Transport of a self-propelled tracer through a hairy cylindrical channel: interplay of stickiness and activity

Abstract

Active transport of biomolecules assisted by motor proteins is imperative for the proper functioning of cellular activities. Inspired by the diffusion of active agents in crowded cellular channels, we computationally investigate the transport of an active tracer through a polymer grafted cylindrical channel by varying the activity of the tracer and stickiness of the tracer to the polymers. Our results reveal that the passive tracer exhibits profound subdiffusion with increasing stickiness by exploring deep into the grafted polymeric zone, while purely repulsive one prefers to diffuse through the pore-like space created along the cylindrical axis of the channel. In contrast, the active tracer shows faster dynamics and intermediate superdiffusion even though the tracer preferentially stays close to the dense polymeric region. This observation is further supported by the sharp peaks in the density profile of the probability of radial displacement of the tracer. We discover that the activity plays an important role in deciding the pathway that the tracer takes through the narrow channel. Interestingly, increasing the activity washes out the effect of stickiness. Adding to this, van-Hove functions manifest that the active tracer dynamics deviates from Gaussianity, and the degree of deviation grows with the activity. Our work has direct implications on how effective transportation and delivery of cargo can be achieved through a confined medium where activity, interactions, and crowding are interplaying. Looking ahead, these factors will be crucial for understanding the mechanism of artificial self-powered machines navigating through the cellular channels and performing in vivo challenging tasks.

to appear in Soft Matter

References in corpus (5)

• Non-universal tracer diffusion in crowded media of non-inert obstacles
• Collective dynamics effect transient subdiffusion of inert tracers in gel networks
• Tracer diffusion in a sea of polymers with binding zones: mobile vs frozen traps
• Translational and rotational dynamics of a self-propelled Janus probe in crowded environments
• Autonomously Probing Viscoelasticity in Disordered Suspensions

Cited by in corpus (4)

• Dynamics of self-propelled tracer particles inside a polymer network
• A new framework for computing a general local self-diffusion coefficient using statistical mechanics
• Motion of an active particle with dynamical disorder
• Dynamics of a spherical self-propelled tracer in a polymeric medium: interplay of self-propulsion, stickiness, and crowding