Traction Force Microscopy with DNA FluoroCubes

Area of Science:

• Biophysics
• Cell Biology
• Materials Science

Background:

• Mechanical forces at the cell-substrate interface regulate crucial cellular processes.
• High-resolution mapping of these forces is essential but technically challenging.
• Conventional traction force microscopy (TFM) uses fluorescent beads as fiducial markers.

Purpose of the Study:

• To introduce and validate fluorescently labeled DNA nanostructures (FluoroCubes) as advanced fiducial markers for TFM.
• To enhance the spatial resolution and sensitivity of traction force measurements.
• To develop a versatile platform for probing interfacial forces at biointerfaces.

Main Methods:

• Grafting DNA nanostructures (FluoroCubes) onto polydimethylsiloxane (PDMS) substrates, co-anchored with RGD peptides.
• Utilizing biotin-NeutrAvidin chemistry for controlled fiducial density.
• Employing total internal reflection fluorescence (TIRF) microscopy.
• Applying a modified multichannel optical flow algorithm for displacement and force reconstruction.

Main Results:

• FluoroCubes offer stable tethering, resist internalization, and enable dense, minimally perturbative labeling.
• The platform demonstrates improved displacement sensitivity and force reconstruction resolution compared to conventional methods.
• Achieved reproducible, high-resolution traction force mapping.

Conclusions:

• FluoroCube-functionalized substrates represent a significant advancement in traction force microscopy.
• This method provides a reproducible and high-resolution approach for mapping interfacial mechanical forces.
• The platform is versatile for future integration with DNA-based molecular sensors for advanced biointerface studies.