Temporal Variation in Single-Cell Power-Law Rheology Spans the Ensemble Variation of Cell Population.

Area of Science:

• Cellular mechanics
• Biophysics
• Rheology

Background:

• Cytoskeletal organization dictates cell rheological properties, like the complex shear modulus (G*).
• While ensemble variations in G* are known, detailed temporal changes within single cells remain unclear.

Purpose of the Study:

• Investigate temporal variations in fibroblast cell rheology.
• Examine changes under spatially confined conditions restricting cell movement and shape.
• Probe the relationship between temporal and ensemble rheological statistics.

Main Methods:

• Utilized atomic force microscopy (AFM) for oscillatory deformation.
• Measured temporal evolution of G* at a fixed location within individual fibroblast cells.
• Confined cells to limit translational motion and maintain shape.

Main Results:

• Temporal variations in power-law rheology quantitatively matched ensemble variations.
• Demonstrated that cell rheology adheres to the ergodic hypothesis.
• Autocorrelation analysis of G* indicated a characteristic timescale for mechanical state evolution.

Conclusions:

• Single-cell rheology in confined environments exhibits ergodic behavior.
• Temporal mechanical state evolution in cells occurs over a defined timescale.
• Findings provide insights into dynamic cellular mechanical properties.