Intracellular viscoelasticity of HeLa cells during cell division studied by video particle-tracking microrheology

Abstract

Cell division plays an important role in regulating cell proliferation and differentiation. It is managed by a complex sequence of cytoskeleton alteration that induces dividing cells to change their morphology to facilitate their division. The change in cytoskeleton structure is expected to affect the intracellular viscoelasticity, which may also contribute to cellular dynamic deformation during cell division. However, the intracellular viscoelasticity during cell division is not yet well understood. In this study, we injected 100-nm (diameter) carboxylated polystyrene beads into the cytoplasm of HeLa cells and applied video particle tracking microrheology to measure their intracellular viscoelasticity at different phases during cell division. The Brownian motion of the intracellular nanoprobes was analyzed to compute the viscoelasticity of HeLa cells in terms of the elastic modulus and viscous modulus as a function of frequency. Our experimental results indicate that during the course of cell division, both intracellular elasticity and viscosity increase in the transition from the metaphase to the anaphase, plausibly due to the remodeling of cytoskeleton and redistributions of molecular motors, but remain approximately the same from the anaphase to the telophase.

The Effect of Enterohemorrhagic E. coli Infection on the Cell Mechanics of Host Cells

“…These aspects are related to various physiological and pathological functions such as cell division [2], proliferation [3], differentiation [4], [5], invasion [6] and metastasis [7], [8]. The dynamics of cytoskeletal organization include nucleation, polymerization and depolymerization, branching, cross-linking, and bundling actin filaments into actin stress fibers [1].…”

“…Video particle tracking microrheology (VPTM) is a technique to measure the local shear moduli (both viscous and elastic) of complex materials with a spatial resolution on the order of a few microns, and requiring sample volumes on the order of only a few micro-liters [2], [8], [28]–[36]. A typical experimental setup includes a microscope stage equipped with an objective lens and a charge-coupled device (CCD) camera linked to a computer to record the motion of micron-size particles in the test sample.…”

Microrheometric upconversion-based techniques for intracellular viscosity measurements

“…Passive techniques are based on the measurement of the thermal fluctuations of a probe, which could be endogenous (organelle, vesicle or molecule) or exogenous (internalized particle o molecule). 1,[5][6][7] The Brownian motion of the probe could be tracked by using video-based methods or by the analysis of its emission, in the case of luminescent probes. 5,[8][9][10] On the other hand, active techniques exert a force over the cell to test its response to the applied stimulus.…”

“…1,[5][6][7] The Brownian motion of the probe could be tracked by using video-based methods or by the analysis of its emission, in the case of luminescent probes. 5,[8][9][10] On the other hand, active techniques exert a force over the cell to test its response to the applied stimulus. 11,12 The action could be performed directly over the cell or by using a probe (usually polystyrene or silica beads).…”

High Resolution Measurements of Viscoelastic Properties of Complex Biological Systems Using Rotating Optical Tweezers

“…Despite some work being done on these systems, e.g., fluorescence correlation spectroscopy [47], trapping cellular organelles [5,80,107], video particle tracking microrheology [22], force spectrum microscopy [48] and rotational magnetic spectroscopy [12], it is still extremely difficult to make rapid measurements inside living cells.…”