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Updated: May 28, 2026
08:40
Light-driven Molecular Motors on Surfaces for Single Molecular Imaging
Published on: March 13, 2019
Biomolecular Machines as Active Matter: Kinetic Asymmetry and Nonequilibrium Function.
1Department of Physics and Astronomy, The University of Maine, Orono, Maine, USA.
Small (Weinheim an Der Bergstrasse, Germany)
|May 27, 2026
Summary
Biomolecular machines are active matter that use energy to create directional motion through kinetic asymmetry, not direct force. This active matter perspective clarifies how chemical energy drives biological processes.
Area of Science:
- Molecular Biophysics
- Nonequilibrium Statistical Mechanics
- Active Matter Physics
Background:
- Biological molecular machines function far from thermodynamic equilibrium.
- Their motion is overdamped with negligible inertia, maintaining mechanical equilibrium.
- Thermal fluctuations drive equipartition among accessible degrees of freedom.
Purpose of the Study:
- To propose that biomolecular machines are elementary units of active matter.
- To explain how these machines sustain nonequilibrium probability currents by consuming free energy.
- To reframe the understanding of energy transduction and directional motion in biological systems.
Main Methods:
- Conceptual framework based on active matter principles.
- Analysis of thermodynamic equilibrium and nonequilibrium statistical mechanics.
- Application of the ratchet principle to explain directionality.
Main Results:
- Biomolecular machines are best understood as active matter units.
- ATP hydrolysis provides energy but not direction; directionality arises from kinetic asymmetry.
- Nonequilibrium probability currents are sustained by continuous free energy consumption.
Conclusions:
- Framing biomolecular machines as active matter unifies biophysics and statistical mechanics.
- Chemical free energy is transduced into motion and work via probability fluxes and kinetic asymmetry.
- This perspective emphasizes probability fluxes and kinetic asymmetry over forces and power strokes.
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