Traction cytometry: regularization in the Fourier approach and comparisons with finite element method

Area of Science:

• Cellular mechanics
• Biophysics
• Biomaterials

Background:

• Cellular traction forces are critical for biological processes.
• Fourier Transform Traction Cytometry (FTTC) is a common method for quantifying these forces.
• Existing methods have limitations in accuracy and noise sensitivity.

Purpose of the Study:

• To evaluate and compare different traction force microscopy methods.
• To assess the accuracy and noise sensitivity of Regularized FTTC (Reg-FTTC) and Finite Element (FE) methods.
• To establish optimal regularization parameters for improved traction force calculations.

Main Methods:

• Implementation of L2 regularization for Reg-FTTC.
• Definition of an optimal regularization parameter (γ*) based on maximum curvature.
• Comparison of Reg-FTTC, FTTC, and FE methods using mouse embryonic fibroblast (MEF) cells.

Main Results:

• Reg-FTTC with optimal γ* accurately reconstructs tractions, even with up to 5% noise.
• Reg-FTTC shows significant improvement over standard FTTC.
• FE method provides intermediate reconstruction accuracy compared to Reg-FTTC.
• Using cell-specific optimal γ values reduces traction measurement variability.

Conclusions:

• Reg-FTTC with optimized regularization is a robust method for traction force microscopy.
• This approach improves upon standard FTTC and offers better accuracy than FE methods for certain stress ranges.
• Cell-specific parameter optimization is crucial for reliable traction force quantification.