Hydrogel-based molecular tension fluorescence microscopy for investigating receptor-mediated rigidity sensing

Area of Science:

• Biophysics
• Cell Biology
• Biomaterials Science

Background:

• Extracellular matrix (ECM) rigidity is a key mechanical cue influencing cellular functions.
• Current methods for measuring cellular forces lack the spatial resolution and sensitivity needed to fully understand rigidity sensing.

Purpose of the Study:

• To develop a novel method for studying molecular force mechanisms in rigidity sensing.
• To investigate how cells, including fibroblasts and T cells, respond to substrate rigidity at the molecular level.

Main Methods:

• Functionalization of DNA tension probes on soft hydrogel surfaces.
• Utilizing molecular tension fluorescence microscopy (MTFM) on a standard confocal microscope.
• Developing controllable and reliable hydrogel-based platforms for force measurements.

Main Results:

• Fibroblasts increase force-bearing integrins and modulate sampling frequency for focal adhesion maturation in response to rigidity.
• ECM rigidity enhances the pN force of T cell receptor-ligand bonds and T cell mechanical sampling frequency, promoting T cell activation.
• The developed MTFM method provides detailed molecular force information for rigidity-dependent biological processes.

Conclusions:

• Hydrogel-based MTFM offers a simple and effective approach to study molecular forces in rigidity sensing.
• Cellular responses to ECM rigidity involve dynamic recruitment and sampling of force-bearing molecules.
• This technique opens new avenues for exploring mechanobiology and immune cell dynamics.