Measure the ATP chemical potential difference (Δμ) in living cellular systems for active gel theory

Develop and implement experimental methods to directly measure the difference in chemical potentials Δμ between ATP and its hydrolysis products in living cellular systems, enabling quantitative determination of the activity parameter and active stress in active gel models of the acto-myosin cytoskeleton.

Background

Active gel theory relates generated mechanical stress to an activity parameter tied to the ATP hydrolysis thermodynamic drive Δμ. While other phenomenological quantities can be inferred, Δμ itself has not been directly measured in cellular contexts.

Direct measurement of Δμ would strengthen the quantitative link between theoretical predictions and experimental observations of cytoskeletal flows and stresses.

References

The remaining quantity Au could in principle be assessed by standard techniques from chemical physics, which, however, would need to be adapted to cellular systems. For the time being, such a measurement has not been performed.

— Acto-myosin clusters as active units shaping living matter  (2408.05119 - Kruse et al., 2024) in Box 2: Theory of active gels for morphogenesis