# An Opto‐Actuated Hydrogel for Cell Mechanoactuation and Real‐Time Force Monitoring

## TL;DR

Scientists created a light-activated hydrogel that applies forces to cells and tracks their mechanical responses in real time, revealing how cells react to mechanical stimuli.

## Contribution

A novel opto-actuated hydrogel interface that enables real-time monitoring of cellular force responses at the subcellular level.

## Key findings

- Reversible talin recruitment occurs in response to applied forces.
- F-actin polymerization is enhanced when focal adhesions are mechanically stimulated.
- Cell traction forces decrease when force is applied to focal adhesions.

## Abstract

Cellular force sensing and transduction are fundamental processes in development, homeostasis, and disease. To understand how cells detect and integrate mechanical forces, we need non‐invasive methods to apply forces at the molecular scale while monitoring cellular responses within physiological contexts. Here, we present a mechanoactuated hydrogel interface that can exert forces on integrin adhesion receptors and allows monitoring of traction force responses in real time. The actuation is achieved by light excitation of a rotary molecular motor presenting an adhesion peptide to bind integrins at the cell membrane and to a hydrogel surface via flexible polymer chains. Illumination results in chain twisting and an applied pulling force on the linked integrin receptors within subcellular illuminated areas. Fluorescent particles in the hydrogel allow parallel quantification of cellular forces by traction force microscopy. With this methodology, we monitored talin recruitment, actin organization, and traction force generation and their reversibility in response to applied forces by the rotary motor‐interface. We demonstrate reversible talin recruitment, enhanced F‐actin polymerization, and a reduction in cell traction force when force is applied to focal adhesions. This research expands the application of nano machine‐based actuation within soft hydrogels and showcases its capabilities.

Researchers developed a mechanoactuated hydrogel interface where nanomachines exert forces on adhesion receptors and allow monitoring of traction force responses in real time. They demonstrate reversible talin recruitment, enhanced F‐actin polymerization, and a reduction in cell traction force when force is locally applied to focal adhesions of adherent cells.