic, M. Articles by Suresh, S. Search for Related Content PubMed PubMed Citation Articles by Puig-de-Morales-Marinkovic, M. Articles by Suresh, S.

VASCULAR BIOLOGY

Viscoelasticity of the human red blood cell

¹Department of Environmental Health, Harvard School of Public Health, Boston; ²Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts; ³Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, Wisconsin; and ⁴Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts

Submitted 7 November 2006 ; accepted in final form 7 April 2007

We report here the first measurements of the complex modulus of the isolated red blood cell (RBC). Because the RBC is often larger than capillary diameter, important determinants of microcirculatory function are RBC deformability and its changes with pathologies, such as sickle cell disease and malaria. A functionalized ferrimagnetic microbead was attached to the membrane of healthy RBC and then subjected to an oscillatory magnetic field. The resulting torque caused cell deformation. From the oscillatory forcing and resulting bead motions, which were tracked optically, we computed elastic and frictional moduli, g' and g''', respectively, from 0.1 to 100 Hz. The g' was nearly frequency independent and dominated the response at all but the highest frequencies measured. Over three frequency decades, g''' increased as a power law with an exponent of 0.64, a result not predicted by any simple model. These data suggest that RBC relaxation times that have been reported previously, and any models that rest upon them, are artifactual; the artifact, we suggest, arises from forcing to an exponential fit data of limited temporal duration. A linear range of response was observed, but, as forcing amplitude increased, nonlinearities became clearly apparent. A finite element model suggests that membrane bending was localized to the vicinity of the bead and dominated membrane shear. While the mechanisms accounting for these RBC dynamics remain unclear, methods described here establish new avenues for the exploration of connections among the mechanical, chemical, and biological characteristics of the RBC in health and disease.

storage modulus; loss modulus; magnetic twisting cytometry; erythrocyte; viscoelasticity; rheology

This article has been cited by other articles:

				M. Marinkovic, M. Diez-Silva, I. Pantic, J. J. Fredberg, S. Suresh, and J. P. Butler Febrile temperature leads to significant stiffening of Plasmodium falciparum parasitized erythrocytes Am J Physiol Cell Physiol, January 1, 2009; 296(1): C59 - C64. [Abstract] [Full Text] [PDF]