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Biophysics in the Understanding, Diagnosis, and Treatment of Infectious Diseases Poster Abstracts
49
1-POS
Board 1
Computational Simulation of Mechanical Interactions between a Cell and its Environment
Considering Focal Adhesions and Substrate Stiffness
Tamer Abdalrahman
1
, Laura Dubuis
1,2
, Neil Davies
2
, Jason Green
2
, Thomas Franz
1
.
1
Division of Biomedical Engineering, University of Cape Town, Observatory, Western Cape,
South Africa,
2
Cardiovascular Research Unit, University of Cape Town, Observatory, Western
Cape, South Africa.
Introduction
Cell and viral mechanics including cell-environment, cell-cell and cell-virion interactions may
play important roles in aetiology of infectious diseases. Exploring these interactions
experimentally is often challenging, and computational modelling offers a complementary
approach of inquiry.
Methods
The three-dimensional geometry of a fibroblast, distinguishing cytosol and nucleus, was
reconstructed from confocal micrographs (ScanIP, Simpleware Ltd, Exeter, UK) of a cell
cultured two-dimensionally and stained with phalloidin (for actin fibres) and Hoechst (for
nucleus). The geometry was imported in ABAQUS 6.12 (Dassault Systèmes, Providence, USA)
and complemented with a 0.01 μm thick membrane enveloping the cytosol and a flat substrate
(thickness: 10 μm). Focal adhesions (FA) were represented with estimated sizes and locations
using cohesive elements. Mechanical properties of the cell components from literature were
used, and the elastic modulus of the substrate was varied (E
Sub
= 0.01, 0.14, 1, and 10 MPa). The
substrate was stretched to λ = 1.1 (equivalent to a strain of 9.5e
-2
) and the resulting deformation
of the cell was assessed for different substrate moduli.
Results
The largest maximum principal strain predicted for E
Sub
= 0.01, 0.14, 1, and 10 MPa,
respectively, was 4.58e
-4
, 5.27e
-4
, 5.33e
-4
and 5.34e
-4
in the membrane, 1.18e
-3
, 1.33e
-3
, 1.34e
-
3
and 1.34e
-3
in the cytosol, 6.88e
-6
, 8.17e
-6
, 8.27e
-6
and 8.29e
-6
in the nucleus, and 1.87, 1.96,
1.97 and 1.97 in the FA.
Discussion
The maximum FA strains are likely to be overestimated due to absence of a detachment criterion
in the FA formulation. Nevertheless, the results indicate increased cell deformation with
increased substrate modulus for a simple case and present a point of departure for the
advancement of the models and methods towards the assessment of more complex in cell and
virion mechanics.