Dynamic micro-mechanical properties of cultured rat atrial myocytes
measured by atomic force microscopy.
Shroff, Sanjeev G., Donald R. Saner, Ratneshwar Lal.
Cardiology Section, Department of Medicine, University of Chicago,
MC-5084, 5841 South Maryland Avenue, Chicago, Illinois 60637,
U.S.A.
APStracts 2:0132C, 1995.
The Atomic Force Microscope (AFM) was used to quantify micro
-mechanical properties (i.e., localized to an area of 0.015 m2) of
cultured rat atrial myocytes. Quiescent cells in calcium-free
solution were quite compressible over the nuclear region, e.g., a
force of 3-4 nN produced 180-225 nm cell indentation. Transverse
stiffness of quiescent cells increased by 2 fold following an
increase in extracellular calcium from 0 to 5 mM and by 16 fold after
fixation with formalin. There was 5-8 fold variation in stiffness of
quiescent cells over the cell surface such that stiffness was lowest
over the nuclear region and it increased towards the cell periphery.
These regional variations correlated with the cytoskeletal
heterogeneity as revealed by the AFM and fluorescence imaging.
Localized contractile activity of beating cells could be monitored in
terms of the surface deformation with high transverse spatial (1-3
nm) and temporal (60-100 [mu]s) resolutions. Alterations in cell
contractile activity with physiologic perturbations and dynamic
changes in cell stiffness during a single contraction could be
observed. These results demonstrate the feasibility of AFM-based
characterization of highly localized, cellular micro-mechanical
properties. Relationships among localized cell mechanical behavior
and the underlying biochemical and/or structural environment, a
crucial aspect in understanding cellular (dys)function, can now be
directly examined.
Received 14 November 1994; accepted in final form 2 March 1995.
APS Manuscript Number C669-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 21 March 1995.