Transition-path times of individual molecular shuttles under mechanical equilibrium show symmetry

Measuring individual trajectories during the operation of synthetic devices is crucial for a thorough understanding of this operation. Here, we use optical tweezers to measure individual transition paths of molecular shuttles under mechanical equilibrium. Our results showed that the transition-path times present wide distributions, indicating a statistically independent and variable behavior while maintaining a time-reversal symmetry derived from the principle of microscopic reversibility. Furthermore, we show that thermodynamic variables can be extracted from the transition-path times using the principle of microscopic reversibility. These measurements provide a first experimental look at the principle of microscopic reversibility in molecular shuttles and pave the way for a detailed and quantitative understanding of the dynamics of synthetic molecular machines.