Active particle transport in pulsating three-dimensional geometries

We study the transport of active Brownian particles (ABPs) in three-dimensional (3D) spatially periodic oscillatory geometries. We establish a generalized Fick-Jacobs approach that reduces a 3D system to an effective one-dimensional (1D) system, assuming that particles quickly reach a steady state in the transverse directions of the geometry. The resulting 1D framework connects passive, static, and pulsating limits and provides robust predictions. The transport characteristics of ABPs are computed semianalytically and corroborated by numerical simulations. At the optimal frequency of the geometry oscillation, particles exhibit higher average velocity 〈 v 〉 and effective diffusion coefficient D eff , resembling the phenomena of stochastic resonance. This effect is further enhanced by the self-propelled velocity of ABPs and the amplitude of geometry oscillations. These findings have significant implications for the development of micro- and nanofluidic devices with enhanced control over particle transport and precise manipulation of small-scale biomedical devices.