Inferring scale-dependent non-equilibrium activity using carbon nanotubes

Area of Science:

• Biophysics
• Cell Biology
• Soft Matter Physics

Background:

• Living systems exhibit complex multiscale structures and functions driven by irreversible, stochastic molecular interactions.
• Quantifying the dynamics of non-equilibrium activity in these systems is challenging due to a lack of suitable methods.

Purpose of the Study:

• To develop and apply a novel method for characterizing the multiscale dynamics of non-equilibrium activity in biological networks.
• To dissect the functional coupling between microscopic dynamics and emergent large-scale activities.

Main Methods:

• Utilized single-walled carbon nanotubes as probes within Xenopus egg extract actomyosin networks.
• Measured time-reversal asymmetry in the conformational dynamics of filaments to quantify non-equilibrium activity.
• Analyzed bending-mode amplitudes to characterize spatiotemporal dynamics.

Main Results:

• The developed method successfully quantified non-equilibrium activity in the actomyosin network.
• The technique demonstrated sensitivity to perturbations in the actomyosin network and adenosine triphosphate/adenosine diphosphate ratios.
• Established a relationship between spatiotemporal scales of non-equilibrium activity and physical parameters of embedded filaments.

Conclusions:

• The study presents a generalizable tool for characterizing steady-state non-equilibrium activity in complex, high-dimensional biological systems.
• This method provides insights into the structure-function relationship in living systems by quantifying underlying dynamics.
• Advances the understanding of biophysical processes governing cellular functions like motility and division.