From Displacement to Angle: Diamond-Based 3D Rotation Sensing for High-Precision Cellular Force Measurement

Area of Science:

• Mechanobiology
• Biophysics
• Materials Science

Background:

• Cellular traction forces are crucial for cell migration and tissue development.
• Conventional methods using bead or micropillar displacement have limitations, including geometric-nonlinearity errors and inability to capture 3D motion.

Purpose of the Study:

• To develop a novel, high-precision method for quantifying cellular traction forces.
• To overcome the limitations of displacement-based force measurement techniques.

Main Methods:

• Utilized fluorescent nanodiamonds (FNDs) as embedded 3D orientation markers on polydimethylsiloxane (PDMS) micropillars.
• Integrated optically detected magnetic resonance (ODMR) with laser polarization modulation (LPM) to determine FND orientation with sub-degree precision (~0.5°).
• Developed an angle-based measurement framework for force reconstruction from pillar rotation.

Main Results:

• The novel method accurately quantifies forces by measuring pillar rotation angles, providing robust readouts for large deformations.
• Finite-element simulations showed a >10% reduction in force estimation errors compared to linear displacement-based methods.
• Successfully captured 3D pillar deformations, including bending and in-plane rotation, previously inaccessible.

Conclusions:

• Diamond-based angular force microscopy is established as a high-precision platform for mechanobiology research.
• This technique enhances the understanding of cell-matrix interactions and biomechanical processes.
• Offers a more comprehensive approach to studying cellular forces and their impact.