Cytoskeletal Strains in Modeled Optohydrodynamically Stressed Healthy and Diseased Biological Cells

Abstract

Controlled external chemomechanical stimuli have been shown to influence cellular and tissue regeneration/degeneration, especially with regards to distinct disease sequelae or health maintenance. Recently, a unique three-dimensional stress state was mathematically derived to describe the experimental stresses applied to isolated living cells suspended in an optohydrodynamic trap (optical tweezers combined with microfluidics). These formulae were previously developed in two and three dimensions from the fundamental equations describing creeping flows past a suspended sphere. The objective of the current study is to determine the full-field cellular strain response due to the applied three-dimensional stress environment through a multiphysics computational simulation. In this investigation, the multiscale cytoskeletal structures are modeled as homogeneous, isotropic, and linearly elastic. The resulting computational biophysics can be directly compared with experimental strain measurements, other modeling interpretations of cellular mechanics including the liquid drop theory, and biokinetic models of biomolecule dynamics. The described multiphysics computational framework will facilitate more realistic cytoskeletal model interpretations, whose intracellular structures can be distinctly defined, including the cellular membrane substructures, nucleus, and organelles.

Fluid–Structure Interactions Analysis of Shear‐Induced Modulation of a Mesenchymal Stem Cell: An Image‐Based Study

“…The recorded stress values are in a logical concordance with previous experimental and computational studies of cell biomechanics using fluid flow . Several recent cell biomechanical investigations applied flow‐induced shear stresses in the physiologic range on adherent cells .…”

“…It has been shown that cells would experience about 350 mPa normal stress due to the flow passing over it . Kohles et al, treating the mechanical properties of a single cell in a macroscopic approach as an isotropic homogenous continuum model , recorded a maximum value of 500 mPa effective stress along with 10% volumetric strain in normal healthy cells . A maximum value of 5‐μm cell deformation was also reported by Kohles et al in the assumed flow velocity of 2000 μm/s .…”

“…A recent investigation by Toh and Voldman suggests no significant change in the cell‐attached area of an embryonic stem cell upon increasing the fluid shear stress from 0.063 dyn/cm 2 to 0.25 dyn/cm 2 , but it reveals rather a higher expression of endothelial markers as a result of total cell compression at higher flow rates . Kohles et al also reported an increase in strain values recorded inside the cell at higher flow velocities .…”