DNA Origami Tension Sensors (DOTS) for Single-Molecule Force Measurements at Fluid Intermembrane Junctions

Area of Science:

• Immunology
• Biophysics
• Nanotechnology

Background:

• T cell receptor (TCR) engagement with antigens initiates adaptive immunity.
• Mechanical forces at the piconewton (pN) scale critically influence TCR-antigen interactions and immune responses.
• Quantifying these forces at the single-molecule level is essential but challenging due to low antigen thresholds for T cell activation.

Purpose of the Study:

• To develop and validate a novel method for high-resolution, single-molecule force mapping of TCR-antigen interactions.
• To investigate the role of mechanical forces in T cell activation at the single-molecule level.
• To enable precise measurement of forces involved in immune synapse formation.

Main Methods:

• Development of single-molecule DNA origami tension sensors (smDOTS) with spectral fingerprint density reporters and tunable cholesterol anchors.
• Utilizing smDOTS for high-resolution force mapping at fluid cell membranes.
• Employing multiplexing to simultaneously image sensors with varying force thresholds.

Main Results:

• Demonstrated unprecedented measurements of TCR-antigen forces, detecting magnitudes between 8 and 19 pN.
• Successfully tracked ligand translocation dynamics at the single-molecule level.
• Showcased the capability of multiplexed sensors for simultaneous force threshold imaging.

Conclusions:

• smDOTS provide a powerful tool for quantifying TCR-antigen forces with high resolution.
• This technology advances the understanding of mechanical force dynamics in T cell signaling and immune responses.
• Future applications include detailed analysis of bond lifetimes and force dynamics in immune cell interactions.